linux-kernel - Re: [PATCH 4/6 v3] ftrace/x86_32: Clean up ftrace_regs

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Date:   Mon, 20 Mar 2017 09:01:33 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...capital.net>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 4/6 v3] ftrace/x86_32: Clean up ftrace_regs_caller

On Sat, Mar 18, 2017 at 05:09:27PM -0400, Steven Rostedt wrote:
> @@ -111,12 +114,11 @@ GLOBAL(ftrace_regs_call)
>  	popl	%es
>  	popl	%fs
>  	popl	%gs
> -	addl	$8, %esp			/* Skip orig_ax and ip */
> -	popf					/* Pop flags at end (no addl to corrupt flags) */
> -	jmp	.Lftrace_ret
>  
> -	popf
> -	jmp	ftrace_stub
> +	/* use lea to not affect flags */
> +	lea	3*4(%esp), %esp			/* Skip orig_ax, ip and flags */
> +
> +	jmp	.Lftrace_ret
>  #else /* ! CONFIG_DYNAMIC_FTRACE */
>  
>  ENTRY(mcount)

That last comment should be

  /* Skip orig_ax, ip and cs */

Otherwise:

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

-- 
Josh