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From: David Daney <david.daney@cavium.com>
To: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
Cc: linux-mips@linux-mips.org, Ralf Baechle <ralf@linux-mips.org>
Subject: Re: [PATCH] MIPS: SMTC: Correct saving of CP0_STATUS
Date: Mon, 29 Aug 2011 16:45:20 -0700	[thread overview]
Message-ID: <4E5C2490.6040203@cavium.com> (raw)
In-Reply-To: <20110829232029.GA15763@zapo>

[-- Attachment #1: Type: text/plain, Size: 481 bytes --]

On 08/29/2011 04:20 PM, Edgar E. Iglesias wrote:
> Hi,
>
> Commit 362e696428590f7d0a5d0971a2d04b0372a761b8
> reorders a bunch of insns to improve the flow of the pipeline but
> for MT_SMTC kernels, AFAICT, the saving of CP0_STATUS seems wrong.

Indeed.

>
> Am I missing something?
>

It does look like in the MIPS_MT_SMTC case we are clobbering the value 
in v1.

> If not here is a patch, tested with qemu.
>

How about the attached completely untested one instead?

David Daney

[-- Attachment #2: 0001-MIPS-Don-t-clobber-CP0_STATUS-vaue-for-CONFIG_MIPS_M.patch --]
[-- Type: text/plain, Size: 967 bytes --]

>From d0035295ae34bcf84d601b1e25e2642fe0802752 Mon Sep 17 00:00:00 2001
From: David Daney <david.daney@cavium.com>
Date: Mon, 29 Aug 2011 16:42:12 -0700
Subject: [PATCH] MIPS: Don't clobber CP0_STATUS vaue for CONFIG_MIPS_MT_SMTC

Untested, but it looks nice.

Reported-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: David Daney <david.daney@cavium.com>
---
 arch/mips/include/asm/stackframe.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
index 569681e..51a3a0c 100644
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
@@ -195,9 +195,9 @@
 		 * to cover the pipeline delay.
 		 */
 		.set	mips32
-		mfc0	v1, CP0_TCSTATUS
+		mfc0	k0, CP0_TCSTATUS
 		.set	mips0
-		LONG_S	v1, PT_TCSTATUS(sp)
+		LONG_S	k0, PT_TCSTATUS(sp)
 #endif /* CONFIG_MIPS_MT_SMTC */
 		LONG_S	$4, PT_R4(sp)
 		LONG_S	$5, PT_R5(sp)
-- 
1.7.2.3


WARNING: multiple messages have this Message-ID (diff)
From: David Daney <david.daney@cavium.com>
To: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
Cc: linux-mips@linux-mips.org, Ralf Baechle <ralf@linux-mips.org>
Subject: Re: [PATCH] MIPS: SMTC: Correct saving of CP0_STATUS
Date: Mon, 29 Aug 2011 16:45:20 -0700	[thread overview]
Message-ID: <4E5C2490.6040203@cavium.com> (raw)
Message-ID: <20110829234520.A521dnOMOl2aQ7pdMe0MNfbOBZwWKxceIShIcs8f2xM@z> (raw)
In-Reply-To: <20110829232029.GA15763@zapo>

[-- Attachment #1: Type: text/plain, Size: 481 bytes --]

On 08/29/2011 04:20 PM, Edgar E. Iglesias wrote:
> Hi,
>
> Commit 362e696428590f7d0a5d0971a2d04b0372a761b8
> reorders a bunch of insns to improve the flow of the pipeline but
> for MT_SMTC kernels, AFAICT, the saving of CP0_STATUS seems wrong.

Indeed.

>
> Am I missing something?
>

It does look like in the MIPS_MT_SMTC case we are clobbering the value 
in v1.

> If not here is a patch, tested with qemu.
>

How about the attached completely untested one instead?

David Daney

[-- Attachment #2: 0001-MIPS-Don-t-clobber-CP0_STATUS-vaue-for-CONFIG_MIPS_M.patch --]
[-- Type: text/plain, Size: 966 bytes --]

From d0035295ae34bcf84d601b1e25e2642fe0802752 Mon Sep 17 00:00:00 2001
From: David Daney <david.daney@cavium.com>
Date: Mon, 29 Aug 2011 16:42:12 -0700
Subject: [PATCH] MIPS: Don't clobber CP0_STATUS vaue for CONFIG_MIPS_MT_SMTC

Untested, but it looks nice.

Reported-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: David Daney <david.daney@cavium.com>
---
 arch/mips/include/asm/stackframe.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
index 569681e..51a3a0c 100644
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
@@ -195,9 +195,9 @@
 		 * to cover the pipeline delay.
 		 */
 		.set	mips32
-		mfc0	v1, CP0_TCSTATUS
+		mfc0	k0, CP0_TCSTATUS
 		.set	mips0
-		LONG_S	v1, PT_TCSTATUS(sp)
+		LONG_S	k0, PT_TCSTATUS(sp)
 #endif /* CONFIG_MIPS_MT_SMTC */
 		LONG_S	$4, PT_R4(sp)
 		LONG_S	$5, PT_R5(sp)
-- 
1.7.2.3


  reply	other threads:[~2011-08-29 23:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-29 23:20 [PATCH] MIPS: SMTC: Correct saving of CP0_STATUS Edgar E. Iglesias
2011-08-29 23:45 ` David Daney [this message]
2011-08-29 23:45   ` David Daney
2011-08-29 23:53   ` David Daney
2011-08-29 23:55   ` Kevin D. Kissell
2011-08-30  0:14     ` David Daney
2011-08-30  0:35       ` Kevin D. Kissell
2011-08-30 11:16         ` Edgar E. Iglesias
2011-08-30 16:54           ` Kevin D. Kissell
2011-09-14 15:12             ` Ralf Baechle
2011-09-14 18:20               ` Kevin D. Kissell
2011-08-30  5:57   ` Edgar E. Iglesias
2011-09-15 16:00   ` Ralf Baechle
2011-09-17  1:23     ` Edgar E. Iglesias
2011-09-17  2:00       ` Ralf Baechle
2011-09-17  2:08         ` Edgar E. Iglesias

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