From: Catalin Marinas <catalin.marinas@arm.com>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Ard Biesheuvel <ardb@kernel.org>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Peter Oberparleiter <oberpar@linux.ibm.com>,
Kees Cook <keescook@chromium.org>,
Peter Zijlstra <peterz@infradead.org>,
Bill Wendling <wcw@google.com>,
Sami Tolvanen <samitolvanen@google.com>,
Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
Nathan Chancellor <nathan@kernel.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
LKML <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, Borislav Petkov <bp@alien8.de>,
Martin Liska <mliska@suse.cz>, Jonathan Corbet <corbet@lwn.net>,
Fangrui Song <maskray@google.com>,
Linux Doc Mailing List <linux-doc@vger.kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
Johannes Berg <johannes.berg@intel.com>,
linux-toolchains@vger.kernel.org, Marco Elver <elver@google.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-s390 <linux-s390@vger.kernel.org>
Subject: Re: [PATCH 2/2] Kconfig: CC_HAS_NO_PROFILE_FN_ATTR, depend on for GCOV and PGO
Date: Tue, 22 Jun 2021 10:25:34 +0100 [thread overview]
Message-ID: <20210622092533.GB3555@arm.com> (raw)
In-Reply-To: <CAKwvOd=9oAGPeuQmWnAMOxZn2ii_CRmyWnheoyXGcd09-U_CwA@mail.gmail.com>
On Mon, Jun 21, 2021 at 01:43:54PM -0700, Nick Desaulniers wrote:
> On Mon, Jun 21, 2021 at 11:50 AM Bill Wendling <morbo@google.com> wrote:
> > On Mon, Jun 21, 2021 at 11:22 AM Nick Desaulniers
> > <ndesaulniers@google.com> wrote:
> > > On Fri, Jun 18, 2021 at 11:23 PM Marco Elver <elver@google.com> wrote:
> > > > On Sat, 19 Jun 2021 at 01:30, Nick Desaulniers <ndesaulniers@google.com> wrote:
> > > > > We don't want compiler instrumentation to touch noinstr functions, which
> > > > > are annotated with the no_profile function attribute. Add a Kconfig test
> > > > > for this and make PGO and GCOV depend on it.
> > > > >
> > > > > Cc: Masahiro Yamada <masahiroy@kernel.org>
> > > > > Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
> > > > > Link: https://lore.kernel.org/lkml/YMTn9yjuemKFLbws@hirez.programming.kicks-ass.net/
> > > > > Link: https://lore.kernel.org/lkml/YMcssV%2Fn5IBGv4f0@hirez.programming.kicks-ass.net/
> > > > > Suggested-by: Peter Zijlstra <peterz@infradead.org>
> > > > > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> > > > > ---
> > > > > init/Kconfig | 3 +++
> > > > > kernel/gcov/Kconfig | 1 +
> > > > > kernel/pgo/Kconfig | 3 ++-
> > > > > 3 files changed, 6 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/init/Kconfig b/init/Kconfig
> > > > > index 1ea12c64e4c9..540f862b40c6 100644
> > > > > --- a/init/Kconfig
> > > > > +++ b/init/Kconfig
> > > > > @@ -83,6 +83,9 @@ config TOOLS_SUPPORT_RELR
> > > > > config CC_HAS_ASM_INLINE
> > > > > def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
> > > > >
> > > > > +config CC_HAS_NO_PROFILE_FN_ATTR
> > > > > + def_bool $(success,echo '__attribute__((no_profile)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
> > > > > +
> > > > > config CONSTRUCTORS
> > > > > bool
> > > > >
> > > > > diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
> > > > > index 58f87a3092f3..19facd4289cd 100644
> > > > > --- a/kernel/gcov/Kconfig
> > > > > +++ b/kernel/gcov/Kconfig
> > > > > @@ -5,6 +5,7 @@ config GCOV_KERNEL
> > > > > bool "Enable gcov-based kernel profiling"
> > > > > depends on DEBUG_FS
> > > > > depends on !CC_IS_CLANG || CLANG_VERSION >= 110000
> > > > > + depends on !X86 || (X86 && CC_HAS_NO_PROFILE_FN_ATTR)
> > > >
> > > > [+Cc Mark]
> > > >
> > > > arm64 is also starting to rely on noinstr working properly.
> > >
> > > Sure,
> > > Will, Catalin, other arm64 folks:
> > > Any thoughts on requiring GCC 7.1+/Clang 13.0+ for GCOV support? That
> > > way we can better guarantee that GCOV (and eventually, PGO) don't
> > > touch noinstr functions?
> > >
> > > If that's ok, I'll add modify the above like:
> > >
> > > + depends on !ARM64 || (ARM64 && CC_HAS_NO_PROFILE_FN_ATTR)
> >
> > Wouldn't "!ARM64 || CC_HAS_NO_PROFILE_FN_ATTR" be more succinct?
>
> We need to be able to express via Kconfig "GCOV should not be enabled
> for architectures that use noinstr when the toolchain does not support
> __attribute__((no_profile_instrument_function))."
>
> Where "architectures that use noinstr" are currently arm64, s390, and
> x86. So I guess we could do:
>
> + depends on !ARM64 || !S390 || !X86 || CC_HAS_NO_PROFILE_FN_ATTR
I think you want:
depends on !(ARM64 || S390 || X86) || CC_HAS_NO_PROFILE_FN_ATTR
> (We could add a Kconfig for ARCH_WANTS_NO_INSTR, which might be more
> informative than listed out architectures which might be non-obvious
> to passers-by).
That would probably look better.
--
Catalin
next prev parent reply other threads:[~2021-06-22 9:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-18 23:30 [PATCH 0/2] no_profile fn attr and Kconfig for GCOV+PGO Nick Desaulniers
2021-06-18 23:30 ` [PATCH 1/2] compiler_attributes.h: define __no_profile, add to noinstr Nick Desaulniers
2021-06-19 11:26 ` Miguel Ojeda
2021-06-19 11:32 ` Miguel Ojeda
2021-06-21 18:10 ` Nick Desaulniers
2021-06-21 18:24 ` Fangrui Song
2021-06-21 19:09 ` Miguel Ojeda
2021-06-18 23:30 ` [PATCH 2/2] Kconfig: CC_HAS_NO_PROFILE_FN_ATTR, depend on for GCOV and PGO Nick Desaulniers
2021-06-19 6:23 ` Marco Elver
2021-06-21 18:22 ` Nick Desaulniers
2021-06-21 18:50 ` Bill Wendling
2021-06-21 20:43 ` Nick Desaulniers
2021-06-21 21:15 ` Nathan Chancellor
2021-06-22 9:25 ` Catalin Marinas [this message]
2021-06-22 9:29 ` Mark Rutland
2021-06-22 9:32 ` Catalin Marinas
2021-06-18 23:52 ` [PATCH 0/2] no_profile fn attr and Kconfig for GCOV+PGO Fangrui Song
2021-06-19 2:45 ` Kees Cook
2021-06-20 8:08 ` Bill Wendling
2021-06-20 14:53 ` Miguel Ojeda
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=20210622092533.GB3555@arm.com \
--to=catalin.marinas@arm.com \
--cc=akpm@linux-foundation.org \
--cc=ardb@kernel.org \
--cc=arnd@arndb.de \
--cc=borntraeger@de.ibm.com \
--cc=bp@alien8.de \
--cc=clang-built-linux@googlegroups.com \
--cc=corbet@lwn.net \
--cc=dvyukov@google.com \
--cc=elver@google.com \
--cc=gor@linux.ibm.com \
--cc=hca@linux.ibm.com \
--cc=johannes.berg@intel.com \
--cc=keescook@chromium.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux-toolchains@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=luc.vanoostenryck@gmail.com \
--cc=mark.rutland@arm.com \
--cc=masahiroy@kernel.org \
--cc=maskray@google.com \
--cc=miguel.ojeda.sandonis@gmail.com \
--cc=mliska@suse.cz \
--cc=morbo@google.com \
--cc=nathan@kernel.org \
--cc=ndesaulniers@google.com \
--cc=oberpar@linux.ibm.com \
--cc=peterz@infradead.org \
--cc=samitolvanen@google.com \
--cc=wcw@google.com \
--cc=will@kernel.org \
--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).