From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk1-f193.google.com ([209.85.222.193]:43756 "EHLO mail-qk1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728422AbfJGWAG (ORCPT ); Mon, 7 Oct 2019 18:00:06 -0400 Date: Mon, 7 Oct 2019 18:00:02 -0400 From: Arvind Sankar Subject: [PATCH] lib/string: make memzero_explicit inline instead of external Message-ID: <20191007220000.GA408752@rani.riverdale.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1d17349e-98ab-b582-6981-b484b0e970b6@redhat.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, Ingo Molnar , Hans de Goede Cc: linux-crypto@vger.kernel.org, linux-s390@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Herbert Xu , Ard Biesheuvel , Stephan Mueller 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. Fixes: 906a4bb97f5d ("crypto: sha256 - Use get/put_unaligned_be32 to get input, memzero_explicit") Reviewed-by: Hans de Goede Tested-by: Hans de Goede Signed-off-by: Arvind Sankar --- 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 b2f9df7f0761..b6ccdc2c7f02 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 cd7a10c19210..08ec58cc673b 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 -- 2.21.0