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authorDavid Wilder <dwilder@us.ibm.com>2007-03-26 20:42:40 +0200
committerHeiko Carstens <heiko.carstens@de.ibm.com>2007-03-26 20:43:46 +0200
commitb70842df77615309d76bcdd63bd289993e0844f2 (patch)
tree1bfcc510b19b87375ee21b0782e3d2e964b92e49 /arch/s390
parentafbc1e994ddcf3b6fe2dc928ee8dc31a5d0c3118 (diff)
[S390] kprobes: Align probe address.
Running a probe on s390 with a probe address that is not 4 byte aligned results in a Kernel BUG. The problem is that the stura instruction used by swap_instruction requires the destination address to be 4 byte aligned. As stura only writes 4 bytes, aligning to the next 4 byte aligned address results in the breakpoint instruction being stored past the probe address. The fix is to align the address backward (to the previous 4 byte aligned address) and writing the two byte breakpoint instruction in the appropriate bytes. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: David Wilder <dwilder@us.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/kprobes.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 8af549e9573..993f3538149 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -167,7 +167,7 @@ static int __kprobes swap_instruction(void *aref)
* shall not cross any page boundaries (vmalloc area!) when writing
* the new instruction.
*/
- addr = (u32 *)ALIGN((unsigned long)args->ptr, 4);
+ addr = (u32 *)((unsigned long)args->ptr & -4UL);
if ((unsigned long)args->ptr & 2)
instr = ((*addr) & 0xffff0000) | args->new;
else