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From: "H. Peter Anvin" <hpa@zytor.com>
To: Andrew Haley <aph@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H.J. Lu" <hjl.tools@gmail.com>,
	rostedt@goodmis.org, Ingo Molnar <mingo@elte.hu>,
	LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	feng.tang@intel.com, Peter Zijlstra <peterz@infradead.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	David Daney <ddaney@caviumnetworks.com>,
	Richard Guenther <richard.guenther@gmail.com>,
	gcc <gcc@gcc.gnu.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH][GIT PULL][v2.6.32] tracing/x86: Add check to detect GCC messing with mcount prologue
Date: Tue, 24 Nov 2009 11:55:27 -0800	[thread overview]
Message-ID: <4B0C3A2F.20703@zytor.com> (raw)
In-Reply-To: <4B0C13F4.5090106@redhat.com>

On 11/24/2009 09:12 AM, Andrew Haley wrote:
>>
>> If we're changing gcc anyway, then let's add the option of intercepting
>> the function at the point where the machine state is well-defined by
>> ABI, which is before the function stack frame is set up.
> 
> Hmm.  On the x86 I suppose we could just inject a naked call instruction,
> but not all aeches allow us to call anything before we've saved the return
> address.  Or are you talking x86 only?
> 

For x86, we should use a naked call.

For architectures where that is not possible, we should use a minimal
sequence such that the ABI state at the invocation point is 100% derivable.

On MIPS, for example, we could use a sequence such as:

	mov at, ra
	jal __fentry__

It would be up to __fentry__ to save the value in at and to restore it
back into ra before resuming, meaning that __fentry__ has a nonstandard
calling convention.

	-hpa

  parent reply	other threads:[~2009-11-24 19:59 UTC|newest]

Thread overview: 93+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <200911172214.nAHMEBh2023787@imap1.linux-foundation.org>
2009-11-18 19:30 ` [patch for 2.6.32? 1/3] hrtimers: remove the "timer_stats_active" check when setting the start info Thomas Gleixner
2009-11-18 20:24   ` [tip:timers/urgent] hrtimer: Fix /proc/timer_list regression tip-bot for Feng Tang
2009-11-19  7:20     ` Ingo Molnar
2009-11-19 10:05       ` Thomas Gleixner
2009-11-19 14:30         ` BUG: function graph tracer function frame assumptions Thomas Gleixner
2009-11-19 15:37           ` BUG: GCC-4.4.x changes the function frame on some functions Thomas Gleixner
2009-11-19 15:44             ` Andrew Haley
2009-11-19 15:54               ` H. Peter Anvin
2009-11-19 15:57                 ` Richard Guenther
2009-11-19 16:02               ` Steven Rostedt
2009-11-19 16:11                 ` H. Peter Anvin
2009-11-19 16:19                 ` Frederic Weisbecker
2009-11-19 16:06               ` Thomas Gleixner
2009-11-19 16:17                 ` Andrew Haley
2009-11-19 16:43                   ` Thomas Gleixner
2009-11-19 16:12               ` Steven Rostedt
2009-11-19 15:45             ` H. Peter Anvin
2009-11-19 15:49               ` Richard Guenther
2009-11-19 15:52                 ` Richard Guenther
2009-11-19 17:37                 ` Andi Kleen
2009-11-19 17:39             ` Linus Torvalds
2009-11-19 17:51               ` Thomas Gleixner
2009-11-19 17:59               ` Steven Rostedt
2009-11-19 18:03                 ` Richard Guenther
2009-11-19 18:22                   ` Andrew Haley
2009-11-19 18:41                     ` Linus Torvalds
2009-11-19 18:43                       ` Linus Torvalds
2009-11-19 18:54                         ` Linus Torvalds
2009-11-19 19:01                           ` Thomas Gleixner
2009-11-23  9:16                             ` Jakub Jelinek
2009-11-23  9:51                               ` Thomas Gleixner
2009-11-19 19:10                           ` David Daney
2009-11-19 19:28                             ` Steven Rostedt
2009-11-19 19:46                               ` Frederic Weisbecker
2009-11-19 19:54                                 ` Kai Tietz
2009-11-19 20:05                                   ` Frederic Weisbecker
2009-11-19 20:05                                 ` Steven Rostedt
2009-11-19 20:17                                   ` Steven Rostedt
2009-11-19 20:28                                     ` Frederic Weisbecker
2009-11-19 20:25                                   ` Frederic Weisbecker
2009-11-19 20:36                                     ` Linus Torvalds
2009-11-19 20:44                                       ` Steven Rostedt
2009-11-19 19:50                               ` H. Peter Anvin
2009-11-19 20:06                                 ` Linus Torvalds
2009-11-19 21:12                                   ` Jeff Law
2009-11-19 20:10                                 ` Steven Rostedt
2009-11-19 21:05                                 ` Jeff Law
2009-11-19 18:31                   ` Thomas Gleixner
2009-11-19 18:38                   ` Linus Torvalds
2009-11-19 18:47                     ` Ingo Molnar
2009-11-19 19:06                       ` Steven Rostedt
2009-11-19 19:50                         ` Ingo Molnar
2009-11-20  9:57                         ` [PATCH] gcc mcount-nofp was " Andi Kleen
2009-11-20 12:34                           ` Steven Rostedt
2009-11-20 19:06                             ` H. Peter Anvin
2009-11-19 20:36                     ` Thomas Gleixner
2009-11-19 18:20             ` Andrew Haley
2009-11-19 18:33               ` Steven Rostedt
2009-11-19 18:36                 ` Andrew Pinski
2009-11-19 18:36                 ` Andrew Haley
2009-11-19 18:37                 ` H. Peter Anvin
2009-11-19 18:39               ` Thomas Gleixner
2009-11-20  5:23           ` [PATCH][GIT PULL][v2.6.32] tracing/x86: Add check to detect GCC messing with mcount prologue Steven Rostedt
2009-11-20  5:32             ` Steven Rostedt
2009-11-20 17:00             ` Steven Rostedt
2009-11-20 17:13               ` H. Peter Anvin
2009-11-20 19:35               ` Andrew Haley
2009-11-20 19:46                 ` Steven Rostedt
2009-11-20 19:49                   ` H. Peter Anvin
2009-11-22  9:38                 ` H.J. Lu
2009-11-22 17:20                   ` Andrew Haley
2009-11-22 23:30                     ` H.J. Lu
2009-11-24 14:43                       ` Andrew Haley
2009-11-24 14:55                         ` Thomas Gleixner
2009-11-24 15:06                           ` Jakub Jelinek
2009-11-24 15:32                             ` Andrew Haley
2009-11-24 15:36                               ` Jakub Jelinek
2009-11-24 15:46                                 ` Andrew Haley
2009-11-24 16:38                                   ` H. Peter Anvin
2009-11-24 17:12                                     ` Andrew Haley
2009-11-24 17:30                                       ` Steven Rostedt
2009-11-25 20:05                                         ` H. Peter Anvin
2009-11-24 19:55                                       ` H. Peter Anvin [this message]
2009-11-25 15:29                             ` Thomas Gleixner
2009-11-25 15:44                               ` Ingo Molnar
2009-11-25 15:53                                 ` Thomas Gleixner
2009-11-25 16:25                                   ` Ingo Molnar
2009-11-25 16:44                                 ` Jakub Jelinek
2009-11-25 20:12                                   ` H. Peter Anvin
2009-11-25 21:00                                     ` Andrew Haley
2009-11-22  9:05               ` Ingo Molnar
2009-11-20 10:30   ` [tip:timers/urgent] hrtimer: Fix /proc/timer_list regression tip-bot for Feng Tang
2009-11-20 14:19     ` Heiko Carstens

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