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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B999DC433E0 for ; Fri, 19 Jun 2020 08:18:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9AD5B207FC for ; Fri, 19 Jun 2020 08:18:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731351AbgFSIRC (ORCPT ); Fri, 19 Jun 2020 04:17:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731290AbgFSIQH (ORCPT ); Fri, 19 Jun 2020 04:16:07 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7B1DC06174E; Fri, 19 Jun 2020 01:16:06 -0700 (PDT) Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jmCBr-0003oh-UA; Fri, 19 Jun 2020 10:16:00 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 67AA51C0085; Fri, 19 Jun 2020 10:15:58 +0200 (CEST) Date: Fri, 19 Jun 2020 08:15:58 -0000 From: "tip-bot2 for Peter Zijlstra" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: objtool/core] objtool: Fix noinstr vs KCOV Cc: "Peter Zijlstra (Intel)" , Dmitry Vyukov , x86 , LKML MIME-Version: 1.0 Message-ID: <159255455812.16989.2009345164870958211.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the objtool/core branch of tip: Commit-ID: 0f1441b44e823a74f3f3780902a113e07c73fbf6 Gitweb: https://git.kernel.org/tip/0f1441b44e823a74f3f3780902a113e07c73fbf6 Author: Peter Zijlstra AuthorDate: Fri, 12 Jun 2020 16:05:26 +02:00 Committer: Peter Zijlstra CommitterDate: Thu, 18 Jun 2020 17:36:33 +02:00 objtool: Fix noinstr vs KCOV Since many compilers cannot disable KCOV with a function attribute, help it to NOP out any __sanitizer_cov_*() calls injected in noinstr code. This turns: 12: e8 00 00 00 00 callq 17 13: R_X86_64_PLT32 __sanitizer_cov_trace_pc-0x4 into: 12: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 13: R_X86_64_NONE __sanitizer_cov_trace_pc-0x4 Just like recordmcount does. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Dmitry Vyukov --- arch/x86/Kconfig | 2 +- tools/objtool/arch.h | 2 ++ tools/objtool/arch/x86/decode.c | 18 ++++++++++++++++++ tools/objtool/arch/x86/include/arch_elf.h | 6 ++++++ tools/objtool/check.c | 19 +++++++++++++++++++ 5 files changed, 46 insertions(+), 1 deletion(-) create mode 100644 tools/objtool/arch/x86/include/arch_elf.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 6a0cc52..883da0a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -67,7 +67,7 @@ config X86 select ARCH_HAS_FILTER_PGPROT select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_GCOV_PROFILE_ALL - select ARCH_HAS_KCOV if X86_64 + select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION select ARCH_HAS_MEM_ENCRYPT select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h index eda15a5..3c59677 100644 --- a/tools/objtool/arch.h +++ b/tools/objtool/arch.h @@ -84,4 +84,6 @@ unsigned long arch_jump_destination(struct instruction *insn); unsigned long arch_dest_rela_offset(int addend); +const char *arch_nop_insn(int len); + #endif /* _ARCH_H */ diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index 4b504fc..9872195 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -565,3 +565,21 @@ void arch_initial_func_cfi_state(struct cfi_init_state *state) state->regs[16].base = CFI_CFA; state->regs[16].offset = -8; } + +const char *arch_nop_insn(int len) +{ + static const char nops[5][5] = { + /* 1 */ { 0x90 }, + /* 2 */ { 0x66, 0x90 }, + /* 3 */ { 0x0f, 0x1f, 0x00 }, + /* 4 */ { 0x0f, 0x1f, 0x40, 0x00 }, + /* 5 */ { 0x0f, 0x1f, 0x44, 0x00, 0x00 }, + }; + + if (len < 1 || len > 5) { + WARN("invalid NOP size: %d\n", len); + return NULL; + } + + return nops[len-1]; +} diff --git a/tools/objtool/arch/x86/include/arch_elf.h b/tools/objtool/arch/x86/include/arch_elf.h new file mode 100644 index 0000000..69cc426 --- /dev/null +++ b/tools/objtool/arch/x86/include/arch_elf.h @@ -0,0 +1,6 @@ +#ifndef _OBJTOOL_ARCH_ELF +#define _OBJTOOL_ARCH_ELF + +#define R_NONE R_X86_64_NONE + +#endif /* _OBJTOOL_ARCH_ELF */ diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 91a67db..478267a 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -12,6 +12,7 @@ #include "check.h" #include "special.h" #include "warn.h" +#include "arch_elf.h" #include #include @@ -766,6 +767,24 @@ static int add_call_destinations(struct objtool_file *file) insn->call_dest = rela->sym; /* + * Many compilers cannot disable KCOV with a function attribute + * so they need a little help, NOP out any KCOV calls from noinstr + * text. + */ + if (insn->sec->noinstr && + !strncmp(insn->call_dest->name, "__sanitizer_cov_", 16)) { + if (rela) { + rela->type = R_NONE; + elf_write_rela(file->elf, rela); + } + + elf_write_insn(file->elf, insn->sec, + insn->offset, insn->len, + arch_nop_insn(insn->len)); + insn->type = INSN_NOP; + } + + /* * Whatever stack impact regular CALLs have, should be undone * by the RETURN of the called function. *