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authorRobin Getz <robin.getz@analog.com>2007-10-29 11:14:15 +0100
committerBryan Wu <bryan.wu@analog.com>2007-10-29 11:14:15 +0100
commitaa770aa790f3a5f3ff568388d02aea2ef78773ec (patch)
treec100fc10a4cdbd9bc0104846795babcad915dd71
parentBlackfin arch: fix bug: tell users if the kernel is recovering from a fault c... (diff)
downloadlinux-aa770aa790f3a5f3ff568388d02aea2ef78773ec.tar.xz
linux-aa770aa790f3a5f3ff568388d02aea2ef78773ec.zip
Blackfin arch: Fix random crash issue found by Michael.
This is fixes a problem where we could jump to the wrong address. By doing a "p0 = reti; jump (p0)". If a different, higher level interrupt came in, just before, rather than returning to the calling function, we would return to a random place in the kernel. This very elegant fix from Bernd grabs the return location off the stack, and places it into P0, so when we do a return, it goes to the correct place. Signed-off-by: Robin Getz <robin.getz@analog.com> Signed-off-by: Bryan Wu <bryan.wu@analog.com>
-rw-r--r--arch/blackfin/kernel/entry.S6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/blackfin/kernel/entry.S b/arch/blackfin/kernel/entry.S
index 65c5ba4260b0..65f4e67a65c4 100644
--- a/arch/blackfin/kernel/entry.S
+++ b/arch/blackfin/kernel/entry.S
@@ -54,9 +54,11 @@ ENTRY(_ret_from_fork)
[sp + PT_IPEND] = r0;
/* do a 'fake' RTI by jumping to [RETI]
* to avoid clearing supervisor mode in child
- */
+ */
+ r0 = [sp + PT_PC];
+ [sp + PT_P0] = r0;
+
RESTORE_ALL_SYS
- p0 = reti;
jump (p0);
ENDPROC(_ret_from_fork)