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Re: [PATCH] i386: Assembly Implementation cleanup

On 08/12/2015 09:22 PM, H.J. Lu wrote:
> On Wed, Aug 12, 2015 at 8:06 AM, H.J. Lu <> wrote:
>> On Wed, Aug 12, 2015 at 8:01 AM, Florian Weimer <> wrote:
>>> On 08/12/2015 02:44 PM, H.J. Lu wrote:
>>>> Is there a way to truly inline syscall with 6 arguments, not by calling
>>>> __libc_do_syscall?
> With my GCC 5 patch:
> This updated patch will generate optimized code when GCC 5
> or above is used.  Any comments?

I like it.  Perhaps you could quote a bit of disassembly in the commit

I would suggest to define a new macro (say,
__usues_many_argument_syscall or something shorter) which expands to
"__attribute__ ((optimize ("omit-frame-pointer), noinline))” on i386 and
apply it to the function in the C source file, instead of adding it to
the makefiles (assuming that this works, I have not tried it).  This
way, it would be more explicit what happens.  In the documentation of
the new macro, quote a typical GCC error message if a many-argument
system call is used without it.

(There are quite a few -fomit-frame-pointer settings in the makefiles,
some of which are curious.)

Florian Weimer / Red Hat Product Security

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