From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3B58C7618F for ; Mon, 22 Jul 2019 21:33:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8EA5F21900 for ; Mon, 22 Jul 2019 21:33:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Afs+F9ie" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732746AbfGVVdk (ORCPT ); Mon, 22 Jul 2019 17:33:40 -0400 Received: from mail-pl1-f201.google.com ([209.85.214.201]:54458 "EHLO mail-pl1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729004AbfGVVdk (ORCPT ); Mon, 22 Jul 2019 17:33:40 -0400 Received: by mail-pl1-f201.google.com with SMTP id u10so20606940plq.21 for ; Mon, 22 Jul 2019 14:33:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=rVOg24+M5qJa9OkZXsdMYSLJniYg2tsuNVu94YuzcEo=; b=Afs+F9ieOa/EPV1dzQyvuiFqLf2MUxuSTxxTY5avgW5jl0yYZ3oLeorckrrFuUDbHK UJ64F4gEzWc6mUvllYnymQLfp2a9+3XmoFawqasnXzeWbE9itSbdrmIDjZI71kY26zTg bXOKJ8HNTUIVcm8Eipi+ugx0PEg3c/1eQ0dBLu4bHy7VpwSegvZCMW4IBtdyKt+ieIbS L/s8bfV/CkShj/5CgmrKlr8hoOBRBJzB+ISlEcxgZAA4RZqk0ByEcemfVkQBkkoHLZWy UwyMvWq2sW9LXZp5bUCdhhhu1tPcmLjaNWMZOyg5Jhf0ATcwihm2XMmY6nX2+0N0xzzD RRPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=rVOg24+M5qJa9OkZXsdMYSLJniYg2tsuNVu94YuzcEo=; b=S0pNSxC+W2lkThWxG7lno3mCKL1/Ze4CGEcUnKbnkdtWfqQ8zS3HuQTL48jJJQAzeT kss3cyS17Cpz0YJcs7u5FaIPC/Bq59JYiGafJvXfzcdbeLdLGwBKCnufRjDdhcySsiXX uNJg39HWkUb4qJMcpXhFcv0PIHGNMdLoH8OWQoYN2z5+rnl6o6djBq1UJKkqfCKyAjmj 0qxz+U+hat7lg6Pu4pG+Mn2+L4w1hOTUm2qMit+pMtYIEvrQtppFgEhG6KXIypZzJRww XRyZJrAvISvffFkvPuCMiEHvEKqDPrKtuOJnHZ0aSS/Mr2PMReagz9kqw3G+lQmnwwEh +Jpw== X-Gm-Message-State: APjAAAWtihpKPM8d9CmvyQhKHRhyd1geRhPw1Yhssh7Lrq9tyY/fgegO pbSCFY3G7GFVGc1/RazGlB6qc8ijOb+Y6O5y1vY= X-Google-Smtp-Source: APXvYqxiiEidjjZE2vCTG8UXg1lYh25a/CqJJboWtCObuIQA2sdNULjY0SH46bcBxqRdQ0Wt8gb2ePSOtwdQtk6L9qg= X-Received: by 2002:a63:724f:: with SMTP id c15mr75142798pgn.257.1563831218735; Mon, 22 Jul 2019 14:33:38 -0700 (PDT) Date: Mon, 22 Jul 2019 14:32:44 -0700 Message-Id: <20190722213250.238685-1-ndesaulniers@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.22.0.657.g960e92d24f-goog Subject: [PATCH v2 1/2] x86/purgatory: do not use __builtin_memcpy and __builtin_memset From: Nick Desaulniers To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de Cc: peterz@infradead.org, clang-built-linux@googlegroups.com, Nick Desaulniers , Vaibhav Rustagi , Manoj Gupta , Alistair Delva , "H. Peter Anvin" , x86@kernel.org, Allison Randal , Alexios Zavras , Enrico Weigelt , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 $0, %rax 0000000000000347: R_X86_64_64 memset 34f: ff e0 Such code results in infinite recursion at runtime. This is observed when doing kexec. Instead, reuse an implementation from arch/x86/boot/compressed/string.c if we define warn as a symbol. Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality") Link: https://bugs.chromium.org/p/chromium/issues/detail?id=984056 Reported-by: Vaibhav Rustagi Tested-by: Vaibhav Rustagi Debugged-by: Vaibhav Rustagi Debugged-by: Manoj Gupta Suggested-by: Alistair Delva Signed-off-by: Vaibhav Rustagi Signed-off-by: Nick Desaulniers --- Changes v1 -> v2: * Add Fixes tag. * Move this patch to first in the series. arch/x86/purgatory/Makefile | 3 +++ arch/x86/purgatory/purgatory.c | 6 ++++++ arch/x86/purgatory/string.c | 23 ----------------------- 3 files changed, 9 insertions(+), 23 deletions(-) delete mode 100644 arch/x86/purgatory/string.c diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index 3cf302b26332..91ef244026d2 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -6,6 +6,9 @@ purgatory-y := purgatory.o stack.o setup-x86_$(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 6d8d5a34c377..b607bda786f6 100644 --- a/arch/x86/purgatory/purgatory.c +++ b/arch/x86/purgatory/purgatory.c @@ -68,3 +68,9 @@ 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 01ad43873ad9..000000000000 --- a/arch/x86/purgatory/string.c +++ /dev/null @@ -1,23 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * Simple string functions. - * - * Copyright (C) 2014 Red Hat Inc. - * - * Author: - * Vivek Goyal - */ - -#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); -} -- 2.22.0.657.g960e92d24f-goog