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2020-05-11powerpc/vdso32: Fallback on getres syscall when clock is unknownChristophe Leroy1-3/+3
There are other clocks than the standard ones, for instance per process clocks. Therefore, being above the last standard clock doesn't mean it is a bad clock. So, fallback to syscall instead of returning -EINVAL inconditionaly. Fixes: e33ffc956b08 ("powerpc/vdso32: implement clock_getres entirely") Cc: stable@vger.kernel.org # v5.6+ Reported-by: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Aurelien Jarno <aurelien@aurel32.net> Link: https://lore.kernel.org/r/7316a9e2c0c2517923eb4b0411c4a08d15e675a4.1589017281.git.christophe.leroy@csgroup.eu
2020-03-25.gitignore: add SPDX License IdentifierMasahiro Yamada1-0/+1
Add SPDX License Identifier to all .gitignore files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23powerpc/vdso32: miscellaneous optimisationsChristophe Leroy3-14/+13
Various optimisations by inverting branches and removing redundant instructions. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/b4e79f963845545bcce1459cd6fcfe46bdde7863.1575273217.git.christophe.leroy@c-s.fr
2020-01-23powerpc/vdso32: implement clock_getres entirelyChristophe Leroy1-8/+11
clock_getres returns hrtimer_res for all clocks but coarse ones for which it returns KTIME_LOW_RES. return EINVAL for unknown clocks. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/37f94e47c91070b7606fb3ec3fe6fd2302a475a0.1575273217.git.christophe.leroy@c-s.fr
2020-01-23powerpc/vdso32: use LOAD_REG_IMMEDIATE()Christophe Leroy1-4/+2
Use LOAD_REG_IMMEDIATE() to load registers with immediate value. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/36f111437e66e601929308f5d5dce230e1ce472f.1575273217.git.christophe.leroy@c-s.fr
2020-01-23powerpc/vdso32: Don't read cache line size from the datapage on PPC32.Christophe Leroy1-0/+23
On PPC32, the cache lines have a fixed size known at build time. Don't read it from the datapage. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/dfa7b35e27e01964fcda84bf1ed8b2b31cf93826.1575273217.git.christophe.leroy@c-s.fr
2020-01-23powerpc/vdso32: inline __get_datapage()Christophe Leroy3-37/+12
__get_datapage() is only a few instructions to retrieve the address of the page where the kernel stores data to the VDSO. By inlining this function into its users, a bl/blr pair and a mflr/mtlr pair is avoided, plus a few reg moves. The improvement is noticeable (about 55 nsec/call on an 8xx) vdsotest before the patch: gettimeofday: vdso: 731 nsec/call clock-gettime-realtime-coarse: vdso: 668 nsec/call clock-gettime-monotonic-coarse: vdso: 745 nsec/call vdsotest after the patch: gettimeofday: vdso: 677 nsec/call clock-gettime-realtime-coarse: vdso: 613 nsec/call clock-gettime-monotonic-coarse: vdso: 690 nsec/call Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/c39ef7f3dfa25356b01e211d539671f279086c09.1575273217.git.christophe.leroy@c-s.fr
2020-01-23powerpc/vdso32: Add support for CLOCK_{REALTIME/MONOTONIC}_COARSEChristophe Leroy1-7/+57
This is copied and adapted from commit 5c929885f1bb ("powerpc/vdso64: Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE") from Santosh Sivaraj <santosh@fossix.org> Benchmark from vdsotest-all: clock-gettime-realtime: syscall: 3601 nsec/call clock-gettime-realtime: libc: 1072 nsec/call clock-gettime-realtime: vdso: 931 nsec/call clock-gettime-monotonic: syscall: 4034 nsec/call clock-gettime-monotonic: libc: 1213 nsec/call clock-gettime-monotonic: vdso: 1076 nsec/call clock-gettime-realtime-coarse: syscall: 2722 nsec/call clock-gettime-realtime-coarse: libc: 805 nsec/call clock-gettime-realtime-coarse: vdso: 668 nsec/call clock-gettime-monotonic-coarse: syscall: 2949 nsec/call clock-gettime-monotonic-coarse: libc: 882 nsec/call clock-gettime-monotonic-coarse: vdso: 745 nsec/call Additional test passed with: vdsotest -d 30 clock-gettime-monotonic-coarse verify Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://github.com/linuxppc/issues/issues/41 Link: https://lore.kernel.org/r/d1d24a376e396540194eeb85a2efe481e92ade24.1575273217.git.christophe.leroy@c-s.fr
2020-01-23powerpc/32: Add VDSO version of getcpu on non SMPChristophe Leroy3-4/+19
Commit 18ad51dd342a ("powerpc: Add VDSO version of getcpu") added getcpu() for PPC64 only, by making use of a user readable general purpose SPR. PPC32 doesn't have any such SPR. For non SMP, just return CPU id 0 from the VDSO directly. PPC32 doesn't support CONFIG_NUMA so NUMA node is always 0. Before the patch, vdsotest reported: getcpu: syscall: 1572 nsec/call getcpu: libc: 1787 nsec/call getcpu: vdso: not tested Now, vdsotest reports: getcpu: syscall: 1582 nsec/call getcpu: libc: 502 nsec/call getcpu: vdso: 187 nsec/call Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/eaac4b6494ecff1811220fccc895bf282aab884a.1575273217.git.christophe.leroy@c-s.fr
2019-12-05powerpc: Fix vDSO clock_getres()Vincenzo Frascino1-2/+5
clock_getres in the vDSO library has to preserve the same behaviour of posix_get_hrtimer_res(). In particular, posix_get_hrtimer_res() does: sec = 0; ns = hrtimer_resolution; and hrtimer_resolution depends on the enablement of the high resolution timers that can happen either at compile or at run time. Fix the powerpc vdso implementation of clock_getres keeping a copy of hrtimer_resolution in vdso data and using that directly. Fixes: a7f290dad32e ("[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel") Cc: stable@vger.kernel.org Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr> Acked-by: Shuah Khan <skhan@linuxfoundation.org> [chleroy: changed CLOCK_REALTIME_RES to CLOCK_HRTIMER_RES] Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/a55eca3a5e85233838c2349783bcb5164dae1d09.1575273217.git.christophe.leroy@c-s.fr
2019-11-21y2038: fix typo in powerpc vdso "LOPART"Arnd Bergmann1-2/+2
The earlier patch introduced a typo, change LOWPART back to LOPART. Fixes: 176ed98c8a76 ("y2038: vdso: powerpc: avoid timespec references") Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-11-15y2038: vdso: powerpc: avoid timespec referencesArnd Bergmann1-4/+2
As a preparation to stop using 'struct timespec' in the kernel, change the powerpc vdso implementation: - split up the vdso data definition to have equivalent members for seconds and nanoseconds instead of an xtime structure - use timespec64 as an intermediate for the xtime update - change the asm-offsets definition to be based the appropriate fixed-length types This is only a temporary fix for changing the types, in order to actually support a 64-bit safe vdso32 version of clock_gettime(), the entire powerpc vdso should be replaced with the generic lib/vdso/ implementation. If that happens first, this patch becomes obsolete. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-08-28powerpc/32s: drop CPU_FTR_USE_RTC featureChristophe Leroy2-1/+5
CPU_FTR_USE_RTC feature only applies to powerpc601. Drop this feature and replace it with tests on CONFIG_PPC_BOOK3S_601. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/170411e2360861f4a95c21faad43519a08bc4040.1566834712.git.christophe.leroy@c-s.fr
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156Thomas Gleixner1-13/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner4-20/+4
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-01powerpc/vdso: Drop unnecessary cc-ldoptionNick Desaulniers1-3/+2
Towards the goal of removing cc-ldoption, it seems that --hash-style= was added to binutils 2.17.50.0.2 in 2006. The minimal required version of binutils for the kernel according to Documentation/process/changes.rst is 2.20. Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-04-08powerpc/vdso32: fix CLOCK_MONOTONIC on PPC64Christophe Leroy1-1/+1
Commit b5b4453e7912 ("powerpc/vdso64: Fix CLOCK_MONOTONIC inconsistencies across Y2038") changed the type of wtom_clock_sec to s64 on PPC64. Therefore, VDSO32 needs to read it with a 4 bytes shift in order to retrieve the lower part of it. Fixes: b5b4453e7912 ("powerpc/vdso64: Fix CLOCK_MONOTONIC inconsistencies across Y2038") Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-02-23powerpc: Enable kcovAndrew Donnellan1-0/+1
kcov provides kernel coverage data that's useful for fuzzing tools like syzkaller. Wire up kcov support on powerpc. Disable kcov instrumentation on the same files where we currently disable gcov and UBSan instrumentation, plus some additional exclusions which appear necessary to boot on book3e machines. Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Daniel Axtens <dja@axtens.net> # e6500 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-09-14powerpc/vdso: Correct call frame informationAlan Modra2-0/+2
Call Frame Information is used by gdb for back-traces and inserting breakpoints on function return for the "finish" command. This failed when inside __kernel_clock_gettime. More concerning than difficulty debugging is that CFI is also used by stack frame unwinding code to implement exceptions. If you have an app that needs to handle asynchronous exceptions for some reason, and you are unlucky enough to get one inside the VDSO time functions, your app will crash. What's wrong: There is control flow in __kernel_clock_gettime that reaches label 99 without saving lr in r12. CFI info however is interpreted by the unwinder without reference to control flow: It's a simple matter of "Execute all the CFI opcodes up to the current address". That means the unwinder thinks r12 contains the return address at label 99. Disabuse it of that notion by resetting CFI for the return address at label 99. Note that the ".cfi_restore lr" could have gone anywhere from the "mtlr r12" a few instructions earlier to the instruction at label 99. I put the CFI as late as possible, because in general that's best practice (and if possible grouped with other CFI in order to reduce the number of CFI opcodes executed when unwinding). Using r12 as the return address is perfectly fine after the "mtlr r12" since r12 on that code path still contains the return address. __get_datapage also has a CFI error. That function temporarily saves lr in r0, and reflects that fact with ".cfi_register lr,r0". A later use of r0 means the CFI at that point isn't correct, as r0 no longer contains the return address. Fix that too. Signed-off-by: Alan Modra <amodra@gmail.com> Tested-by: Reza Arbab <arbab@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2018-07-18powerpc: Add build salt to the vDSOLaura Abbott1-0/+3
The vDSO needs to have a unique build id in a similar manner to the kernel and modules. Use the build salt macro. Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-06-01powerpc/kbuild: Remove CROSS32 defines from top level powerpc MakefileNicholas Piggin1-4/+11
Switch VDSO32 build over to use CROSS32_COMPILE directly, and have it pass in -m32 after the standard c_flags. This allows endianness overrides to be removed and the endian and bitness flags moved into standard flags variables. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman3-0/+3
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>
2017-08-10powerpc/time: refactor MFTB() to limit number of ifdefsChristophe Leroy1-9/+3
The 8xx cannot access the TBL and TBU registers using mfspr/mtspr It must be accessed using mftb/mftbu Due to this, there is a number of places with #ifdef CONFIG_8xx This patch defines new macros MFTBL(x) and MFTBU(x) on the same model as MFTB(x) and tries to make use of them as much as possible. In arch/powerpc/include/asm/timex.h, we also remove the ifdef for the asm() operands as the compiler doesn't mind unused operands Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10powerpc/vdso: Fix build rules to rebuild vdsos correctlyNicholas Piggin1-3/+3
When using if_changed, we need to add FORCE as a dependency (see Documentation/kbuild/makefiles.txt) otherwise we don't get command line change checking amongst other things. This has resulted in vdsos not being rebuilt when switching between big and little endian. The vdso64/32ld commands have to be changed around to avoid pulling FORCE into the linker command line (code copied from x86). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-01-20powerpc: enable UBSAN supportDaniel Axtens1-0/+1
This hooks up UBSAN support for PowerPC. So far it's found some interesting cases where we don't properly sanitise input to shifts, including one in our futex handling. Nothing critical, but interesting and worth fixing. [valentinrothberg@gmail.com: arch/powerpc/Kconfig: fix typo in select statement] Signed-off-by: Daniel Axtens <dja@axtens.net> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-26powerpc: Standardise on NR_syscalls rather than __NR_syscalls.Rashmica Gupta1-1/+1
Most architectures use NR_syscalls as the #define for the number of syscalls. We use __NR_syscalls, and then define NR_syscalls as __NR_syscalls. __NR_syscalls is not used outside arch code, whereas NR_syscalls is. So as NR_syscalls must be defined and __NR_syscalls does not, replace __NR_syscalls with NR_syscalls. Signed-off-by: Rashmica Gupta <rashmicy@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-10-01powerpc/vdso: Avoid link stack corruption in __get_datapage()Michael Neuling1-5/+7
powerpc has a link register (lr) used for calling functions. We "bl <func>" to call a function, and "blr" to return back to the call site. The lr is only a single register, so if we call another function from inside this function (ie. nested calls), software must save away the lr on the software stack before calling the new function. Before returning (ie. before the "blr"), the lr is restored by software from the software stack. This makes branch prediction quite difficult for the processor as it will only know the branch target just before the "blr". To help with this, modern powerpc processors keep a (non-architected) hardware stack of lr called a "link stack". When a "bl <func>" is run, the lr is pushed onto this stack. When a "blr" is called, the branch predictor pops the lr value from the top of the link stack, and uses it to predict the branch target. Hence the processor pipeline knows a lot earlier the branch target. This works great but there are some cases where you call "bl" but without a matching "blr". Once such case is when trying to determine the program counter (which can't be read directly). Here you "bl+4; mflr" to get the program counter. If you do this, the link stack will get out of sync with reality, causing the branch predictor to mis-predict subsequent function returns. To avoid this, modern micro-architectures have a special case of bl. Using the form "bcl 20,31,+4", ensures the processor doesn't push to the link stack. The 32 and 64 bit variants of __get_datapage() use a "bl; mflr" to determine the loaded address of the VDSO. The current versions of these attempt to use this special bl variant. Unfortunately they use +8 rather than the required +4. Hence the current code results in the link stack getting out of sync with reality and hence the resulting performance degradation. This patch moves it to bcl+4 by moving __kernel_datapage_offset out of __get_datapage(). With this patch, running a gettimeofday() (which uses __get_datapage()) microbenchmark we get a decent bump in performance on POWER7/8. For the benchmark in tools/testing/selftests/powerpc/benchmarks/gettimeofday.c POWER8: 64bit gets ~4% improvement 32bit gets ~9% improvement POWER7: 64bit gets ~7% improvement Signed-off-by: Michael Neuling <mikey@neuling.org> Reported-by: Aaron Sawdey <sawdey@us.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-10-01powerpc/vdso: Emit GNU & SysV hashesMichael Ellerman1-1/+1
Andy Lutomirski says: Some dynamic loaders may be slightly faster if a GNU hash is available. This is unlikely to have any measurable effect on the time it takes to resolve vdso symbols (since there are so few of them). In some contexts, it can be a win for a different reason: if every DSO has a GNU hash section, then libc can avoid calculating SysV hashes at all. Both musl and glibc appear to have this optimization. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-11-27powerpc: 32 bit getcpu VDSO function uses 64 bit instructionsAnton Blanchard1-2/+2
I used some 64 bit instructions when adding the 32 bit getcpu VDSO function. Fix it. Fixes: 18ad51dd342a ("powerpc: Add VDSO version of getcpu") Cc: stable@vger.kernel.org Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-03-19powerpc/booke64: Use SPRG7 for VDSOScott Wood1-1/+1
Previously SPRG3 was marked for use by both VDSO and critical interrupts (though critical interrupts were not fully implemented). In commit 8b64a9dfb091f1eca8b7e58da82f1e7d1d5fe0ad ("powerpc/booke64: Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman made an attempt to resolve this conflict by restoring the VDSO value early in the critical interrupt, but this has some issues: - It's incompatible with EXCEPTION_COMMON which restores r13 from the by-then-overwritten scratch (this cost me some debugging time). - It forces critical exceptions to be a special case handled differently from even machine check and debug level exceptions. - It didn't occur to me that it was possible to make this work at all (by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after I made (most of) this patch. :-) It might be worth investigating using a load rather than SPRG on return from all exceptions (except TLB misses where the scratch never leaves the SPRG) -- it could save a few cycles. Until then, let's stick with SPRG for all exceptions. Since we cannot use SPRG4-7 for scratch without corrupting the state of a KVM guest, move VDSO to SPRG7 on book3e. Since neither SPRG4-7 nor critical interrupts exist on book3s, SPRG3 is still used for VDSO there. Signed-off-by: Scott Wood <scottwood@freescale.com> Cc: Mihai Caraman <mihai.caraman@freescale.com> Cc: Anton Blanchard <anton@samba.org> Cc: Paul Mackerras <paulus@samba.org> Cc: kvm-ppc@vger.kernel.org
2014-02-17powerpc: Use unstripped VDSO image for more accurate profiling dataAnton Blanchard1-1/+1
We are seeing a lot of hits in the VDSO that are not resolved by perf. A while(1) gettimeofday() loop shows the issue: 27.64% [vdso] [.] 0x000000000000060c 22.57% [vdso] [.] 0x0000000000000628 16.88% [vdso] [.] 0x0000000000000610 12.39% [vdso] [.] __kernel_gettimeofday 6.09% [vdso] [.] 0x00000000000005f8 3.58% test [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18 2.94% [vdso] [.] __kernel_datapage_offset 2.90% test [.] main We are using a stripped VDSO image which means only symbols with relocation info can be resolved. There isn't a lot of point to stripping the VDSO, the debug info is only about 1kB: 4680 arch/powerpc/kernel/vdso64/vdso64.so 5815 arch/powerpc/kernel/vdso64/vdso64.so.dbg By using the unstripped image, we can resolve all the symbols in the VDSO and the perf profile data looks much better: 76.53% [vdso] [.] __do_get_tspec 12.20% [vdso] [.] __kernel_gettimeofday 5.05% [vdso] [.] __get_datapage 3.20% test [.] main 2.92% test [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18 Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-01-15powerpc: Delete non-required instances of include <linux/init.h>Paul Gortmaker1-1/+0
None of these files are actually using any __init type directives and hence don't need to include <linux/init.h>. Most are just a left over from __devinit and __cpuinit removal, or simply due to code getting copied from one driver to the next. The one instance where we add an include for init.h covers off a case where that file was implicitly getting it from another header which itself didn't need it. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-11-22powerpc/8xx: mfspr SPRN_TBRx in lieu of mftb/mftbu is not supportedLEROY Christophe1-0/+6
Commit beb2dc0a7a84be003ce54e98b95d65cc66e6e536 breaks the MPC8xx which seems to not support using mfspr SPRN_TBRx instead of mftb/mftbu despite what is written in the reference manual. This patch reverts to the use of mftb/mftbu when CONFIG_8xx is selected. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Scott Wood <scottwood@freescale.com>
2013-10-11powerpc: Add ability to build little endian kernelsIan Munsie1-0/+4
This patch allows the kbuild system to successfully compile a kernel for the little endian PowerPC64 architecture. A subsequent patch will add the CONFIG_CPU_LITTLE_ENDIAN kernel config option which must be set to build such a kernel. If cross compiling, CROSS_COMPILE must point to a suitable toolchain (compiled for the powerpc64le-linux and powerpcle-linux targets). Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-08-20powerpc: Convert some mftb/mftbu into mfsprScott Wood1-3/+3
Some CPUs (such as e500v1/v2) don't implement mftb and will take a trap. mfspr should work on everything that has a timebase, and is the preferred instruction according to ISA v2.06. Currently we get away with mftb on 85xx because the assembler converts it to mfspr due to -Wa,-me500. However, that flag has other effects that are undesireable for certain targets (e.g. lwsync is converted to sync), and is hostile to multiplatform kernels. Thus we would like to stop setting it for all e500-family builds. mftb/mftbu instances which are in 85xx code or common code are converted. Instances which will never run on 85xx are left alone. Signed-off-by: Scott Wood <scottwood@freescale.com>
2013-04-23powerpc: Add VDSO version of timeAdhemerval Zanella2-0/+27
On 04/18/2013 07:38 PM, Anton Blanchard wrote: > Since you are only reading one long you shouldn't need to check the > update count and loop, you will always see a consistent value. The > system call version of time() just does an unprotected load for example. Fixed. > With the above change and with Michael's comments covered (decent > changelog entry and Signed-off-by): > > Acked-by: Anton Blanchard <anton@samba.org> Thanks for the review, below the updated patch: From: Adhemerval Zanella <azanella@linux.vnet.ibm.com> This patch implement the time syscall as vDSO. The performance speedups are: Baseline PPC32: 380 nsec Baseline PPC64: 350 nsec vdso PPC32: 20 nsec vsdo PPC64: 20 nsec Tested on 64 bit build with both 32 bit and 64 bit userland. Acked-by: Anton Blanchard <anton@samba.org> Signed-off-by: Adhemerval Zanella <azanella@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-11powerpc: Add VDSO version of getcpuAnton Blanchard3-1/+51
We have a request for a fast method of getting CPU and NUMA node IDs from userspace. This patch implements a getcpu VDSO function, similar to x86. Ben suggested we use SPRG3 which is userspace readable. SPRG3 can be modified by a KVM guest, so we save the SPRG3 value in the paca and restore it when transitioning from the guest to the host. I have a glibc patch that implements sched_getcpu on top of this. Testing on a POWER7: baseline: 538 cycles vdso: 30 cycles Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-03-31Fix common misspellingsLucas De Marchi1-1/+1
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2010-10-13powerpc/Makefiles: Change to new flag variablesmatt mooney1-3/+3
Replace EXTRA_CFLAGS with ccflags-y and EXTRA_AFLAGS with asflags-y. Signed-off-by: matt mooney <mfm@muteddisk.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-07-09powerpc: Rework VDSO gettimeofday to prevent time going backwardsPaul Mackerras1-142/+42
Currently it is possible for userspace to see the result of gettimeofday() going backwards by 1 microsecond, assuming that userspace is using the gettimeofday() in the VDSO. The VDSO gettimeofday() algorithm computes the time in "xsecs", which are units of 2^-20 seconds, or approximately 0.954 microseconds, using the algorithm now = (timebase - tb_orig_stamp) * tb_to_xs + stamp_xsec and then converts the time in xsecs to seconds and microseconds. The kernel updates the tb_orig_stamp and stamp_xsec values every tick in update_vsyscall(). If the length of the tick is not an integer number of xsecs, then some precision is lost in converting the current time to xsecs. For example, with CONFIG_HZ=1000, the tick is 1ms long, which is 1048.576 xsecs. That means that stamp_xsec will advance by either 1048 or 1049 on each tick. With the right conditions, it is possible for userspace to get (timebase - tb_orig_stamp) * tb_to_xs being 1049 if the kernel is slightly late in updating the vdso_datapage, and then for stamp_xsec to advance by 1048 when the kernel does update it, and for userspace to then see (timebase - tb_orig_stamp) * tb_to_xs being zero due to integer truncation. The result is that time appears to go backwards by 1 microsecond. To fix this we change the VDSO gettimeofday to use a new field in the VDSO datapage which stores the nanoseconds part of the time as a fractional number of seconds in a 0.32 binary fraction format. (Or put another way, as a 32-bit number in units of 0.23283 ns.) This is convenient because we can use the mulhwu instruction to convert it to either microseconds or nanoseconds. Since it turns out that computing the time of day using this new field is simpler than either using stamp_xsec (as gettimeofday does) or stamp_xtime.tv_nsec (as clock_gettime does), this converts both gettimeofday and clock_gettime to use the new field. The existing __do_get_tspec function is converted to use the new field and take a parameter in r7 that indicates the desired resolution, 1,000,000 for microseconds or 1,000,000,000 for nanoseconds. The __do_get_xsec function is then unused and is deleted. The new algorithm is now = ((timebase - tb_orig_stamp) << 12) * tb_to_xs + (stamp_xtime_seconds << 32) + stamp_sec_fraction with 'now' in units of 2^-32 seconds. That is then converted to seconds and either microseconds or nanoseconds with seconds = now >> 32 partseconds = ((now & 0xffffffff) * resolution) >> 32 The 32-bit VDSO code also makes a further simplification: it ignores the bottom 32 bits of the tb_to_xs value, which is a 0.64 format binary fraction. Doing so gets rid of 4 multiply instructions. Assuming a timebase frequency of 1GHz or less and an update interval of no more than 10ms, the upper 32 bits of tb_to_xs will be at least 4503599, so the error from ignoring the low 32 bits will be at most 2.2ns, which is more than an order of magnitude less than the time taken to do gettimeofday or clock_gettime on our fastest processors, so there is no possibility of seeing inconsistent values due to this. This also moves update_gtod() down next to its only caller, and makes update_vsyscall use the time passed in via the wall_time argument rather than accessing xtime directly. At present, wall_time always points to xtime, but that could change in future. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-27powerpc: Fix segment mapping in vdso32Andreas Schwab1-2/+2
Due to missing segment assignments the .text section was put in the NOTES segment (and marked as NOTE section), and the .got was put in the DYNAMIC segment. Signed-off-by: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-09-21Use macros for .data.page_aligned section.Tim Abbott1-1/+2
This patch changes the remaining direct references to .data.page_aligned in C and assembly code to use the macros in include/linux/linkage.h. Signed-off-by: Tim Abbott <tabbott@ksplice.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-09-20kbuild: rename ld-option to cc-ldoptionSam Ravnborg1-1/+1
ld-option is misnamed as it test options to gcc, not to ld. Renamed it to reflect this. Cc: Andi Kleen <andi@firstfloor.org> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-08-20powerpc: Enable GCOVMichael Ellerman1-0/+1
Make it possible to enable GCOV code coverage measurement on powerpc. Lightly tested on 64-bit, seems to work as expected. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2008-12-21powerpc/mm: Introduce MMU featuresBenjamin Herrenschmidt1-0/+3
We're soon running out of CPU features and I need to add some new ones for various MMU related bits, so this patch separates the MMU features from the CPU features. I moved over the 32-bit MMU related ones, added base features for MMU type families, but didn't move over any 64-bit only feature yet. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-11-06powerpc: Improve resolution of VDSO clock_gettimePaul Mackerras1-83/+125
Currently the clock_gettime implementation in the VDSO produces a result with microsecond resolution for the cases that are handled without a system call, i.e. CLOCK_REALTIME and CLOCK_MONOTONIC. The nanoseconds field of the result is obtained by computing a microseconds value and multiplying by 1000. This changes the code in the VDSO to do the computation for clock_gettime with nanosecond resolution. That means that the resolution of the result will ultimately depend on the timebase frequency. Because the timestamp in the VDSO datapage (stamp_xsec, the real time corresponding to the timebase count in tb_orig_stamp) is in units of 2^-20 seconds, it doesn't have sufficient resolution for computing a result with nanosecond resolution. Therefore this adds a copy of xtime to the VDSO datapage and updates it in update_gtod() along with the other time-related fields. Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-03powerpc: Fixup lwsync at runtimeKumar Gala1-0/+3
To allow for a single kernel image on e500 v1/v2/mc we need to fixup lwsync at runtime. On e500v1/v2 lwsync causes an illop so we need to patch up the code. We default to 'sync' since that is always safe and if the cpu is capable we will replace 'sync' with 'lwsync'. We introduce CPU_FTR_LWSYNC as a way to determine at runtime if this is needed. This flag could be moved elsewhere since we dont really use it for the normal CPU_FTR purpose. Finally we only store the relative offset in the fixup section to keep it as small as possible rather than using a full fixup_entry. Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-01powerpc: Introduce infrastructure for feature sections with alternativesMichael Ellerman1-1/+1
The current feature section logic only supports nop'ing out code, this means if you want to choose at runtime between instruction sequences, one or both cases will have to execute the nop'ed out contents of the other section, eg: BEGIN_FTR_SECTION or 1,1,1 END_FTR_SECTION_IFSET(FOO) BEGIN_FTR_SECTION or 2,2,2 END_FTR_SECTION_IFCLR(FOO) and the resulting code will be either, or 1,1,1 nop or, nop or 2,2,2 For small code segments this is fine, but for larger code blocks and in performance criticial code segments, it would be nice to avoid the nops. This commit starts to implement logic to allow the following: BEGIN_FTR_SECTION or 1,1,1 FTR_SECTION_ELSE or 2,2,2 ALT_FTR_SECTION_END_IFSET(FOO) and the resulting code will be: or 1,1,1 or, or 2,2,2 We achieve this by extending the existing FTR macros. The current feature section semantic just becomes a special case, ie. if the else case is empty we nop out the default case. The key limitation is that the size of the else case must be less than or equal to the size of the default case. If the else case is smaller the remainder of the section is nop'ed. We let the linker put the else case code in with the rest of the text, so that relative branches from the else case are more likley to link, this has the disadvantage that we can't free the unused else cases. This commit introduces the required macro and linker script changes, but does not enable the patching of the alternative sections. We also need to update two hand-made section entries in reg.h and timex.h Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-11-20[POWERPC] vdso: Fixes for cache block sizesOlof Johansson1-12/+29
The current VDSO implementation is hardcoded to 128 byte cache blocks, which are only used on IBM's 64-bit processors. Convert it to get the cache block sizes out of vdso_data instead, similar to how the ppc64 in-kernel cache flush does it. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-16powerpc32 vDSO: linker script indentationRoland McGrath1-101/+118
This cleans up the formatting in the vDSO linker script, mostly just the use of whitespace. It's intended to approximate the kernel standard conventions for indenting C, treating elements of the linker script about like initialized variable definitions. Signed-off-by: Roland McGrath <roland@redhat.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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