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46e714c7 |
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26-Dec-2023 |
Suren Baghdasaryan <surenb@google.com> |
arch/mm/fault: fix major fault accounting when retrying under per-VMA lock A test [1] in Android test suite started failing after [2] was merged. It turns out that after handling a major fault under per-VMA lock, the process major fault counter does not register that fault as major. Before [2] read faults would be done under mmap_lock, in which case FAULT_FLAG_TRIED flag is set before retrying. That in turn causes mm_account_fault() to account the fault as major once retry completes. With per-VMA locks we often retry because a fault can't be handled without locking the whole mm using mmap_lock. Therefore such retries do not set FAULT_FLAG_TRIED flag. This logic does not work after [2] because we can now handle read major faults under per-VMA lock and upon retry the fact there was a major fault gets lost. Fix this by setting FAULT_FLAG_TRIED after retrying under per-VMA lock if VM_FAULT_MAJOR was returned. Ideally we would use an additional VM_FAULT bit to indicate the reason for the retry (could not handle under per-VMA lock vs other reason) but this simpler solution seems to work, so keeping it simple. [1] https://cs.android.com/android/platform/superproject/+/master:test/vts-testcase/kernel/api/drop_caches_prop/drop_caches_test.cpp [2] https://lore.kernel.org/all/20231006195318.4087158-6-willy@infradead.org/ Link: https://lkml.kernel.org/r/20231226214610.109282-1-surenb@google.com Fixes: 12214eba1992 ("mm: handle read faults under the VMA lock") Signed-off-by: Suren Baghdasaryan <surenb@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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b1fba034 |
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25-Sep-2023 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc: Support execute-only on all powerpc Introduce PAGE_EXECONLY_X macro which provides exec-only rights. The _X may be seen as redundant with the EXECONLY but it helps keep consistency, all macros having the EXEC right have _X. And put it next to PAGE_NONE as PAGE_EXECONLY_X is somehow PAGE_NONE + EXEC just like all other SOMETHING_X are just SOMETHING + EXEC. On book3s/64 PAGE_EXECONLY becomes PAGE_READONLY_X. On book3s/64, as PAGE_EXECONLY is only valid for Radix add VM_READ flag in vm_get_page_prot() for non-Radix. And update access_error() so that a non exec fault on a VM_EXEC only mapping is always invalid, even when the underlying layer don't always generate a fault for that. For 8xx, set PAGE_EXECONLY_X as _PAGE_NA | _PAGE_EXEC. For others, only set it as just _PAGE_EXEC With that change, 8xx, e500 and 44x fully honor execute-only protection. On 40x that is a partial implementation of execute-only. The implementation won't be complete because once a TLB has been loaded via the Instruction TLB miss handler, it will be possible to read the page. But at least it can't be read unless it is executed first. On 603 MMU, TLB missed are handled by SW and there are separate DTLB and ITLB. Execute-only is therefore now supported by not loading DTLB when read access is not permitted. On hash (604) MMU it is more tricky because hash table is common to load/store and execute. Nevertheless it is still possible to check whether _PAGE_READ is set before loading hash table for a load/store access. At least it can't be read unless it is executed first. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/4283ea9cbef9ff2fbee468904800e1962bc8fc18.1695659959.git.christophe.leroy@csgroup.eu
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#
4089eef0 |
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30-Jun-2023 |
Suren Baghdasaryan <surenb@google.com> |
mm: drop per-VMA lock when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED handle_mm_fault returning VM_FAULT_RETRY or VM_FAULT_COMPLETED means mmap_lock has been released. However with per-VMA locks behavior is different and the caller should still release it. To make the rules consistent for the caller, drop the per-VMA lock when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED. Currently the only path returning VM_FAULT_RETRY under per-VMA locks is do_swap_page and no path returns VM_FAULT_COMPLETED for now. [willy@infradead.org: fix riscv] Link: https://lkml.kernel.org/r/CAJuCfpE6GWEx1rPBmNpUfoD5o-gNFz9-UFywzCE2PbEGBiVz7g@mail.gmail.com Link: https://lkml.kernel.org/r/20230630211957.1341547-4-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Peter Xu <peterx@redhat.com> Tested-by: Conor Dooley <conor.dooley@microchip.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Minchan Kim <minchan@google.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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284e0592 |
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24-Jul-2023 |
Matthew Wilcox (Oracle) <willy@infradead.org> |
mm: remove CONFIG_PER_VMA_LOCK ifdefs Patch series "Handle most file-backed faults under the VMA lock", v3. This patchset adds the ability to handle page faults on parts of files which are already in the page cache without taking the mmap lock. This patch (of 10): Provide lock_vma_under_rcu() when CONFIG_PER_VMA_LOCK is not defined to eliminate ifdefs in the users. Link: https://lkml.kernel.org/r/20230724185410.1124082-1-willy@infradead.org Link: https://lkml.kernel.org/r/20230724185410.1124082-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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e6fe228c |
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15-Jun-2023 |
Michael Ellerman <mpe@ellerman.id.au> |
powerpc/mm: Convert to using lock_mm_and_find_vma() Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
70d4cbc8 |
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27-Feb-2023 |
Laurent Dufour <ldufour@linux.ibm.com> |
powerc/mm: try VMA lock-based page fault handling first Attempt VMA lock-based page fault handling first, and fall back to the existing mmap_lock-based handling if that fails. Copied from "x86/mm: try VMA lock-based page fault handling first" [ldufour@linux.ibm.com: powerpc/mm: fix mmap_lock bad unlock] Link: https://lkml.kernel.org/r/20230306154244.17560-1-ldufour@linux.ibm.com Link: https://lore.kernel.org/linux-mm/842502FB-F99C-417C-9648-A37D0ECDC9CE@linux.ibm.com Link: https://lkml.kernel.org/r/20230227173632.3292573-32-surenb@google.com Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Cc: Sachin Sant <sachinp@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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f2c7e356 |
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09-Mar-2023 |
Russell Currey <ruscur@russell.cc> |
powerpc/mm: Fix false detection of read faults To support detection of read faults with Radix execute-only memory, the vma_is_accessible() check in access_error() (which checks for PROT_NONE) was replaced with a check to see if VM_READ was missing, and if so, returns true to assert the fault was caused by a bad read. This is incorrect, as it ignores that both VM_WRITE and VM_EXEC imply read on powerpc, as defined in protection_map[]. This causes mappings containing VM_WRITE or VM_EXEC without VM_READ to misreport the cause of page faults, since the MMU is still allowing reads. Correct this by restoring the original vma_is_accessible() check for PROT_NONE mappings, and adding a separate check for Radix PROT_EXEC-only mappings. Fixes: 395cac7752b9 ("powerpc/mm: Support execute-only memory on the Radix MMU") Reported-by: Michal Suchánek <msuchanek@suse.de> Link: https://lore.kernel.org/r/20230308152702.GR19419@kitsune.suse.cz Tested-by: Benjamin Gray <bgray@linux.ibm.com> Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230310050834.63105-1-ruscur@russell.cc
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335e1a91 |
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27-Sep-2022 |
Haren Myneni <haren@linux.ibm.com> |
powerpc: Ignore DSI error caused by the copy/paste instruction The data storage interrupt (DSI) error will be generated when the paste operation is issued on the suspended Nest Accelerator (NX) window due to NX state changes. The hypervisor expects the partition to ignore this error during page fault handling. To differentiate DSI caused by an actual HW configuration or by the NX window, a new “ibm,pi-features” type value is defined. Byte 0, bit 3 of pi-attribute-specifier-type is now defined to indicate this DSI error. If this error is not ignored, the user space can get SIGBUS when the NX request is issued. This patch adds changes to read ibm,pi-features property and ignore DSI error during page fault handling if MMU_FTR_NX_DSI is defined. Signed-off-by: Haren Myneni <haren@linux.ibm.com> [mpe: Mention PAPR version in comment] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/b9cd844b85eb8f70459109ce1b14e44c4cc85fa7.camel@linux.ibm.com
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#
395cac77 |
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16-Aug-2022 |
Russell Currey <ruscur@russell.cc> |
powerpc/mm: Support execute-only memory on the Radix MMU Add support for execute-only memory (XOM) for the Radix MMU by using an execute-only mapping, as opposed to the RX mapping used by powerpc's other MMUs. The Hash MMU already supports XOM through the execute-only pkey, which is a separate mechanism shared with x86. A PROT_EXEC-only mapping will map to RX, and then the pkey will be applied on top of it. mmap() and mprotect() consumers in userspace should observe the same behaviour on Hash and Radix despite the differences in implementation. Replacing the vma_is_accessible() check in access_error() with a read check should be functionally equivalent for non-Radix MMUs, since it follows write and execute checks. For Radix, the change enables detecting faults on execute-only mappings where vma_is_accessible() would return true. Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220817050640.406017-1-ruscur@russell.cc
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d9272525 |
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30-May-2022 |
Peter Xu <peterx@redhat.com> |
mm: avoid unnecessary page fault retires on shared memory types I observed that for each of the shared file-backed page faults, we're very likely to retry one more time for the 1st write fault upon no page. It's because we'll need to release the mmap lock for dirty rate limit purpose with balance_dirty_pages_ratelimited() (in fault_dirty_shared_page()). Then after that throttling we return VM_FAULT_RETRY. We did that probably because VM_FAULT_RETRY is the only way we can return to the fault handler at that time telling it we've released the mmap lock. However that's not ideal because it's very likely the fault does not need to be retried at all since the pgtable was well installed before the throttling, so the next continuous fault (including taking mmap read lock, walk the pgtable, etc.) could be in most cases unnecessary. It's not only slowing down page faults for shared file-backed, but also add more mmap lock contention which is in most cases not needed at all. To observe this, one could try to write to some shmem page and look at "pgfault" value in /proc/vmstat, then we should expect 2 counts for each shmem write simply because we retried, and vm event "pgfault" will capture that. To make it more efficient, add a new VM_FAULT_COMPLETED return code just to show that we've completed the whole fault and released the lock. It's also a hint that we should very possibly not need another fault immediately on this page because we've just completed it. This patch provides a ~12% perf boost on my aarch64 test VM with a simple program sequentially dirtying 400MB shmem file being mmap()ed and these are the time it needs: Before: 650.980 ms (+-1.94%) After: 569.396 ms (+-1.38%) I believe it could help more than that. We need some special care on GUP and the s390 pgfault handler (for gmap code before returning from pgfault), the rest changes in the page fault handlers should be relatively straightforward. Another thing to mention is that mm_account_fault() does take this new fault as a generic fault to be accounted, unlike VM_FAULT_RETRY. I explicitly didn't touch hmm_vma_fault() and break_ksm() because they do not handle VM_FAULT_RETRY even with existing code, so I'm literally keeping them as-is. Link: https://lkml.kernel.org/r/20220530183450.42886-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vineet Gupta <vgupta@kernel.org> Acked-by: Guo Ren <guoren@kernel.org> Acked-by: Max Filippov <jcmvbkbc@gmail.com> Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> [arm part] Acked-by: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Stafford Horne <shorne@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Brian Cain <bcain@quicinc.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Richard Weinberger <richard@nod.at> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Will Deacon <will@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Simek <monstr@monstr.eu> Cc: Matt Turner <mattst88@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: David Hildenbrand <david@redhat.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Chris Zankel <chris@zankel.net> Cc: Hugh Dickins <hughd@google.com> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Rich Felker <dalias@libc.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Helge Deller <deller@gmx.de> Cc: Yoshinori Sato <ysato@users.osdn.me> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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76222808 |
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04-Mar-2022 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc: Move C prototypes out of asm-prototypes.h We originally added asm-prototypes.h in commit 42f5b4cacd78 ("powerpc: Introduce asm-prototypes.h"). It's purpose was for prototypes of C functions that are only called from asm, in order to fix sparse warnings about missing prototypes. A few months later Nick added a different use case in commit 4efca4ed05cb ("kbuild: modversions for EXPORT_SYMBOL() for asm") for C prototypes for exported asm functions. This is basically the inverse of our original usage. Since then we've added various prototypes to asm-prototypes.h for both reasons, meaning we now need to unstitch it all. Dispatch prototypes of C functions into relevant headers and keep only the prototypes for functions defined in assembly. For the time being, leave prom_init() there because moving it into asm/prom.h or asm/setup.h conflicts with drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowrom.o This will be fixed later by untaggling asm/pci.h and asm/prom.h or by renaming the function in shadowrom.c Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/62d46904eca74042097acf4cb12c175e3067f3d1.1646413435.git.christophe.leroy@csgroup.eu
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d4679ac8 |
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22-Feb-2022 |
Michael Ellerman <mpe@ellerman.id.au> |
powerpc/64s: Don't use DSISR for SLB faults Since commit 46ddcb3950a2 ("powerpc/mm: Show if a bad page fault on data is read or write.") we use page_fault_is_write(regs->dsisr) in __bad_page_fault() to determine if the fault is for a read or write, and change the message printed accordingly. But SLB faults, aka Data Segment Interrupts, don't set DSISR (Data Storage Interrupt Status Register) to a useful value. All ISA versions from v2.03 through v3.1 specify that the Data Segment Interrupt sets DSISR "to an undefined value". As far as I can see there's no mention of SLB faults setting DSISR in any BookIV content either. This manifests as accesses that should be a read being incorrectly reported as writes, for example, using the xmon "dump" command: 0:mon> d 0x5deadbeef0000000 5deadbeef0000000 [359526.415354][ C6] BUG: Unable to handle kernel data access on write at 0x5deadbeef0000000 [359526.415611][ C6] Faulting instruction address: 0xc00000000010a300 cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf400] pc: c00000000010a300: mread+0x90/0x190 If we disassemble the PC, we see a load instruction: 0:mon> di c00000000010a300 c00000000010a300 89490000 lbz r10,0(r9) We can also see in exceptions-64s.S that the data_access_slb block doesn't set IDSISR=1, which means it doesn't load DSISR into pt_regs. So the value we're using to determine if the fault is a read/write is some stale value in pt_regs from a previous page fault. Rework the printing logic to separate the SLB fault case out, and only print read/write in the cases where we can determine it. The result looks like eg: 0:mon> d 0x5deadbeef0000000 5deadbeef0000000 [ 721.779525][ C6] BUG: Unable to handle kernel data access at 0x5deadbeef0000000 [ 721.779697][ C6] Faulting instruction address: 0xc00000000014cbe0 cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf390] 0:mon> d 0 0000000000000000 [ 742.793242][ C6] BUG: Kernel NULL pointer dereference at 0x00000000 [ 742.793316][ C6] Faulting instruction address: 0xc00000000014cbe0 cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf390] Fixes: 46ddcb3950a2 ("powerpc/mm: Show if a bad page fault on data is read or write.") Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Link: https://lore.kernel.org/r/20220222113449.319193-1-mpe@ellerman.id.au
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36ef159f |
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14-Jan-2022 |
Qi Zheng <zhengqi.arch@bytedance.com> |
mm: remove redundant check about FAULT_FLAG_ALLOW_RETRY bit Since commit 4064b9827063 ("mm: allow VM_FAULT_RETRY for multiple times") allowed VM_FAULT_RETRY for multiple times, the FAULT_FLAG_ALLOW_RETRY bit of fault_flag will not be changed in the page fault path, so the following check is no longer needed: flags & FAULT_FLAG_ALLOW_RETRY So just remove it. [akpm@linux-foundation.org: coding style fixes] Link: https://lkml.kernel.org/r/20211110123358.36511-1-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Kirill Shutemov <kirill@shutemov.name> Cc: Peter Xu <peterx@redhat.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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935b534c |
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01-Dec-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/64s: Move and rename do_bad_slb_fault as it is not hash specific slb.c is hash-specific SLB management, but do_bad_slb_fault deals with segment interrupts that occur with radix MMU as well. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211201144153.2456614-5-npiggin@gmail.com
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cd5d5e60 |
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01-Jul-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/mm: Fix lockup on kernel exec fault The powerpc kernel is not prepared to handle exec faults from kernel. Especially, the function is_exec_fault() will return 'false' when an exec fault is taken by kernel, because the check is based on reading current->thread.regs->trap which contains the trap from user. For instance, when provoking a LKDTM EXEC_USERSPACE test, current->thread.regs->trap is set to SYSCALL trap (0xc00), and the fault taken by the kernel is not seen as an exec fault by set_access_flags_filter(). Commit d7df2443cd5f ("powerpc/mm: Fix spurious segfaults on radix with autonuma") made it clear and handled it properly. But later on commit d3ca587404b3 ("powerpc/mm: Fix reporting of kernel execute faults") removed that handling, introducing test based on error_code. And here is the problem, because on the 603 all upper bits of SRR1 get cleared when the TLB instruction miss handler bails out to ISI. Until commit cbd7e6ca0210 ("powerpc/fault: Avoid heavy search_exception_tables() verification"), an exec fault from kernel at a userspace address was indirectly caught by the lack of entry for that address in the exception tables. But after that commit the kernel mainly relies on KUAP or on core mm handling to catch wrong user accesses. Here the access is not wrong, so mm handles it. It is a minor fault because PAGE_EXEC is not set, set_access_flags_filter() should set PAGE_EXEC and voila. But as is_exec_fault() returns false as explained in the beginning, set_access_flags_filter() bails out without setting PAGE_EXEC flag, which leads to a forever minor exec fault. As the kernel is not prepared to handle such exec faults, the thing to do is to fire in bad_kernel_fault() for any exec fault taken by the kernel, as it was prior to commit d3ca587404b3. Fixes: d3ca587404b3 ("powerpc/mm: Fix reporting of kernel execute faults") Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Acked-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/024bb05105050f704743a0083fe3548702be5706.1625138205.git.christophe.leroy@csgroup.eu
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7153d4bf |
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14-Apr-2021 |
Xiongwei Song <sxwjean@gmail.com> |
powerpc/traps: Enhance readability for trap types Define macros to list ppc interrupt types in interttupt.h, replace the reference of the trap hex values with these macros. Referred the hex numbers in arch/powerpc/kernel/exceptions-64e.S, arch/powerpc/kernel/exceptions-64s.S, arch/powerpc/kernel/head_*.S, arch/powerpc/kernel/head_booke.h and arch/powerpc/include/asm/kvm_asm.h. Signed-off-by: Xiongwei Song <sxwjean@gmail.com> [mpe: Resolve conflicts in nmi_disables_ftrace(), fix 40x build] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1618398033-13025-1-git-send-email-sxwjean@me.com
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c45ba4f4 |
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16-Mar-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: clean up do_page_fault search_exception_tables + __bad_page_fault can be substituted with bad_page_fault, do_page_fault no longer needs to return a value to asm for any sub-architecture, and __bad_page_fault can be static. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210316104206.407354-10-npiggin@gmail.com
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d738ee8d |
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16-Mar-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/64e/interrupt: handle bad_page_fault in C With non-volatile registers saved on interrupt, bad_page_fault can now be called by do_page_fault. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210316104206.407354-9-npiggin@gmail.com
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98c26a72 |
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15-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/mm: Remove unneeded #ifdef CONFIG_PPC_MEM_KEYS In fault.c, #ifdef CONFIG_PPC_MEM_KEYS is not needed because all functions are always defined, and arch_vma_access_permitted() always returns true when CONFIG_PPC_MEM_KEYS is not defined so access_pkey_error() will return false so bad_access_pkey() will never be called. Include linux/pkeys.h to get a definition of vma_pkeys() for bad_access_pkey(). Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/8038392f38d81f2ad169347efac29146f553b238.1615819955.git.christophe.leroy@csgroup.eu
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af6f2ce8 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Call bad_page_fault() from do_page_fault() Now that non volatile registers are saved at all time, no need to split bad_page_fault() out of do_page_fault(). Remove handle_page_fault() and use do_page_fault() directly. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/cfb95be8863204cc2bf45a22ea44dd1d0dc16b7f.1615552867.git.christophe.leroy@csgroup.eu
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90cbac0e |
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04-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc: Enable KFENCE for PPC32 Add architecture specific implementation details for KFENCE and enable KFENCE for the ppc32 architecture. In particular, this implements the required interface in <asm/kfence.h>. KFENCE requires that attributes for pages from its memory pool can individually be set. Therefore, force the Read/Write linear map to be mapped at page granularity. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Acked-by: Marco Elver <elver@google.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/8dfe1bd2abde26337c1d8c1ad0acfcc82185e0d5.1614868445.git.christophe.leroy@csgroup.eu
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e4bb64c7 |
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10-Feb-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: remove interrupt handler functions from the noinstr section The allyesconfig ppc64 kernel fails to link with relocations unable to fit after commit 3a96570ffceb ("powerpc: convert interrupt handlers to use wrappers"), which is due to the interrupt handler functions being put into the .noinstr.text section, which the linker script places on the opposite side of the main .text section from the interrupt entry asm code which calls the handlers. This results in a lot of linker stubs that overwhelm the 252-byte sized space we allow for them, or in the case of BE a .opd relocation link error for some reason. It's not required to put interrupt handlers in the .noinstr section, previously they used NOKPROBE_SYMBOL, so take them out and replace with a NOKPROBE_SYMBOL in the wrapper macro. Remove the explicit NOKPROBE_SYMBOL macros in the interrupt handler functions. This makes a number of interrupt handlers nokprobe that were not prior to the interrupt wrappers commit, but since that commit they were made nokprobe due to being in .noinstr.text, so this fix does not change that. The fixes tag is different to the commit that first exposes the problem because it is where the wrapper macros were introduced. Fixes: 8d41fc618ab8 ("powerpc: interrupt handler wrapper functions") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Slightly fix up comment wording] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210211063636.236420-1-npiggin@gmail.com
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540d4d34 |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/64: context tracking move to interrupt wrappers This moves exception_enter/exit calls to wrapper functions for synchronous interrupts. More interrupt handlers are covered by this than previously. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-33-npiggin@gmail.com
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a008f8f9 |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/64s/hash: improve context tracking of hash faults This moves the 64s/hash context tracking from hash_page_mm() to __do_hash_fault(), so it's no longer called by OCXL / SPU accelerators, which was certainly the wrong thing to be doing, because those callers are not low level interrupt handlers, so should have entered a kernel context tracking already. Then remain in kernel context for the duration of the fault, rather than enter/exit for the hash fault then enter/exit for the page fault, which is pointless. Even still, calling exception_enter/exit in __do_hash_fault seems questionable because that's touching per-cpu variables, tracing, etc., which might have been interrupted by this hash fault or themselves cause hash faults. But maybe I miss something because hash_page_mm very deliberately calls trace_hash_fault too, for example. So for now go with it, it's no worse than before, in this regard. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-32-npiggin@gmail.com
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e6f8a6c8 |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: add interrupt_cond_local_irq_enable helper Simple helper for synchronous interrupt handlers (i.e., process-context) to enable interrupts if it was taken in an interrupts-enabled context. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-30-npiggin@gmail.com
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3a96570f |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: convert interrupt handlers to use wrappers Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-29-npiggin@gmail.com
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31d6490c |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/mm: Remove stale do_page_fault comment referring to SLB faults SLB faults no longer call do_page_fault, this was removed somewhere between 2.6.0 and 2.6.12. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-17-npiggin@gmail.com
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f4c03b0e |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/64s: move bad_page_fault handling to C This simplifies code, and it is also useful when introducing interrupt handler wrappers when introducing wrapper functionality that doesn't cope with asm entry code calling into more than one handler function. 32-bit and 64e still have some such cases, which limits some ways they can use interrupt wrappers. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-15-npiggin@gmail.com
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4cb84284 |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: rearrange do_page_fault error case to be inside exception_enter This keeps the context tracking over the entire interrupt handler which helps later with moving context tracking into interrupt wrappers. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-14-npiggin@gmail.com
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71f47976 |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/64s: add do_bad_page_fault_segv handler This function acts like an interrupt handler so it needs to follow the standard interrupt handler function signature which will be introduced in a future change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-13-npiggin@gmail.com
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8458c628 |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: bad_page_fault get registers from regs Similar to the previous patch this makes interrupt handler function types more regular so they can be wrapped with the next patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-12-npiggin@gmail.com
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a01a3f2d |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: remove arguments from fault handler functions Make mm fault handlers all just take the pt_regs * argument and load DAR/DSISR from that. Make those that return a value return long. This is done to make the function signatures match other handlers, which will help with a future patch to add wrappers. Explicit arguments could be added for performance but that would require more wrapper macro variants. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-7-npiggin@gmail.com
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5f1888a0 |
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08-Dec-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/fault: Perform exception fixup in do_page_fault() Exception fixup doesn't require the heady full regs saving, do it from do_page_fault() directly. For that, split bad_page_fault() in two parts. As bad_page_fault() can also be called from other places than handle_page_fault(), it will still perform exception fixup and fallback on __bad_page_fault(). handle_page_fault() directly calls __bad_page_fault() as the exception fixup will now be done by do_page_fault() Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/bd07d6fef9237614cd6d318d8f19faeeadaa816b.1607491748.git.christophe.leroy@csgroup.eu
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cbd7e6ca |
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08-Dec-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/fault: Avoid heavy search_exception_tables() verification search_exception_tables() is an heavy operation, we have to avoid it. When KUAP is selected, we'll know the fault has been blocked by KUAP. When it is blocked by KUAP, check whether we are in an expected userspace access place. If so, emit a warning to spot something is going work. Otherwise, just remain silent, it will likely Oops soon. When KUAP is not selected, it behaves just as if the address was already in the TLBs and no fault was generated. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/9870f01e293a5a76c4f4e4ddd4a6b0f63038c591.1607491748.git.christophe.leroy@csgroup.eu
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3dc12dfe |
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08-Dec-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/mm: Move the WARN() out of bad_kuap_fault() In order to prepare the removal of calls to search_exception_tables() on the fast path, move the WARN() out of bad_kuap_fault(). Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/9501311014bd6507e04b27a0c3035186ccf65cd5.1607491748.git.christophe.leroy@csgroup.eu
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5250d026 |
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08-Dec-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/fault: Unnest definition of page_fault_is_write() and page_fault_is_bad() To make it more readable, separate page_fault_is_write() and page_fault_is_bad() to avoir several levels of #ifdefs Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/6afaac2495248d68f94c438c5ec36b6010931de5.1607491748.git.christophe.leroy@csgroup.eu
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7ceb4002 |
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08-Dec-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/mm: sanity_check_fault() should work for all, not only BOOK3S The verification and message introduced by commit 374f3f5979f9 ("powerpc/mm/hash: Handle user access of kernel address gracefully") applies to all platforms, it should not be limited to BOOK3S. Make the BOOK3S version of sanity_check_fault() the one for all, and bail out earlier if not BOOK3S. Fixes: 374f3f5979f9 ("powerpc/mm/hash: Handle user access of kernel address gracefully") Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/fe199d5af3578d3bf80035d203a94d742a7a28af.1607491748.git.christophe.leroy@csgroup.eu
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475c8749 |
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07-Dec-2020 |
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> |
powerpc/book3s64/kuap: Improve error reporting with KUAP This partially reverts commit eb232b162446 ("powerpc/book3s64/kuap: Improve error reporting with KUAP") and update the fault handler to print [ 55.022514] Kernel attempted to access user page (7e6725b70000) - exploit attempt? (uid: 0) [ 55.022528] BUG: Unable to handle kernel data access on read at 0x7e6725b70000 [ 55.022533] Faulting instruction address: 0xc000000000e8b9bc [ 55.022540] Oops: Kernel access of bad area, sig: 11 [#1] .... when the kernel access userspace address without unlocking AMR. bad_kuap_fault() is added as part of commit 5e5be3aed230 ("powerpc/mm: Detect bad KUAP faults") to catch userspace access incorrectly blocked by AMR. Hence retain the full stack dump there even with hash translation. Also, add a comment explaining the difference between hash and radix. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201208031539.84878-1-aneesh.kumar@linux.ibm.com
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eb232b16 |
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26-Nov-2020 |
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> |
powerpc/book3s64/kuap: Improve error reporting with KUAP With hash translation use DSISR_KEYFAULT to identify a wrong access. With Radix we look at the AMR value and type of fault. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201127044424.40686-17-aneesh.kumar@linux.ibm.com
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428fdc09 |
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11-Aug-2020 |
Peter Xu <peterx@redhat.com> |
mm/powerpc: use general page fault accounting Use the general page fault accounting by passing regs into handle_mm_fault(). Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Link: http://lkml.kernel.org/r/20200707225021.200906-17-peterx@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bce617ed |
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11-Aug-2020 |
Peter Xu <peterx@redhat.com> |
mm: do page fault accounting in handle_mm_fault Patch series "mm: Page fault accounting cleanups", v5. This is v5 of the pf accounting cleanup series. It originates from Gerald Schaefer's report on an issue a week ago regarding to incorrect page fault accountings for retried page fault after commit 4064b9827063 ("mm: allow VM_FAULT_RETRY for multiple times"): https://lore.kernel.org/lkml/20200610174811.44b94525@thinkpad/ What this series did: - Correct page fault accounting: we do accounting for a page fault (no matter whether it's from #PF handling, or gup, or anything else) only with the one that completed the fault. For example, page fault retries should not be counted in page fault counters. Same to the perf events. - Unify definition of PERF_COUNT_SW_PAGE_FAULTS: currently this perf event is used in an adhoc way across different archs. Case (1): for many archs it's done at the entry of a page fault handler, so that it will also cover e.g. errornous faults. Case (2): for some other archs, it is only accounted when the page fault is resolved successfully. Case (3): there're still quite some archs that have not enabled this perf event. Since this series will touch merely all the archs, we unify this perf event to always follow case (1), which is the one that makes most sense. And since we moved the accounting into handle_mm_fault, the other two MAJ/MIN perf events are well taken care of naturally. - Unify definition of "major faults": the definition of "major fault" is slightly changed when used in accounting (not VM_FAULT_MAJOR). More information in patch 1. - Always account the page fault onto the one that triggered the page fault. This does not matter much for #PF handlings, but mostly for gup. More information on this in patch 25. Patchset layout: Patch 1: Introduced the accounting in handle_mm_fault(), not enabled. Patch 2-23: Enable the new accounting for arch #PF handlers one by one. Patch 24: Enable the new accounting for the rest outliers (gup, iommu, etc.) Patch 25: Cleanup GUP task_struct pointer since it's not needed any more This patch (of 25): This is a preparation patch to move page fault accountings into the general code in handle_mm_fault(). This includes both the per task flt_maj/flt_min counters, and the major/minor page fault perf events. To do this, the pt_regs pointer is passed into handle_mm_fault(). PERF_COUNT_SW_PAGE_FAULTS should still be kept in per-arch page fault handlers. So far, all the pt_regs pointer that passed into handle_mm_fault() is NULL, which means this patch should have no intented functional change. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Chris Zankel <chris@zankel.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Greentime Hu <green.hu@gmail.com> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200707225021.200906-1-peterx@redhat.com Link: http://lkml.kernel.org/r/20200707225021.200906-2-peterx@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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773b3e53 |
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24-Jul-2020 |
Michael Ellerman <mpe@ellerman.id.au> |
powerpc/mm: Remove custom stack expansion checking We have powerpc specific logic in our page fault handling to decide if an access to an unmapped address below the stack pointer should expand the stack VMA. The logic aims to prevent userspace from doing bad accesses below the stack pointer. However as long as the stack is < 1MB in size, we allow all accesses without further checks. Adding some debug I see that I can do a full kernel build and LTP run, and not a single process has used more than 1MB of stack. So for the majority of processes the logic never even fires. We also recently found a nasty bug in this code which could cause userspace programs to be killed during signal delivery. It went unnoticed presumably because most processes use < 1MB of stack. The generic mm code has also grown support for stack guard pages since this code was originally written, so the most heinous case of the stack expanding into other mappings is now handled for us. Finally although some other arches have special logic in this path, from what I can tell none of x86, arm64, arm and s390 impose any extra checks other than those in expand_stack(). So drop our complicated logic and like other architectures just let the stack expand as long as its within the rlimit. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Daniel Axtens <dja@axtens.net> Link: https://lore.kernel.org/r/20200724092528.1578671-4-mpe@ellerman.id.au
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63dee5df |
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24-Jul-2020 |
Michael Ellerman <mpe@ellerman.id.au> |
powerpc: Allow 4224 bytes of stack expansion for the signal frame We have powerpc specific logic in our page fault handling to decide if an access to an unmapped address below the stack pointer should expand the stack VMA. The code was originally added in 2004 "ported from 2.4". The rough logic is that the stack is allowed to grow to 1MB with no extra checking. Over 1MB the access must be within 2048 bytes of the stack pointer, or be from a user instruction that updates the stack pointer. The 2048 byte allowance below the stack pointer is there to cover the 288 byte "red zone" as well as the "about 1.5kB" needed by the signal delivery code. Unfortunately since then the signal frame has expanded, and is now 4224 bytes on 64-bit kernels with transactional memory enabled. This means if a process has consumed more than 1MB of stack, and its stack pointer lies less than 4224 bytes from the next page boundary, signal delivery will fault when trying to expand the stack and the process will see a SEGV. The total size of the signal frame is the size of struct rt_sigframe (which includes the red zone) plus __SIGNAL_FRAMESIZE (128 bytes on 64-bit). The 2048 byte allowance was correct until 2008 as the signal frame was: struct rt_sigframe { struct ucontext uc; /* 0 1440 */ /* --- cacheline 11 boundary (1408 bytes) was 32 bytes ago --- */ long unsigned int _unused[2]; /* 1440 16 */ unsigned int tramp[6]; /* 1456 24 */ struct siginfo * pinfo; /* 1480 8 */ void * puc; /* 1488 8 */ struct siginfo info; /* 1496 128 */ /* --- cacheline 12 boundary (1536 bytes) was 88 bytes ago --- */ char abigap[288]; /* 1624 288 */ /* size: 1920, cachelines: 15, members: 7 */ /* padding: 8 */ }; 1920 + 128 = 2048 Then in commit ce48b2100785 ("powerpc: Add VSX context save/restore, ptrace and signal support") (Jul 2008) the signal frame expanded to 2304 bytes: struct rt_sigframe { struct ucontext uc; /* 0 1696 */ <-- /* --- cacheline 13 boundary (1664 bytes) was 32 bytes ago --- */ long unsigned int _unused[2]; /* 1696 16 */ unsigned int tramp[6]; /* 1712 24 */ struct siginfo * pinfo; /* 1736 8 */ void * puc; /* 1744 8 */ struct siginfo info; /* 1752 128 */ /* --- cacheline 14 boundary (1792 bytes) was 88 bytes ago --- */ char abigap[288]; /* 1880 288 */ /* size: 2176, cachelines: 17, members: 7 */ /* padding: 8 */ }; 2176 + 128 = 2304 At this point we should have been exposed to the bug, though as far as I know it was never reported. I no longer have a system old enough to easily test on. Then in 2010 commit 320b2b8de126 ("mm: keep a guard page below a grow-down stack segment") caused our stack expansion code to never trigger, as there was always a VMA found for a write up to PAGE_SIZE below r1. That meant the bug was hidden as we continued to expand the signal frame in commit 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context") (Feb 2013): struct rt_sigframe { struct ucontext uc; /* 0 1696 */ /* --- cacheline 13 boundary (1664 bytes) was 32 bytes ago --- */ struct ucontext uc_transact; /* 1696 1696 */ <-- /* --- cacheline 26 boundary (3328 bytes) was 64 bytes ago --- */ long unsigned int _unused[2]; /* 3392 16 */ unsigned int tramp[6]; /* 3408 24 */ struct siginfo * pinfo; /* 3432 8 */ void * puc; /* 3440 8 */ struct siginfo info; /* 3448 128 */ /* --- cacheline 27 boundary (3456 bytes) was 120 bytes ago --- */ char abigap[288]; /* 3576 288 */ /* size: 3872, cachelines: 31, members: 8 */ /* padding: 8 */ /* last cacheline: 32 bytes */ }; 3872 + 128 = 4000 And commit 573ebfa6601f ("powerpc: Increase stack redzone for 64-bit userspace to 512 bytes") (Feb 2014): struct rt_sigframe { struct ucontext uc; /* 0 1696 */ /* --- cacheline 13 boundary (1664 bytes) was 32 bytes ago --- */ struct ucontext uc_transact; /* 1696 1696 */ /* --- cacheline 26 boundary (3328 bytes) was 64 bytes ago --- */ long unsigned int _unused[2]; /* 3392 16 */ unsigned int tramp[6]; /* 3408 24 */ struct siginfo * pinfo; /* 3432 8 */ void * puc; /* 3440 8 */ struct siginfo info; /* 3448 128 */ /* --- cacheline 27 boundary (3456 bytes) was 120 bytes ago --- */ char abigap[512]; /* 3576 512 */ <-- /* size: 4096, cachelines: 32, members: 8 */ /* padding: 8 */ }; 4096 + 128 = 4224 Then finally in 2017, commit 1be7107fbe18 ("mm: larger stack guard gap, between vmas") exposed us to the existing bug, because it changed the stack VMA to be the correct/real size, meaning our stack expansion code is now triggered. Fix it by increasing the allowance to 4224 bytes. Hard-coding 4224 is obviously unsafe against future expansions of the signal frame in the same way as the existing code. We can't easily use sizeof() because the signal frame structure is not in a header. We will either fix that, or rip out all the custom stack expansion checking logic entirely. Fixes: ce48b2100785 ("powerpc: Add VSX context save/restore, ptrace and signal support") Cc: stable@vger.kernel.org # v2.6.27+ Reported-by: Tom Lane <tgl@sss.pgh.pa.us> Tested-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200724092528.1578671-2-mpe@ellerman.id.au
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c1e8d7c6 |
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08-Jun-2020 |
Michel Lespinasse <walken@google.com> |
mmap locking API: convert mmap_sem comments Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d8ed45c5 |
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08-Jun-2020 |
Michel Lespinasse <walken@google.com> |
mmap locking API: use coccinelle to convert mmap_sem rwsem call sites This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e31cf2f4 |
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08-Jun-2020 |
Mike Rapoport <rppt@kernel.org> |
mm: don't include asm/pgtable.h if linux/mm.h is already included Patch series "mm: consolidate definitions of page table accessors", v2. The low level page table accessors (pXY_index(), pXY_offset()) are duplicated across all architectures and sometimes more than once. For instance, we have 31 definition of pgd_offset() for 25 supported architectures. Most of these definitions are actually identical and typically it boils down to, e.g. static inline unsigned long pmd_index(unsigned long address) { return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); } static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) { return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address); } These definitions can be shared among 90% of the arches provided XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined. For architectures that really need a custom version there is always possibility to override the generic version with the usual ifdefs magic. These patches introduce include/linux/pgtable.h that replaces include/asm-generic/pgtable.h and add the definitions of the page table accessors to the new header. This patch (of 12): The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the functions involving page table manipulations, e.g. pte_alloc() and pmd_alloc(). So, there is no point to explicitly include <asm/pgtable.h> in the files that include <linux/mm.h>. The include statements in such cases are remove with a simple loop: for f in $(git grep -l "include <linux/mm.h>") ; do sed -i -e '/include <asm\/pgtable.h>/ d' $f done Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7ba68b21 |
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05-May-2020 |
Jordan Niethe <jniethe5@gmail.com> |
powerpc: Add a probe_user_read_inst() function Introduce a probe_user_read_inst() function to use in cases where probe_user_read() is used for getting an instruction. This will be more useful for prefixed instructions. Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Reviewed-by: Alistair Popple <alistair@popple.id.au> [mpe: Don't write to *inst on error, fold in __user annotations] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-14-jniethe5@gmail.com
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94afd069 |
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05-May-2020 |
Jordan Niethe <jniethe5@gmail.com> |
powerpc: Use a datatype for instructions Currently unsigned ints are used to represent instructions on powerpc. This has worked well as instructions have always been 4 byte words. However, ISA v3.1 introduces some changes to instructions that mean this scheme will no longer work as well. This change is Prefixed Instructions. A prefixed instruction is made up of a word prefix followed by a word suffix to make an 8 byte double word instruction. No matter the endianness of the system the prefix always comes first. Prefixed instructions are only planned for powerpc64. Introduce a ppc_inst type to represent both prefixed and word instructions on powerpc64 while keeping it possible to exclusively have word instructions on powerpc32. Signed-off-by: Jordan Niethe <jniethe5@gmail.com> [mpe: Fix compile error in emulate_spe()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-12-jniethe5@gmail.com
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8094892d |
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05-May-2020 |
Jordan Niethe <jniethe5@gmail.com> |
powerpc: Use a function for getting the instruction op code In preparation for using a data type for instructions that can not be directly used with the '>>' operator use a function for getting the op code of an instruction. Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Reviewed-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-9-jniethe5@gmail.com
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777e26f0 |
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05-May-2020 |
Jordan Niethe <jniethe5@gmail.com> |
powerpc: Use an accessor for instructions In preparation for introducing a more complicated instruction type to accommodate prefixed instructions use an accessor for getting an instruction as a u32. Signed-off-by: Jordan Niethe <jniethe5@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-8-jniethe5@gmail.com
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c46241a3 |
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04-May-2020 |
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> |
powerpc/pkeys: Check vma before returning key fault error to the user If multiple threads in userspace keep changing the protection keys mapping a range, there can be a scenario where kernel takes a key fault but the pkey value found in the siginfo struct is a permissive one. This can confuse the userspace as shown in the below test case. /* use this to control the number of test iterations */ static void pkeyreg_set(int pkey, unsigned long rights) { unsigned long reg, shift; shift = (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY; asm volatile("mfspr %0, 0xd" : "=r"(reg)); reg &= ~(((unsigned long) PKEY_BITS_MASK) << shift); reg |= (rights & PKEY_BITS_MASK) << shift; asm volatile("mtspr 0xd, %0" : : "r"(reg)); } static unsigned long pkeyreg_get(void) { unsigned long reg; asm volatile("mfspr %0, 0xd" : "=r"(reg)); return reg; } static int sys_pkey_mprotect(void *addr, size_t len, int prot, int pkey) { return syscall(SYS_pkey_mprotect, addr, len, prot, pkey); } static int sys_pkey_alloc(unsigned long flags, unsigned long access_rights) { return syscall(SYS_pkey_alloc, flags, access_rights); } static int sys_pkey_free(int pkey) { return syscall(SYS_pkey_free, pkey); } static int faulting_pkey; static int permissive_pkey; static pthread_barrier_t pkey_set_barrier; static pthread_barrier_t mprotect_barrier; static void pkey_handle_fault(int signum, siginfo_t *sinfo, void *ctx) { unsigned long pkeyreg; /* FIXME: printf is not signal-safe but for the current purpose, it gets the job done. */ printf("pkey: exp = %d, got = %d\n", faulting_pkey, sinfo->si_pkey); fflush(stdout); assert(sinfo->si_code == SEGV_PKUERR); assert(sinfo->si_pkey == faulting_pkey); /* clear pkey permissions to let the faulting instruction continue */ pkeyreg_set(faulting_pkey, 0x0); } static void *do_mprotect_fault(void *p) { unsigned long rights, pkeyreg, pgsize; unsigned int i; void *region; int pkey; srand(time(NULL)); pgsize = sysconf(_SC_PAGESIZE); rights = PKEY_DISABLE_WRITE; region = p; /* allocate key, no permissions */ assert((pkey = sys_pkey_alloc(0, PKEY_DISABLE_ACCESS)) > 0); pkeyreg_set(4, 0x0); /* cache the pkey here as the faulting pkey for future reference in the signal handler */ faulting_pkey = pkey; printf("%s: faulting pkey = %d\n", __func__, faulting_pkey); /* try to allocate, mprotect and free pkeys repeatedly */ for (i = 0; i < NUM_ITERATIONS; i++) { /* sync up with the other thread here */ pthread_barrier_wait(&pkey_set_barrier); /* make sure that the pkey used by the non-faulting thread is made permissive for this thread's context too so that no faults are triggered because it still might have been set to a restrictive value */ // pkeyreg_set(permissive_pkey, 0x0); /* sync up with the other thread here */ pthread_barrier_wait(&mprotect_barrier); /* perform mprotect */ assert(!sys_pkey_mprotect(region, pgsize, PROT_READ | PROT_WRITE, pkey)); /* choose a random byte from the protected region and attempt to write to it, this will generate a fault */ *((char *) region + (rand() % pgsize)) = rand(); /* restore pkey permissions as the signal handler may have cleared the bit out for the sake of continuing */ pkeyreg_set(pkey, PKEY_DISABLE_WRITE); } /* free pkey */ sys_pkey_free(pkey); return NULL; } static void *do_mprotect_nofault(void *p) { unsigned long pgsize; unsigned int i, j; void *region; int pkey; pgsize = sysconf(_SC_PAGESIZE); region = p; /* try to allocate, mprotect and free pkeys repeatedly */ for (i = 0; i < NUM_ITERATIONS; i++) { /* allocate pkey, all permissions */ assert((pkey = sys_pkey_alloc(0, 0)) > 0); permissive_pkey = pkey; /* sync up with the other thread here */ pthread_barrier_wait(&pkey_set_barrier); pthread_barrier_wait(&mprotect_barrier); /* perform mprotect on the common page, no faults will be triggered as this is most permissive */ assert(!sys_pkey_mprotect(region, pgsize, PROT_READ | PROT_WRITE, pkey)); /* free pkey */ assert(!sys_pkey_free(pkey)); } return NULL; } int main(int argc, char **argv) { pthread_t fault_thread, nofault_thread; unsigned long pgsize; struct sigaction act; pthread_attr_t attr; cpu_set_t fault_cpuset, nofault_cpuset; unsigned int i; void *region; /* allocate memory region to protect */ pgsize = sysconf(_SC_PAGESIZE); assert(region = memalign(pgsize, pgsize)); CPU_ZERO(&fault_cpuset); CPU_SET(0, &fault_cpuset); CPU_ZERO(&nofault_cpuset); CPU_SET(8, &nofault_cpuset); assert(!pthread_attr_init(&attr)); /* setup sigsegv signal handler */ act.sa_handler = 0; act.sa_sigaction = pkey_handle_fault; assert(!sigprocmask(SIG_SETMASK, 0, &act.sa_mask)); act.sa_flags = SA_SIGINFO; act.sa_restorer = 0; assert(!sigaction(SIGSEGV, &act, NULL)); /* setup barrier for the two threads */ pthread_barrier_init(&pkey_set_barrier, NULL, 2); pthread_barrier_init(&mprotect_barrier, NULL, 2); /* setup and start threads */ assert(!pthread_create(&fault_thread, &attr, &do_mprotect_fault, region)); assert(!pthread_setaffinity_np(fault_thread, sizeof(cpu_set_t), &fault_cpuset)); assert(!pthread_create(&nofault_thread, &attr, &do_mprotect_nofault, region)); assert(!pthread_setaffinity_np(nofault_thread, sizeof(cpu_set_t), &nofault_cpuset)); /* cleanup */ assert(!pthread_attr_destroy(&attr)); assert(!pthread_join(fault_thread, NULL)); assert(!pthread_join(nofault_thread, NULL)); assert(!pthread_barrier_destroy(&pkey_set_barrier)); assert(!pthread_barrier_destroy(&mprotect_barrier)); free(region); puts("PASS"); return EXIT_SUCCESS; } The above test can result the below failure without this patch. pkey: exp = 3, got = 3 pkey: exp = 3, got = 4 a.out: pkey-siginfo-race.c:100: pkey_handle_fault: Assertion `sinfo->si_pkey == faulting_pkey' failed. Aborted Check for vma access before considering this a key fault. If vma pkey allow access retry the acess again. Test case is written by Sandipan Das <sandipan@linux.ibm.com> hence added SOB from him. Signed-off-by: Sandipan Das <sandipan@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200505071729.54912-3-aneesh.kumar@linux.ibm.com
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fe4a6856 |
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04-May-2020 |
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> |
powerpc/pkeys: Avoid using lockless page table walk Fetch pkey from vma instead of linux page table. Also document the fact that in some cases the pkey returned in siginfo won't be the same as the one we took keyfault on. Even with linux page table walk, we can end up in a similar scenario. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200505071729.54912-2-aneesh.kumar@linux.ibm.com
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3122e80e |
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06-Apr-2020 |
Anshuman Khandual <anshuman.khandual@arm.com> |
mm/vma: make vma_is_accessible() available for general use Lets move vma_is_accessible() helper to include/linux/mm.h which makes it available for general use. While here, this replaces all remaining open encodings for VMA access check with vma_is_accessible(). Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Guo Ren <guoren@kernel.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Guo Ren <guoren@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paulburton@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Nick Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/1582520593-30704-3-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4064b982 |
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01-Apr-2020 |
Peter Xu <peterx@redhat.com> |
mm: allow VM_FAULT_RETRY for multiple times The idea comes from a discussion between Linus and Andrea [1]. Before this patch we only allow a page fault to retry once. We achieved this by clearing the FAULT_FLAG_ALLOW_RETRY flag when doing handle_mm_fault() the second time. This was majorly used to avoid unexpected starvation of the system by looping over forever to handle the page fault on a single page. However that should hardly happen, and after all for each code path to return a VM_FAULT_RETRY we'll first wait for a condition (during which time we should possibly yield the cpu) to happen before VM_FAULT_RETRY is really returned. This patch removes the restriction by keeping the FAULT_FLAG_ALLOW_RETRY flag when we receive VM_FAULT_RETRY. It means that the page fault handler now can retry the page fault for multiple times if necessary without the need to generate another page fault event. Meanwhile we still keep the FAULT_FLAG_TRIED flag so page fault handler can still identify whether a page fault is the first attempt or not. Then we'll have these combinations of fault flags (only considering ALLOW_RETRY flag and TRIED flag): - ALLOW_RETRY and !TRIED: this means the page fault allows to retry, and this is the first try - ALLOW_RETRY and TRIED: this means the page fault allows to retry, and this is not the first try - !ALLOW_RETRY and !TRIED: this means the page fault does not allow to retry at all - !ALLOW_RETRY and TRIED: this is forbidden and should never be used In existing code we have multiple places that has taken special care of the first condition above by checking against (fault_flags & FAULT_FLAG_ALLOW_RETRY). This patch introduces a simple helper to detect the first retry of a page fault by checking against both (fault_flags & FAULT_FLAG_ALLOW_RETRY) and !(fault_flag & FAULT_FLAG_TRIED) because now even the 2nd try will have the ALLOW_RETRY set, then use that helper in all existing special paths. One example is in __lock_page_or_retry(), now we'll drop the mmap_sem only in the first attempt of page fault and we'll keep it in follow up retries, so old locking behavior will be retained. This will be a nice enhancement for current code [2] at the same time a supporting material for the future userfaultfd-writeprotect work, since in that work there will always be an explicit userfault writeprotect retry for protected pages, and if that cannot resolve the page fault (e.g., when userfaultfd-writeprotect is used in conjunction with swapped pages) then we'll possibly need a 3rd retry of the page fault. It might also benefit other potential users who will have similar requirement like userfault write-protection. GUP code is not touched yet and will be covered in follow up patch. Please read the thread below for more information. [1] https://lore.kernel.org/lkml/20171102193644.GB22686@redhat.com/ [2] https://lore.kernel.org/lkml/20181230154648.GB9832@redhat.com/ Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Suggested-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Brian Geffon <bgeffon@google.com> Cc: Bobby Powers <bobbypowers@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: Denis Plotnikov <dplotnikov@virtuozzo.com> Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Martin Cracauer <cracauer@cons.org> Cc: Marty McFadden <mcfadden8@llnl.gov> Cc: Matthew Wilcox <willy@infradead.org> Cc: Maya Gokhale <gokhale2@llnl.gov> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Link: http://lkml.kernel.org/r/20200220160246.9790-1-peterx@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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dde16072 |
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01-Apr-2020 |
Peter Xu <peterx@redhat.com> |
mm: introduce FAULT_FLAG_DEFAULT Although there're tons of arch-specific page fault handlers, most of them are still sharing the same initial value of the page fault flags. Say, merely all of the page fault handlers would allow the fault to be retried, and they also allow the fault to respond to SIGKILL. Let's define a default value for the fault flags to replace those initial page fault flags that were copied over. With this, it'll be far easier to introduce new fault flag that can be used by all the architectures instead of touching all the archs. Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Brian Geffon <bgeffon@google.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bobby Powers <bobbypowers@gmail.com> Cc: Denis Plotnikov <dplotnikov@virtuozzo.com> Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Martin Cracauer <cracauer@cons.org> Cc: Marty McFadden <mcfadden8@llnl.gov> Cc: Matthew Wilcox <willy@infradead.org> Cc: Maya Gokhale <gokhale2@llnl.gov> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Link: http://lkml.kernel.org/r/20200220160238.9694-1-peterx@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c9a0dad1 |
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01-Apr-2020 |
Peter Xu <peterx@redhat.com> |
powerpc/mm: use helper fault_signal_pending() Let powerpc code to use the new helper, by moving the signal handling earlier before the retry logic. Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Brian Geffon <bgeffon@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bobby Powers <bobbypowers@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: Denis Plotnikov <dplotnikov@virtuozzo.com> Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Martin Cracauer <cracauer@cons.org> Cc: Marty McFadden <mcfadden8@llnl.gov> Cc: Matthew Wilcox <willy@infradead.org> Cc: Maya Gokhale <gokhale2@llnl.gov> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Link: http://lkml.kernel.org/r/20200220160222.9422-1-peterx@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6ec20aa2 |
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24-Jan-2020 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/32s: Fix bad_kuap_fault() At the moment, bad_kuap_fault() reports a fault only if a bad access to userspace occurred while access to userspace was not granted. But if a fault occurs for a write outside the allowed userspace segment(s) that have been unlocked, bad_kuap_fault() fails to detect it and the kernel loops forever in do_page_fault(). Fix it by checking that the accessed address is within the allowed range. Fixes: a68c31fc01ef ("powerpc/32s: Implement Kernel Userspace Access Protection") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/f48244e9485ada0a304ed33ccbb8da271180c80d.1579866752.git.christophe.leroy@c-s.fr
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0f9aee0c |
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23-Dec-2019 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: Don't log user reads to 0xffffffff Running vdsotest leaves many times the following log: [ 79.629901] vdsotest[396]: User access of kernel address (ffffffff) - exploit attempt? (uid: 0) A pointer set to (-1) is likely a programming error similar to a NULL pointer and is not worth logging as an exploit attempt. Don't log user accesses to 0xffffffff. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/0728849e826ba16f1fbd6fa7f5c6cc87bd64e097.1577087627.git.christophe.leroy@c-s.fr
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def0bfdb |
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23-Jan-2020 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc: use probe_user_read() and probe_user_write() Instead of opencoding, use probe_user_read() to failessly read a user location and probe_user_write() for writing to user. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/e041f5eedb23f09ab553be8a91c3de2087147320.1579800517.git.christophe.leroy@c-s.fr
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46ddcb39 |
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21-Aug-2019 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: Show if a bad page fault on data is read or write. DSISR (or ESR on some CPUs) has a bit to tell if the fault is due to a read or a write. Display it. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Santosh Sivaraj <santosh@fossix.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/4f88d7e6fda53b5f80a71040ab400242f6c8cb93.1566400889.git.christophe.leroy@c-s.fr
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b98cca44 |
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16-Jul-2019 |
Anshuman Khandual <anshuman.khandual@arm.com> |
mm, kprobes: generalize and rename notify_page_fault() as kprobe_page_fault() Architectures which support kprobes have very similar boilerplate around calling kprobe_fault_handler(). Use a helper function in kprobes.h to unify them, based on the x86 code. This changes the behaviour for other architectures when preemption is enabled. Previously, they would have disabled preemption while calling the kprobe handler. However, preemption would be disabled if this fault was due to a kprobe, so we know the fault was not due to a kprobe handler and can simply return failure. This behaviour was introduced in commit a980c0ef9f6d ("x86/kprobes: Refactor kprobes_fault() like kprobe_exceptions_notify()") [anshuman.khandual@arm.com: export kprobe_fault_handler()] Link: http://lkml.kernel.org/r/1561133358-8876-1-git-send-email-anshuman.khandual@arm.com Link: http://lkml.kernel.org/r/1560420444-25737-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: James Hogan <jhogan@kernel.org> Cc: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2874c5fd |
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27-May-2019 |
Thomas Gleixner <tglx@linutronix.de> |
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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2e1661d2 |
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23-May-2019 |
Eric W. Biederman <ebiederm@xmission.com> |
signal: Remove the task parameter from force_sig_fault As synchronous exceptions really only make sense against the current task (otherwise how are you synchronous) remove the task parameter from from force_sig_fault to make it explicit that is what is going on. The two known exceptions that deliver a synchronous exception to a stopped ptraced task have already been changed to force_sig_fault_to_task. The callers have been changed with the following emacs regular expression (with obvious variations on the architectures that take more arguments) to avoid typos: force_sig_fault[(]\([^,]+\)[,]\([^,]+\)[,]\([^,]+\)[,]\W+current[)] -> force_sig_fault(\1,\2,\3) Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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f8eac901 |
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05-Feb-2019 |
Eric W. Biederman <ebiederm@xmission.com> |
signal: Remove task parameter from force_sig_mceerr All of the callers pass current into force_sig_mceer so remove the task parameter to make this obvious. This also makes it clear that force_sig_mceerr passes current into force_sig_info. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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5e5be3ae |
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18-Apr-2019 |
Michael Ellerman <mpe@ellerman.id.au> |
powerpc/mm: Detect bad KUAP faults When KUAP is enabled we have logic to detect page faults that occur outside of a valid user access region and are blocked by the AMR. What we don't have at the moment is logic to detect a fault *within* a valid user access region, that has been incorrectly blocked by AMR. This is not meant to ever happen, but it can if we incorrectly save/restore the AMR, or if the AMR was overwritten for some other reason. Currently if that happens we assume it's just a regular fault that will be corrected by handling the fault normally, so we just return. But there is nothing the fault handling code can do to fix it, so the fault just happens again and we spin forever, leading to soft lockups. So add some logic to detect that case and WARN() if we ever see it. Arguably it should be a BUG(), but it's more polite to fail the access and let the kernel continue, rather than taking down the box. There should be no data integrity issue with failing the fault rather than BUG'ing, as we're just going to disallow an access that should have been allowed. To make the code a little easier to follow, unroll the condition at the end of bad_kernel_fault() and comment each case, before adding the call to bad_kuap_fault(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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de78a9c4 |
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18-Apr-2019 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc: Add a framework for Kernel Userspace Access Protection This patch implements a framework for Kernel Userspace Access Protection. Then subarches will have the possibility to provide their own implementation by providing setup_kuap() and allow/prevent_user_access(). Some platforms will need to know the area accessed and whether it is accessed from read, write or both. Therefore source, destination and size and handed over to the two functions. mpe: Rename to allow/prevent rather than unlock/lock, and add read/write wrappers. Drop the 32-bit code for now until we have an implementation for it. Add kuap to pt_regs for 64-bit as well as 32-bit. Don't split strings, use pr_crit_ratelimited(). Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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0fb1c25a |
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18-Apr-2019 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc: Add skeleton for Kernel Userspace Execution Prevention This patch adds a skeleton for Kernel Userspace Execution Prevention. Then subarches implementing it have to define CONFIG_PPC_HAVE_KUEP and provide setup_kuep() function. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> [mpe: Don't split strings, use pr_crit_ratelimited()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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96d4f267 |
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03-Jan-2019 |
Linus Torvalds <torvalds@linux-foundation.org> |
Remove 'type' argument from access_ok() function Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ffca395b |
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28-Nov-2018 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: Fix reporting of kernel execute faults on the 8xx On the 8xx, no-execute is set via PPP bits in the PTE. Therefore a no-exec fault generates DSISR_PROTFAULT error bits, not DSISR_NOEXEC_OR_G. This patch adds DSISR_PROTFAULT in the test mask. Fixes: d3ca587404b3 ("powerpc/mm: Fix reporting of kernel execute faults") Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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49a502ea |
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14-Dec-2018 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: Make NULL pointer deferences explicit on bad page faults. As several other arches including x86, this patch makes it explicit that a bad page fault is a NULL pointer dereference when the fault address is lower than PAGE_SIZE In the mean time, this page makes all bad_page_fault() messages shorter so that they remain on one single line. And it prefixes them by "BUG: " so that they get easily grepped. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> [mpe: Avoid pr_cont()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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374f3f59 |
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26-Nov-2018 |
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> |
powerpc/mm/hash: Handle user access of kernel address gracefully In commit 2865d08dd9ea ("powerpc/mm: Move the DSISR_PROTFAULT sanity check") we moved the protection fault access check before the vma lookup. That means we hit that WARN_ON when user space accesses a kernel address. Before that commit this was handled by find_vma() not finding vma for the kernel address and considering that access as bad area access. Avoid the confusing WARN_ON and convert that to a ratelimited printk. With the patch we now get: for load: a.out[5997]: User access of kernel address (c00000000000dea0) - exploit attempt? (uid: 1000) a.out[5997]: segfault (11) at c00000000000dea0 nip 1317c0798 lr 7fff80d6441c code 1 in a.out[1317c0000+10000] a.out[5997]: code: 60000000 60420000 3c4c0002 38427790 4bffff20 3c4c0002 38427784 fbe1fff8 a.out[5997]: code: f821ffc1 7c3f0b78 60000000 e9228030 <89290000> 993f002f 60000000 383f0040 for exec: a.out[6067]: User access of kernel address (c00000000000dea0) - exploit attempt? (uid: 1000) a.out[6067]: segfault (11) at c00000000000dea0 nip c00000000000dea0 lr 129d507b0 code 1 a.out[6067]: Bad NIP, not dumping instructions. Fixes: 2865d08dd9ea ("powerpc/mm: Move the DSISR_PROTFAULT sanity check") Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Tested-by: Breno Leitao <leitao@debian.org> [mpe: Don't split printk() string across lines] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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d7b45615 |
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13-Dec-2018 |
Suraj Jitindar Singh <sjitindarsingh@gmail.com> |
KVM: PPC: Book3S HV: Implement functions to access quadrants 1 & 2 The POWER9 radix mmu has the concept of quadrants. The quadrant number is the two high bits of the effective address and determines the fully qualified address to be used for the translation. The fully qualified address consists of the effective lpid, the effective pid and the effective address. This gives then 4 possible quadrants 0, 1, 2, and 3. When accessing these quadrants the fully qualified address is obtained as follows: Quadrant | Hypervisor | Guest -------------------------------------------------------------------------- | EA[0:1] = 0b00 | EA[0:1] = 0b00 0 | effLPID = 0 | effLPID = LPIDR | effPID = PIDR | effPID = PIDR -------------------------------------------------------------------------- | EA[0:1] = 0b01 | 1 | effLPID = LPIDR | Invalid Access | effPID = PIDR | -------------------------------------------------------------------------- | EA[0:1] = 0b10 | 2 | effLPID = LPIDR | Invalid Access | effPID = 0 | -------------------------------------------------------------------------- | EA[0:1] = 0b11 | EA[0:1] = 0b11 3 | effLPID = 0 | effLPID = LPIDR | effPID = 0 | effPID = 0 -------------------------------------------------------------------------- In the Guest; Quadrant 3 is normally used to address the operating system since this uses effPID=0 and effLPID=LPIDR, meaning the PID register doesn't need to be switched. Quadrant 0 is normally used to address user space since the effLPID and effPID are taken from the corresponding registers. In the Host; Quadrant 0 and 3 are used as above, however the effLPID is always 0 to address the host. Quadrants 1 and 2 can be used by the host to address guest memory using a guest effective address. Since the effLPID comes from the LPID register, the host loads the LPID of the guest it would like to access (and the PID of the process) and can perform accesses to a guest effective address. This means quadrant 1 can be used to address the guest user space and quadrant 2 can be used to address the guest operating system from the hypervisor, using a guest effective address. Access to the quadrants can cause a Hypervisor Data Storage Interrupt (HDSI) due to being unable to perform partition scoped translation. Previously this could only be generated from a guest and so the code path expects us to take the KVM trampoline in the interrupt handler. This is no longer the case so we modify the handler to call bad_page_fault() to check if we were expecting this fault so we can handle it gracefully and just return with an error code. In the hash mmu case we still raise an unknown exception since quadrants aren't defined for the hash mmu. Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
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5b3e84fc |
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17-Nov-2018 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc: change CONFIG_PPC_STD_MMU to CONFIG_PPC_BOOK3S Today we have: config PPC_BOOK3S def_bool y depends on PPC_BOOK3S_32 || PPC_BOOK3S_64 config PPC_STD_MMU def_bool y depends on PPC_BOOK3S PPC_STD_MMU is therefore redundant with PPC_BOOK3S. Lets remove it. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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f383d8b4 |
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18-Sep-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/powerpc: Use force_sig_fault where appropriate Reviewed-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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5d8fb8a5 |
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18-Sep-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/powerpc: Specialize _exception_pkey for handling pkey exceptions Now that _exception no longer calls _exception_pkey it is no longer necessary to handle any signal with any si_code. All pkey exceptions are SIGSEGV with paired with SEGV_PKUERR. So just handle that case and remove the now unnecessary parameters from _exception_pkey. Reviewed-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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cd60ab7a |
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18-Sep-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/powerpc: Remove pkey parameter from __bad_area_nosemaphore Now that bad_key_fault_exception no longer calls __bad_area_nosemaphore there is no reason for __bad_area_nosemaphore to handle pkeys. Reviewed-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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#
8eb2ba25 |
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18-Sep-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/powerpc: Call _exception_pkey directly from bad_key_fault_exception This removes the need for other code paths to deal with pkey exceptions. Reviewed-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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#
9f2ee693 |
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18-Sep-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/powerpc: Remove pkey parameter from __bad_area There are no callers of __bad_area that pass in a pkey parameter so it makes no sense to take one. Reviewed-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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#
f654fc07 |
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19-Apr-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/powerpc: Use force_sig_mceerr as appropriate In do_sigbus isolate the mceerr signaling code and call force_sig_mceerr instead of falling through to the force_sig_info that works for all of the other signals. Reviewed-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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#
50a7ca3c |
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17-Aug-2018 |
Souptick Joarder <jrdr.linux@gmail.com> |
mm: convert return type of handle_mm_fault() caller to vm_fault_t Use new return type vm_fault_t for fault handler. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t") In this patch all the caller of handle_mm_fault() are changed to return vm_fault_t type. Link: http://lkml.kernel.org/r/20180617084810.GA6730@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Tony Luck <tony.luck@intel.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: James Hogan <jhogan@kernel.org> Cc: Ley Foon Tan <lftan@altera.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: David S. Miller <davem@davemloft.net> Cc: Richard Weinberger <richard@nod.at> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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45ef5992 |
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05-Jul-2018 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc: remove unnecessary inclusion of asm/tlbflush.h asm/tlbflush.h is only needed for: - using functions xxx_flush_tlb_xxx() - using MMU_NO_CONTEXT - including asm-generic/pgtable.h Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
0e36b0d1 |
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23-May-2018 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: Only read faulting instruction when necessary in do_page_fault() Commit a7a9dcd882a67 ("powerpc: Avoid taking a data miss on every userspace instruction miss") has shown that limiting the read of faulting instruction to likely cases improves performance. This patch goes further into this direction by limiting the read of the faulting instruction to the only cases where it is likely needed. On an MPC885, with the same benchmark app as in the commit referred above, we see a reduction of about 3900 dTLB misses (approx 3%): Before the patch: Performance counter stats for './fault 500' (10 runs): 683033312 cpu-cycles ( +- 0.03% ) 134538 dTLB-load-misses ( +- 0.03% ) 46099 iTLB-load-misses ( +- 0.02% ) 19681 faults ( +- 0.02% ) 5.389747878 seconds time elapsed ( +- 0.06% ) With the patch: Performance counter stats for './fault 500' (10 runs): 682112862 cpu-cycles ( +- 0.03% ) 130619 dTLB-load-misses ( +- 0.03% ) 46073 iTLB-load-misses ( +- 0.05% ) 19681 faults ( +- 0.01% ) 5.381342641 seconds time elapsed ( +- 0.07% ) The proper work of the huge stack expansion was tested with the following app: int main(int argc, char **argv) { char buf[1024 * 1025]; sprintf(buf, "Hello world !\n"); printf(buf); exit(0); } Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Add include of pagemap.h to fix build errors] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
8a0b1120 |
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23-May-2018 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: Use instruction symbolic names in store_updates_sp() Use symbolic names defined in asm/ppc-opcode.h instead of hardcoded values. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
3eb0f519 |
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17-Apr-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal: Ensure every siginfo we send has all bits initialized Call clear_siginfo to ensure every stack allocated siginfo is properly initialized before being passed to the signal sending functions. Note: It is not safe to depend on C initializers to initialize struct siginfo on the stack because C is allowed to skip holes when initializing a structure. The initialization of struct siginfo in tracehook_report_syscall_exit was moved from the helper user_single_step_siginfo into tracehook_report_syscall_exit itself, to make it clear that the local variable siginfo gets fully initialized. In a few cases the scope of struct siginfo has been reduced to make it clear that siginfo siginfo is not used on other paths in the function in which it is declared. Instances of using memset to initialize siginfo have been replaced with calls clear_siginfo for clarity. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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#
f2ed480f |
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07-Mar-2018 |
Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> |
powerpc/mm/keys: Update documentation and remove unnecessary check Adds more code comments. We also remove an unnecessary pkey check after we check for pkey error in this patch. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
99cd1302 |
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18-Jan-2018 |
Ram Pai <linuxram@us.ibm.com> |
powerpc: Deliver SEGV signal on pkey violation The value of the pkey, whose protection got violated, is made available in si_pkey field of the siginfo structure. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
e6c2a479 |
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18-Jan-2018 |
Ram Pai <linuxram@us.ibm.com> |
powerpc: Handle exceptions caused by pkey violation Handle Data and Instruction exceptions caused by memory protection-key. The CPU will detect the key fault if the HPTE is already programmed with the key. However if the HPTE is not hashed, a key fault will not be detected by the hardware. The software will detect pkey violation in such a case. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
2271db20 |
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11-Jan-2018 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc: Use the TRAP macro whenever comparing a trap number Trap numbers can have extra bits at the bottom that need to be filtered out. There are a few cases where we don't do that. It's possible that we got lucky but better safe than sorry. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
ecb101ae |
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31-Dec-2017 |
John Sperbeck <jsperbeck@google.com> |
powerpc/mm: Fix SEGV on mapped region to return SEGV_ACCERR The recent refactoring of the powerpc page fault handler in commit c3350602e876 ("powerpc/mm: Make bad_area* helper functions") caused access to protected memory regions to indicate SEGV_MAPERR instead of the traditional SEGV_ACCERR in the si_code field of a user-space signal handler. This can confuse debug libraries that temporarily change the protection of memory regions, and expect to use SEGV_ACCERR as an indication to restore access to a region. This commit restores the previous behavior. The following program exhibits the issue: $ ./repro read || echo "FAILED" $ ./repro write || echo "FAILED" $ ./repro exec || echo "FAILED" #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <signal.h> #include <sys/mman.h> #include <assert.h> static void segv_handler(int n, siginfo_t *info, void *arg) { _exit(info->si_code == SEGV_ACCERR ? 0 : 1); } int main(int argc, char **argv) { void *p = NULL; struct sigaction act = { .sa_sigaction = segv_handler, .sa_flags = SA_SIGINFO, }; assert(argc == 2); p = mmap(NULL, getpagesize(), (strcmp(argv[1], "write") == 0) ? PROT_READ : 0, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); assert(p != MAP_FAILED); assert(sigaction(SIGSEGV, &act, NULL) == 0); if (strcmp(argv[1], "read") == 0) printf("%c", *(unsigned char *)p); else if (strcmp(argv[1], "write") == 0) *(unsigned char *)p = 0; else if (strcmp(argv[1], "exec") == 0) ((void (*)(void))p)(); return 1; /* failed to generate SEGV */ } Fixes: c3350602e876 ("powerpc/mm: Make bad_area* helper functions") Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: John Sperbeck <jsperbeck@google.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [mpe: Add commit references in change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
4915349b |
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08-Aug-2017 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/8xx: Use symbolic names for DSISR bits in DSI Use symbolic names for DSISR bits in DSI Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
968159c0 |
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08-Aug-2017 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/8xx: Getting rid of remaining use of CONFIG_8xx Two config options exist to define powerpc MPC8xx: * CONFIG_PPC_8xx * CONFIG_8xx arch/powerpc/platforms/Kconfig.cputype has contained the following comment about CONFIG_8xx item for some years: "# this is temp to handle compat with arch=ppc" arch/powerpc is now the only place with remaining use of CONFIG_8xx: get rid of them. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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6ff4d3e9 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc: Remove old unused icswx based coprocessor support We have a whole pile of unused code to maintain the ACOP register, allocate coprocessor PIDs and handle ACOP faults. This mechanism was used for the HFI adapter on POWER7 which is dead and gone and whose driver never went upstream. It was used on some A2 core based stuff that also never saw the light of day. Take out all that code. There is still some POWER8 coprocessor code that uses icswx but it's kernel only and thus doesn't use any of that infrastructure. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
8f5ca0b3 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Cleanup check for stack expansion When hitting below a VM_GROWSDOWN vma (typically growing the stack), we check whether it's a valid stack-growing instruction and we check the distance to GPR1. This is largely open coded with lots of comments, so move it out to a helper. While at it, make store_update_sp a boolean. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
f43bb27e |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Don't lose "major" fault indication on retry If the first iteration returns VM_FAULT_MAJOR but the second one doesn't, we fail to account the fault as a major fault. This fixes it and brings the code in line with x86. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
bd0d63f8 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Move page fault VMA access checks to a helper Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
d2e0d2c5 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Set fault flags earlier Move out the code that sets FAULT_FLAG_WRITE so the block that check access permissions can be extracted. While at it also set FAULT_FLAG_INSTRUCTION which will be used for protection keys. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
b15021d9 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Add a bunch of (un)likely annotations to do_page_fault Mostly for the failure cases Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
11ccdd33 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Move/simplify faulthandler_disabled() and !mm check Do the check before we re-enable interrupts and clean the code up a bit. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
2865d08d |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Move the DSISR_PROTFAULT sanity check This has a page of comment explaining what's going on right in the middle of do_page_fault() which makes things a bit hard to follow. Move it to a helper instead. Also do the test earlier as there's no point waiting until after we found the VMA. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
04aafdc6 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Cosmetic fix to page fault accounting No need to break those lines, they aren't that long Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
3da02648 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Move CMO accounting out of do_page_fault into a helper It makes do_page_fault() more readable. No functional change. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
b5c8f0fd |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Rework mm_fault_error() First, handle the normal retry failure in do_page_fault itself, since it's a simple return statement. That allows us to remove the "continue" special return code from mm_fault_error(). Once that's done, we can have an implementation much closer to x86 where we only call mm_fault_error() if VM_FAULT_ERROR is set and directly return. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
c3350602 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Make bad_area* helper functions Instead of goto labels, instead call those functions and return. This gets us closer to x86 and allows us to shring do_page_fault() even more. The main difference with x86 is that those function return a value which we then return from do_page_fault(). That value is our return value from do_page_fault() which we use to generate kernel faults. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
d3ca5874 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Fix reporting of kernel execute faults We currently test for is_exec and DSISR_PROTFAULT but that doesn't make sense as this is the wrong error bit to test for an execute permission failure. In fact, we had code that would return early if we had an exec fault in kernel mode so I think that was just dead code anyway. Finally the location of that test is awkward and prevents further simplifications. So instead move that test into a helper along with the existing early test for kernel exec faults and out of range accesses, and put it all in a "bad_kernel_fault()" helper. While at it test the correct error bits. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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65d47fd4 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Simplify returns from __do_page_fault Now that we moved the exception state handling to a wrapper, we can just directly return rather than "goto bail" Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
bb4be50e |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Move debugger check to notify_page_fault() unclutters the main path Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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f3d96e69 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Overhaul handling of bad page faults A bad page fault is when the HW signals an error such as a bad copy/paste, an AMO error, or some other type of error that will not be fixed by updating the PTE. Use a helper page_fault_is_bad() to check for bad page faults thus removing the per-processor family open-coding in __do_page_fault() and trigger a SIGBUS rather than a SIGSEGV which is more appropriate. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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e6c8290a |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Move error_code checks for bad faults earlier There's no point looking for the VMA etc.. when we already know we are going to fail. This adds some code to set "code" for the si_code but that will be gone in subsequent patches. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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41b464e5 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Move out definition of CPU specific is_write bits Define a common page_fault_is_write() helper and use it Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
d300627c |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/6xx: Handle DABR match before calling do_page_fault On legacy 6xx 32-bit procesors, we checked for the DABR match bit in DSISR from do_page_fault(), in the middle of a pile of ifdef's because all other CPU types do it in assembly prior to calling do_page_fault. Fix that. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [mpe: Add #ifdef CONFIG_6xx] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
c433ec04 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Pre-filter SRR1 bits before do_page_fault() By filtering the relevant SRR1 bits in the assembly rather than in do_page_fault() itself, we avoid a conditional branch (since we already come from different path for data and instruction faults). This will allow more simplifications later Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
7afad422 |
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18-Jul-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Move exception_enter/exit to a do_page_fault wrapper This will allow simplifying the returns from do_page_fault Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
92aa2fe0 |
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19-Apr-2017 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: The 8xx doesn't call do_page_fault() for breakpoints The 8xx has a dedicated exception for breakpoints, that directly calls do_break() Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
da929f6a |
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19-Apr-2017 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: Evaluate user_mode(regs) only once in do_page_fault() Analysis of the assembly code shows that when using user_mode(regs), at least the 'andi.' is redone all the time, and also the 'lwz ,132(r31)' most of the time. With the new form, the 'is_user' is mapped to cr4, then all further use of is_user results in just things like 'beq cr4,218 <do_page_fault+0x218>' Without the patch: 50: 81 1e 00 84 lwz r8,132(r30) 54: 71 09 40 00 andi. r9,r8,16384 58: 40 82 00 0c bne 64 <do_page_fault+0x64> 84: 81 3e 00 84 lwz r9,132(r30) 8c: 71 2a 40 00 andi. r10,r9,16384 90: 41 a2 01 64 beq 1f4 <do_page_fault+0x1f4> d4: 81 3e 00 84 lwz r9,132(r30) dc: 71 28 40 00 andi. r8,r9,16384 e0: 41 82 02 08 beq 2e8 <do_page_fault+0x2e8> 108: 81 3e 00 84 lwz r9,132(r30) 110: 71 28 40 00 andi. r8,r9,16384 118: 41 82 02 28 beq 340 <do_page_fault+0x340> 1e4: 81 3e 00 84 lwz r9,132(r30) 1e8: 71 2a 40 00 andi. r10,r9,16384 1ec: 40 82 01 68 bne 354 <do_page_fault+0x354> 228: 81 3e 00 84 lwz r9,132(r30) 22c: 71 28 40 00 andi. r8,r9,16384 230: 41 82 ff c4 beq 1f4 <do_page_fault+0x1f4> 288: 71 2a 40 00 andi. r10,r9,16384 294: 41 a2 fe 60 beq f4 <do_page_fault+0xf4> 50c: 81 3e 00 84 lwz r9,132(r30) 514: 71 2a 40 00 andi. r10,r9,16384 518: 40 a2 fc e0 bne 1f8 <do_page_fault+0x1f8> 534: 81 3e 00 84 lwz r9,132(r30) 53c: 71 2a 40 00 andi. r10,r9,16384 540: 41 82 fc b8 beq 1f8 <do_page_fault+0x1f8> This patch creates a local var called 'is_user' which contains the result of user_mode(regs) With the patch: 20: 81 03 00 84 lwz r8,132(r3) 48: 55 09 97 fe rlwinm r9,r8,18,31,31 58: 2e 09 00 00 cmpwi cr4,r9,0 5c: 40 92 00 0c bne cr4,68 <do_page_fault+0x68> 88: 41 b2 01 90 beq cr4,218 <do_page_fault+0x218> d4: 40 92 01 d0 bne cr4,2a4 <do_page_fault+0x2a4> 120: 41 b2 00 f8 beq cr4,218 <do_page_fault+0x218> 138: 41 b2 ff a0 beq cr4,d8 <do_page_fault+0xd8> 1d4: 40 92 00 e0 bne cr4,2b4 <do_page_fault+0x2b4> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
97a011e6 |
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19-Apr-2017 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: Remove a redundant test in do_page_fault() The result of (trap == 0x400) is already in is_exec. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
e8de85ca |
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19-Apr-2017 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/mm: Only call store_updates_sp() on stores in do_page_fault() Function store_updates_sp() checks whether the faulting instruction is a store updating r1. Therefore we can limit its calls to store exceptions. This patch is an improvement of commit a7a9dcd882a67 ("powerpc: Avoid taking a data miss on every userspace instruction miss") With the same microbenchmark app, run with 500 as argument, on an MPC885 we get: Before this patch: 152000 DTLB misses After this patch: 147000 DTLB misses Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
a7a9dcd8 |
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03-Apr-2017 |
Anton Blanchard <anton@samba.org> |
powerpc: Avoid taking a data miss on every userspace instruction miss Early on in do_page_fault() we call store_updates_sp(), regardless of the type of exception. For an instruction miss this doesn't make sense, because we only use this information to detect if a data miss is the result of a stack expansion instruction or not. Worse still, it results in a data miss within every userspace instruction miss handler, because we try and load the very instruction we are about to install a pte for! A simple exec microbenchmark runs 6% faster on POWER8 with this fix: #include <stdlib.h> #include <stdio.h> #include <unistd.h> int main(int argc, char *argv[]) { unsigned long left = atol(argv[1]); char leftstr[16]; if (left-- == 0) return 0; sprintf(leftstr, "%ld", left); execlp(argv[0], argv[0], leftstr, NULL); perror("exec failed\n"); return 0; } Pass the number of iterations on the command line (eg 10000) and time how long it takes to execute. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
819cdcdb |
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14-Feb-2017 |
Laurent Dufour <ldufour@linux.vnet.ibm.com> |
powerpc/mm: Move mmap_sem unlocking in do_page_fault() Since the fault retry is now handled earlier, we can release the mmap_sem lock earlier too and remove later unlocking previously done in mm_fault_error(). Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
14c02e41 |
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14-Feb-2017 |
Laurent Dufour <ldufour@linux.vnet.ibm.com> |
powerpc/mm: Handle VM_FAULT_RETRY earlier In do_page_fault() if handle_mm_fault() returns VM_FAULT_RETRY, retry the page fault handling before anything else. This would simplify the handling of the mmap_sem lock in this part of the code. Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
c2294e0f |
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14-Feb-2017 |
Laurent Dufour <ldufour@linux.vnet.ibm.com> |
powerpc/mm: Move mmap_sem unlock up from do_sigbus Move mmap_sem releasing in the do_sigbus()'s unique caller : mm_fault_error() No functional changes. Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
68db0cf1 |
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08-Feb-2017 |
Ingo Molnar <mingo@kernel.org> |
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
18061c17 |
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30-Jan-2017 |
Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> |
powerpc/mm: Update PROTFAULT handling in the page fault path With radix, we can get page fault with DSISR_PROTFAULT value set in case of PROT_NONE or autonuma mapping. The PROT_NONE case in handled by the vma check where we consider the access bad. For autonuma we should fall through and fixup the access mask correctly. Without this patch we trigger the WARN_ON() on radix. This code moves that WARN_ON() within a radix_enabled() check. I also moved the WARN_ON() outside the if condition making it apply for all type of faults (exec/write/read). It is also conditionalized for book3s, because BOOK3E can also get a PROTFAULT to handle the D/I cache sync. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
d7df2443 |
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02-Feb-2017 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Fix spurrious segfaults on radix with autonuma When autonuma (Automatic NUMA balancing) marks a PTE inaccessible it clears all the protection bits but leave the PTE valid. With the Radix MMU, an attempt at executing from such a PTE will take a fault with bit 35 of SRR1 set "SRR1_ISI_N_OR_G". It is thus incorrect to treat all such faults as errors. We should pass them to handle_mm_fault() for autonuma to deal with. The case of pages that are really not executable is handled by the existing test for VM_EXEC further down. That leaves us with catching the kernel attempts at executing user pages. We can catch that earlier, even before we do find_vma. It is never valid on powerpc for the kernel to take an exec fault to begin with. So fold that test with the existing test for the kernel faulting on kernel addresses to bail out early. Fixes: 1d18ad026844 ("powerpc/mm: Detect instruction fetch denied and report") Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
0ab5171b |
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29-Nov-2016 |
Balbir Singh <bsingharora@gmail.com> |
powerpc/mm: Fix no execute fault handling on pre-POWER5 Aneesh/Ben reported that the change to do_page_fault() we made in commit 1d18ad026844 ("powerpc/mm: Detect instruction fetch denied and report") needs to handle the case where CPU_FTR_COHERENT_ICACHE is missing but we have CPU_FTR_NOEXECUTE. In those cases the check added for SRR1_ISI_N_OR_G might trigger a false positive. This patch adds a check for CPU_FTR_COHERENT_ICACHE in addition to the MSR value. Fixes: 1d18ad026844 ("powerpc/mm: Detect instruction fetch denied and report") Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
1d18ad02 |
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14-Nov-2016 |
Balbir Singh <bsingharora@gmail.com> |
powerpc/mm: Detect instruction fetch denied and report ISA 3 allows for prevention of instruction fetch and execution of user mode pages. If such an error occurs, SRR1 bit 35 reports the error. We catch and report the error in do_page_fault(). Signed-off-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
61a92f70 |
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13-Oct-2016 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: Add support for relative exception tables This halves the exception table size on 64-bit builds, and it allows build-time sorting of exception tables to work on relocated kernels. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Minor asm fixups and bits to keep the selftests working] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
03465f89 |
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16-Sep-2016 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: Use kprobe blacklist for exception handlers Currently we mark the C implementations of some exception handlers as __kprobes. This has the effect of putting them in the ".kprobes.text" section, which separates them from the rest of the text. Instead we can use the blacklist macros to add the symbols to a blacklist which kprobes will check. This allows the linker to move exception handler functions close to callers and avoids trampolines in larger kernels. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Reword change log a bit] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
8a39b05f |
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16-Aug-2016 |
Paul Gortmaker <paul.gortmaker@windriver.com> |
powerpc: migrate exception table users off module.h and onto extable.h These files were only including module.h for exception table related functions. We've now separated that content out into its own file "extable.h" so now move over to that and avoid all the extra header content in module.h that we don't really need to compile these files. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
dcddffd4 |
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26-Jul-2016 |
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
mm: do not pass mm_struct into handle_mm_fault We always have vma->vm_mm around. Link: http://lkml.kernel.org/r/1466021202-61880-8-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
eab861a7 |
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01-Jul-2015 |
Anton Blanchard <anton@samba.org> |
powerpc: Add plain English description for alignment exception oopses If we take an alignment exception which we cannot fix, the oops currently prints: Unable to handle kernel paging request for unknown fault Lets print something more useful: Unable to handle kernel paging request for unaligned access at address 0xc0000000f77bba8f Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
70ffdb93 |
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11-May-2015 |
David Hildenbrand <dahi@linux.vnet.ibm.com> |
mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler Introduce faulthandler_disabled() and use it to check for irq context and disabled pagefaults (via pagefault_disable()) in the pagefault handlers. Please note that we keep the in_atomic() checks in place - to detect whether in irq context (in which case preemption is always properly disabled). In contrast, preempt_disable() should never be used to disable pagefaults. With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt counter, and therefore the result of in_atomic() differs. We validate that condition by using might_fault() checks when calling might_sleep(). Therefore, add a comment to faulthandler_disabled(), describing why this is needed. faulthandler_disabled() and pagefault_disable() are defined in linux/uaccess.h, so let's properly add that include to all relevant files. This patch is based on a patch from Thomas Gleixner. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-7-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
842915f5 |
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12-Feb-2015 |
Mel Gorman <mgorman@suse.de> |
ppc64: add paranoid warnings for unexpected DSISR_PROTFAULT ppc64 should not be depending on DSISR_PROTFAULT and it's unexpected if they are triggered. This patch adds warnings just in case they are being accidentally depended upon. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
8a0516ed |
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12-Feb-2015 |
Mel Gorman <mgorman@suse.de> |
mm: convert p[te|md]_numa users to p[te|md]_protnone_numa Convert existing users of pte_numa and friends to the new helper. Note that the kernel is broken after this patch is applied until the other page table modifiers are also altered. This patch layout is to make review easier. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by: Sasha Levin <sasha.levin@oracle.com> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
33692f27 |
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29-Jan-2015 |
Linus Torvalds <torvalds@linux-foundation.org> |
vm: add VM_FAULT_SIGSEGV handling support The core VM already knows about VM_FAULT_SIGBUS, but cannot return a "you should SIGSEGV" error, because the SIGSEGV case was generally handled by the caller - usually the architecture fault handler. That results in lots of duplication - all the architecture fault handlers end up doing very similar "look up vma, check permissions, do retries etc" - but it generally works. However, there are cases where the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV. In particular, when accessing the stack guard page, libsigsegv expects a SIGSEGV. And it usually got one, because the stack growth is handled by that duplicated architecture fault handler. However, when the generic VM layer started propagating the error return from the stack expansion in commit fee7e49d4514 ("mm: propagate error from stack expansion even for guard page"), that now exposed the existing VM_FAULT_SIGBUS result to user space. And user space really expected SIGSEGV, not SIGBUS. To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those duplicate architecture fault handlers about it. They all already have the code to handle SIGSEGV, so it's about just tying that new return value to the existing code, but it's all a bit annoying. This is the mindless minimal patch to do this. A more extensive patch would be to try to gather up the mostly shared fault handling logic into one generic helper routine, and long-term we really should do that cleanup. Just from this patch, you can generally see that most architectures just copied (directly or indirectly) the old x86 way of doing things, but in the meantime that original x86 model has been improved to hold the VM semaphore for shorter times etc and to handle VM_FAULT_RETRY and other "newer" things, so it would be a good idea to bring all those improvements to the generic case and teach other architectures about them too. Reported-and-tested-by: Takashi Iwai <tiwai@suse.de> Tested-by: Jan Engelhardt <jengelh@inai.de> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots" Cc: linux-arch@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
c51a6821 |
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19-Sep-2014 |
LEROY Christophe <christophe.leroy@c-s.fr> |
powerpc/8xx: Invalidate non present TLB as early as possible 8xx sometimes need to load a invalid/non-present TLBs in it DTLB asm handler. These must be invalidated separaly as linux mm doesn't. Commit 5efab4a02c89c252fb4cce097aafde5f8208dbfe was invalidating them in arch/powerpc/mm/fault.c. This patch does the invalidation earlier in order to free the TLB as soon as possible. This also has the advantage of removing some 8xx specific code from fault.c Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Scott Wood <scottwood@freescale.com>
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#
9d57472f |
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24-Sep-2014 |
Anton Blanchard <anton@samba.org> |
powerpc: Fill in si_addr_lsb siginfo field Fill in the si_addr_lsb siginfo field so the hwpoison code can pass to userspace the length of memory that has been corrupted. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
3913fdd7 |
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24-Sep-2014 |
Anton Blanchard <anton@samba.org> |
powerpc: Add VM_FAULT_HWPOISON handling to powerpc page fault handler do_page_fault was missing knowledge of HWPOISON, and we would oops if userspace tried to access a poisoned page: kernel BUG at arch/powerpc/mm/fault.c:180! Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
63af5262 |
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24-Sep-2014 |
Anton Blanchard <anton@samba.org> |
powerpc: Simplify do_sigbus Exit out early for a kernel fault, avoiding indenting of most of the function. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
a70857e4 |
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12-Sep-2014 |
Aaron Tomlin <atomlin@redhat.com> |
sched: Add helper for task stack page overrun checking This facility is used in a few places so let's introduce a helper function to improve code readability. Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: oleg@redhat.com Cc: riel@redhat.com Cc: prarit@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: mpe@ellerman.id.au Cc: tglx@linutronix.de Cc: hannes@cmpxchg.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1410527779-8133-3-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
d4311ff1 |
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12-Sep-2014 |
Aaron Tomlin <atomlin@redhat.com> |
init/main.c: Give init_task a canary Tasks get their end of stack set to STACK_END_MAGIC with the aim to catch stack overruns. Currently this feature does not apply to init_task. This patch removes this restriction. Note that a similar patch was posted by Prarit Bhargava some time ago but was never merged: http://marc.info/?l=linux-kernel&m=127144305403241&w=2 Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: tglx@linutronix.de Cc: hannes@cmpxchg.org Cc: Alex Thorlton <athorlton@sgi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Daeseok Youn <daeseok.youn@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1410527779-8133-2-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
759496ba |
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12-Sep-2013 |
Johannes Weiner <hannes@cmpxchg.org> |
arch: mm: pass userspace fault flag to generic fault handler Unlike global OOM handling, memory cgroup code will invoke the OOM killer in any OOM situation because it has no way of telling faults occuring in kernel context - which could be handled more gracefully - from user-triggered faults. Pass a flag that identifies faults originating in user space from the architecture-specific fault handlers to generic code so that memcg OOM handling can be improved. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
69e044dd |
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10-Sep-2013 |
Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> |
powerpc: Fix possible deadlock on page fault stack_grow_into/14082 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<c000000000206d28>] .might_fault+0x78/0xe0 but task is already holding lock: (&mm->mmap_sem){++++++}, at: [<c0000000007ffd8c>] .do_page_fault+0x24c/0x910 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&mm->mmap_sem); lock(&mm->mmap_sem); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by stack_grow_into/14082: #0: (&mm->mmap_sem){++++++}, at: [<c0000000007ffd8c>] .do_page_fault+0x24c/0x910 stack backtrace: CPU: 21 PID: 14082 Comm: stack_grow_into Not tainted 3.10.0-10.el7.ppc64.debug #1 Call Trace: [c0000003d396b850] [c000000000016e7c] .show_stack+0x7c/0x1f0 (unreliable) [c0000003d396b920] [c000000000813fc8] .dump_stack+0x28/0x3c [c0000003d396b990] [c000000000124b90] .__lock_acquire+0x1640/0x1800 [c0000003d396bab0] [c00000000012570c] .lock_acquire+0xac/0x250 [c0000003d396bb80] [c000000000206d54] .might_fault+0xa4/0xe0 [c0000003d396bbf0] [c0000000007ffe2c] .do_page_fault+0x2ec/0x910 [c0000003d396be30] [c0000000000092e8] handle_page_fault+0x10/0x30 Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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7ffcf8ec |
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06-Aug-2013 |
Anton Blanchard <anton@samba.org> |
powerpc: Fix little endian lppaca, slb_shadow and dtl_entry The lppaca, slb_shadow and dtl_entry hypervisor structures are big endian, so we have to byte swap them in little endian builds. LE KVM hosts will also need to be fixed but for now add an #error to remind us. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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ba12eede |
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13-May-2013 |
Li Zhong <zhong@linux.vnet.ibm.com> |
powerpc: Exception hooks for context tracking subsystem This is the exception hooks for context tracking subsystem, including data access, program check, single step, instruction breakpoint, machine check, alignment, fp unavailable, altivec assist, unknown exception, whose handlers might use RCU. This patch corresponds to [PATCH] x86: Exception hooks for userspace RCU extended QS commit 6ba3c97a38803883c2eee489505796cb0a727122 But after the exception handling moved to generic code, and some changes in following two commits: 56dd9470d7c8734f055da2a6bac553caf4a468eb context_tracking: Move exception handling to generic code 6c1e0256fad84a843d915414e4b5973b7443d48d context_tracking: Restore correct previous context state on exception exit it is able for exception hooks to use the generic code above instead of a redundant arch implementation. Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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9422de3e |
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20-Dec-2012 |
Michael Neuling <mikey@neuling.org> |
powerpc: Hardware breakpoints rewrite to handle non DABR breakpoint registers This is a rewrite so that we don't assume we are using the DABR throughout the code. We now use the arch_hw_breakpoint to store the breakpoint in a generic manner in the thread_struct, rather than storing the raw DABR value. The ptrace GET/SET_DEBUGREG interface currently passes the raw DABR in from userspace. We keep this functionality, so that future changes (like the POWER8 DAWR), will still fake the DABR to userspace. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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c2d23f91 |
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12-Dec-2012 |
David Rientjes <rientjes@google.com> |
mm, oom: remove statically defined arch functions of same name out_of_memory() is a globally defined function to call the oom killer. x86, sh, and powerpc all use a function of the same name within file scope in their respective fault.c unnecessarily. Inline the functions into the pagefault handlers to clean the code up. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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45cac65b |
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08-Oct-2012 |
Shaohua Li <shli@kernel.org> |
readahead: fault retry breaks mmap file read random detection .fault now can retry. The retry can break state machine of .fault. In filemap_fault, if page is miss, ra->mmap_miss is increased. In the second try, since the page is in page cache now, ra->mmap_miss is decreased. And these are done in one fault, so we can't detect random mmap file access. Add a new flag to indicate .fault is tried once. In the second try, skip ra->mmap_miss decreasing. The filemap_fault state machine is ok with it. I only tested x86, didn't test other archs, but looks the change for other archs is obvious, but who knows :) Signed-off-by: Shaohua Li <shaohua.li@fusionio.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9e184e0a |
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07-Aug-2012 |
Eric W. Biederman <ebiederm@xmission.com> |
userns: On ppc convert current_uid from a kuid before printing. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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41ab5266 |
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23-Aug-2012 |
Ananth N Mavinakayanahalli <ananth@in.ibm.com> |
powerpc: Add trap_nr to thread_struct Add thread_struct.trap_nr and use it to store the last exception the thread experienced. In this patch, we populate the field at various places where we force_sig_info() to the process. This is also used in uprobes to determine if the probed instruction caused an exception. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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ae3a197e |
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28-Mar-2012 |
David Howells <dhowells@redhat.com> |
Disintegrate asm/system.h for PowerPC Disintegrate asm/system.h for PowerPC. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> cc: linuxppc-dev@lists.ozlabs.org
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9be72573 |
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01-Mar-2012 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc: Add support for page fault retry and fatal signals Other architectures such as x86 and ARM have been growing new support for features like retrying page faults after dropping the mm semaphore to break contention, or being able to return from a stuck page fault when a SIGKILL is pending. This refactors our implementation of do_page_fault() to move the error handling out of line in a way similar to x86 and adds support for those two features. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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a546498f |
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06-Mar-2012 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc: Call do_page_fault() with interrupts off We currently turn interrupts back to their previous state before calling do_page_fault(). This can be annoying when debugging as a bad fault will potentially have lost some processor state before getting into the debugger. We also end up calling some generic code with interrupts enabled such as notify_page_fault() with interrupts enabled, which could be unexpected. This changes our code to behave more like other architectures, and make the assembly entry code call into do_page_faults() with interrupts disabled. They are conditionally re-enabled from within do_page_fault() in the same spot x86 does it. While there, add the might_sleep() test in the case of a successful trylock of the mmap semaphore, again like x86. Also fix a bug in the existing assembly where r12 (_MSR) could get clobbered by C calls (the DTL accounting in the exception common macro and DISABLE_INTS) in some cases. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- v2. Add the r12 clobber fix
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c3dcf53a |
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29-Sep-2011 |
Jimi Xenidis <jimix@pobox.com> |
powerpc/icswx: Simple ACOP fault handler This patch adds a fault handler that responds to illegal Coprocessor types. Currently all CTs are treated and illegal. There are two ways to report the fault back to the application. If the application used the record form ("icswx.") then the architected "reject" is emulated. If the application did not used the record form ("icswx") then it is selectable by config whether the failure is silent (as architected) or a SIGILL is generated. In all cases pr_warn() is used to log the bad CT. Signed-off-by: Jimi Xenidis <jimix@pobox.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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a8b0ca17 |
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27-Jun-2011 |
Peter Zijlstra <a.p.zijlstra@chello.nl> |
perf: Remove the nmi parameter from the swevent and overflow interface The nmi parameter indicated if we could do wakeups from the current context, if not, we would set some state and self-IPI and let the resulting interrupt do the wakeup. For the various event classes: - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from the PMI-tail (ARM etc.) - tracepoint: nmi=0; since tracepoint could be from NMI context. - software: nmi=[0,1]; some, like the schedule thing cannot perform wakeups, and hence need 0. As one can see, there is very little nmi=1 usage, and the down-side of not using it is that on some platforms some software events can have a jiffy delay in wakeup (when arch_irq_work_raise isn't implemented). The up-side however is that we can remove the nmi parameter and save a bunch of conditionals in fast paths. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Michael Cree <mcree@orcon.net.nz> Cc: Will Deacon <will.deacon@arm.com> Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com> Cc: Anton Blanchard <anton@samba.org> Cc: Eric B Munson <emunson@mgebm.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: David S. Miller <davem@davemloft.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Don Zickus <dzickus@redhat.com> Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
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76462232 |
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03-Jun-2011 |
Christian Dietrich <christian.dietrich@informatik.uni-erlangen.de> |
arch/powerpc: use printk_ratelimited instead of printk_ratelimit Since printk_ratelimit() shouldn't be used anymore (see comment in include/linux/printk.h), replace it with printk_ratelimited. Signed-off-by: Christian Dietrich <christian.dietrich@informatik.uni-erlangen.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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28b54990 |
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24-Aug-2010 |
Anton Blanchard <anton@samba.org> |
powerpc: Check end of stack canary at oops time Add a check for the stack canary when we oops, similar to x86. This should make it clear that we overran our stack: Unable to handle kernel paging request for data at address 0x24652f63700ac689 Faulting instruction address: 0xc000000000063d24 Thread overran stack, or stack corrupted Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
e460c2c9 |
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06-May-2010 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc: Invoke oom-killer from page fault As explained in commit 1c0fe6e3bd, we want to call the architecture independent oom killer when getting an unexplained OOM from handle_mm_fault, rather than simply killing current. Cc: linuxppc-dev@ozlabs.org Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: linux-arch@vger.kernel.org Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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9c7cc234 |
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29-Mar-2010 |
K.Prasad <prasad@linux.vnet.ibm.com> |
powerpc: Disable interrupts for data breakpoint exceptions Data address breakpoint exceptions are currently handled along with page-faults which require interrupts to remain in enabled state. Since exception handling for data breakpoints aren't pre-empt safe, we handle them separately. Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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5efab4a0 |
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19-Nov-2009 |
Joakim Tjernlund <joakim.tjernlund@transmode.se> |
powerpc/8xx: Invalidate non present TLBs 8xx sometimes need to load a invalid/non-present TLBs in it DTLB asm handler. These must be invalidated separaly as linux mm don't. Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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cdd6c482 |
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20-Sep-2009 |
Ingo Molnar <mingo@elte.hu> |
perf: Do the big rename: Performance Counters -> Performance Events Bye-bye Performance Counters, welcome Performance Events! In the past few months the perfcounters subsystem has grown out its initial role of counting hardware events, and has become (and is becoming) a much broader generic event enumeration, reporting, logging, monitoring, analysis facility. Naming its core object 'perf_counter' and naming the subsystem 'perfcounters' has become more and more of a misnomer. With pending code like hw-breakpoints support the 'counter' name is less and less appropriate. All in one, we've decided to rename the subsystem to 'performance events' and to propagate this rename through all fields, variables and API names. (in an ABI compatible fashion) The word 'event' is also a bit shorter than 'counter' - which makes it slightly more convenient to write/handle as well. Thanks goes to Stephane Eranian who first observed this misnomer and suggested a rename. User-space tooling and ABI compatibility is not affected - this patch should be function-invariant. (Also, defconfigs were not touched to keep the size down.) This patch has been generated via the following script: FILES=$(find * -type f | grep -vE 'oprofile|[^K]config') sed -i \ -e 's/PERF_EVENT_/PERF_RECORD_/g' \ -e 's/PERF_COUNTER/PERF_EVENT/g' \ -e 's/perf_counter/perf_event/g' \ -e 's/nb_counters/nb_events/g' \ -e 's/swcounter/swevent/g' \ -e 's/tpcounter_event/tp_event/g' \ $FILES for N in $(find . -name perf_counter.[ch]); do M=$(echo $N | sed 's/perf_counter/perf_event/g') mv $N $M done FILES=$(find . -name perf_event.*) sed -i \ -e 's/COUNTER_MASK/REG_MASK/g' \ -e 's/COUNTER/EVENT/g' \ -e 's/\<event\>/event_id/g' \ -e 's/counter/event/g' \ -e 's/Counter/Event/g' \ $FILES ... to keep it as correct as possible. This script can also be used by anyone who has pending perfcounters patches - it converts a Linux kernel tree over to the new naming. We tried to time this change to the point in time where the amount of pending patches is the smallest: the end of the merge window. Namespace clashes were fixed up in a preparatory patch - and some stylistic fallout will be fixed up in a subsequent patch. ( NOTE: 'counters' are still the proper terminology when we deal with hardware registers - and these sed scripts are a bit over-eager in renaming them. I've undone some of that, but in case there's something left where 'counter' would be better than 'event' we can undo that on an individual basis instead of touching an otherwise nicely automated patch. ) Suggested-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Howells <dhowells@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <linux-arch@vger.kernel.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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d06063cc |
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10-Apr-2009 |
Linus Torvalds <torvalds@linux-foundation.org> |
Move FAULT_FLAG_xyz into handle_mm_fault() callers This allows the callers to now pass down the full set of FAULT_FLAG_xyz flags to handle_mm_fault(). All callers have been (mechanically) converted to the new calling convention, there's almost certainly room for architectures to clean up their code and then add FAULT_FLAG_RETRY when that support is added. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f4dbfa8f |
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11-Jun-2009 |
Peter Zijlstra <a.p.zijlstra@chello.nl> |
perf_counter: Standardize event names Pure renames only, to PERF_COUNT_HW_* and PERF_COUNT_SW_*. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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78f13e95 |
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08-Apr-2009 |
Peter Zijlstra <a.p.zijlstra@chello.nl> |
perf_counter: allow for data addresses to be recorded Paul suggested we allow for data addresses to be recorded along with the traditional IPs as power can provide these. For now, only the software pagefault events provide data addresses, but in the future power might as well for some events. x86 doesn't seem capable of providing this atm. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> LKML-Reference: <20090408130409.394816925@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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ac17dc8e |
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12-Mar-2009 |
Peter Zijlstra <a.p.zijlstra@chello.nl> |
perf_counter: provide major/minor page fault software events Provide separate sw counters for major and minor page faults. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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7dd1fcc2 |
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12-Mar-2009 |
Peter Zijlstra <a.p.zijlstra@chello.nl> |
perf_counter: provide pagefault software events We use the generic software counter infrastructure to provide page fault events. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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8d30c14c |
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10-Feb-2009 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Rework I$/D$ coherency (v3) This patch reworks the way we do I and D cache coherency on PowerPC. The "old" way was split in 3 different parts depending on the processor type: - Hash with per-page exec support (64-bit and >= POWER4 only) does it at hashing time, by preventing exec on unclean pages and cleaning pages on exec faults. - Everything without per-page exec support (32-bit hash, 8xx, and 64-bit < POWER4) does it for all page going to user space in update_mmu_cache(). - Embedded with per-page exec support does it from do_page_fault() on exec faults, in a way similar to what the hash code does. That leads to confusion, and bugs. For example, the method using update_mmu_cache() is racy on SMP where another processor can see the new PTE and hash it in before we have cleaned the cache, and then blow trying to execute. This is hard to hit but I think it has bitten us in the past. Also, it's inefficient for embedded where we always end up having to do at least one more page fault. This reworks the whole thing by moving the cache sync into two main call sites, though we keep different behaviours depending on the HW capability. The call sites are set_pte_at() which is now made out of line, and ptep_set_access_flags() which joins the former in pgtable.c The base idea for Embedded with per-page exec support, is that we now do the flush at set_pte_at() time when coming from an exec fault, which allows us to avoid the double fault problem completely (we can even improve the situation more by implementing TLB preload in update_mmu_cache() but that's for later). If for some reason we didn't do it there and we try to execute, we'll hit the page fault, which will do a minor fault, which will hit ptep_set_access_flags() to do things like update _PAGE_ACCESSED or _PAGE_DIRTY if needed, we just make this guys also perform the I/D cache sync for exec faults now. This second path is the catch all for things that weren't cleaned at set_pte_at() time. For cpus without per-pag exec support, we always do the sync at set_pte_at(), thus guaranteeing that when the PTE is visible to other processors, the cache is clean. For the 64-bit hash with per-page exec support case, we keep the old mechanism for now. I'll look into changing it later, once I've reworked a bit how we use _PAGE_EXEC. This is also a first step for adding _PAGE_EXEC support for embedded platforms Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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f048aace |
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18-Dec-2008 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc/mm: Add SMP support to no-hash TLB handling This commit moves the whole no-hash TLB handling out of line into a new tlb_nohash.c file, and implements some basic SMP support using IPIs and/or broadcast tlbivax instructions. Note that I'm using local invalidations for D->I cache coherency. At worst, if another processor is trying to execute the same and has the old entry in its TLB, it will just take a fault and re-do the TLB flush locally (it won't re-do the cache flush in any case). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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a6326e98 |
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13-Nov-2008 |
Robert Jennings <rcj@linux.vnet.ibm.com> |
powerpc: Correct page-in counter for CMM with 64k pages Linux will report the number of page-ins so that the hypervisor can better determine partition memory pressure. The hardware page size and the OS page size can be different. In the case where the hardware page size is 4k and the OS is running with 64k pages the code in commit 409001948d9f221c94a61c3ee96de112755fc04d ("powerpc: Update page-in counter for CMM") would under-report the number of pages. This corrects the reporting to the hypervisor by incrementing the page_in count by 1 << PAGE_FACTOR each time. Reported-by: Andrew Theurer <habanero@linux.vnet.ibm.com> Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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#
1330deb0 |
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13-Nov-2008 |
David Howells <dhowells@redhat.com> |
CRED: Wrap task credential accesses in the PowerPC arch Wrap access to task credentials so that they can be separated more easily from the task_struct during the introduction of COW creds. Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id(). Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more sense to use RCU directly rather than a convenient wrapper; these will be addressed by later patches. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: linuxppc-dev@ozlabs.org Signed-off-by: James Morris <jmorris@namei.org>
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#
40900194 |
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21-Oct-2008 |
Brian King <brking@linux.vnet.ibm.com> |
powerpc: Update page-in counter for CMM A new field has been added to the VPA as a method for the client OS to communicate to firmware the number of page-ins it is performing when running collaborative memory overcommit. The hypervisor will use this information to better determine if a partition is experiencing memory pressure and needs more memory allocated to it. Signed-off-by: Brian King <brking@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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d6a61bfc |
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23-Jul-2008 |
Luis Machado <luisgpm@linux.vnet.ibm.com> |
powerpc: BookE hardware watchpoint support This patch implements support for HW based watchpoint via the DBSR_DAC (Data Address Compare) facility of the BookE processors. It does so by interfacing with the existing DABR breakpoint code and adding the necessary bits and pieces for the new bits to be properly set or cleared Signed-off-by: Luis Machado <luisgpm@br.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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1bc54c03 |
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07-Jul-2008 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
powerpc: rework 4xx PTE access and TLB miss This is some preliminary work to improve TLB management on SW loaded TLB powerpc platforms. This introduce support for non-atomic PTE operations in pgtable-ppc32.h and removes write back to the PTE from the TLB miss handlers. In addition, the DSI interrupt code no longer tries to fixup write permission, this is left to generic code, and _PAGE_HWWRITE is gone. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
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c3b75bd7 |
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17-Jan-2008 |
Michael Neuling <mikey@neuling.org> |
[POWERPC] Make setjmp/longjmp code usable outside of xmon This makes the setjmp/longjmp code used by xmon, generically available to other code. It also removes the requirement for debugger hooks to be only called on 0x300 (data storage) exception. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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df3c9019 |
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19-Nov-2007 |
joe@perches.com <joe@perches.com> |
[POWERPC] Add missing spaces in printk formats Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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e701d269 |
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29-Oct-2007 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
[POWERPC] 4xx: Fix 4xx flush_tlb_page() On 4xx CPUs, the current implementation of flush_tlb_page() uses a low level _tlbie() assembly function that only works for the current PID. Thus, invalidations caused by, for example, a COW fault triggered by get_user_pages() from a different context will not work properly, causing among other things, gdb breakpoints to fail. This patch adds a "pid" argument to _tlbie() on 4xx processors, and uses it to flush entries in the right context. FSL BookE also gets the argument but it seems they don't need it (their tlbivax form ignores the PID when invalidating according to the document I have). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
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b460cbc5 |
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19-Oct-2007 |
Serge E. Hallyn <serue@us.ibm.com> |
pid namespaces: define is_global_init() and is_container_init() is_init() is an ambiguous name for the pid==1 check. Split it into is_global_init() and is_container_init(). A cgroup init has it's tsk->pid == 1. A global init also has it's tsk->pid == 1 and it's active pid namespace is the init_pid_ns. But rather than check the active pid namespace, compare the task structure with 'init_pid_ns.child_reaper', which is initialized during boot to the /sbin/init process and never changes. Changelog: 2.6.22-rc4-mm2-pidns1: - Use 'init_pid_ns.child_reaper' to determine if a given task is the global init (/sbin/init) process. This would improve performance and remove dependence on the task_pid(). 2.6.21-mm2-pidns2: - [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc, ppc,avr32}/traps.c for the _exception() call to is_global_init(). This way, we kill only the cgroup if the cgroup's init has a bug rather than force a kernel panic. [akpm@linux-foundation.org: fix comment] [sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c] [bunk@stusta.de: kernel/pid.c: remove unused exports] [sukadev@us.ibm.com: Fix capability.c to work with threaded init] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Acked-by: Pavel Emelianov <xemul@openvz.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Herbert Poetzel <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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08ae6cc1 |
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18-Jul-2007 |
Paul Mackerras <paulus@samba.org> |
[POWERPC] Allow exec faults on readable areas on classic 32-bit PowerPC Classic 32-bit PowerPC CPUs, and the early 64-bit PowerPC CPUs, don't provide a way to prevent execution from readable pages, that is, the MMU doesn't distinguish between data reads and instruction reads, although a different exception is taken for faults in data accesses and instruction accesses. Commit 9ba4ace39fdfe22268daca9f28c5df384ae462cf, in the course of fixing another bug, added a check that meant that a page fault due to an instruction access would fail if the vma did not have the VM_EXEC flag set. This gives an inconsistent enforcement on these CPUs of the no-execute status of the vma (since reading from the page is sufficient to allow subsequent execution from it), and causes old versions of ppc32 glibc (2.2 and earlier) to fail, since they rely on executing the word before the GOT but don't have it marked executable. This fixes the problem by allowing execution from readable (or writable) areas on CPUs which do not provide separate control over data and instruction reads. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Jon Loeliger <jdl@freescale.com>
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83c54070 |
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19-Jul-2007 |
Nick Piggin <npiggin@suse.de> |
mm: fault feedback #2 This patch completes Linus's wish that the fault return codes be made into bit flags, which I agree makes everything nicer. This requires requires all handle_mm_fault callers to be modified (possibly the modifications should go further and do things like fault accounting in handle_mm_fault -- however that would be for another patch). [akpm@linux-foundation.org: fix alpha build] [akpm@linux-foundation.org: fix s390 build] [akpm@linux-foundation.org: fix sparc build] [akpm@linux-foundation.org: fix sparc64 build] [akpm@linux-foundation.org: fix ia64 build] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Matthew Wilcox <willy@debian.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> [ Still apparently needs some ARM and PPC loving - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9ba4ace3 |
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19-Jun-2007 |
Segher Boessenkool <segher@kernel.crashing.org> |
[POWERPC] PowerPC: Prevent data exception in kernel space (32-bit) The "is_exec" branch of the protection check in do_page_fault() didn't do anything on 32-bit PowerPC. So if a userland program jumps to a page with Linux protection flags "---p", all the tests happily fall through, and handle_mm_fault() is called, which in turn calls handle_pte_fault(), which calls update_mmu_cache(), which goes flush the dcache to a page with no access rights. Boom. This fixes it. Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org> Cc: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
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effe24bd |
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12-Jun-2007 |
will schmidt <will_schmidt@vnet.ibm.com> |
[POWERPC] During VM oom condition, kill all threads in process group We have had complaints where a threaded application is left in a bad state after one of it's threads is killed when we hit a VM: out_of_memory condition. Killing just one of the process threads can leave the application in a bad state, whereas killing the entire process group would allow for the application to restart, or be otherwise handled, and makes it very obvious that something has gone wrong. This change allows the entire process group to be taken down, rather than just the one thread. lightly tested on powerpc Signed-off-by: Will <will_schmidt@vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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1eeb66a1 |
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08-May-2007 |
Christoph Hellwig <hch@lst.de> |
move die notifier handling to common code This patch moves the die notifier handling to common code. Previous various architectures had exactly the same code for it. Note that the new code is compiled unconditionally, this should be understood as an appel to the other architecture maintainer to implement support for it aswell (aka sprinkling a notify_die or two in the proper place) arm had a notifiy_die that did something totally different, I renamed it to arm_notify_die as part of the patch and made it static to the file it's declared and used at. avr32 used to pass slightly less information through this interface and I brought it into line with the other architectures. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: fix vmalloc_sync_all bustage] [bryan.wu@analog.com: fix vmalloc_sync_all in nommu] Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: <linux-arch@vger.kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Bryan Wu <bryan.wu@analog.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9f90b997 |
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30-Apr-2007 |
Christoph Hellwig <hch@infradead.org> |
[POWERPC] Minor fault path optimization Call the kprobes pagefault handler directly instead of going through the complex notifier chain. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Paul Mackerras <paulus@samba.org>
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a416dd8d |
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07-Nov-2006 |
Michael Ellerman <michael@ellerman.id.au> |
[PATCH] Do a single one-line printk in bad_page_fault() bad_page_fault() prints a message telling the user what type of bad fault we took. The first line of this message is currently implemented as two separate printks. This has the unfortunate effect that if several cpus simultaneously take a bad fault, the first and second parts of the printk get jumbled up, which looks dodge and is hard to read. So do a single one-line printk for each fault type. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
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f400e198 |
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29-Sep-2006 |
Sukadev Bhattiprolu <sukadev@us.ibm.com> |
[PATCH] pidspace: is_init() This is an updated version of Eric Biederman's is_init() patch. (http://lkml.org/lkml/2006/2/6/280). It applies cleanly to 2.6.18-rc3 and replaces a few more instances of ->pid == 1 with is_init(). Further, is_init() checks pid and thus removes dependency on Eric's other patches for now. Eric's original description: There are a lot of places in the kernel where we test for init because we give it special properties. Most significantly init must not die. This results in code all over the kernel test ->pid == 1. Introduce is_init to capture this case. With multiple pid spaces for all of the cases affected we are looking for only the first process on the system, not some other process that has pid == 1. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: <lxc-devel@lists.sourceforge.net> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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df67b3da |
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29-Sep-2006 |
Jason Baron <jbaron@redhat.com> |
[PATCH] make PROT_WRITE imply PROT_READ Make PROT_WRITE imply PROT_READ for a number of architectures which don't support write only in hardware. While looking at this, I noticed that some architectures which do not support write only mappings already take the exact same approach. For example, in arch/alpha/mm/fault.c: " if (cause < 0) { if (!(vma->vm_flags & VM_EXEC)) goto bad_area; } else if (!cause) { /* Allow reads even for write-only mappings */ if (!(vma->vm_flags & (VM_READ | VM_WRITE))) goto bad_area; } else { if (!(vma->vm_flags & VM_WRITE)) goto bad_area; } " Thus, this patch brings other architectures which do not support write only mappings in-line and consistent with the rest. I've verified the patch on ia64, x86_64 and x86. Additional discussion: Several architectures, including x86, can not support write-only mappings. The pte for x86 reserves a single bit for protection and its two states are read only or read/write. Thus, write only is not supported in h/w. Currently, if i 'mmap' a page write-only, the first read attempt on that page creates a page fault and will SEGV. That check is enforced in arch/blah/mm/fault.c. However, if i first write that page it will fault in and the pte will be set to read/write. Thus, any subsequent reads to the page will succeed. It is this inconsistency in behavior that this patch is attempting to address. Furthermore, if the page is swapped out, and then brought back the first read will also cause a SEGV. Thus, any arbitrary read on a page can potentially result in a SEGV. According to the SuSv3 spec, "if the application requests only PROT_WRITE, the implementation may also allow read access." Also as mentioned, some archtectures, such as alpha, shown above already take the approach that i am suggesting. The counter-argument to this raised by Arjan, is that the kernel is enforcing the write only mapping the best it can given the h/w limitations. This is true, however Alan Cox, and myself would argue that the inconsitency in behavior, that is applications can sometimes work/sometimes fails is highly undesireable. If you read through the thread, i think people, came to an agreement on the last patch i posted, as nobody has objected to it... Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Andi Kleen <ak@muc.de> Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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6ab3d562 |
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30-Jun-2006 |
Jörn Engel <joern@wohnheim.fh-wedel.de> |
Remove obsolete #include <linux/config.h> Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
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4f9e87c0 |
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26-Jun-2006 |
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> |
[PATCH] Notify page fault call chain for powerpc Overloading of page fault notification with the notify_die() has performance issues(since the only interested components for page fault is kprobes and/or kdb) and hence this patch introduces the new notifier call chain exclusively for page fault notifications their by avoiding notifying unnecessary components in the do_page_fault() code path. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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fc5266ea |
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31-Mar-2006 |
Anton Blanchard <anton@samba.org> |
[PATCH] powerpc: trivial spelling fixes in fault.c This comment exceeded my bad spelling threshold :) Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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bab70a4a |
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28-Mar-2006 |
Eugene Surovegin <ebs@ebshome.net> |
[PATCH] lock PTE before updating it in 440/BookE page fault handler Fix 44x and BookE page fault handler to correctly lock PTE before trying to pte_update() it, otherwise this PTE might be swapped out after pte_present() check but before pte_uptdate() call, resulting in corrupted PTE. This can happen with enabled preemption and low memory condition. Signed-off-by: Eugene Surovegin <ebs@ebshome.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
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2ef9481e |
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23-Jan-2006 |
Jon Mason <jdmason@us.ibm.com> |
[PATCH] powerpc: trivial: modify comments to refer to new location of files This patch removes all self references and fixes references to files in the now defunct arch/ppc64 tree. I think this accomplises everything wanted, though there might be a few references I missed. Signed-off-by: Jon Mason <jdmason@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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bce6c5fd |
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08-Jan-2006 |
Anton Blanchard <anton@samba.org> |
[PATCH] powerpc: DABR exceptions should report the address not the PC When taking a DABR exception we were reporting the PC. It makes more sense to report the address that caused the exception, and the gdb guys would like it that way. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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723925b7 |
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06-Nov-2005 |
Olof Johansson <olof@lixom.net> |
[PATCH] powerpc: Nicer printing of address at oops Add nicer printing of faulting address on unresolvable kernel faults. Makes life a little easier for those who don't know how to decode our register contents at oops time. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
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cffb09ce |
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26-Oct-2005 |
Kumar Gala <galak@freescale.com> |
[PATCH] powerpc: Fix warning related to do_dabr do_dabr() is not relevant on 40x or Book-E processors so dont build it Signed-off-by: Kumar K. Gala <kumar.gala@freescale.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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14cf11af |
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26-Sep-2005 |
Paul Mackerras <paulus@samba.org> |
powerpc: Merge enough to start building in arch/powerpc. This creates the directory structure under arch/powerpc and a bunch of Kconfig files. It does a first-cut merge of arch/powerpc/mm, arch/powerpc/lib and arch/powerpc/platforms/powermac. This is enough to build a 32-bit powermac kernel with ARCH=powerpc. For now we are getting some unmerged files from arch/ppc/kernel and arch/ppc/syslib, or arch/ppc64/kernel. This makes some minor changes to files in those directories and files outside arch/powerpc. The boot directory is still not merged. That's going to be interesting. Signed-off-by: Paul Mackerras <paulus@samba.org>
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