From: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H . Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v3 0/6] locking/rwsem/x86: Add stack frame dependency for some inline asm
Date: Mon, 25 Sep 2017 16:34:19 -0500 [thread overview]
Message-ID: <20170925213419.GA23713@miguelinux-clr.zpn.intel.com> (raw)
In-Reply-To: <20170925190321.xr2akcksnwmww363@treble>
On Mon, Sep 25, 2017 at 02:03:21PM -0500, Josh Poimboeuf wrote:
> On Mon, Sep 25, 2017 at 02:00:43PM -0500, Josh Poimboeuf wrote:
> > On Mon, Sep 25, 2017 at 12:34:19PM -0500, Miguel Bernal Marin wrote:
> > > On Wed, Sep 20, 2017 at 04:24:18PM -0500, Josh Poimboeuf wrote:
> > > > On Tue, Sep 19, 2017 at 06:37:39PM -0500, Miguel Bernal Marin wrote:
> > > > > Some warning were showed by objtool using gcc 7.2.0
> > > > >
> > > > > kernel/locking/rwsem.o: warning: objtool: up_read()+0x11: call without frame pointer save/setup
> > > > > kernel/locking/rwsem.o: warning: objtool: up_write()+0x17: call without frame pointer save/setup
> > > > > kernel/locking/rwsem.o: warning: objtool: downgrade_write()+0x22: call without frame pointer save/setup
> > > > >
> > > > > which means gcc placed an inline asm function and its call instruction before
> > > > > the frame pointer setup.
> > > > >
> > > > > This series forces a stack frame to be created before the call instruction
> > > > > by listing the stack pointer as an output operand in the inline asm statement.
> > > > >
> > > > > Also to be easy to maintain and understand the operands from the extended
> > > > > assembler instructions were converted to named operands.
> > > >
> > > > I've got a patch going around which will change the way we do this, so
> > > > you'll probably need to do a v3 after my patch gets merged. I'll add
> > > > you to cc for the next revision.
> > > >
> > >
> > > With your new patches (at v4.14.-rc2) the warning is not seen any more,
> > > so I will send only the named operand patches (in separate thread), as
> > > this fix is not more needed.
> >
> > Any chance you tested with GCC 7? With GCC 6 and older you might still
> > see the warnings.
>
> Sorry, reading again it looks like your warnings only started showing up
> in GCC 7.2.0? If so, then it does make sense that your fix isn't needed
> any more, because my patch fixed this issue for *all* inline asm for GCC
> 7+.
>
Yes it was with GCC 7.2.0
> --
> Josh
--
Regards,
Miguel Bernal Marin Open Source Technology Center
https://clearlinux.org Intel Corporation
prev parent reply other threads:[~2017-09-25 21:34 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-06 5:26 [PATCH 0/3] locking/rwsem/x86: Add stack frame dependency for some inline asm Miguel Bernal Marin
2017-09-06 5:26 ` [PATCH 1/3] locking/rwsem/x86: Add stack frame dependency for __up_read() Miguel Bernal Marin
2017-09-06 5:26 ` [PATCH 2/3] locking/rwsem/x86: Add stack frame dependency for __up_write() Miguel Bernal Marin
2017-09-06 5:26 ` [PATCH 3/3] locking/rwsem/x86: Add stack frame dependency for __downgrade_write() Miguel Bernal Marin
2017-09-06 21:33 ` Josh Poimboeuf
2017-09-06 22:14 ` Miguel Bernal Marin
2017-09-07 7:04 ` Peter Zijlstra
2017-09-06 22:44 ` [PATCH v2 0/3] locking/rwsem/x86: Add stack frame dependency for some inline asm Miguel Bernal Marin
2017-09-06 22:44 ` [PATCH v2 1/3] locking/rwsem/x86: Add stack frame dependency for __up_read() Miguel Bernal Marin
2017-09-07 7:12 ` Ingo Molnar
2017-09-14 21:42 ` Miguel Bernal Marin
2017-09-06 22:45 ` [PATCH v2 2/3] locking/rwsem/x86: Add stack frame dependency for __up_write() Miguel Bernal Marin
2017-09-06 22:45 ` [PATCH v2 3/3] locking/rwsem/x86: Add stack frame dependency for __downgrade_write() Miguel Bernal Marin
2017-09-06 23:05 ` [PATCH v2 0/3] locking/rwsem/x86: Add stack frame dependency for some inline asm Josh Poimboeuf
2017-09-19 23:37 ` [PATCH v3 0/6] " Miguel Bernal Marin
2017-09-19 23:37 ` [PATCH v3 1/6] locking/rwsem/x86: Add stack frame dependency for __up_read() Miguel Bernal Marin
2017-09-19 23:37 ` [PATCH v3 2/6] locking/rwsem/x86: Add stack frame dependency for __up_write() Miguel Bernal Marin
2017-09-19 23:37 ` [PATCH v3 3/6] locking/rwsem/x86: Add stack frame dependency for __downgrade_write() Miguel Bernal Marin
2017-09-19 23:37 ` [PATCH v3 4/6] x86, asm/rwsem: Use named operands in __up_read() Miguel Bernal Marin
2017-09-19 23:37 ` [PATCH v3 5/6] x86, asm/rwsem: Use named operands in __up_write() Miguel Bernal Marin
2017-09-19 23:37 ` [PATCH v3 6/6] x86, asm/rwsem: Use named operands in __downgrade_write() Miguel Bernal Marin
2017-09-20 21:24 ` [PATCH v3 0/6] locking/rwsem/x86: Add stack frame dependency for some inline asm Josh Poimboeuf
2017-09-21 16:59 ` Miguel Bernal Marin
2017-09-25 17:34 ` Miguel Bernal Marin
2017-09-25 19:00 ` Josh Poimboeuf
2017-09-25 19:03 ` Josh Poimboeuf
2017-09-25 21:34 ` Miguel Bernal Marin [this message]
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