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57b77b75 |
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04-Mar-2024 |
Qi Zheng <zhengqi.arch@bytedance.com> |
s390: supplement for ptdesc conversion After commit 6326c26c1514 ("s390: convert various pgalloc functions to use ptdescs"), there are still some positions that use page->{lru, index} instead of ptdesc->{pt_list, pt_index}. In order to make the use of ptdesc->{pt_list, pt_index} clearer, it would be better to convert them as well. [zhengqi.arch@bytedance.com: fix build failure] Link: https://lkml.kernel.org/r/20240305072154.26168-1-zhengqi.arch@bytedance.com Link: https://lkml.kernel.org/r/04beaf3255056ffe131a5ea595736066c1e84756.1709541697.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
02e790ee |
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03-Nov-2023 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: make pte_free_tlb() similar to pXd_free_tlb() Make pte_free_tlb() look similar to pXd_free_tlb() family functions. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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0031f1c7 |
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03-Nov-2023 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: use compound page order to distinguish page tables CRSTs always have size of four pages, while 2KB-size page tables always occupy a single page. Use that information to distinguish page tables from CRSTs. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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d08d4e7c |
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12-Oct-2023 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: use full 4KB page for 2KB PTE Cease using 4KB pages to host two 2KB PTEs. That greatly simplifies the memory management code at the expense of page tables memory footprint. Instead of two PTEs per 4KB page use only upper half of the parent page for a single PTE. With that the list of half-used pages pgtable_list becomes unneeded. Further, the upper byte of the parent page _refcount counter does not need to be used for fragments tracking and could be left alone. Commit 8211dad62798 ("s390: add pte_free_defer() for pgtables sharing page") introduced the use of PageActive flag to coordinate a deferred free with 2KB page table fragments tracking. Since there is no tracking anymore, there is no need for using PageActive flag. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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#
65d37f16 |
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27-Oct-2023 |
Heiko Carstens <hca@linux.ibm.com> |
s390/cmma: move arch_set_page_dat() to header file In order to be usable for early boot code move the simple arch_set_page_dat() function to header file, and add its counter-part arch_set_page_nodat(). Also change the parameters, and the function name slightly. This is required since there aren't any struct pages available in early boot code, and renaming of functions is done to make sure that all users are converted to the new API. Instead of a pointer to a struct page a virtual address is passed, and instead of an order the number of pages for which the page state needs be set. Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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0547e0bd |
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23-Oct-2023 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: add missing conversion to use ptdescs Commit 6326c26c1514 ("s390: convert various pgalloc functions to use ptdescs") missed to convert tlb_remove_table() into tlb_remove_ptdesc() in few locations. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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#
1954da4a |
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20-Oct-2023 |
Heiko Carstens <hca@linux.ibm.com> |
s390/mm: add missing arch_set_page_dat() call to gmap allocations If the cmma no-dat feature is available all pages that are not used for dynamic address translation are marked as "no-dat" with the ESSA instruction. This information is visible to the hypervisor, so that the hypervisor can optimize purging of guest TLB entries. This also means that pages which are used for dynamic address translation must not be marked as "no-dat", since the hypervisor may then incorrectly not purge guest TLB entries. Region, segment, and page tables allocated within the gmap code are incorrectly marked as "no-dat", since an explicit call to arch_set_page_dat() is missing, which would remove the "no-dat" mark. In order to fix this add a new gmap_alloc_crst() function which should be used to allocate region and segment tables, and which also calls arch_set_page_dat(). Also add the arch_set_page_dat() call to page_table_alloc_pgste(). Cc: <stable@vger.kernel.org> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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7bc8b8eb |
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15-Oct-2023 |
Heiko Carstens <hca@linux.ibm.com> |
s390/mm: remove __GFP_HIGHMEM masking Remove unnecessary __GFP_HIGHMEM masking, which was introduced with commit 6326c26c1514 ("s390: convert various pgalloc functions to use ptdescs"). Also remove a whitespace change which was introduced with the same commit. Link: https://lore.kernel.org/all/CAOzc2px-SFSnmjcPriiB3cm1fNj3+YC8S0VSp4t1QvDR0f4E2A@mail.gmail.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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527618ab |
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11-Sep-2023 |
Heiko Carstens <hca@linux.ibm.com> |
s390/ctlreg: add struct ctlreg Add struct ctlreg to enforce strict type checking / usage for control register functions. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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2372d391 |
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11-Sep-2023 |
Heiko Carstens <hca@linux.ibm.com> |
s390/ctlreg: use local_ctl_load() and local_ctl_store() where possible Convert all single control register usages of __local_ctl_load() and __local_ctl_store() to local_ctl_load() and local_ctl_store(). This also requires to change the type of some struct lowcore members from __u64 to unsigned long. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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8d5e98f8 |
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11-Sep-2023 |
Heiko Carstens <hca@linux.ibm.com> |
s390/ctlreg: add local and system prefix to some functions Add local and system prefix to some functions to clarify they change control register contents on either the local CPU or the on all CPUs. This results in the following API: Two defines which load and save multiple control registers. The defines correlate with the following C prototypes: void __local_ctl_load(unsigned long *, unsigned int cr_low, unsigned int cr_high); void __local_ctl_store(unsigned long *, unsigned int cr_low, unsigned int cr_high); Two functions which locally set or clear one bit for a specified control register: void local_ctl_set_bit(unsigned int cr, unsigned int bit); void local_ctl_clear_bit(unsigned int cr, unsigned int bit); Two functions which set or clear one bit for a specified control register on all CPUs: void system_ctl_set_bit(unsigned int cr, unsigned int bit); void system_ctl_clear_bit(unsigend int cr, unsigned int bit); Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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#
fdd9da76 |
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02-Oct-2023 |
Joel Granados <j.granados@samsung.com> |
S390: Remove now superfluous sentinel elem from ctl_table arrays This commit comes at the tail end of a greater effort to remove the empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) Remove the sentinel element from appldata_table, s390dbf_table, topology_ctl_table, cmm_table and page_table_sysctl. Reduced the memory allocation in appldata_register_ops by 1 effectively removing the sentinel from ops->ctl_table. This removal is safe because register_sysctl_sz and register_sysctl use the array size in addition to checking for the sentinel. Tested-by: Alexander Gordeev <agordeev@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Joel Granados <j.granados@samsung.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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#
6326c26c |
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07-Aug-2023 |
Vishal Moola (Oracle) <vishal.moola@gmail.com> |
s390: convert various pgalloc functions to use ptdescs As part of the conversions to replace pgtable constructor/destructors with ptdesc equivalents, convert various page table functions to use ptdescs. Some of the functions use the *get*page*() helper functions. Convert these to use pagetable_alloc() and ptdesc_address() instead to help standardize page tables further. Link: https://lkml.kernel.org/r/20230807230513.102486-15-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Guo Ren <guoren@kernel.org> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Jonas Bonn <jonas@southpole.se> Cc: Matthew Wilcox <willy@infradead.org> Cc: Palmer Dabbelt <palmer@rivosinc.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
8211dad6 |
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11-Jul-2023 |
Hugh Dickins <hughd@google.com> |
s390: add pte_free_defer() for pgtables sharing page Add s390-specific pte_free_defer(), to free table page via call_rcu(). pte_free_defer() will be called inside khugepaged's retract_page_tables() loop, where allocating extra memory cannot be relied upon. This precedes the generic version to avoid build breakage from incompatible pgtable_t. This version is more complicated than others: because s390 fits two 2K page tables into one 4K page (so page->rcu_head must be shared between both halves), and already uses page->lru (which page->rcu_head overlays) to list any free halves; with clever management by page->_refcount bits. Build upon the existing management, adjusted to follow a new rule: that a page is never on the free list if pte_free_defer() was used on either half (marked by PageActive). And for simplicity, delay calling RCU until both halves are freed. Not adding back unallocated fragments to the list in pte_free_defer() can result in wasting some amount of memory for pagetables, depending on how long the allocated fragment will stay in use. In practice, this effect is expected to be insignificant, and not justify a far more complex approach, which might allow to add the fragments back later in __tlb_remove_table(), where we might not have a stable mm any more. [hughd@google.com: Claudio finds warning on mm_has_pgste() more useful than on mm_alloc_pgste()] Link: https://lkml.kernel.org/r/3bc095ba-a180-ce3b-82b1-2bfc64612f3@google.com Link: https://lkml.kernel.org/r/94eccf5f-264c-8abe-4567-e77f4b4e14a@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Tested-by: Alexander Gordeev <agordeev@linux.ibm.com> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Huang, Ying <ying.huang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Russell King <linux@armlinux.org.uk> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zack Rusin <zackr@vmware.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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d28d86a0 |
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17-Mar-2023 |
Heiko Carstens <hca@linux.ibm.com> |
s390/mm: make use of atomic_fetch_xor() Make use of atomic_fetch_xor() instead of an atomic_cmpxchg() loop to implement atomic_xor_bits() (aka atomic_xor_return()). This makes the C code more readable and in addition generates better code, since for z196 and newer a single lax instruction is generated instead of a cmpxchg() loop. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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7ddc873d |
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10-Mar-2023 |
Luis Chamberlain <mcgrof@kernel.org> |
s390: simplify one-level sysctl registration for page_table_sysctl There is no need to declare an extra tables to just create directory, this can be easily be done with a prefix path with register_sysctl(). Simplify this registration. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/20230310234525.3986352-6-mcgrof@kernel.org Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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f413f685 |
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07-Feb-2022 |
Heiko Carstens <hca@linux.ibm.com> |
s390/mm: use CRST_ALLOC_ORDER instead of number Use CRST_ALLOC_ORDER to make it more obvious what the order means, and also to be consistent with other code, e.g. the vmemmap code. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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4c88bb96 |
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04-Nov-2021 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: check 2KB-fragment page on release When CONFIG_DEBUG_VM is defined check that pending remove and tracking nibbles (bits 31-24 of the page refcount) are cleared. Should the earlier stages of the page lifespan have a race or logical error, such check could help in exposing the issue. Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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1194372d |
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04-Nov-2021 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: better annotate 2KB pagetable fragments handling Explicitly encode immediate value of pending remove nibble (bits 31-28) and tracking nibble (bits 27-24) of the page refcount whenever these nibbles are tested or changed, for better readability. Also, add some comments describing how the fragments are handled. Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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c2c22493 |
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04-Nov-2021 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: fix 2KB pgtable release race There is a race on concurrent 2KB-pgtables release paths when both upper and lower halves of the containing parent page are freed, one via page_table_free_rcu() + __tlb_remove_table(), and the other via page_table_free(). The race might lead to a corruption as result of remove of list item in page_table_free() concurrently with __free_page() in __tlb_remove_table(). Let's assume first the lower and next the upper 2KB-pgtables are freed from a page. Since both halves of the page are allocated the tracking byte (bits 24-31 of the page _refcount) has value of 0x03 initially: CPU0 CPU1 ---- ---- page_table_free_rcu() // lower half { // _refcount[31..24] == 0x03 ... atomic_xor_bits(&page->_refcount, 0x11U << (0 + 24)); // _refcount[31..24] <= 0x12 ... table = table | (1U << 0); tlb_remove_table(tlb, table); } ... __tlb_remove_table() { // _refcount[31..24] == 0x12 mask = _table & 3; // mask <= 0x01 ... page_table_free() // upper half { // _refcount[31..24] == 0x12 ... atomic_xor_bits( &page->_refcount, 1U << (1 + 24)); // _refcount[31..24] <= 0x10 // mask <= 0x10 ... atomic_xor_bits(&page->_refcount, mask << (4 + 24)); // _refcount[31..24] <= 0x00 // mask <= 0x00 ... if (mask != 0) // == false break; fallthrough; ... if (mask & 3) // == false ... else __free_page(page); list_del(&page->lru); ^^^^^^^^^^^^^^^^^^ RACE! ^^^^^^^^^^^^^^^^^^^^^ } ... } The problem is page_table_free() releases the page as result of lower nibble unset and __tlb_remove_table() observing zero too early. With this update page_table_free() will use the similar logic as page_table_free_rcu() + __tlb_remove_table(), and mark the fragment as pending for removal in the upper nibble until after the list_del(). In other words, the parent page is considered as unreferenced and safe to release only when the lower nibble is cleared already and unsetting a bit in upper nibble results in that nibble turned zero. Cc: stable@vger.kernel.org Suggested-by: Vlastimil Babka <vbabka@suse.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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da001fce |
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08-Dec-2021 |
Heiko Carstens <hca@linux.ibm.com> |
s390/pgalloc: use pointers instead of unsigned long values After adding the missing __va()/__pa() calls to the base asce functions there are even more casts in the code than before. Make the code more readable by passing and using pointers to page tables, instead of using unsigned values for the same purpose. This allows to get rid of nearly all casts within the code. Suggested-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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2f882800 |
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07-Dec-2021 |
Heiko Carstens <hca@linux.ibm.com> |
s390/pgalloc: add virt/phys address handling to base asce functions The base asce functions create/free page tables open-coded to make sure that the returned asce and page tables do not make use of any enhanced DAT features like e.g. large pages. This is required for some I/O functions that use an asce, like e.g. some service call requests. Handling of virtual vs physical addresses is missing; therefore add that now. Note: this currently doesn't fix a real bug, since virtual addresses are indentical to physical ones. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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2a444fdc |
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11-Feb-2021 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: fix phys vs virt confusion in pgtable allocation routines The physical address of page tables is passed around and used as virtual address in various locations. Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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87d59863 |
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16-Nov-2020 |
Heiko Carstens <hca@linux.ibm.com> |
s390/mm: remove set_fs / rework address space handling Remove set_fs support from s390. With doing this rework address space handling and simplify it. As a result address spaces are now setup like this: CPU running in | %cr1 ASCE | %cr7 ASCE | %cr13 ASCE ----------------------------|-----------|-----------|----------- user space | user | user | kernel kernel, normal execution | kernel | user | kernel kernel, kvm guest execution | gmap | user | kernel To achieve this the getcpu vdso syscall is removed in order to avoid secondary address mode and a separate vdso address space in for user space. The getcpu vdso syscall will be implemented differently with a subsequent patch. The kernel accesses user space always via secondary address space. This happens in different ways: - with mvcos in home space mode and directly read/write to secondary address space - with mvcs/mvcp in primary space mode and copy from primary space to secondary space or vice versa - with e.g. cs in secondary space mode and access secondary space Switching translation modes happens with sacf before and after instructions which access user space, like before. Lazy handling of control register reloading is removed in the hope to make everything simpler, but at the cost of making kernel entry and exit a bit slower. That is: on kernel entry the primary asce is always changed to contain the kernel asce, and on kernel exit the primary asce is changed again so it contains the user asce. In kernel mode there is only one exception to the primary asce: when kvm guests are executed the primary asce contains the gmap asce (which describes the guest address space). The primary asce is reset to kernel asce whenever kvm guest execution is interrupted, so that this doesn't has to be taken into account for any user space accesses. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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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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316ec154 |
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15-Apr-2020 |
Christian Borntraeger <borntraeger@de.ibm.com> |
s390/mm: fix page table upgrade vs 2ndary address mode accesses A page table upgrade in a kernel section that uses secondary address mode will mess up the kernel instructions as follows: Consider the following scenario: two threads are sharing memory. On CPU1 thread 1 does e.g. strnlen_user(). That gets to old_fs = enable_sacf_uaccess(); len = strnlen_user_srst(src, size); and " la %2,0(%1)\n" " la %3,0(%0,%1)\n" " slgr %0,%0\n" " sacf 256\n" "0: srst %3,%2\n" in strnlen_user_srst(). At that point we are in secondary space mode, control register 1 points to kernel page table and instruction fetching happens via c1, rather than usual c13. Interrupts are not disabled, for obvious reasons. On CPU2 thread 2 does MAP_FIXED mmap(), forcing the upgrade of page table from 3-level to e.g. 4-level one. We'd allocated new top-level table, set it up and now we hit this: notify = 1; spin_unlock_bh(&mm->page_table_lock); } if (notify) on_each_cpu(__crst_table_upgrade, mm, 0); OK, we need to actually change over to use of new page table and we need that to happen in all threads that are currently running. Which happens to include the thread 1. IPI is delivered and we have static void __crst_table_upgrade(void *arg) { struct mm_struct *mm = arg; if (current->active_mm == mm) set_user_asce(mm); __tlb_flush_local(); } run on CPU1. That does static inline void set_user_asce(struct mm_struct *mm) { S390_lowcore.user_asce = mm->context.asce; OK, user page table address updated... __ctl_load(S390_lowcore.user_asce, 1, 1); ... and control register 1 set to it. clear_cpu_flag(CIF_ASCE_PRIMARY); } IPI is run in home space mode, so it's fine - insns are fetched using c13, which always points to kernel page table. But as soon as we return from the interrupt, previous PSW is restored, putting CPU1 back into secondary space mode, at which point we no longer get the kernel instructions from the kernel mapping. The fix is to only fixup the control registers that are currently in use for user processes during the page table update. We must also disable interrupts in enable_sacf_uaccess to synchronize the cr and thread.mm_segment updates against the on_each-cpu. Fixes: 0aaba41b58bc ("s390: remove all code using the access register mode") Cc: stable@vger.kernel.org # 4.15+ Reported-by: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> References: CVE-2020-11884 Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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f7555608 |
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19-Mar-2020 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: cleanup virtual memory constants usage Remove duplicate definitions and consolidate usage of virutal and address translation constants. Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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6a3eb35e |
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28-Feb-2020 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: remove page table downgrade support This update consolidates page table handling code. Because there are hardly any 31-bit binaries left we do not need to optimize for that. No extra efforts are needed to ensure that a compat task does not map anything above 2GB. The TASK_SIZE limit for 31-bit tasks is 2GB already and the generic code does check that a resulting map address would not surpass that limit. Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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2c7749b9 |
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10-Mar-2020 |
Joe Perches <joe@perches.com> |
s390: use fallthrough; Convert the various uses of fallthrough comments to fallthrough; Done via script Link: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe.com/ Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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31932757 |
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08-Mar-2020 |
Alexander Gordeev <agordeev@linux.ibm.com> |
s390/mm: optimize page table upgrade routine There is a maximum of two new tables allocated on page table upgrade. Because we know that a loop the current implementation is based on could be unrolled with some improvements: * upgrade from 3 to 5 levels happens in one go - without an unnecessary re-take of page_table_lock in-between; * page tables initialization moved out of the atomic code; Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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b4ed71f5 |
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25-Sep-2019 |
Mark Rutland <mark.rutland@arm.com> |
mm: treewide: clarify pgtable_page_{ctor,dtor}() naming The naming of pgtable_page_{ctor,dtor}() seems to have confused a few people, and until recently arm64 used these erroneously/pointlessly for other levels of page table. To make it incredibly clear that these only apply to the PTE level, and to align with the naming of pgtable_pmd_page_{ctor,dtor}(), let's rename them to pgtable_pte_page_{ctor,dtor}(). These changes were generated with the following shell script: ---- git grep -lw 'pgtable_page_.tor' | while read FILE; do sed -i '{s/pgtable_page_ctor/pgtable_pte_page_ctor/}' $FILE; sed -i '{s/pgtable_page_dtor/pgtable_pte_page_dtor/}' $FILE; done ---- ... with the documentation re-flowed to remain under 80 columns, and whitespace fixed up in macros to keep backslashes aligned. There should be no functional change as a result of this patch. Link: http://lkml.kernel.org/r/20190722141133.3116-1-mark.rutland@arm.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ac7a0fce |
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25-Jun-2019 |
Vasily Gorbik <gor@linux.ibm.com> |
s390/mm: use shared variables for sysctl range check Since commit eec4844fae7c ("proc/sysctl: add shared variables for range check") special shared variables are available for sysctl range check. Reuse them for /proc/sys/vm/allocate_pgste proc handler. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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9de7d833 |
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18-Sep-2018 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/tlb: Convert to generic mmu_gather No change in behavior intended. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: aneesh.kumar@linux.vnet.ibm.com Cc: heiko.carstens@de.ibm.com Cc: linux@armlinux.org.uk Cc: npiggin@gmail.com Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/20180918125151.31744-3-schwidefsky@de.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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814cedbc |
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27-Nov-2018 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: correct pgtable_bytes on page table downgrade The downgrade of a page table from 3 levels to 2 levels for a 31-bit compat process removes a pmd table which has to be counted against pgtable_bytes. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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0d4e68e2 |
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30-Oct-2018 |
Paul E. McKenney <paulmck@kernel.org> |
s390/mm: Convert tlb_table_flush() to use call_rcu() Now that call_rcu()'s callback is not invoked until after all preempt-disable regions of code have completed (in addition to explicitly marked RCU read-side critical sections), call_rcu() can be used in place of call_rcu_sched(). This commit therefore makes that change. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: <linux-s390@vger.kernel.org>
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e12e4044 |
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15-Oct-2018 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: fix mis-accounting of pgtable_bytes In case a fork or a clone system fails in copy_process and the error handling does the mmput() at the bad_fork_cleanup_mm label, the following warning messages will appear on the console: BUG: non-zero pgtables_bytes on freeing mm: 16384 The reason for that is the tricks we play with mm_inc_nr_puds() and mm_inc_nr_pmds() in init_new_context(). A normal 64-bit process has 3 levels of page table, the p4d level and the pud level are folded. On process termination the free_pud_range() function in mm/memory.c will subtract 16KB from pgtable_bytes with a mm_dec_nr_puds() call, but there actually is not really a pud table. One issue with this is the fact that pgtable_bytes is usually off by a few kilobytes, but the more severe problem is that for a failed fork or clone the free_pgtables() function is not called. In this case there is no mm_dec_nr_puds() or mm_dec_nr_pmds() that go together with the mm_inc_nr_puds() and mm_inc_nr_pmds in init_new_context(). The pgtable_bytes will be off by 16384 or 32768 bytes and we get the BUG message. The message itself is purely cosmetic, but annoying. To fix this override the mm_pmd_folded, mm_pud_folded and mm_p4d_folded function to check for the true size of the address space. Reported-by: Li Wang <liwang@redhat.com> Tested-by: Li Wang <liwang@redhat.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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5bedf8aa |
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23-Jun-2018 |
Vasily Gorbik <gor@linux.ibm.com> |
s390/mm: correct allocate_pgste proc_handler callback Since proc_dointvec does not perform value range control, proc_dointvec_minmax should be used to limit value range, which is clearly intended here, as the internal representation of the value: unsigned int alloc_pgste:1; In fact it currently works, since we have mm->context.alloc_pgste = page_table_allocate_pgste || ... ... since commit 23fefe119ceb5 ("s390/kvm: avoid global config of vm.alloc_pgste=1") Before that it was mm->context.alloc_pgste = page_table_allocate_pgste; which was broken. That was introduced with commit 0b46e0a3ec0d7 ("s390/kvm: remove delayed reallocation of page tables for KVM"). Fixes: 0b46e0a3ec0d7 ("s390/kvm: remove delayed reallocation of page tables for KVM") Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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dfa75863 |
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29-Jun-2018 |
Eric Farman <farman@linux.ibm.com> |
s390/mm: fix refcount usage for 4K pgste s390 no longer uses the _mapcount field in struct page to identify the page table format being used. While the code was diligent in handling the different mappings, it neglected to turn "off" the map bits when alloc_pgste was being used. This resulted in bits remaining "on" in the _refcount field, and thus an artifically huge "in use" count that prevents the pages from actually being released by __free_page. There's opportunity for improvement in the "1 vs 3" vs "1U vs 3U" vs "0x1 vs 0x11" etc. variations for all these calls, I am just keeping things simple compared to neighboring code. Fixes: 620b4e903179 ("s390: use _refcount for pgtables") Reported-by: Halil Pasic <pasic@linux.ibm.com> Bisected-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Eric Farman <farman@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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620b4e90 |
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07-Jun-2018 |
Matthew Wilcox <willy@infradead.org> |
s390: use _refcount for pgtables Patch series "Rearrange struct page", v6. As presented at LSFMM, this patch-set rearranges struct page to give more contiguous usable space to users who have allocated a struct page for their own purposes. For a graphical view of before-and-after, see the first two tabs of https://docs.google.com/spreadsheets/d/1tvCszs_7FXrjei9_mtFiKV6nW1FLnYyvPvW-qNZhdog/edit?usp=sharing Highlights: - deferred_list now really exists in struct page instead of just a comment. - hmm_data also exists in struct page instead of being a nasty hack. - x86's PGD pages have a real pointer to the mm_struct. - VMalloc pages now have all sorts of extra information stored in them to help with debugging and tuning. - rcu_head is no longer tied to slab in case anyone else wants to free pages by RCU. - slub's counters no longer share space with _refcount. - slub's freelist+counters are now naturally dword aligned. - slub loses a parameter to a lot of functions and a sysfs file. This patch (of 17): s390 borrows the storage used for _mapcount in struct page in order to account whether the bottom or top half is being used for 2kB page tables. I want to use that for something else, so use the top byte of _refcount instead of the bottom byte of _mapcount. _refcount may temporarily be incremented by other CPUs that see a stale pointer to this page in the page cache, but each CPU can only increment it by one, and there are no systems with 2^24 CPUs today, so they will not change the upper byte of _refcount. We do have to be a little careful not to lose any of their writes (as they will subsequently decrement the counter). Link: http://lkml.kernel.org/r/20180518194519.3820-2-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Christoph Lameter <cl@linux.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1caf170d |
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13-Jun-2017 |
Heiko Carstens <hca@linux.ibm.com> |
s390/mm: provide base_asce_alloc() / base_asce_free() helper functions Provide base_asce_alloc() and base_asce_free() helper functions which can be used to allocate an ASCE and all required region, segment and page tables required to access memory regions of the virtual kernel address space. Both, the ASCE and all tables, do not use any features that correspond to e.g. enhanced DAT features. This is required for some I/O functions that pass an ASCE, like e.g. some service call requests, but which may not use any enhanced features. Acked-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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8d306f53 |
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04-Dec-2017 |
Heiko Carstens <hca@linux.ibm.com> |
s390/mm: fix off-by-one bug in 5-level page table handling Martin Cermak reported that setting a uprobe doesn't work. Reason for this is that the common uprobes code tries to get an unmapped area at the last possible page within an address space. This broke with commit 1aea9b3f9210 ("s390/mm: implement 5 level pages tables") which introduced an off-by-one bug which prevents to map anything at the last possible page within an address space. The check with the off-by-one bug however can be removed since with commit 8ab867cb0806 ("s390/mm: fix BUG_ON in crst_table_upgrade") the necessary check is done at both call sites. Reported-by: Martin Cermak <mcermak@redhat.com> Bisected-by: Thomas Richter <tmricht@linux.vnet.ibm.com> Fixes: 1aea9b3f9210 ("s390/mm: implement 5 level pages tables") Cc: <stable@vger.kernel.org> # v4.13+ Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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0aaba41b |
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21-Aug-2017 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390: remove all code using the access register mode The vdso code for the getcpu() and the clock_gettime() call use the access register mode to access the per-CPU vdso data page with the current code. An alternative to the complicated AR mode is to use the secondary space mode. This makes the vdso faster and quite a bit simpler. The downside is that the uaccess code has to be changed quite a bit. Which instructions are used depends on the machine and what kind of uaccess operation is requested. The instruction dictates which ASCE value needs to be loaded into %cr1 and %cr7. The different cases: * User copy with MVCOS for z10 and newer machines The MVCOS instruction can copy between the primary space (aka user) and the home space (aka kernel) directly. For set_fs(KERNEL_DS) the kernel ASCE is loaded into %cr1. For set_fs(USER_DS) the user space is already loaded in %cr1. * User copy with MVCP/MVCS for older machines To be able to execute the MVCP/MVCS instructions the kernel needs to switch to primary mode. The control register %cr1 has to be set to the kernel ASCE and %cr7 to either the kernel ASCE or the user ASCE dependent on set_fs(KERNEL_DS) vs set_fs(USER_DS). * Data access in the user address space for strnlen / futex To use "normal" instruction with data from the user address space the secondary space mode is used. The kernel needs to switch to primary mode, %cr1 has to contain the kernel ASCE and %cr7 either the user ASCE or the kernel ASCE, dependent on set_fs. To load a new value into %cr1 or %cr7 is an expensive operation, the kernel tries to be lazy about it. E.g. for multiple user copies in a row with MVCP/MVCS the replacement of the vdso ASCE in %cr7 with the user ASCE is done only once. On return to user space a CPU bit is checked that loads the vdso ASCE again. To enable and disable the data access via the secondary space two new functions are added, enable_sacf_uaccess and disable_sacf_uaccess. The fact that a context is in secondary space uaccess mode is stored in the mm_segment_t value for the task. The code of an interrupt may use set_fs as long as it returns to the previous state it got with get_fs with another call to set_fs. The code in finish_arch_post_lock_switch simply has to do a set_fs with the current mm_segment_t value for the task. For CPUs with MVCOS: CPU running in | %cr1 ASCE | %cr7 ASCE | --------------------------------------|-----------|-----------| user space | user | vdso | kernel, USER_DS, normal-mode | user | vdso | kernel, USER_DS, normal-mode, lazy | user | user | kernel, USER_DS, sacf-mode | kernel | user | kernel, KERNEL_DS, normal-mode | kernel | vdso | kernel, KERNEL_DS, normal-mode, lazy | kernel | kernel | kernel, KERNEL_DS, sacf-mode | kernel | kernel | For CPUs without MVCOS: CPU running in | %cr1 ASCE | %cr7 ASCE | --------------------------------------|-----------|-----------| user space | user | vdso | kernel, USER_DS, normal-mode | user | vdso | kernel, USER_DS, normal-mode lazy | kernel | user | kernel, USER_DS, sacf-mode | kernel | user | kernel, KERNEL_DS, normal-mode | kernel | vdso | kernel, KERNEL_DS, normal-mode, lazy | kernel | kernel | kernel, KERNEL_DS, sacf-mode | kernel | kernel | The lines with "lazy" refer to the state after a copy via the secondary space with a delayed reload of %cr1 and %cr7. There are three hardware address spaces that can cause a DAT exception, primary, secondary and home space. The exception can be related to four different fault types: user space fault, vdso fault, kernel fault, and the gmap faults. Dependent on the set_fs state and normal vs. sacf mode there are a number of fault combinations: 1) user address space fault via the primary ASCE 2) gmap address space fault via the primary ASCE 3) kernel address space fault via the primary ASCE for machines with MVCOS and set_fs(KERNEL_DS) 4) vdso address space faults via the secondary ASCE with an invalid address while running in secondary space in problem state 5) user address space fault via the secondary ASCE for user-copy based on the secondary space mode, e.g. futex_ops or strnlen_user 6) kernel address space fault via the secondary ASCE for user-copy with secondary space mode with set_fs(KERNEL_DS) 7) kernel address space fault via the primary ASCE for user-copy with secondary space mode with set_fs(USER_DS) on machines without MVCOS. 8) kernel address space fault via the home space ASCE Replace user_space_fault() with a new function get_fault_type() that can distinguish all four different fault types. With these changes the futex atomic ops from the kernel and the strnlen_user will get a little bit slower, as well as the old style uaccess with MVCP/MVCS. All user accesses based on MVCOS will be as fast as before. On the positive side, the user space vdso code is a lot faster and Linux ceases to use the complicated AR mode. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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b2441318 |
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01-Nov-2017 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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41879ff6 |
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04-Oct-2017 |
Heiko Carstens <hca@linux.ibm.com> |
s390/mm: use memset64 instead of clear_table Use memset64 instead of the (now) open-coded variant clear_table. Performance wise there is no difference. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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#
f28a4b4d |
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17-Aug-2017 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: use a single lock for the fields in mm_context_t The three locks 'lock', 'pgtable_lock' and 'gmap_lock' in the mm_context_t can be reduced to a single lock. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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#
2fc4876e |
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31-Aug-2017 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: use VM_BUG_ON in crst_table_[upgrade|downgrade] The BUG_ON in crst_table_[upgrade|downgrade] is a debugging aid, replace it with VM_BUG_ON. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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#
f1c1174f |
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04-Jul-2017 |
Heiko Carstens <hca@linux.ibm.com> |
s390/mm: use new mm defines instead of magic values Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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#
c9b5ad54 |
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13-Jun-2016 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: tag normal pages vs pages used in page tables The ESSA instruction has a new option that allows to tag pages that are not used as a page table. Without the tag the hypervisor has to assume that any guest page could be used in a page table inside the guest. This forces the hypervisor to flush all guest TLB entries whenever a host page table entry is invalidated. With the tag the host can skip the TLB flush if the page is tagged as normal page. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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#
1aea9b3f |
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24-Apr-2017 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: implement 5 level pages tables Add the logic to upgrade the page table for a 64-bit process to five levels. This increases the TASK_SIZE from 8PB to 16EB-4K. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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#
ee71d16d |
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20-Apr-2017 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: make TASK_SIZE independent from the number of page table levels The TASK_SIZE for a process should be maximum possible size of the address space, 2GB for a 31-bit process and 8PB for a 64-bit process. The number of page table levels required for a given memory layout is a consequence of the mapped memory areas and their location. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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faee35a5 |
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07-Mar-2017 |
Michal Hocko <mhocko@suse.com> |
s390: get rid of superfluous __GFP_REPEAT __GFP_REPEAT has a rather weak semantic but since it has been introduced around 2.6.12 it has been ignored for low order allocations. page_table_alloc then uses the flag for a single page allocation. This means that this flag has never been actually useful here because it has always been used only for PAGE_ALLOC_COSTLY requests. An earlier attempt to remove the flag 10d58bf297e2 ("s390: get rid of superfluous __GFP_REPEAT") has missed this one but the situation is very same here. Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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#
10d58bf2 |
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24-Jun-2016 |
Michal Hocko <mhocko@suse.com> |
s390: get rid of superfluous __GFP_REPEAT __GFP_REPEAT has a rather weak semantic but since it has been introduced around 2.6.12 it has been ignored for low order allocations. page_table_alloc then uses the flag for a single page allocation. This means that this flag has never been actually useful here because it has always been used only for PAGE_ALLOC_COSTLY requests. Link: http://lkml.kernel.org/r/1464599699-30131-14-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
4be130a0 |
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07-Mar-2016 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: add shadow gmap support For a nested KVM guest the outer KVM host needs to create shadow page tables for the nested guest. This patch adds the basic support to the guest address space (gmap) code. For each guest address space the inner KVM host creates, the first outer KVM host needs to create shadow page tables. The address space is identified by the ASCE loaded into the control register 1 at the time the inner SIE instruction for the second nested KVM guest is executed. The outer KVM host creates the shadow tables starting with the table identified by the ASCE on a on-demand basis. The outer KVM host will get repeated faults for all the shadow tables needed to run the second KVM guest. While a shadow page table for the second KVM guest is active the access to the origin region, segment and page tables needs to be restricted for the first KVM guest. For region and segment and page tables the first KVM guest may read the memory, but write attempt has to lead to an unshadow. This is done using the page invalid and read-only bits in the page table of the first KVM guest. If the first guest re-accesses one of the origin pages of a shadow, it gets a fault and the affected parts of the shadow page table hierarchy needs to be removed again. PGSTE tables don't have to be shadowed, as all interpretation assist can't deal with the invalid bits in the shadow pte being set differently than the original ones provided by the first KVM guest. Many bug fixes and improvements by David Hildenbrand. Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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#
8ecb1a59 |
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08-Mar-2016 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: use RCU for gmap notifier list and the per-mm gmap list The gmap notifier list and the gmap list in the mm_struct change rarely. Use RCU to optimize the reader of these lists. Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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723cacbd |
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15-Apr-2016 |
Gerald Schaefer <gerald.schaefer@linux.ibm.com> |
s390/mm: fix asce_bits handling with dynamic pagetable levels There is a race with multi-threaded applications between context switch and pagetable upgrade. In switch_mm() a new user_asce is built from mm->pgd and mm->context.asce_bits, w/o holding any locks. A concurrent mmap with a pagetable upgrade on another thread in crst_table_upgrade() could already have set new asce_bits, but not yet the new mm->pgd. This would result in a corrupt user_asce in switch_mm(), and eventually in a kernel panic from a translation exception. Fix this by storing the complete asce instead of just the asce_bits, which can then be read atomically from switch_mm(), so that it either sees the old value or the new value, but no mixture. Both cases are OK. Having the old value would result in a page fault on access to the higher level memory, but the fault handler would see the new mm->pgd, if it was a valid access after the mmap on the other thread has completed. So as worst-case scenario we would have a page fault loop for the racing thread until the next time slice. Also remove dead code and simplify the upgrade/downgrade path, there are no upgrades from 2 levels, and only downgrades from 3 levels for compat tasks. There are also no concurrent upgrades, because the mmap_sem is held with down_write() in do_mmap, so the flush and table checks during upgrade can be removed. Reported-by: Michael Munday <munday@ca.ibm.com> Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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#
1e133ab2 |
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08-Mar-2016 |
Martin Schwidefsky <schwidefsky@de.ibm.com> |
s390/mm: split arch/s390/mm/pgtable.c The pgtable.c file is quite big, before it grows any larger split it into pgtable.c, pgalloc.c and gmap.c. In addition move the gmap related header definitions into the new gmap.h header and all of the pgste helpers from pgtable.h to pgtable.c. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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