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* powerpc: replace #include <asm/export.h> with #include <linux/export.h>Masahiro Yamada2023-08-161-1/+1
| | | | | | | | | | | | | | | | Commit ddb5cdbafaaa ("kbuild: generate KSYMTAB entries by modpost") deprecated <asm/export.h>, which is now a wrapper of <linux/export.h>. Replace #include <asm/export.h> with #include <linux/export.h>. After all the <asm/export.h> lines are converted, <asm/export.h> and <asm-generic/export.h> will be removed. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [mpe: Fixup selftests that stub asm/export.h] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230806150954.394189-2-masahiroy@kernel.org
* powerpc: add CFUNC assembly label annotationNicholas Piggin2023-04-201-2/+2
| | | | | | | | | | | | | This macro is to be used in assembly where C functions are called. pcrel addressing mode requires branches to functions with a localentry value of 1 to have either a trailing nop or @notoc. This macro permits the latter without changing callers. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Add dummy definitions to fix selftests build] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230408021752.862660-5-npiggin@gmail.com
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner2019-05-301-5/+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 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>
* powerpc/64: Fix memcmp reading past the end of src/destMichael Ellerman2019-03-251-4/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Chandan reported that fstests' generic/026 test hit a crash: BUG: Unable to handle kernel data access at 0xc00000062ac40000 Faulting instruction address: 0xc000000000092240 Oops: Kernel access of bad area, sig: 11 [#1] LE SMP NR_CPUS=2048 DEBUG_PAGEALLOC NUMA pSeries CPU: 0 PID: 27828 Comm: chacl Not tainted 5.0.0-rc2-next-20190115-00001-g6de6dba64dda #1 NIP: c000000000092240 LR: c00000000066a55c CTR: 0000000000000000 REGS: c00000062c0c3430 TRAP: 0300 Not tainted (5.0.0-rc2-next-20190115-00001-g6de6dba64dda) MSR: 8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE> CR: 44000842 XER: 20000000 CFAR: 00007fff7f3108ac DAR: c00000062ac40000 DSISR: 40000000 IRQMASK: 0 GPR00: 0000000000000000 c00000062c0c36c0 c0000000017f4c00 c00000000121a660 GPR04: c00000062ac3fff9 0000000000000004 0000000000000020 00000000275b19c4 GPR08: 000000000000000c 46494c4500000000 5347495f41434c5f c0000000026073a0 GPR12: 0000000000000000 c0000000027a0000 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: c00000062ea70020 c00000062c0c38d0 0000000000000002 0000000000000002 GPR24: c00000062ac3ffe8 00000000275b19c4 0000000000000001 c00000062ac30000 GPR28: c00000062c0c38d0 c00000062ac30050 c00000062ac30058 0000000000000000 NIP memcmp+0x120/0x690 LR xfs_attr3_leaf_lookup_int+0x53c/0x5b0 Call Trace: xfs_attr3_leaf_lookup_int+0x78/0x5b0 (unreliable) xfs_da3_node_lookup_int+0x32c/0x5a0 xfs_attr_node_addname+0x170/0x6b0 xfs_attr_set+0x2ac/0x340 __xfs_set_acl+0xf0/0x230 xfs_set_acl+0xd0/0x160 set_posix_acl+0xc0/0x130 posix_acl_xattr_set+0x68/0x110 __vfs_setxattr+0xa4/0x110 __vfs_setxattr_noperm+0xac/0x240 vfs_setxattr+0x128/0x130 setxattr+0x248/0x600 path_setxattr+0x108/0x120 sys_setxattr+0x28/0x40 system_call+0x5c/0x70 Instruction dump: 7d201c28 7d402428 7c295040 38630008 38840008 408201f0 4200ffe8 2c050000 4182ff6c 20c50008 54c61838 7d201c28 <7d402428> 7d293436 7d4a3436 7c295040 The instruction dump decodes as: subfic r6,r5,8 rlwinm r6,r6,3,0,28 ldbrx r9,0,r3 ldbrx r10,0,r4 <- Which shows us doing an 8 byte load from c00000062ac3fff9, which crosses the page boundary at c00000062ac40000 and faults. It's not OK for memcmp to read past the end of the source or destination buffers if that would cross a page boundary, because we don't know that the next page is mapped. As pointed out by Segher, we can read past the end of the source or destination as long as we don't cross a 4K boundary, because that's our minimum page size on all platforms. The bug is in the code at the .Lcmp_rest_lt8bytes label. When we get there we know that s1 is 8-byte aligned and we have at least 1 byte to read, so a single 8-byte load won't read past the end of s1 and cross a page boundary. But we have to be more careful with s2. So check if it's within 8 bytes of a 4K boundary and if so go to the byte-by-byte loop. Fixes: 2d9ee327adce ("powerpc/64: Align bytes before fall back to .Lshort in powerpc64 memcmp()") Cc: stable@vger.kernel.org # v4.19+ Reported-by: Chandan Rajendra <chandan@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org> Tested-by: Chandan Rajendra <chandan@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/64: add 32 bytes prechecking before using VMX optimization on memcmp()Simon Guo2018-07-241-11/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is based on the previous VMX patch on memcmp(). To optimize ppc64 memcmp() with VMX instruction, we need to think about the VMX penalty brought with: If kernel uses VMX instruction, it needs to save/restore current thread's VMX registers. There are 32 x 128 bits VMX registers in PPC, which means 32 x 16 = 512 bytes for load and store. The major concern regarding the memcmp() performance in kernel is KSM, who will use memcmp() frequently to merge identical pages. So it will make sense to take some measures/enhancement on KSM to see whether any improvement can be done here. Cyril Bur indicates that the memcmp() for KSM has a higher possibility to fail (unmatch) early in previous bytes in following mail. https://patchwork.ozlabs.org/patch/817322/#1773629 And I am taking a follow-up on this with this patch. Per some testing, it shows KSM memcmp() will fail early at previous 32 bytes. More specifically: - 76% cases will fail/unmatch before 16 bytes; - 83% cases will fail/unmatch before 32 bytes; - 84% cases will fail/unmatch before 64 bytes; So 32 bytes looks a better choice than other bytes for pre-checking. The early failure is also true for memcmp() for non-KSM case. With a non-typical call load, it shows ~73% cases fail before first 32 bytes. This patch adds a 32 bytes pre-checking firstly before jumping into VMX operations, to avoid the unnecessary VMX penalty. It is not limited to KSM case. And the testing shows ~20% improvement on memcmp() average execution time with this patch. And note the 32B pre-checking is only performed when the compare size is long enough (>=4K currently) to allow VMX operation. The detail data and analysis is at: https://github.com/justdoitqd/publicFiles/blob/master/memcmp/README.md Signed-off-by: Simon Guo <wei.guo.simon@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/64: enhance memcmp() with VMX instruction for long bytes comparisionSimon Guo2018-07-241-2/+239
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch add VMX primitives to do memcmp() in case the compare size is equal or greater than 4K bytes. KSM feature can benefit from this. Test result with following test program(replace the "^>" with ""): ------ ># cat tools/testing/selftests/powerpc/stringloops/memcmp.c >#include <malloc.h> >#include <stdlib.h> >#include <string.h> >#include <time.h> >#include "utils.h" >#define SIZE (1024 * 1024 * 900) >#define ITERATIONS 40 int test_memcmp(const void *s1, const void *s2, size_t n); static int testcase(void) { char *s1; char *s2; unsigned long i; s1 = memalign(128, SIZE); if (!s1) { perror("memalign"); exit(1); } s2 = memalign(128, SIZE); if (!s2) { perror("memalign"); exit(1); } for (i = 0; i < SIZE; i++) { s1[i] = i & 0xff; s2[i] = i & 0xff; } for (i = 0; i < ITERATIONS; i++) { int ret = test_memcmp(s1, s2, SIZE); if (ret) { printf("return %d at[%ld]! should have returned zero\n", ret, i); abort(); } } return 0; } int main(void) { return test_harness(testcase, "memcmp"); } ------ Without this patch (but with the first patch "powerpc/64: Align bytes before fall back to .Lshort in powerpc64 memcmp()." in the series): 4.726728762 seconds time elapsed ( +- 3.54%) With VMX patch: 4.234335473 seconds time elapsed ( +- 2.63%) There is ~+10% improvement. Testing with unaligned and different offset version (make s1 and s2 shift random offset within 16 bytes) can archieve higher improvement than 10%.. Signed-off-by: Simon Guo <wei.guo.simon@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* powerpc/64: Align bytes before fall back to .Lshort in powerpc64 memcmp()Simon Guo2018-07-241-7/+133
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently memcmp() 64bytes version in powerpc will fall back to .Lshort (compare per byte mode) if either src or dst address is not 8 bytes aligned. It can be opmitized in 2 situations: 1) if both addresses are with the same offset with 8 bytes boundary: memcmp() can compare the unaligned bytes within 8 bytes boundary firstly and then compare the rest 8-bytes-aligned content with .Llong mode. 2) If src/dst addrs are not with the same offset of 8 bytes boundary: memcmp() can align src addr with 8 bytes, increment dst addr accordingly, then load src with aligned mode and load dst with unaligned mode. This patch optmizes memcmp() behavior in the above 2 situations. Tested with both little/big endian. Performance result below is based on little endian. Following is the test result with src/dst having the same offset case: (a similar result was observed when src/dst having different offset): (1) 256 bytes Test with the existing tools/testing/selftests/powerpc/stringloops/memcmp: - without patch 29.773018302 seconds time elapsed ( +- 0.09% ) - with patch 16.485568173 seconds time elapsed ( +- 0.02% ) -> There is ~+80% percent improvement (2) 32 bytes To observe performance impact on < 32 bytes, modify tools/testing/selftests/powerpc/stringloops/memcmp.c with following: ------- #include <string.h> #include "utils.h" -#define SIZE 256 +#define SIZE 32 #define ITERATIONS 10000 int test_memcmp(const void *s1, const void *s2, size_t n); -------- - Without patch 0.244746482 seconds time elapsed ( +- 0.36%) - with patch 0.215069477 seconds time elapsed ( +- 0.51%) -> There is ～+13% improvement (3) 0~8 bytes To observe <8 bytes performance impact, modify tools/testing/selftests/powerpc/stringloops/memcmp.c with following: ------- #include <string.h> #include "utils.h" -#define SIZE 256 -#define ITERATIONS 10000 +#define SIZE 8 +#define ITERATIONS 1000000 int test_memcmp(const void *s1, const void *s2, size_t n); ------- - Without patch 1.845642503 seconds time elapsed ( +- 0.12% ) - With patch 1.849767135 seconds time elapsed ( +- 0.26% ) -> They are nearly the same. (-0.2%) Signed-off-by: Simon Guo <wei.guo.simon@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
* ppc: move exports to definitionsAl Viro2016-08-071-0/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* powerpc: Add 64bit optimised memcmpAnton Blanchard2015-01-231-0/+233
I noticed ksm spending quite a lot of time in memcmp on a large KVM box. The current memcmp loop is very unoptimised - byte at a time compares with no loop unrolling. We can do much much better. Optimise the loop in a few ways: - Unroll the byte at a time loop - For large (at least 32 byte) comparisons that are also 8 byte aligned, use an unrolled modulo scheduled loop using 8 byte loads. This is similar to our glibc memcmp. A simple microbenchmark testing 10000000 iterations of an 8192 byte memcmp was used to measure the performance: baseline: 29.93 s modified: 1.70 s Just over 17x faster. v2: Incorporated some suggestions from Segher: - Use andi. instead of rdlicl. - Convert bdnzt eq, to bdnz. It's just duplicating the earlier compare and was a relic from a previous version. - Don't use cr5, we have plans to use that CR field for fast local atomics. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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