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Date:   Mon, 21 Jun 2021 11:24:18 -0700
From:   Fangrui Song <maskray@google.com>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        Kees Cook <keescook@chromium.org>,
        Peter Zijlstra <peterz@infradead.org>,
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        Sami Tolvanen <samitolvanen@google.com>,
        Peter Oberparleiter <oberpar@linux.ibm.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
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        Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Will Deacon <will@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
        Andrew Morton <akpm@linux-foundation.org>,
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Subject: Re: [PATCH 1/2] compiler_attributes.h: define __no_profile, add to
 noinstr
Message-ID: <20210621182418.57qbumtovysrlkwy@google.com>
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On 2021-06-21, Nick Desaulniers wrote:
>On Sat, Jun 19, 2021 at 4:32 AM Miguel Ojeda
><miguel.ojeda.sandonis@gmail.com> wrote:
>>
>> On Sat, Jun 19, 2021 at 1:26 PM Miguel Ojeda
>> <miguel.ojeda.sandonis@gmail.com> wrote:
>> >
>> > I am not sure if it is best or not to have the GCC link in order to be
>> > consistent with the rest of the links (they are for the docs only). Do
>> > we know if GCC going to implement it soon?
>>
>> i.e. if GCC does not implement it yet we use elsewhere this kind of
>> marker instead:
>>
>>      * Optional: not supported by gcc
>>
>> The first of its kind, normally it is clang/icc there ;-)
>
>:^) GCC does have an attribute since GCC 7.1 for this.
>https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80223#c11
>I'm moving Clang over to use that in
>https://reviews.llvm.org/D104658
>Once that lands, I'll send a v2 (without carrying any reviewed by tags).

Thanks! __attribute__((no_profile_instrument_function)) looks good to me.

Also a reminder that __GCC4_has_attribute___no_profile in v1 misses two
underscores. v2 no_profile_instrument_function may need to fix this.


Reviewed-by: Fangrui Song <maskray@google.com>

>>
>> We could nevertheless have the link there, something like:
>>
>>     * Optional: not supported by GCC
>>                 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80223
>
>-- 
>Thanks,
>~Nick Desaulniers