From: dave.martin@linaro.org (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 4/5] ARM: entry: Remove unnecessary masking when decoding Thumb-2 instructions
Date: Wed, 10 Aug 2011 11:13:42 +0100 [thread overview]
Message-ID: <1312971223-28165-5-git-send-email-dave.martin@linaro.org> (raw)
In-Reply-To: <1312971223-28165-1-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>
---
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
next prev parent reply other threads:[~2011-08-10 10:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-10 10:13 [RFC PATCH 0/5] Fix Thumb-2 undef handling for mixed-arch kernels Dave Martin
2011-08-10 10:13 ` [RFC PATCH 1/5] ARM: Make cpu_alignment into a global variable Dave Martin
2011-08-10 11:38 ` Tixy
2011-08-10 10:13 ` [RFC PATCH 2/5] ARM: s3c24xx: Reference cpu_architecture as " Dave Martin
2011-08-10 10:13 ` [RFC PATCH 3/5] ARM: kprobes: " Dave Martin
2011-08-10 11:43 ` Tixy
2011-08-10 10:13 ` Dave Martin [this message]
2011-08-10 10:13 ` [RFC PATCH 5/5] ARM: entry: Fix Thumb-2 undef handling for multi-CPU kernels Dave Martin
2011-08-10 11:55 ` Tixy
2011-08-11 13:04 ` Dave Martin
2011-09-01 14:52 ` Arnd Bergmann
2011-09-07 10:54 ` Dave Martin
2011-09-12 10:33 ` Dave Martin
2011-08-10 11:31 ` [RFC PATCH 0/5] Fix Thumb-2 undef handling for mixed-arch kernels Tixy
2011-08-11 13:10 ` Dave Martin
2011-08-15 23:13 ` Nicolas Pitre
2011-08-16 9:04 ` Dave Martin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1312971223-28165-5-git-send-email-dave.martin@linaro.org \
--to=dave.martin@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).