Re: [PATCH v2] microblaze: nommu: Don't clobber R11 on syscalls

From: Michal Simek
Date: Tue Dec 15 2009 - 02:24:47 EST


steve@xxxxxxxxxxxxxxx wrote:
The noMMU syscall trap has a bug that causes R11 to be zero on return to userland. Remove the extra "save" of R11 responsible for the bug, as well
as an unnecessary extra "load".

It seems to me that this patch means that you tested it.
But anyway I was pretty sure that I am right that's why I did this change myself. This patch is already in Linus tree.

Thanks for test,
Michal


Signed-off-by: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>
---
diff -uprN a/arch/microblaze/kernel/entry-nommu.S b/arch/microblaze/kernel/entry-nommu.S
--- a/arch/microblaze/kernel/entry-nommu.S 2009-12-09 17:05:11.000000000 -0600
+++ b/arch/microblaze/kernel/entry-nommu.S 2009-12-14 11:29:37.000000000 -0600
@@ -208,8 +208,6 @@ ENTRY(_user_exception)
lwi r1, r1, TS_THREAD_INFO /* get the thread info */
/* calculate kernel stack pointer */
addik r1, r1, THREAD_SIZE - PT_SIZE
- swi r11, r0, PER_CPU(R11_SAVE) /* temporarily save r11 */
- lwi r11, r0, PER_CPU(KM) /* load mode indicator */
2:
swi r11, r1, PT_MODE /* store the mode */
lwi r11, r0, PER_CPU(R11_SAVE) /* reload r11 */



--
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian
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