From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org, oberpar@linux.ibm.com, linux-kernel@vger.kernel.org
Cc: johannes.berg@intel.com, ndesaulniers@google.com,
nathan@kernel.org, keescook@chromium.org, elver@google.com,
mark.rutland@arm.com
Subject: [PATCH] gcov,x86: Mark GCOV broken for x86
Date: Mon, 14 Jun 2021 12:17:21 +0200 [thread overview]
Message-ID: <YMcssV/n5IBGv4f0@hirez.programming.kicks-ass.net> (raw)
As recently discovered, there is no function attribute to disable the
-fprofile-generate instrumentation. As such, GCOV is fundamentally
incompatible with architectures that rely on 'noinstr' for correctness.
Until such time as that compilers have added a function attribute to
disable this instrumentation, mark GCOV as broken.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/Kconfig | 2 +-
kernel/gcov/Kconfig | 4 ++++
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 86dae426798b..c0f8c9d4c31a 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -75,7 +75,7 @@ config X86
select ARCH_HAS_FAST_MULTIPLIER
select ARCH_HAS_FILTER_PGPROT
select ARCH_HAS_FORTIFY_SOURCE
- select ARCH_HAS_GCOV_PROFILE_ALL
+ select ARCH_HAS_GCOV_BROKEN
select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
select ARCH_HAS_MEM_ENCRYPT
select ARCH_HAS_MEMBARRIER_SYNC_CORE
diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
index 58f87a3092f3..74b028a66ebe 100644
--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -1,10 +1,14 @@
# SPDX-License-Identifier: GPL-2.0-only
menu "GCOV-based kernel profiling"
+config ARCH_HAS_GCOV_BROKEN
+ def_bool n
+
config GCOV_KERNEL
bool "Enable gcov-based kernel profiling"
depends on DEBUG_FS
depends on !CC_IS_CLANG || CLANG_VERSION >= 110000
+ depends on !ARCH_HAS_GCOV_BROKEN
select CONSTRUCTORS
default n
help
next reply other threads:[~2021-06-14 10:18 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-14 10:17 Peter Zijlstra [this message]
2021-06-14 10:31 ` [PATCH] gcov,x86: Mark GCOV broken for x86 Marco Elver
2021-06-14 14:43 ` Peter Oberparleiter
2021-06-18 11:13 ` Peter Zijlstra
2021-06-21 13:53 ` Peter Oberparleiter
2021-06-14 16:05 ` Nick Desaulniers
2021-06-14 16:20 ` Peter Zijlstra
2021-06-14 18:05 ` Nick Desaulniers
2021-06-14 18:20 ` Borislav Petkov
2021-06-14 19:03 ` Nick Desaulniers
2021-06-14 19:28 ` Borislav Petkov
2021-06-14 18:31 ` Fangrui Song
2021-06-14 19:07 ` Peter Zijlstra
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=YMcssV/n5IBGv4f0@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=elver@google.com \
--cc=johannes.berg@intel.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=nathan@kernel.org \
--cc=ndesaulniers@google.com \
--cc=oberpar@linux.ibm.com \
--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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).