On Mon, Aug 17, 2020 at 03:02:10PM -0700, Nick Desaulniers wrote: > This reverts commit 5f074f3e192f10c9fade898b9b3b8812e3d83342. > > Use `-fno-builtin-bcmp` instead. > > The issue with using `-fno-builtin-*` flags was that they were not > retained during an LTO link with LLVM. This was fixed in clang-11 by > https://reviews.llvm.org/D71193 > (0508c994f0b14144041f2cfd3ba9f9a80f03de08), which is also the minimum > supported version of clang for LTO. > > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- > Makefile | 1 + > include/linux/string.h | 3 --- > lib/string.c | 20 -------------------- > 3 files changed, 1 insertion(+), 23 deletions(-) > > diff --git a/Makefile b/Makefile > index 211a1b6f6478..722ff5864275 100644 > --- a/Makefile > +++ b/Makefile > @@ -964,6 +964,7 @@ endif > # to provide implementations of these routines, then prevent the compiler from > # emitting calls to what will be undefined symbols. > KBUILD_CFLAGS += -fno-builtin-stpcpy > +KBUILD_CFLAGS += -fno-builtin-bcmp I personally think that this hunk should be its own patch before this one then have this patch just be the revert, that way there is no regression across a bisect (if one were to ever occur) and so the revert is a straight 'git revert', rather than have something else mixed in that requires reading the actual changelog text. No objections if you disagree though. > # include additional Makefiles when needed > include-y := scripts/Makefile.extrawarn > diff --git a/include/linux/string.h b/include/linux/string.h > index b1f3894a0a3e..f3bdb74bc230 100644 > --- a/include/linux/string.h > +++ b/include/linux/string.h > @@ -155,9 +155,6 @@ extern void * memscan(void *,int,__kernel_size_t); > #ifndef __HAVE_ARCH_MEMCMP > extern int memcmp(const void *,const void *,__kernel_size_t); > #endif > -#ifndef __HAVE_ARCH_BCMP > -extern int bcmp(const void *,const void *,__kernel_size_t); > -#endif > #ifndef __HAVE_ARCH_MEMCHR > extern void * memchr(const void *,int,__kernel_size_t); > #endif > diff --git a/lib/string.c b/lib/string.c > index 6012c385fb31..69328b8353e1 100644 > --- a/lib/string.c > +++ b/lib/string.c > @@ -922,26 +922,6 @@ __visible int memcmp(const void *cs, const void *ct, size_t count) > EXPORT_SYMBOL(memcmp); > #endif > > -#ifndef __HAVE_ARCH_BCMP > -/** > - * bcmp - returns 0 if and only if the buffers have identical contents. > - * @a: pointer to first buffer. > - * @b: pointer to second buffer. > - * @len: size of buffers. > - * > - * The sign or magnitude of a non-zero return value has no particular > - * meaning, and architectures may implement their own more efficient bcmp(). So > - * while this particular implementation is a simple (tail) call to memcmp, do > - * not rely on anything but whether the return value is zero or non-zero. > - */ > -#undef bcmp > -int bcmp(const void *a, const void *b, size_t len) > -{ > - return memcmp(a, b, len); > -} > -EXPORT_SYMBOL(bcmp); > -#endif > - > #ifndef __HAVE_ARCH_MEMSCAN > /** > * memscan - Find a character in an area of memory. > -- > 2.28.0.220.ged08abb693-goog > Cheers, Nathan
