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From: dave.martin@linaro.org (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/3] ARM: entry: Remove unnecessary masking when decoding Thumb-2 instructions
Date: Thu, 18 Aug 2011 18:01:53 +0100	[thread overview]
Message-ID: <1313686914-29481-3-git-send-email-dave.martin@linaro.org> (raw)
In-Reply-To: <1313686914-29481-1-git-send-email-dave.martin@linaro.org>

When testing whether a Thumb-2 instruction is 32 bits long or not,
the masking done in order to test bits 11-15 of the first
instruction halfword won't affect the result of the comparison, so
remove it.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
Reviewed-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
---
 arch/arm/kernel/entry-armv.S |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index a87cbf8..b7236d4 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -262,8 +262,7 @@ __und_svc:
 	ldr	r0, [r4, #-4]
 #else
 	ldrh	r0, [r4, #-2]			@ Thumb instruction at LR - 2
-	and	r9, r0, #0xf800
-	cmp	r9, #0xe800			@ 32-bit instruction if xx >= 0
+	cmp	r0, #0xe800			@ 32-bit instruction if xx >= 0
 	ldrhhs	r9, [r4]			@ bottom 16 bits
 	orrhs	r0, r9, r0, lsl #16
 #endif
@@ -445,8 +444,7 @@ __und_usr:
  ARM(	ldrht	r5, [r4], #2	)
  THUMB(	ldrht	r5, [r4]	)
  THUMB(	add	r4, r4, #2	)
-	and	r0, r5, #0xf800			@ mask bits 111x x... .... ....
-	cmp	r0, #0xe800			@ 32bit instruction if xx != 0
+	cmp	r5, #0xe800			@ 32bit instruction if xx != 0
 	blo	__und_usr_unknown
 3:	ldrht	r0, [r4]
 	add	r2, r2, #2			@ r2 is PC + 2, make it PC + 4
-- 
1.7.4.1

  parent reply	other threads:[~2011-08-18 17:01 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-18 17:01 [PATCH v2 0/3] Fix Thumb-2 undef handling for mixed-arch kernels Dave Martin
2011-08-18 17:01 ` [PATCH v2 1/3] ARM: Make cpu_architecture into a global variable Dave Martin
2011-08-18 17:01 ` Dave Martin [this message]
2011-08-18 17:01 ` [PATCH v2 3/3] ARM: entry: Fix Thumb-2 undef handling for multi-CPU kernels Dave Martin
2011-08-18 22:29 ` [PATCH v2 0/3] Fix Thumb-2 undef handling for mixed-arch kernels Russell King - ARM Linux
2011-08-19  8:44   ` Tixy
2011-08-19  9:10     ` Dave Martin
2011-08-19  9:22       ` Tixy
2011-08-19  9:00   ` Dave Martin

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