From patchwork Tue Aug 13 21:19:30 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 171222 Delivered-To: patch@linaro.org Received: by 2002:a92:d204:0:0:0:0:0 with SMTP id y4csp1406858ily; Tue, 13 Aug 2019 14:19:43 -0700 (PDT) X-Google-Smtp-Source: APXvYqz+dIoQNXfqbhqSGqmI5njCQ+hTV/OZwGIacxBurwipXzDYCoi9ZkAS2FCjoTB+c4qKrdEQ X-Received: by 2002:a62:3445:: with SMTP id b66mr43091052pfa.246.1565731183262; Tue, 13 Aug 2019 14:19:43 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1565731183; cv=none; d=google.com; s=arc-20160816; b=UBpazHqTQ8keR12uFOaHLyPLSRF88ghNM6sshUvlPazS7+wNc/qMrWEc7r/0mJcPwV 93hZAr8W4Kb/U8fl2E2OyWF6Dg9buDsFHhGTkTPOL7rpeRB1uXlLzCSjxcJRZn1qWH8e 6jfJer96rLM9Clj0yxgluys6vggrmhitWKyZ6QZiJdRGn0mXFC2IrmbG+YrZF28nMBQd QwIwaH72LoIoNGmMxIzSr4HgtuQnqX8JTUyJNg6zvM15gwm1bhp62S9goow0I9UuysHb CQxM8mTd/fm9E+PYXQ6BHdmk6z0fDORfWCCZWGfjWJj1dWT98OE8jq3N7QTU4P57TyNg Znvg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:from:subject:references :mime-version:message-id:in-reply-to:date:dkim-signature; bh=9ER49LkAApjAQ4CherwlnIMF0QHNLtrlUhDOwjnAQF4=; b=ZlKoIp/tg1atRO9BRN8dPIUNN/cxKr54dPP8jCS2tnhJ5Kc6ZKqpA31bQrkwnb4LBE LlbudAxz7p1q93l03RI1kqbPCaSt7mduPZx/uee21CL3OHW3sOknZ2WFgjTE4V2PTgX4 kOj522/qmQLi8dMzKRdTM7ugb8MTCRqN6mbTM7OXyRA7GFRexMelz1DJaX7Su7Mt5kYh emjopEXYdPvfRwvgkY/NEJcU3VjBA1gWMtVX4vp3257jYxTeDsr5Y02AyrHjYbv3WfPq rWVK+/CCV0GSiFIBBTTQdgbmdjp/S5KWV/lpn8nL8VpBW55xDWta7FwS1LhQdc/A7x/z iPVQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=mA2bsJDI; spf=pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id m11si1596144pjl.104.2019.08.13.14.19.42; Tue, 13 Aug 2019 14:19:43 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=mA2bsJDI; spf=pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726066AbfHMVTm (ORCPT + 14 others); Tue, 13 Aug 2019 17:19:42 -0400 Received: from mail-vk1-f202.google.com ([209.85.221.202]:46653 "EHLO mail-vk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725903AbfHMVTm (ORCPT ); Tue, 13 Aug 2019 17:19:42 -0400 Received: by mail-vk1-f202.google.com with SMTP id j63so46068410vkc.13 for ; Tue, 13 Aug 2019 14:19:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=9ER49LkAApjAQ4CherwlnIMF0QHNLtrlUhDOwjnAQF4=; b=mA2bsJDIFA50wpeXtmasu3xbrZRfayHFzjPbpzQeVObMANrD3wsvvfgtmDi8hFDLqQ pDbcspSZyEIoCQ5gPpJsExfoq7NKl40/h0FvshvhZpPQyFXZJcUKD8UgBk8GtTt9DqsW hKOA0ZZ387zvJm1Qd5T3EcCg6H7gaexYmg3kyr+VWmv1vHif5k9Ha/UNiSLaWEF0If3Q Qx7ojbuDOGlRKVVOxZaUGCXSFxpFp5V9Biltc810bV5KaUQLomIuOUhDl0y6E89RhFko RAJBRPHI/h0V2RrcVfZYzHhHi1cJvpm7PEDMrzecFS6S2DIIrQshIX9lEvDTxVJ/shJH YhZQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=9ER49LkAApjAQ4CherwlnIMF0QHNLtrlUhDOwjnAQF4=; b=JHuEbYPmhNbBW5Hwx7GEX7pmcSf0J0OPh37gYTzzk6nC/S2T5Muun1/6boPEf0tAyV 0IiJeyoGAFjD2JavXtM7eOyxQfIh/ulOmNByFdW3Du8NAA1Qe5lqMc9dDPPxWENSda9j daQLyF5XPkNShM5ix5pPgLgpV/uyZtX5iwa9vmtX172w3jpe9VwI6Ak5xSD/4SmhxFuC vqTJmaN94d0jNqdlOK4g26NfMYpwUz/Pnet6RBazfWL6Ww3Bryv5ZSDEZjCfRuzi1/Oa doSPnUVqYtitcgSzib84549Sa0nIQc3ABM0jAFbcPz/0lPBSxwMnUBnV9SDuqi75mOxl ymLw== X-Gm-Message-State: APjAAAXZS0qC0U2nsTDWoXFd1CXlvKjO7boHcotxOf9WKB0XcId/0pOg ctrFzATQqf3C5ZTYWbKJsMidL+MtWOFhCnFfw6s= X-Received: by 2002:a1f:9915:: with SMTP id b21mr10493141vke.69.1565731180599; Tue, 13 Aug 2019 14:19:40 -0700 (PDT) Date: Tue, 13 Aug 2019 14:19:30 -0700 In-Reply-To: <1565721608151140@kroah.com> Message-Id: <20190813211930.42094-1-ndesaulniers@google.com> Mime-Version: 1.0 References: <1565721608151140@kroah.com> X-Mailer: git-send-email 2.23.0.rc1.153.gdeed80330f-goog Subject: [4.19 PATCH] x86/purgatory: Do not use __builtin_memcpy and __builtin_memset From: Nick Desaulniers To: gregkh@linuxfoundation.org Cc: adelva@google.com, manojgupta@google.com, tglx@linutronix.de, vaibhavrustagi@google.com, stable@vger.kernel.org, Nick Desaulniers Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 4ce97317f41d38584fb93578e922fcd19e535f5b upstream. Implementing memcpy and memset in terms of __builtin_memcpy and __builtin_memset is problematic. GCC at -O2 will replace calls to the builtins with calls to memcpy and memset (but will generate an inline implementation at -Os). Clang will replace the builtins with these calls regardless of optimization level. $ llvm-objdump -dr arch/x86/purgatory/string.o | tail 0000000000000339 memcpy: 339: 48 b8 00 00 00 00 00 00 00 00 movabsq $0, %rax 000000000000033b: R_X86_64_64 memcpy 343: ff e0 jmpq *%rax 0000000000000345 memset: 345: 48 b8 00 00 00 00 00 00 00 00 movabsq $0, %rax 0000000000000347: R_X86_64_64 memset 34f: ff e0 Such code results in infinite recursion at runtime. This is observed when doing kexec. Instead, reuse an implementation from arch/x86/boot/compressed/string.c. This requires to implement a stub function for warn(). Also, Clang may lower memcmp's that compare against 0 to bcmp's, so add a small definition, too. See also: commit 5f074f3e192f ("lib/string.c: implement a basic bcmp") Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality") Reported-by: Vaibhav Rustagi Debugged-by: Vaibhav Rustagi Debugged-by: Manoj Gupta Suggested-by: Alistair Delva Signed-off-by: Nick Desaulniers Signed-off-by: Thomas Gleixner Tested-by: Vaibhav Rustagi Cc: stable@vger.kernel.org Link: https://bugs.chromium.org/p/chromium/issues/detail?id=984056 Link: https://lkml.kernel.org/r/20190807221539.94583-1-ndesaulniers@google.com --- This failed to cherry-pick back cleanly due to the SPDX license identifier not existing in arch/x86/purgatory/string.c in 4.19. `git rm` it anyway. arch/x86/boot/string.c | 8 ++++++++ arch/x86/purgatory/Makefile | 3 +++ arch/x86/purgatory/purgatory.c | 6 ++++++ arch/x86/purgatory/string.c | 25 ------------------------- 4 files changed, 17 insertions(+), 25 deletions(-) delete mode 100644 arch/x86/purgatory/string.c -- 2.23.0.rc1.153.gdeed80330f-goog diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c index c4428a176973..2622c0742c92 100644 --- a/arch/x86/boot/string.c +++ b/arch/x86/boot/string.c @@ -34,6 +34,14 @@ int memcmp(const void *s1, const void *s2, size_t len) return diff; } +/* + * Clang may lower `memcmp == 0` to `bcmp == 0`. + */ +int bcmp(const void *s1, const void *s2, size_t len) +{ + return memcmp(s1, s2, len); +} + int strcmp(const char *str1, const char *str2) { const unsigned char *s1 = (const unsigned char *)str1; diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index 3cf302b26332..91ef244026d2 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -6,6 +6,9 @@ purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string targets += $(purgatory-y) PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y)) +$(obj)/string.o: $(srctree)/arch/x86/boot/compressed/string.c FORCE + $(call if_changed_rule,cc_o_c) + $(obj)/sha256.o: $(srctree)/lib/sha256.c FORCE $(call if_changed_rule,cc_o_c) diff --git a/arch/x86/purgatory/purgatory.c b/arch/x86/purgatory/purgatory.c index 025c34ac0d84..7971f7a8af59 100644 --- a/arch/x86/purgatory/purgatory.c +++ b/arch/x86/purgatory/purgatory.c @@ -70,3 +70,9 @@ void purgatory(void) } copy_backup_region(); } + +/* + * Defined in order to reuse memcpy() and memset() from + * arch/x86/boot/compressed/string.c + */ +void warn(const char *msg) {} diff --git a/arch/x86/purgatory/string.c b/arch/x86/purgatory/string.c deleted file mode 100644 index 795ca4f2cb3c..000000000000 --- a/arch/x86/purgatory/string.c +++ /dev/null @@ -1,25 +0,0 @@ -/* - * Simple string functions. - * - * Copyright (C) 2014 Red Hat Inc. - * - * Author: - * Vivek Goyal - * - * This source code is licensed under the GNU General Public License, - * Version 2. See the file COPYING for more details. - */ - -#include - -#include "../boot/string.c" - -void *memcpy(void *dst, const void *src, size_t len) -{ - return __builtin_memcpy(dst, src, len); -} - -void *memset(void *dst, int c, size_t len) -{ - return __builtin_memset(dst, c, len); -}