linux-kernel - Re: [PATCH v2 0/3] locking/rwsem/x86: Add stack frame dependency for some inline asm

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Message-ID: <20170906230547.mgwjx74m6g7fntif@treble>
Date:   Wed, 6 Sep 2017 18:05:47 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Miguel Bernal Marin <miguel.bernal.marin@...ux.intel.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H . Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
        x86@...nel.org
Subject: Re: [PATCH v2 0/3] locking/rwsem/x86: Add stack frame dependency for
 some inline asm

On Wed, Sep 06, 2017 at 05:44:58PM -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.
> 
> Changes in v2:
>   - Update first parameter from _ASM_ADD to '%3' at __downgrade_write()
> 
> Miguel Bernal Marin (3):
>   locking/rwsem/x86: Add stack frame dependency for __up_read()
>   locking/rwsem/x86: Add stack frame dependency for __up_write()
>   locking/rwsem/x86: Add stack frame dependency for __downgrade_write()
> 
>  arch/x86/include/asm/rwsem.h | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)

For the series:

Reviewed-by: Josh Poimboeuf <jpoimboe@...hat.com>

-- 
Josh