The following commit has been merged into the x86/urgent branch of tip: Commit-ID: bec500777089b3c96c53681fc0aa6fee59711d4a Gitweb: https://git.kernel.org/tip/bec500777089b3c96c53681fc0aa6fee59711d4a Author: Arvind Sankar <nivedita@xxxxxxxxxxxx> AuthorDate: Mon, 07 Oct 2019 18:00:02 -04:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Tue, 08 Oct 2019 13:27:05 +02:00 lib/string: Make memzero_explicit() inline instead of external With the use of the barrier implied by barrier_data(), there is no need for memzero_explicit() to be extern. Making it inline saves the overhead of a function call, and allows the code to be reused in arch/*/purgatory without having to duplicate the implementation. Tested-by: Hans de Goede <hdegoede@xxxxxxxxxx> Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx> Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: H . Peter Anvin <hpa@xxxxxxxxx> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Stephan Mueller <smueller@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: linux-crypto@xxxxxxxxxxxxxxx Cc: linux-s390@xxxxxxxxxxxxxxx Fixes: 906a4bb97f5d ("crypto: sha256 - Use get/put_unaligned_be32 to get input, memzero_explicit") Link: https://lkml.kernel.org/r/20191007220000.GA408752@xxxxxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- include/linux/string.h | 21 ++++++++++++++++++++- lib/string.c | 21 --------------------- 2 files changed, 20 insertions(+), 22 deletions(-) diff --git a/include/linux/string.h b/include/linux/string.h index b2f9df7..b6ccdc2 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -227,7 +227,26 @@ static inline bool strstarts(const char *str, const char *prefix) } size_t memweight(const void *ptr, size_t bytes); -void memzero_explicit(void *s, size_t count); + +/** + * memzero_explicit - Fill a region of memory (e.g. sensitive + * keying data) with 0s. + * @s: Pointer to the start of the area. + * @count: The size of the area. + * + * Note: usually using memset() is just fine (!), but in cases + * where clearing out _local_ data at the end of a scope is + * necessary, memzero_explicit() should be used instead in + * order to prevent the compiler from optimising away zeroing. + * + * memzero_explicit() doesn't need an arch-specific version as + * it just invokes the one of memset() implicitly. + */ +static inline void memzero_explicit(void *s, size_t count) +{ + memset(s, 0, count); + barrier_data(s); +} /** * kbasename - return the last part of a pathname. diff --git a/lib/string.c b/lib/string.c index cd7a10c..08ec58c 100644 --- a/lib/string.c +++ b/lib/string.c @@ -748,27 +748,6 @@ void *memset(void *s, int c, size_t count) EXPORT_SYMBOL(memset); #endif -/** - * memzero_explicit - Fill a region of memory (e.g. sensitive - * keying data) with 0s. - * @s: Pointer to the start of the area. - * @count: The size of the area. - * - * Note: usually using memset() is just fine (!), but in cases - * where clearing out _local_ data at the end of a scope is - * necessary, memzero_explicit() should be used instead in - * order to prevent the compiler from optimising away zeroing. - * - * memzero_explicit() doesn't need an arch-specific version as - * it just invokes the one of memset() implicitly. - */ -void memzero_explicit(void *s, size_t count) -{ - memset(s, 0, count); - barrier_data(s); -} -EXPORT_SYMBOL(memzero_explicit); - #ifndef __HAVE_ARCH_MEMSET16 /** * memset16() - Fill a memory area with a uint16_t
