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bac4cffc |
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25-Sep-2023 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Introduce _PAGE_READ and remove _PAGE_USER On 603 MMU, TLB missed are handled by SW and there are separated DTLB and ITLB. It is therefore possible to implement execute-only protection by not loading DTLB when read access is not permitted. To do that, _PAGE_READ flag is needed but there is no bit available for it in PTE. On the other hand the only real use of _PAGE_USER is to implement PAGE_NONE by clearing _PAGE_USER. As _PAGE_NONE can also be implemented by clearing _PAGE_READ, remove _PAGE_USER and add _PAGE_READ. Then use the virtual address to know whether user rights or kernel rights are to be used. With that change, 603 MMU now honors execute-only protection. For 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/b7702dd5a041ec59055ed2880f4952e94c087a2e.1695659959.git.christophe.leroy@csgroup.eu
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46ebef51 |
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25-Sep-2023 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Add _PAGE_WRITE to supplement _PAGE_RW Several places, _PAGE_RW maps to write permission and don't always imply read. To make it more clear, do as book3s/64 in commit c7d54842deb1 ("powerpc/mm: Use _PAGE_READ to indicate Read access") and use _PAGE_WRITE when more relevant. For the time being _PAGE_WRITE is equivalent to _PAGE_RW but that will change when _PAGE_READ gets added in following patches. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/5798782869fe4d2698f104948dabd17657b89395.1695659959.git.christophe.leroy@csgroup.eu
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3eb3f168 |
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06-Aug-2023 |
Masahiro Yamada <masahiroy@kernel.org> |
powerpc: remove unneeded #include <asm/export.h> There is no EXPORT_SYMBOL line there, hence #include <asm/export.h> is unneeded. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230806150954.394189-1-masahiroy@kernel.org
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90f1b431 |
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27-Nov-2022 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: allow minimum sized kernel stack frames This affects only 64-bit ELFv2 kernels, and reduces the minimum asm-created stack frame size from 112 to 32 byte on those kernels. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-16-npiggin@gmail.com
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2da37761 |
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14-Nov-2022 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Fix objtool unannotated intra-function call warnings Fix several annotations in assembly files on PPC32. [Sathvika Vasireddy: Changed subject line and removed Kconfig change to enable objtool, as it is a part of "objtool/powerpc: Enable objtool to be built on ppc" patch in this series.] Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221114175754.1131267-7-sv@linux.ibm.com
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2a0fb3c1 |
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13-Jun-2022 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Set an IBAT covering up to _einittext during init Always set an IBAT covering up to _einittext during init because when CONFIG_MODULES is not selected there is no reason to have an exception handler for kernel instruction TLB misses. It implies DBAT and IBAT are now totaly independent, IBATs are set by setibat() and DBAT by setbat(). This allows to revert commit 9bb162fa26ed ("powerpc/603: Fix boot failure with DEBUG_PAGEALLOC and KFENCE") Reported-by: Maxime Bizon <mbizon@freebox.fr> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/ce7f04a39593934d9b1ee68c69144ccd3d4da4a1.1655202804.git.christophe.leroy@csgroup.eu
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27e21e8f |
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30-Nov-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Remove _ENTRY() macro _ENTRY() is now redundant with _GLOBAL(). Remove it. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/62a35f8dde2bb74c8d0d7a5430cce07a5a3a6fb6.1638273868.git.christophe.leroy@csgroup.eu
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12318163 |
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30-Nov-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Remove remaining .stabs annotations STABS debug format has been superseded long time ago by DWARF. Remove the few remaining .stabs annotations from old 32 bits code. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/68932ec2ba6b868d35006b96e90f0890f3da3c05.1638273868.git.christophe.leroy@csgroup.eu
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4634bf44 |
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31-Jan-2022 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/603: Clear C bit when PTE is read only On book3s/32 MMU, PP bits don't offer kernel RO protection, kernel pages are always RW. However, on the 603 a page fault is always generated when the C bit (change bit = dirty bit) is not set. Enforce kernel RO protection by clearing C bit in TLB miss handler when the page doesn't have _PAGE_RW flag. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/bbb13848ff0100a76ee9ea95118058c30ae95f2c.1643613343.git.christophe.leroy@csgroup.eu
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9872cbfb |
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31-Jan-2022 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/603: Remove outdated comment Since commit 84de6ab0e904 ("powerpc/603: don't handle PAGE_ACCESSED in TLB miss handlers.") page table is not updated anymore by TLB miss handlers. Remove the comment. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/38b1ffefd2146fa56bf8aa605d476ad9736bbb37.1643613296.git.christophe.leroy@csgroup.eu
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9bb162fa |
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06-Dec-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/603: Fix boot failure with DEBUG_PAGEALLOC and KFENCE Allthough kernel text is always mapped with BATs, we still have inittext mapped with pages, so TLB miss handling is required when CONFIG_DEBUG_PAGEALLOC or CONFIG_KFENCE is set. The final solution should be to set a BAT that also maps inittext but that BAT then needs to be cleared at end of init, and it will require more changes to be able to do it properly. As DEBUG_PAGEALLOC or KFENCE are debugging, performance is not a big deal so let's fix it simply for now to enable easy stable application. Fixes: 035b19a15a98 ("powerpc/32s: Always map kernel text and rodata with BATs") Cc: stable@vger.kernel.org # v5.11+ Reported-by: Maxime Bizon <mbizon@freebox.fr> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/aea33b4813a26bdb9378b5f273f00bd5d4abe240.1638857364.git.christophe.leroy@csgroup.eu
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526d4a4c |
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19-Oct-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Do kuep_lock() and kuep_unlock() in assembly When interrupt and syscall entries where converted to C, KUEP locking and unlocking was also converted. It improved performance by unrolling the loop, and allowed easily implementing boot time deactivation of KUEP. However, null_syscall selftest shows that KUEP is still heavy (361 cycles with KUEP, 212 cycles without). A way to improve more is to group 'mtsr's together, instead of repeating 'addi' + 'mtsr' several times. In order to do that, more registers need to be available. In C, GCC will always be able to provide the requested number of registers, but at the cost of saving some data on the stack, which is counter performant here. So let's do it in assembly, when we have full control of which register can be used. It also has the advantage of locking earlier and unlocking later and it helps GCC generating less tricky code. The only drawback is to make boot time deactivation less straight forward and require 'hand' instruction patching. Group 'mtsr's by 4. With this change, null_syscall selftest reports 336 cycles. Without the change it was 361 cycles, that's a 7% reduction. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/115cb279e9b9948dfd93a065e047081c59e3a2a6.1634627931.git.christophe.leroy@csgroup.eu
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62376365 |
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03-Aug-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Fix napping restore in data storage interrupt (DSI) When a DSI (Data Storage Interrupt) is taken while in NAP mode, r11 doesn't survive the call to power_save_ppc32_restore(). So use r1 instead of r11 as they both contain the virtual stack pointer at that point. Fixes: 4c0104a83fc3 ("powerpc/32: Dismantle EXC_XFER_STD/LITE/TEMPLATE") Cc: stable@vger.kernel.org # v5.13+ Reported-by: Finn Thain <fthain@linux-m68k.org> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/731694e0885271f6ee9ffc179eb4bcee78313682.1628003562.git.christophe.leroy@csgroup.eu
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56afad88 |
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04-Jun-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc: Remove klimit klimit is a global variable initialised at build time with the value of _end. This variable is never modified, so _end symbol can be used directly. Remove klimit. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/9fa9ba6807c17f93f35a582c199c646c4a8bfd9c.1622800638.git.christophe.leroy@csgroup.eu
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e72421a0 |
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07-Jun-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc: Define swapper_pg_dir[] in C Don't duplicate swapper_pg_dir[] in each platform's head.S Define it in mm/pgtable.c Define MAX_PTRS_PER_PGD because on book3s/64 PTRS_PER_PGD is not a constant. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/5e3f1b8a4695c33ccc80aa3870e016bef32b85e1.1623063174.git.christophe.leroy@csgroup.eu
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45b30faf |
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07-Jun-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc: Define empty_zero_page[] in C At the time being, empty_zero_page[] is defined in each platform head.S. Define it in mm/mem.c instead, and put it in BSS section instead of the DATA section. Commit 5227cfa71f9e ("arm64: mm: place empty_zero_page in bss") explains why it is interesting to have it in BSS. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/5838caffa269e0957c5a50cc85477876220298b0.1623063174.git.christophe.leroy@csgroup.eu
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86f46f34 |
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03-Jun-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Initialise KUAP and KUEP in C In order to selectively activate KUAP and KUEP in a following patch, perform KUAP and KUEP initialisation in C. Unlike PPC64, PPC32 doesn't have an early_setup_secondary(), so do it in start_secondary(). Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/87be72023448dd4e476744ed279b8c04b8d08a1c.1622708530.git.christophe.leroy@csgroup.eu
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863771a2 |
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03-Jun-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Convert switch_mmu_context() to C switch_mmu_context() does things that can easily be done in C. For updating user segments, we have update_user_segments(). As mentionned in commit b5efec00b671 ("powerpc/32s: Move KUEP locking/unlocking in C"), update_user_segments() has the loop unrolled which is a significant performance gain. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/05c0875ad8220c03452c3a334946e207c6ca04d6.1622708530.git.christophe.leroy@csgroup.eu
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70d6ebf8 |
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06-May-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/603: Avoid a pile of NOPs when not using SW LRU in TLB exceptions The SW LRU is in an MMU feature section. When not used, that's a dozen of NOPs to fetch for nothing. Define an ALT section that does the few remaining operations. That also avoids a double read on SRR1 in the SW LRU case. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/603725297466959419628ef7964aaf3417fb647d.1620363691.git.christophe.leroy@csgroup.eu
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3a5988b8 |
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06-May-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Remove m8260_gorom() Last user of m8260_gorom() was removed by Commit 917f0af9e5a9 ("powerpc: Remove arch/ppc and include/asm-ppc") removed last user of m8260_gorom(). In fact m8260_gorom() was ported to arch/powerpc/ but the platform using it died with arch/ppc/ Remove it. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/13f7532f21df3196e8c78b4f82a9c8d5487aca35.1620292185.git.christophe.leroy@csgroup.eu
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7fab6397 |
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19-Apr-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Enhance readability of trap types This patch makes use of trap types in head_book3s_32.S Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/bd80ace67757f489fc4ecdb76dd1a71511daba94.1618847273.git.christophe.leroy@csgroup.eu
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acc142b6 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Remove the xfer parameter in EXCEPTION() macro The xfer parameter is not used anymore, remove it. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/17c7d68bd18f7d2f1ab24a1a20d9ed33bbcda741.1615552867.git.christophe.leroy@csgroup.eu
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4c0104a8 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Dismantle EXC_XFER_STD/LITE/TEMPLATE In order to get more control in exception prolog, dismantle all non standard exception macros, finishing with EXC_XFER_STD and EXC_XFER_LITE and EXC_XFER_TEMPLATE. Also remove transfer_to_handler_full and ret_from_except and ret_from_except_full as they are not used anymore. Last parameter of EXCEPTION() is now ignored, will be removed in a later patch to avoid too much churn. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/ca5795d04a220586b7037dbbbe6951dfa9e768eb.1615552867.git.christophe.leroy@csgroup.eu
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8f6ff5bd |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Only restore non volatile registers when required Until now, non volatile registers were restored everytime they were saved, ie using EXC_XFER_STD meant saving and restoring them while EXC_XFER_LITE meant neither saving not restoring them. Now that they are always saved, EXC_XFER_STD means to restore them and EXC_XFER_LITE means to not restore them. Most of the users of EXC_XFER_STD only need to retrieve the non volatile registers. For them there is no need to restore the non volatile registers as they have not been modified. Only very few exceptions require non volatile registers restore. Opencode the few places which require saving of non volatile registers. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/d1cb12d8023cc6afc1f07150565571373c04945c.1615552867.git.christophe.leroy@csgroup.eu
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719e7e21 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Save trap number on stack in exception prolog Saving the trap number into the stack goes into the exception prolog, as EXC_XFER_xxx will soon disappear. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/2ac7a0c9cde2ec2b23cd79e3a54cfedd816a91ae.1615552867.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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e7291556 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Set regs parameter in r3 in transfer_to_handler All exception handlers take regs as first parameter. Instead of setting r3 just before each call to a handler, set it in transfer_to_handler. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/f994a379bb895a2cbd518cb82460ad3f3d3ccdf5.1615552867.git.christophe.leroy@csgroup.eu
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8f844c06 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Provide a name to exception prolog continuation in virtual mode Now that the prolog continuation is separated in .text, give it a name and mark it _ASM_NOKPROBE_SYMBOL. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/d96374218815a6627e1e922ab2aba994050fb87a.1615552867.git.christophe.leroy@csgroup.eu
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dc13b889 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Move exception prolog code into .text once MMU is back on The space in the head section is rather constrained by the fact that exception vectors are spread every 0x100 bytes and sometimes we need to have "out of line" code because it doesn't fit. Now that we are enabling MMU early in the prolog, take that opportunity to jump somewhere else in the .text section where we don't have any space constraint. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/38b31ca4bc782a4985bc7952a675404d7ff27c24.1615552867.git.christophe.leroy@csgroup.eu
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7bf1d7e1 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Use START_EXCEPTION() as much as possible Everywhere where it is possible, use START_EXCEPTION(). This will help for proper exception init in future patches. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/d47c1cc242bbbef8658327503726abdaef9b63ef.1615552867.git.christophe.leroy@csgroup.eu
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5b5e5bc5 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Add vmap_stack_overflow label inside the macro For consistency, add in the macro the label used by exception prolog to branch to stack overflow processing. While at it, enclose the macro in #ifdef CONFIG_VMAP_STACK on the 8xx as already done on book3s/32. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/cf80056f5b946572ad98aea9d915dd25b23beda6.1615552867.git.christophe.leroy@csgroup.eu
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7aa8dd67 |
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11-Mar-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Always enable data translation in exception prolog If the code can use a stack in vm area, it can also use a stack in linear space. Simplify code by removing old non VMAP stack code on PPC32. That means the data translation is now re-enabled early in exception prolog in all cases, not only when using VMAP stacks. While we are touching EXCEPTION_PROLOG macros, remove the unused for_rtas parameter in EXCEPTION_PROLOG_1. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/7cd6440c60a7e8f4f035b245c57720f51e225aae.1615552866.git.christophe.leroy@csgroup.eu
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c119565a |
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31-Jan-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/603: Fix protection of user pages mapped with PROT_NONE On book3s/32, page protection is defined by the PP bits in the PTE which provide the following protection depending on the access keys defined in the matching segment register: - PP 00 means RW with key 0 and N/A with key 1. - PP 01 means RW with key 0 and RO with key 1. - PP 10 means RW with both key 0 and key 1. - PP 11 means RO with both key 0 and key 1. Since the implementation of kernel userspace access protection, PP bits have been set as follows: - PP00 for pages without _PAGE_USER - PP01 for pages with _PAGE_USER and _PAGE_RW - PP11 for pages with _PAGE_USER and without _PAGE_RW For kernelspace segments, kernel accesses are performed with key 0 and user accesses are performed with key 1. As PP00 is used for non _PAGE_USER pages, user can't access kernel pages not flagged _PAGE_USER while kernel can. For userspace segments, both kernel and user accesses are performed with key 0, therefore pages not flagged _PAGE_USER are still accessible to the user. This shouldn't be an issue, because userspace is expected to be accessible to the user. But unlike most other architectures, powerpc implements PROT_NONE protection by removing _PAGE_USER flag instead of flagging the page as not valid. This means that pages in userspace that are not flagged _PAGE_USER shall remain inaccessible. To get the expected behaviour, just mimic other architectures in the TLB miss handler by checking _PAGE_USER permission on userspace accesses as if it was the _PAGE_PRESENT bit. Note that this problem only is only for 603 cores. The 604+ have an hash table, and hash_page() function already implement the verification of _PAGE_USER permission on userspace pages. Fixes: f342adca3afc ("powerpc/32s: Prepare Kernel Userspace Access Protection") Cc: stable@vger.kernel.org # v5.2+ Reported-by: Christoph Plattner <christoph.plattner@thalesgroup.com> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/4a0c6e3bb8f0c162457bf54d9bc6fd8d7b55129f.1612160907.git.christophe.leroy@csgroup.eu
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3642eb21 |
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08-Feb-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32: Preserve cr1 in exception prolog stack check to fix build error THREAD_ALIGN_SHIFT = THREAD_SHIFT + 1 = PAGE_SHIFT + 1 Maximum PAGE_SHIFT is 18 for 256k pages so THREAD_ALIGN_SHIFT is 19 at the maximum. No need to clobber cr1, it can be preserved when moving r1 into CR when we check stack overflow. This reduces the number of instructions in Machine Check Exception prolog and fixes a build failure reported by the kernel test robot on v5.10 stable when building with RTAS + VMAP_STACK + KVM. That build failure is due to too many instructions in the prolog hence not fitting between 0x200 and 0x300. Allthough the problem doesn't show up in mainline, it is still worth the change. Fixes: 98bf2d3f4970 ("powerpc/32s: Fix RTAS machine check with VMAP stack") Cc: stable@vger.kernel.org Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/5ae4d545e3ac58e133d2599e0deb88843cb494fc.1612768623.git.christophe.leroy@csgroup.eu
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6c6aee00 |
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30-Jan-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: add and use unknown_async_exception This is currently the same as unknown_exception, but it will diverge after interrupt wrappers are added and code moved out of asm into the wrappers (e.g., async handlers will check FINISH_NAP). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-22-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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7a24ae2e |
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30-Jan-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: move DABR match out of handle_page_fault handle_page_fault() has some code dedicated to book3s/32 to call do_break() when the DSI is a DABR match. On other platforms, do_break() is handled separately. Do the same for book3s/32, do it earlier in the process of DSI. This change also avoid doing the test on ISI. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210130130852.2952424-4-npiggin@gmail.com
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259149cf |
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17-Dec-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Only build hash code when CONFIG_PPC_BOOK3S_604 is selected It is now possible to only build book3s/32 kernel for CPUs without hash table. Opt out hash related code when CONFIG_PPC_BOOK3S_604 is not selected. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/62df436454ef06e104cc334a0859a2878d7888d5.1608274548.git.christophe.leroy@csgroup.eu
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98bf2d3f |
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22-Dec-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Fix RTAS machine check with VMAP stack When we have VMAP stack, exception prolog 1 sets r1, not r11. When it is not an RTAS machine check, don't trash r1 because it is needed by prolog 1. Fixes: da7bb43ab9da ("powerpc/32: Fix vmap stack - Properly set r1 before activating MMU") Fixes: d2e006036082 ("powerpc/32: Use SPRN_SPRG_SCRATCH2 in exception prologs") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> [mpe: Squash in fixup for RTAS machine check from Christophe] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/bc77d61d1c18940e456a2dee464f1e2eda65a3f0.1608621048.git.christophe.leroy@csgroup.eu
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1b03e71f |
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16-Nov-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Handle PROTFAULT in hash_page() also for CONFIG_PPC_KUAP On hash 32 bits, handling minor protection faults like unsetting dirty flag is heavy if done from the normal page_fault processing, because it implies hash table software lookup for flushing the entry and then a DSI is taken anyway to add the entry back. When KUAP was implemented, as explained in commit a68c31fc01ef ("powerpc/32s: Implement Kernel Userspace Access Protection"), protection faults has been diverted from hash_page() because hash_page() was not able to identify a KUAP fault. Implement KUAP verification in hash_page(), by clearing write permission when the access is a kernel access and Ks is 1. This works regardless of the address because kernel segments always have Ks set to 0 while user segments have Ks set to 0 only when kernel write to userspace is granted. Then protection faults can be handled by hash_page() even for KUAP. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/8a4ffe4798e9ea32aaaccdf85e411bb1beed3500.1605542955.git.christophe.leroy@csgroup.eu
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4b74a35f |
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22-Oct-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Make Hash var static Hash var is used only locally in mmu.c now. No need to set it in head_32.S anymore. Make it static and initialises it to the early hash table. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/786c82a89cdfdaabb32b72a44f7c312fa81d192b.1603348103.git.christophe.leroy@csgroup.eu
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de1cd079 |
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25-Nov-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Use SPRN_SPRG_SCRATCH2 in DSI prolog Use SPRN_SPRG_SCRATCH2 as an alternative scratch register in the early part of DSI prolog in order to avoid clobbering SPRN_SPRG_SCRATCH0/1 used by other prologs. The 603 doesn't like a jump from DataLoadTLBMiss to the 10 nops that are now in the beginning of DSI exception as a result of the feature section. To workaround this, add a jump as alternative. It also avoids fetching 10 nops for nothing. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/f9f8df2a2be93568768ef1ac793639f7914cf103.1606285014.git.christophe.leroy@csgroup.eu
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c4a22611 |
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25-Nov-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/603: Use SPRN_SDR1 to store the pgdir phys address On the 603, SDR1 is not used. In order to free SPRN_SPRG2, use SPRN_SDR1 to store the pgdir phys addr. But only some bits of SDR1 can be used (0xffff01ff). As the pgdir is 4k aligned, rotate it by 4 bits to the left. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/7370574b49d8476878ce5480726197993cb76108.1606285014.git.christophe.leroy@csgroup.eu
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7b107a71 |
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25-Nov-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Fix an FTR_SECTION_ELSE An FTR_SECTION_ELSE is in the middle of BEGIN_MMU_FTR_SECTION/ALT_MMU_FTR_SECTION_END_IFSET Change it to MMU_FTR_SECTION_ELSE Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/61790f1a91692950a6bb5bb53d6d514d9bcdad74.1606285014.git.christophe.leroy@csgroup.eu
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035b19a1 |
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25-Nov-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Always map kernel text and rodata with BATs Since commit 2b279c0348af ("powerpc/32s: Allow mapping with BATs with DEBUG_PAGEALLOC"), there is no real situation where mapping without BATs is required. In order to simplify memory handling, always map kernel text and rodata with BATs even when "nobats" kernel parameter is set. Also fix the 603 TLB miss exceptions that don't require anymore kernel page table if DEBUG_PAGEALLOC. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/da51f7ec632825a4ce43290a904aad61648408c0.1606285013.git.christophe.leroy@csgroup.eu
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7d68c891 |
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18-Aug-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Allow deselecting CONFIG_PPC_FPU on mpc832x The e300c2 core which is embedded in mpc832x CPU doesn't have an FPU. Make it possible to not select CONFIG_PPC_FPU when building a kernel dedicated to that target. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/fcdc60d85baf80eaa0a7f3261d9d889282068216.1597770847.git.christophe.leroy@csgroup.eu
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120c0518 |
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08-Nov-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc: Replace RFI by rfi on book3s/32 and booke For book3s/32 and for booke, RFI is just an rfi. Only 40x has a non trivial RFI. CONFIG_PPC_RTAS is never selected by 40x platforms. Make it more explicit by replacing RFI by rfi wherever possible. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/b901ddfdeb8a0a3b7cb59999599cdfde1bbfe834.1604854583.git.christophe.leroy@csgroup.eu
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01776f07 |
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07-Nov-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Use relocation offset when setting early hash table When calling early_hash_table(), the kernel hasn't been yet relocated to its linking address, so data must be addressed with relocation offset. Add relocation offset to write into Hash in early_hash_table(). Fixes: 69a1593abdbc ("powerpc/32s: Setup the early hash table at all time.") Reported-by: Erhard Furtner <erhard_f@mailbox.org> Reported-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Tested-by: Serge Belyshev <belyshev@depni.sinp.msu.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/9e225a856a8b22e0e77587ee22ab7a2f5bca8753.1604740029.git.christophe.leroy@csgroup.eu
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11522448 |
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10-Oct-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/603: Always fault when _PAGE_ACCESSED is not set The kernel expects pte_young() to work regardless of CONFIG_SWAP. Make sure a minor fault is taken to set _PAGE_ACCESSED when it is not already set, regardless of the selection of CONFIG_SWAP. Fixes: 84de6ab0e904 ("powerpc/603: don't handle PAGE_ACCESSED in TLB miss handlers.") Cc: stable@vger.kernel.org Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/a44367744de54e2315b2f1a8cbbd7f88488072e0.1602342806.git.christophe.leroy@csgroup.eu
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86541879 |
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06-Oct-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Remove #ifdef CONFIG_PPC_BOOK3S_32 in head_book3s_32.S head_book3s_32.S is only built when CONFIG_PPC_BOOK3S_32 is selected. Remove all conditions based on CONFIG_PPC_BOOK3S_32 in the file. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1b68632425d8866d147aea9005004e4594672211.1601975100.git.christophe.leroy@csgroup.eu
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533090e5 |
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06-Oct-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/32s: Rename head_32.S to head_book3s_32.S Unlike PPC64 which had a single head_64.S, PPC32 are multiple ones. There is the head_32.S, selected by default based on the value of BITS and overridden based on some CONFIG_ values. This leads to thinking that it may be selected by different types of PPC32 platform but indeed it ends up being selected by book3s/32 only. Make that explicit by: - Not doing any default selection based on BITS. - Renaming head_32.S to head_book3s_32.S. - Get head_book3s_32.S selected only by CONFIG_PPC_BOOK3S_32. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> [mpe: Fix head_$(BITS).o reference in arch/powerpc/Makefile] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/319d379f696412681c66a987cc75e6abf8f958d2.1601975100.git.christophe.leroy@csgroup.eu
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