From: Greg Ungerer <gerg@snapgear.com>
To: torvalds@linux-foundation.org
Cc: gerg@uclinux.org, linux-kernel@vger.kernel.org
Subject: [M68KNOMMU]: simplify ColdFire resume code
Date: Wed, 25 Jul 2007 22:07:20 +1000 [thread overview]
Message-ID: <200707251207.l6PC7Ks4032174@goober> (raw)
It is useless to preserve THREAD_SR in `resume'. The real user's sr
is actually in the stack. We also don't need to disable interrupts :
we'll never be in an invalid state, the sp switch is atomic.
Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
diff -Naur linux-2.6.22/arch/m68knommu/platform/5307/entry.S linux-2.6.22-uc0/arch/m68knommu/platform/5307/entry.S
--- linux-2.6.22/arch/m68knommu/platform/5307/entry.S 2007-07-12 15:23:02.000000000 +1000
+++ linux-2.6.22-uc0/arch/m68knommu/platform/5307/entry.S 2007-07-12 15:27:01.000000000 +1000
@@ -235,16 +216,12 @@
* Beware - when entering resume, prev (the current task) is
* in a0, next (the new task) is in a1,so don't change these
* registers until their contents are no longer needed.
+ * This is always called in supervisor mode, so don't bother to save
+ * and restore sr; user's process sr is actually in the stack.
*/
ENTRY(resume)
movel %a0, %d1 /* get prev thread in d1 */
- movew %sr,%d0 /* save thread status reg */
- movew %d0,%a0@(TASK_THREAD+THREAD_SR)
-
- oril #0x700,%d0 /* disable interrupts */
- move %d0,%sr
-
movel sw_usp,%d0 /* save usp */
movel %d0,%a0@(TASK_THREAD+THREAD_USP)
@@ -255,7 +232,4 @@
movel %a1@(TASK_THREAD+THREAD_USP),%a0 /* restore thread user stack */
movel %a0, sw_usp
-
- movew %a1@(TASK_THREAD+THREAD_SR),%d0 /* restore thread status reg */
- movew %d0, %sr
rts
reply other threads:[~2007-07-25 12:10 UTC|newest]
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