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authorHeiko Carstens <heiko.carstens@de.ibm.com>2013-08-01 12:16:27 +0400
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2013-08-22 14:20:12 +0400
commit6b169ac9b4342ff3a1499bdeb7596aa4f1bc401b (patch)
tree3697bebddba3158aefd5481e7009ecd5ae5a1291 /arch/s390
parentbee5c2863ef807fa50bbdf8b2bae887c54a97083 (diff)
downloadlinux-6b169ac9b4342ff3a1499bdeb7596aa4f1bc401b.tar.xz
s390/kprobes: add support for compare and branch instructions
The compare and branch instructions (not relative) all need special handling when kprobed: - if a branch was taken, the instruction pointer should be left alone - if a branch was not taken, the instruction pointer must be adjusted The compare and branch instructions family was introduced with the general instruction extension facility (z10). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/kprobes.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 3388b2b2a07d..adbbe7f1cb0d 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -105,14 +105,31 @@ static int __kprobes get_fixup_type(kprobe_opcode_t *insn)
fixup |= FIXUP_RETURN_REGISTER;
break;
case 0xeb:
- if ((insn[2] & 0xff) == 0x44 || /* bxhg */
- (insn[2] & 0xff) == 0x45) /* bxleg */
+ switch (insn[2] & 0xff) {
+ case 0x44: /* bxhg */
+ case 0x45: /* bxleg */
fixup = FIXUP_BRANCH_NOT_TAKEN;
+ break;
+ }
break;
case 0xe3: /* bctg */
if ((insn[2] & 0xff) == 0x46)
fixup = FIXUP_BRANCH_NOT_TAKEN;
break;
+ case 0xec:
+ switch (insn[2] & 0xff) {
+ case 0xe5: /* clgrb */
+ case 0xe6: /* cgrb */
+ case 0xf6: /* crb */
+ case 0xf7: /* clrb */
+ case 0xfc: /* cgib */
+ case 0xfd: /* cglib */
+ case 0xfe: /* cib */
+ case 0xff: /* clib */
+ fixup = FIXUP_BRANCH_NOT_TAKEN;
+ break;
+ }
+ break;
}
return fixup;
}