LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Borislav Petkov <bp@alien8.de>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: "Michael Matz" <matz@suse.de>, "Jakub Jelinek" <jakub@redhat.com>,
	"Sergei Trofimovich" <slyfox@gentoo.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Martin Liška" <mliska@suse.cz>,
	"Masahiro Yamada" <masahiroy@kernel.org>
Subject: Re: [PATCH] x86: Fix early boot crash on gcc-10, next try
Date: Thu, 23 Apr 2020 20:27:28 +0200
Message-ID: <20200423182728.GI26021@zn.tnic> (raw)
In-Reply-To: <CAKwvOdmmuE=o-bGpraR1rJdzDgf2UYvgcx2-S7cdGSFWWkWurA@mail.gmail.com>

On Thu, Apr 23, 2020 at 11:02:09AM -0700, Nick Desaulniers wrote:
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
> 
> It's too bad that $(CC) isn't exported yet; IIUC we include the arch
> specific Makefiles then later export $(CC).  If that was the case, we
> could just use $(CC) in the shell script, rather than passing it along
> as an argument.  Oh well.

Aha, so that's why others pass it. I used
gcc-x86_64-has-stack-protector.sh as an example to slap that one
together.

Below new version with proper commit message this time.

> If I add `echo "hello world"` to the end of
> scripts/x86-check-compiler.sh to verify this stops a build, this is
> the error message I would observe:
> arch/x86/Makefile:6: *** clang check failed. Aborting.  Stop.

Right, or you can comment out the asm("") in the script and then it
matches the "jmp" and thus fails the build. As it should be.

Thx.

---
From: Borislav Petkov <bp@suse.de>
Date: Thu, 23 Apr 2020 19:28:28 +0200
Subject: [PATCH] x86: Check whether the compiler is sane
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Add a check script to verify whether the compiler is sane. This is
x86-only for now and checks one thing only but should be useful for more
checks in the future.

Suggested-by: Martin Liška <mliska@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
---
 arch/x86/Makefile             | 4 ++++
 scripts/x86-check-compiler.sh | 9 +++++++++
 2 files changed, 13 insertions(+)
 create mode 100755 scripts/x86-check-compiler.sh

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 00e378de8bc0..38d3eec5062e 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -1,6 +1,10 @@
 # SPDX-License-Identifier: GPL-2.0
 # Unified Makefile for i386 and x86_64
 
+#  Check the compiler
+sane_compiler := $(shell $(srctree)/scripts/x86-check-compiler.sh $(CC))
+$(if $(sane_compiler),$(error $(CC) check failed. Aborting),)
+
 # select defconfig based on actual architecture
 ifeq ($(ARCH),x86)
   ifeq ($(shell uname -m),x86_64)
diff --git a/scripts/x86-check-compiler.sh b/scripts/x86-check-compiler.sh
new file mode 100755
index 000000000000..b2b5b54b6939
--- /dev/null
+++ b/scripts/x86-check-compiler.sh
@@ -0,0 +1,9 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+# Check whether the compiler tail-call optimizes across an asm() statement.
+# Fail the build if it does.
+
+echo "int foo(int a); int bar(int a) { int r = foo(a); asm(\"\"); return r; }" |\
+	     $* -O2 -x c -c -S - -o - 2>/dev/null |\
+	     grep -E "^[[:blank:]]+jmp[[:blank:]]+.*"
-- 
2.21.0

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply index

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-14 16:44 [PATCH] x86: fix early boot crash on gcc-10 Sergei Trofimovich
2020-03-16 13:04 ` Peter Zijlstra
2020-03-16 13:26   ` Jakub Jelinek
2020-03-16 13:42     ` Peter Zijlstra
2020-03-16 17:54       ` Borislav Petkov
2020-03-16 18:03         ` Jakub Jelinek
2020-03-17 14:36           ` Borislav Petkov
2020-03-17 14:39             ` Jakub Jelinek
2020-03-17 14:49               ` Borislav Petkov
2020-03-17 16:35                 ` David Laight
2020-03-25 13:31                 ` Borislav Petkov
2020-03-26 21:54                   ` Sergei Trofimovich
2020-03-26 22:35                     ` Borislav Petkov
2020-03-28  8:48                       ` [PATCH v2] " Sergei Trofimovich
2020-04-13 14:15                         ` [tip: x86/urgent] x86: Fix " tip-bot2 for Sergei Trofimovich
2020-04-13 16:35                         ` [PATCH v2] x86: fix " Borislav Petkov
2020-04-14 13:50                           ` Michael Matz
2020-04-15  7:48                             ` Borislav Petkov
2020-04-15 14:53                               ` Michael Matz
2020-04-15 22:19                                 ` Sergei Trofimovich
2020-04-17  7:57                                   ` Borislav Petkov
2020-04-17  8:07                                     ` Jakub Jelinek
2020-04-17  8:42                                       ` Borislav Petkov
2020-04-17  8:58                                         ` Jakub Jelinek
2020-04-17  9:09                                           ` Borislav Petkov
2020-04-17 18:15                                             ` Nick Desaulniers
2020-04-17 18:22                                               ` Nick Desaulniers
2020-04-17 19:06                                                 ` Jakub Jelinek
2020-04-17 19:49                                                   ` Nick Desaulniers
2020-04-17 19:53                                                     ` Nick Desaulniers
2020-04-20 14:04                                                     ` Michael Matz
2020-04-22 10:23                                                       ` Borislav Petkov
2020-04-22 11:40                                                         ` Peter Zijlstra
2020-04-22 13:49                                                           ` Borislav Petkov
2020-04-22 13:55                                                             ` Jakub Jelinek
2020-04-22 14:16                                                               ` Martin Liška
2020-04-22 15:06                                                                 ` Michael Matz
2020-04-22 16:53                                                                 ` Borislav Petkov
2020-04-22 17:02                                                                   ` Jakub Jelinek
2020-04-22 18:47                                                                   ` Nick Desaulniers
2020-04-22 18:55                                                         ` Nick Desaulniers
2020-04-22 19:21                                                           ` Borislav Petkov
2020-04-22 21:05                                                             ` Nick Desaulniers
2020-04-22 21:26                                                               ` Borislav Petkov
2020-04-22 22:57                                                                 ` Nick Desaulniers
2020-04-23 12:53                                                                   ` Borislav Petkov
2020-04-23 16:12                                                                     ` [PATCH] x86: Fix early boot crash on gcc-10, next try Borislav Petkov
2020-04-23 17:30                                                                       ` Borislav Petkov
2020-04-23 18:02                                                                         ` Nick Desaulniers
2020-04-23 18:27                                                                           ` Borislav Petkov [this message]
2020-04-27 11:37                                                                         ` [tip: x86/build] x86/build: Check whether the compiler is sane tip-bot2 for Borislav Petkov
2020-04-23 19:40                                                                       ` [PATCH] x86: Fix early boot crash on gcc-10, next try Kees Cook
2020-04-25  1:46                                                                       ` Arvind Sankar
2020-04-25  8:57                                                                         ` Borislav Petkov
2020-04-25 11:09                                                                           ` Jürgen Groß
2020-04-25 15:04                                                                           ` Arvind Sankar
2020-04-25 17:31                                                                             ` Borislav Petkov
2020-04-25 17:52                                                                               ` Borislav Petkov
2020-04-27 17:07                                                                                 ` David Laight
2020-04-25 18:37                                                                               ` Segher Boessenkool
2020-04-25 18:53                                                                                 ` Borislav Petkov
2020-04-25 19:15                                                                                   ` Segher Boessenkool
2020-04-25 22:17                                                                                     ` Borislav Petkov
2020-04-25 22:25                                                                                     ` Arvind Sankar
2020-04-17 10:38                                           ` [PATCH v2] x86: fix early boot crash on gcc-10 Peter Zijlstra
2020-04-18 13:12                                             ` David Laight
2020-04-17 10:41                                     ` Peter Zijlstra
2020-03-16 18:20         ` [PATCH] " Arvind Sankar
2020-03-16 18:54           ` Arvind Sankar
2020-03-16 19:53             ` Arvind Sankar
2020-03-16 20:08               ` Jakub Jelinek
2020-03-16 20:40                 ` Arvind Sankar
2020-03-16 22:12     ` Sergei Trofimovich
2020-03-17 11:46       ` Jakub Jelinek
2020-03-17 18:10         ` Sergei Trofimovich
2020-03-16 18:22 ` Arvind Sankar
2020-03-26 23:16 ` [PATCH v2] " Sergei Trofimovich
2020-04-27 11:37 ` [tip: x86/build] x86: Fix early boot crash on gcc-10, next try tip-bot2 for Borislav Petkov
2020-05-15 11:20 ` [tip: x86/urgent] x86: Fix early boot crash on gcc-10, third try tip-bot2 for Borislav Petkov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200423182728.GI26021@zn.tnic \
    --to=bp@alien8.de \
    --cc=clang-built-linux@googlegroups.com \
    --cc=hpa@zytor.com \
    --cc=jakub@redhat.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=masahiroy@kernel.org \
    --cc=matz@suse.de \
    --cc=mingo@redhat.com \
    --cc=mliska@suse.cz \
    --cc=ndesaulniers@google.com \
    --cc=peterz@infradead.org \
    --cc=slyfox@gentoo.org \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git