[113/151] sparc64: Fix stack debugging IRQ stack regression.

Greg KH
2009-12-17T04:19:23Z

From: David S. Miller <davem@davemloft.net>

[ Upstream commit 166e553a575f09485f6d0df8a1ef3c5991f7d953 ]

Commit 4f70f7a91bffdcc39f088748dc678953eb9a3fbd
(sparc64: Implement IRQ stacks.) has two bugs.

First, the softirq range check forgets to subtract STACK_BIAS
before comparing with %sp. Next, on failure the wrong label
is jumped to, resulting in a bogus stack being loaded.

Reported-by: Igor Kovalenko <igor.v.kovalenko@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
arch/sparc/lib/mcount.S | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/arch/sparc/lib/mcount.S
+++ b/arch/sparc/lib/mcount.S
@@ -64,8 +64,9 @@ mcount:
2: sethi %hi(softirq_stack), %g3
or %g3, %lo(softirq_stack), %g3
ldx [%g3 + %g1], %g7
+ sub %g7, STACK_BIAS, %g7
cmp %sp, %g7
- bleu,pt %xcc, 2f
+ bleu,pt %xcc, 3f
sethi %hi(THREAD_SIZE), %g3
add %g7, %g3, %g7
cmp %sp, %g7
@@ -75,7 +76,7 @@ mcount:
* again, we are already trying to output the stack overflow
* message.
*/
- sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough
+3: sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough
or %g7, %lo(ovstack), %g7
add %g7, OVSTACKSIZE, %g3
sub %g3, STACK_BIAS + 192, %g3