From: Nick Desaulniers <ndesaulniers@google.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Borislav Petkov <bp@alien8.de>, Vasily Gorbik <gor@linux.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
x86@kernel.org, llvm@lists.linux.dev,
linux-sparse@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel test robot <lkp@intel.com>,
Nathan Chancellor <nathan@kernel.org>,
linux-toolchains@vger.kernel.org, apinski@marvell.com
Subject: Re: [PATCH] objtool: prefer memory clobber & %= to volatile & __COUNTER__
Date: Tue, 25 Jan 2022 18:12:20 -0800 [thread overview]
Message-ID: <CAKwvOdnBT74081nCw2hcm2dxCacV0ume_noZ0=Q6e0UiBDF7wg@mail.gmail.com> (raw)
In-Reply-To: <CAKwvOd=P0VAFrrUXV0z5dES9hYP2b8-KwTzyG5=ezeUve=K3QA@mail.gmail.com>
On Tue, Jan 25, 2022 at 4:59 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> On Tue, Jan 25, 2022 at 3:34 PM Segher Boessenkool
> <segher@kernel.crashing.org> wrote:
> >
> > Hi!
> >
> > On Mon, Jan 24, 2022 at 03:26:36PM -0800, Nick Desaulniers wrote:
> >
> > > If this is fixed in gcc-10, then we can probably add a comment with a
> > > FIXME link to the issue or commit to replace __COUNTER__ with %= one
> > > day. If not, then we can probably come up with a reduced test case
> > > for the GCC devs to take a look at, then add the FIXME comment to
> > > kernel sources.
> >
> > Please open a PR?
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104236
Andrew clarified (thanks Andrew!) that %= can't be used as I imagined
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104236#c4
and that I think was alluded to in
commit 3d1e236022cc ("objtool: Prevent GCC from merging annotate_unreachable()")
which is fine, so I'll just need to keep usage of __COUNTER__. I'll
try out a revised approach for this patch tomorrow.
--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2022-01-26 2:12 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-14 1:05 [PATCH] objtool: prefer memory clobber & %= to volatile & __COUNTER__ Nick Desaulniers
2022-01-14 21:58 ` Nathan Chancellor
2022-01-16 13:32 ` Borislav Petkov
2022-01-18 19:22 ` Josh Poimboeuf
2022-01-18 23:01 ` Josh Poimboeuf
2022-01-18 23:33 ` Borislav Petkov
2022-01-19 0:03 ` Josh Poimboeuf
2022-01-19 10:01 ` Borislav Petkov
2022-01-24 23:26 ` Nick Desaulniers
2022-01-24 23:38 ` Nick Desaulniers
2022-01-25 18:49 ` Borislav Petkov
2022-01-25 23:31 ` Segher Boessenkool
2022-01-26 0:59 ` Nick Desaulniers
2022-01-26 2:12 ` Nick Desaulniers [this message]
2022-01-26 11:13 ` Segher Boessenkool
2022-01-31 20:45 ` Nick Desaulniers
2022-01-31 22:13 ` Segher Boessenkool
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