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From: rabin@rab.in (Rabin Vincent)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 06/10] ARM: ftrace: add Thumb-2 support
Date: Wed, 31 Mar 2010 23:55:18 +0530	[thread overview]
Message-ID: <20100331182518.GA30522@debian> (raw)
In-Reply-To: <tnxsk80r2dh.fsf@e102109-lin.cambridge.arm.com>

On Tue, Mar 16, 2010 at 10:23:54AM +0000, Catalin Marinas wrote:
> If the ftrace_stub isn't .globl, the code compiles fine. My approach
> would be something like this:

New patch below:

WARNING: multiple messages have this Message-ID (diff)
From: Rabin Vincent <rabin@rab.in>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-kernel@vger.kernel.org,
	"Abhishek Sagar" <sagar.abhishek@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Steven Rostedt" <rostedt@goodmis.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Frederic Weisbecker" <fweisbec@gmail.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 06/10] ARM: ftrace: add Thumb-2 support
Date: Wed, 31 Mar 2010 23:55:18 +0530	[thread overview]
Message-ID: <20100331182518.GA30522@debian> (raw)
In-Reply-To: <tnxsk80r2dh.fsf@e102109-lin.cambridge.arm.com>

On Tue, Mar 16, 2010 at 10:23:54AM +0000, Catalin Marinas wrote:
> If the ftrace_stub isn't .globl, the code compiles fine. My approach
> would be something like this:

New patch below:

>From bf828a0c069b1bb3f6bf4e68f1dceecab396c286 Mon Sep 17 00:00:00 2001
From: Rabin Vincent <rabin@rab.in>
Date: Sun, 14 Feb 2010 01:18:34 +0530
Subject: [PATCH 06/10] ARM: ftrace: add Thumb-2 support

Fix the mcount routines to build and run on a kernel built with the
Thumb-2 instruction set by correcting the following errors using the
fixes suggested by Catalin Marinas:

 - Problem: The following assembler errors appear at the "adr r0,
   ftrace_stub" instruction:

   entry-common.S: Assembler messages:
   entry-common.S:179: Error: invalid immediate for address calculation (value = 0x00000004)

   Fix: The errors don't occur with a non-global symbol, so use one.

 - Problem: The "mov lr, pc" does not set the lsb when storing the pc in
   lr.  The called function returns with "bx lr", and the mode changes
   to ARM.

   Fix: Add a label on the return address and use "adr lr, BSYM(label)".

We don't modify the old mcount because it won't be built when using
Thumb-2.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Rabin Vincent <rabin@rab.in>
---
 arch/arm/kernel/entry-common.S |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index c7a8c20..f5e75de 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -167,7 +167,7 @@ ENTRY(__gnu_mcount_nc)
 	stmdb	sp!, {r0-r3, lr}
 	ldr	r0, =ftrace_trace_function
 	ldr	r2, [r0]
-	adr	r0, ftrace_stub
+	adr	r0, .Lftrace_stub
 	cmp	r0, r2
 	bne	gnu_trace
 	ldmia	sp!, {r0-r3, ip, lr}
@@ -177,8 +177,9 @@ gnu_trace:
 	ldr	r1, [sp, #20]			@ lr of instrumented routine
 	mov	r0, lr
 	sub	r0, r0, #MCOUNT_INSN_SIZE
-	mov	lr, pc
+	adr	lr, BSYM(1f)
 	mov	pc, r2
+1:
 	ldmia	sp!, {r0-r3, ip, lr}
 	mov	pc, ip
 ENDPROC(__gnu_mcount_nc)
@@ -213,6 +214,7 @@ ENDPROC(mcount)
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 ENTRY(ftrace_stub)
+.Lftrace_stub:
 	mov	pc, lr
 ENDPROC(ftrace_stub)
 
-- 
1.7.0


  reply	other threads:[~2010-03-31 18:25 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-13  6:49 [PATCH 00/10] ARM: ftrace: cleanups, Thumb-2, and dynamic ftrace (v2) Rabin Vincent
2010-03-13  6:49 ` Rabin Vincent
2010-03-13  6:49 ` [PATCH 01/10] ARM: ftrace: clean up mcount assembly indentation Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-03-13  6:49 ` [PATCH 02/10] ARM: ftrace: document mcount formats Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-03-13  6:49 ` [PATCH 03/10] ftrace: allow building without frame pointers Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-03-13 17:36   ` Steven Rostedt
2010-03-13 17:36     ` Steven Rostedt
2010-03-15 18:45     ` Rabin Vincent
2010-03-15 18:45       ` Rabin Vincent
2010-03-14 16:56   ` Steven Rostedt
2010-03-14 16:56     ` Steven Rostedt
2010-03-13  6:49 ` [PATCH 04/10] ARM: " Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-03-13 17:38   ` Steven Rostedt
2010-03-13 17:38     ` Steven Rostedt
2010-03-14 16:56   ` Steven Rostedt
2010-03-14 16:56     ` Steven Rostedt
2010-03-17 16:16     ` Catalin Marinas
2010-03-17 16:16       ` Catalin Marinas
2010-03-13  6:49 ` [PATCH 05/10] ARM: ftrace: add ENDPROC annotations Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-03-13  8:45   ` Russell King - ARM Linux
2010-03-13  8:45     ` Russell King - ARM Linux
2010-04-21 19:23     ` Rabin Vincent
2010-04-21 19:23       ` Rabin Vincent
2010-08-10 17:07       ` Catalin Marinas
2010-08-10 17:07         ` Catalin Marinas
2010-08-10 19:11         ` Rabin Vincent
2010-08-10 19:11           ` Rabin Vincent
2010-03-13  6:49 ` [PATCH 06/10] ARM: ftrace: add Thumb-2 support Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-03-14 22:30   ` Catalin Marinas
2010-03-14 22:30     ` Catalin Marinas
2010-03-15 18:32     ` Rabin Vincent
2010-03-15 18:32       ` Rabin Vincent
2010-03-16 10:23   ` Catalin Marinas
2010-03-16 10:23     ` Catalin Marinas
2010-03-31 18:25     ` Rabin Vincent [this message]
2010-03-31 18:25       ` Rabin Vincent
2010-04-23 15:37       ` Catalin Marinas
2010-04-23 15:37         ` Catalin Marinas
2010-03-13  6:49 ` [PATCH 07/10] ftrace: pass KBUILD_CFLAGS to record_mcount.pl Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-03-13 17:41   ` Steven Rostedt
2010-03-13 17:41     ` Steven Rostedt
2010-03-14 16:56   ` Steven Rostedt
2010-03-14 16:56     ` Steven Rostedt
2010-03-31 18:45     ` Rabin Vincent
2010-03-31 18:45       ` Rabin Vincent
2010-08-03 16:42   ` Rabin Vincent
2010-08-03 16:42     ` Rabin Vincent
2010-08-06 15:31     ` Frederic Weisbecker
2010-08-06 15:31       ` Frederic Weisbecker
2010-08-06 20:23     ` Steven Rostedt
2010-08-06 20:23       ` Steven Rostedt
2010-08-07  5:33       ` Rabin Vincent
2010-08-07  5:33         ` Rabin Vincent
2010-08-07 12:57         ` Steven Rostedt
2010-08-07 12:57           ` Steven Rostedt
2010-03-13  6:49 ` [PATCH 08/10] ARM: ftrace: fix and update dynamic ftrace Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-03-13 17:42   ` Steven Rostedt
2010-03-13 17:42     ` Steven Rostedt
2010-03-14 16:56   ` Steven Rostedt
2010-03-14 16:56     ` Steven Rostedt
2010-03-13  6:49 ` [PATCH 09/10] ARM: ftrace: add Thumb-2 support to " Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-03-13  6:49 ` [PATCH 10/10] ARM: ftrace: enable " Rabin Vincent
2010-03-13  6:49   ` Rabin Vincent
2010-04-21 19:26 ` [PATCH 00/10] ARM: ftrace: cleanups, Thumb-2, and dynamic ftrace (v2) Rabin Vincent
2010-04-21 19:26   ` Rabin Vincent
  -- strict thread matches above, loose matches on Subject: below --
2010-02-13 19:48 [PATCH 06/10] ARM: ftrace: add Thumb-2 support Rabin Vincent
2010-02-13 19:48 [PATCH 00/10] ARM: ftrace: cleanups, Thumb-2, and dynamic ftrace Rabin Vincent
2010-02-13 19:48 ` [PATCH 06/10] ARM: ftrace: add Thumb-2 support Rabin Vincent
2010-02-13 19:48   ` Rabin Vincent
2010-02-13 23:27   ` Catalin Marinas
2010-02-13 23:27     ` Catalin Marinas
2010-02-14 16:38     ` Rabin Vincent
2010-02-14 16:38       ` Rabin Vincent

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