From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755840AbdEEIVG (ORCPT ); Fri, 5 May 2017 04:21:06 -0400 Received: from terminus.zytor.com ([65.50.211.136]:57985 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755326AbdEEIVE (ORCPT ); Fri, 5 May 2017 04:21:04 -0400 Date: Fri, 5 May 2017 01:11:47 -0700 From: tip-bot for Matthias Kaehlcke Message-ID: Cc: tglx@linutronix.de, hpa@zytor.com, peterz@infradead.org, torvalds@linux-foundation.org, md@google.com, mka@chromium.org, mingo@kernel.org, keescook@chromium.org, ghackmann@google.com, grundler@chromium.org, linux-kernel@vger.kernel.org Reply-To: mka@chromium.org, md@google.com, tglx@linutronix.de, peterz@infradead.org, hpa@zytor.com, torvalds@linux-foundation.org, grundler@chromium.org, linux-kernel@vger.kernel.org, mingo@kernel.org, ghackmann@google.com, keescook@chromium.org In-Reply-To: <20170501224741.133938-1-mka@chromium.org> References: <20170501224741.133938-1-mka@chromium.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/mm/kaslr: Use the _ASM_MUL macro for multiplication to work around Clang incompatibility Git-Commit-ID: 121843eb02a6e2fa30aefab64bfe183c97230c75 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 121843eb02a6e2fa30aefab64bfe183c97230c75 Gitweb: http://git.kernel.org/tip/121843eb02a6e2fa30aefab64bfe183c97230c75 Author: Matthias Kaehlcke AuthorDate: Mon, 1 May 2017 15:47:41 -0700 Committer: Ingo Molnar CommitDate: Fri, 5 May 2017 08:31:05 +0200 x86/mm/kaslr: Use the _ASM_MUL macro for multiplication to work around Clang incompatibility The constraint "rm" allows the compiler to put mix_const into memory. When the input operand is a memory location then MUL needs an operand size suffix, since Clang can't infer the multiplication width from the operand. Add and use the _ASM_MUL macro which determines the operand size and resolves to the NUL instruction with the corresponding suffix. This fixes the following error when building with clang: CC arch/x86/lib/kaslr.o /tmp/kaslr-dfe1ad.s: Assembler messages: /tmp/kaslr-dfe1ad.s:182: Error: no instruction mnemonic suffix given and no register operands; can't size instruction Signed-off-by: Matthias Kaehlcke Cc: Grant Grundler Cc: Greg Hackmann Cc: Kees Cook Cc: Linus Torvalds Cc: Michael Davidson Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170501224741.133938-1-mka@chromium.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/asm.h | 1 + arch/x86/lib/kaslr.c | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h index 7acb51c..7a9df3b 100644 --- a/arch/x86/include/asm/asm.h +++ b/arch/x86/include/asm/asm.h @@ -32,6 +32,7 @@ #define _ASM_ADD __ASM_SIZE(add) #define _ASM_SUB __ASM_SIZE(sub) #define _ASM_XADD __ASM_SIZE(xadd) +#define _ASM_MUL __ASM_SIZE(mul) #define _ASM_AX __ASM_REG(ax) #define _ASM_BX __ASM_REG(bx) diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c index 5761a4f..ab2d1d7 100644 --- a/arch/x86/lib/kaslr.c +++ b/arch/x86/lib/kaslr.c @@ -5,6 +5,7 @@ * kernel starts. This file is included in the compressed kernel and * normally linked in the regular. */ +#include #include #include #include @@ -79,7 +80,7 @@ unsigned long kaslr_get_random_long(const char *purpose) } /* Circular multiply for better bit diffusion */ - asm("mul %3" + asm(_ASM_MUL "%3" : "=a" (random), "=d" (raw) : "a" (random), "rm" (mix_const)); random += raw;