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66a5c40f |
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26-Dec-2023 |
Tanzir Hasan <tanzhasanwork@gmail.com> |
kernel.h: removed REPEAT_BYTE from kernel.h This patch creates wordpart.h and includes it in asm/word-at-a-time.h for all architectures. WORD_AT_A_TIME_CONSTANTS depends on kernel.h because of REPEAT_BYTE. Moving this to another header and including it where necessary allows us to not include the bloated kernel.h. Making this implicit dependency on REPEAT_BYTE explicit allows for later improvements in the lib/string.c inclusion list. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Tanzir Hasan <tanzirh@google.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20231226-libstringheader-v6-1-80aa08c7652c@google.com Signed-off-by: Kees Cook <keescook@chromium.org>
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79e8328e |
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01-Aug-2023 |
ndesaulniers@google.com <ndesaulniers@google.com> |
word-at-a-time: use the same return type for has_zero regardless of endianness Compiling big-endian targets with Clang produces the diagnostic: fs/namei.c:2173:13: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical] } while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants))); ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ || fs/namei.c:2173:13: note: cast one or both operands to int to silence this warning It appears that when has_zero was introduced, two definitions were produced with different signatures (in particular different return types). Looking at the usage in hash_name() in fs/namei.c, I suspect that has_zero() is meant to be invoked twice per while loop iteration; using logical-or would not update `bdata` when `a` did not have zeros. So I think it's preferred to always return an unsigned long rather than a bool than update the while loop in hash_name() to use a logical-or rather than bitwise-or. [ Also changed powerpc version to do the same - Linus ] Link: https://github.com/ClangBuiltLinux/linux/issues/1832 Link: https://lore.kernel.org/lkml/20230801-bitwise-v1-1-799bec468dc4@google.com/ Fixes: 36126f8f2ed8 ("word-at-a-time: make the interfaces truly generic") Debugged-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e93dee18 |
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06-May-2022 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc: Don't include asm/ppc_asm.h in other headers asm/ppc_asm.h is not needed in any of the header it is included. It is only needed by irq.c. Include it there and remove it from other headers. word-at-a-time.h only need ex_table.h, so include it instead. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/e2d7b96547037f852c7ed164e4f79e8918c2607a.1651828453.git.christophe.leroy@csgroup.eu
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24bfa6a9 |
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12-Oct-2016 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: EX_TABLE macro for exception tables This macro is taken from s390, and allows more flexibility in changing exception table format. mpe: Put it in ppc_asm.h and only define one version using stringinfy_in_c(). Add some empty definitions and headers to keep the selftests happy. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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b4c11211 |
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29-Apr-2016 |
Anton Blanchard <anton@samba.org> |
powerpc: Fix bad inline asm constraint in create_zero_mask() In create_zero_mask() we have: addi %1,%2,-1 andc %1,%1,%2 popcntd %0,%1 using the "r" constraint for %2. r0 is a valid register in the "r" set, but addi X,r0,X turns it into an li: li r7,-1 andc r7,r7,r0 popcntd r4,r7 Fix this by using the "b" constraint, for which r0 is not a valid register. This was found with a kernel build using gcc trunk, narrowed down to when -frename-registers was enabled at -O2. It is just luck however that we aren't seeing this on older toolchains. Thanks to Segher for working with me to find this issue. Cc: stable@vger.kernel.org Fixes: d0cebfa650a0 ("powerpc: word-at-a-time optimization for 64-bit Little Endian") Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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7a5692e6 |
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07-Oct-2015 |
Chris Metcalf <cmetcalf@ezchip.com> |
arch/powerpc: provide zero_bytemask() for big-endian For some reason, only the little-endian flavor of powerpc provided the zero_bytemask() implementation. Reported-by: Michal Sojka <sojkam1@fel.cvut.cz> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
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8989aa4a |
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18-Sep-2014 |
Anton Blanchard <anton@samba.org> |
powerpc: ppc64le optimised word at a time Use cmpb which compares each byte in two 64 bit values and for each matching byte places 0xff in the target and 0x00 otherwise. A simple hash_name microbenchmark: http://ozlabs.org/~anton/junkcode/hash_name_bench.c shows this version to be 10-20% faster than running the x86 version on POWER8, depending on the length. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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fe2a1bb1 |
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25-Sep-2014 |
Michael Ellerman <mpe@ellerman.id.au> |
selftests/powerpc: Add test of load_unaligned_zero_pad() It is a rarely exercised case, so we want to have a test to ensure it works as required. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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de5946c0 |
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18-Sep-2014 |
Anton Blanchard <anton@samba.org> |
powerpc: Implement load_unaligned_zeropad Implement a bi-arch and bi-endian version of load_unaligned_zeropad. Since the fallback case is so rare, a userspace test harness was used to test this on ppc64le, ppc64 and ppc32: http://ozlabs.org/~anton/junkcode/test_load_unaligned_zeropad.c It uses mprotect to force a SEGV across a page boundary, and a SEGV handler to lookup the exception tables and run the fixup routine. It also compares the result against a normal load. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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d0cebfa6 |
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26-Sep-2013 |
Philippe Bergheaud <felix@linux.vnet.ibm.com> |
powerpc: word-at-a-time optimization for 64-bit Little Endian This is an optimization for the PowerPC in 64-bit little-endian. Bit counting is used in find_zero(), instead of the multiply and shift. It is modelled after Alan Modra's PowerPC LE strlen patch http://sourceware.org/ml/libc-alpha/2013-08/msg00097.html. Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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4c74c330 |
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22-Sep-2013 |
Anton Blanchard <anton@samba.org> |
powerpc: Add little endian support for word-at-a-time functions The powerpc word-at-a-time functions are big endian specific. Bring in the x86 version in order to support little endian builds. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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1629372c |
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27-May-2012 |
Paul Mackerras <paulus@samba.org> |
powerpc: Use the new generic strncpy_from_user() and strnlen_user() This is much the same as for SPARC except that we can do the find_zero() function more efficiently using the count-leading-zeroes instructions. Tested on 32-bit and 64-bit PowerPC. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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