From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@amacapital.net>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC][PATCH 5/5] ftrace/x86-32: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set
Date: Wed, 15 Mar 2017 16:55:45 -0500 [thread overview]
Message-ID: <20170315215545.co7elr7b3lguwaiu@treble> (raw)
In-Reply-To: <20170315200255.828608428@goodmis.org>
On Wed, Mar 15, 2017 at 03:55:32PM -0400, Steven Rostedt wrote:
> +#ifdef USING_FRAME_POINTER
> +# ifdef CC_USING_FENTRY
> + /*
> + * Frame pointers are of ip followed by bp.
> + * Since fentry is an immediate jump, we are left with
> + * parent-ip, function-ip. We need to add a frame with
> + * parent-ip followed by ebp.
> + */
> + pushl 4(%esp) /* parent ip */
> pushl %ebp
> movl %esp, %ebp
> -
> + pushl 2*4(%esp) /* function ip */
> +# endif
> + /* For mcount, the function ip is directly above */
> + pushl %ebp
> + movl %esp, %ebp
> +#endif
More vertical operand alignment issues.
> @@ -85,6 +140,10 @@ ENTRY(ftrace_regs_caller)
> pushl %edx
> pushl %ecx
> pushl %ebx
> +#ifndef USING_FRAME_POINTER
> + /* Load 4 off of the parent ip addr into ebp */
> + lea 14*4(%esp), %ebp
> +#endif
Instead of:
#ifndef USING_FRAME_POINTER
Shouldn't it be:
#ifdef CC_USING_FENTRY
?
Otherwise, if I'm reading it right, with fentry and
CONFIG_FRAME_POINTER=y, ebp will lead to the grandparent's ip instead of
the parent's ip.
--
Josh
next prev parent reply other threads:[~2017-03-15 21:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-15 19:55 [RFC][PATCH 0/5] ftrace/x86_32: Ftrace cleanup and add support for -mfentry Steven Rostedt
2017-03-15 19:55 ` [RFC][PATCH 1/5] x86/ftrace: Rename mcount_64.S to ftrace.S Steven Rostedt
2017-03-15 19:55 ` [RFC][PATCH 2/5] ftrace/x86-32: Move the ftrace specific code out of entry_32.S Steven Rostedt
2017-03-15 19:55 ` [RFC][PATCH 3/5] ftrace/x86_32: Add stack frame pointer to ftrace_caller Steven Rostedt
2017-03-15 21:13 ` Josh Poimboeuf
2017-03-15 19:55 ` [RFC][PATCH 4/5] ftrace/x86_32: Clean up ftrace_regs_caller Steven Rostedt
2017-03-15 21:13 ` Josh Poimboeuf
2017-03-15 23:11 ` Steven Rostedt
2017-03-16 8:39 ` Masami Hiramatsu
2017-03-15 19:55 ` [RFC][PATCH 5/5] ftrace/x86-32: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set Steven Rostedt
2017-03-15 21:55 ` Josh Poimboeuf [this message]
2017-03-15 23:13 ` Steven Rostedt
2017-03-16 9:24 ` Masami Hiramatsu
2017-03-16 13:02 ` Steven Rostedt
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