From 6b169ac9b4342ff3a1499bdeb7596aa4f1bc401b Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 1 Aug 2013 10:16:27 +0200 Subject: [PATCH] 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 Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/kprobes.c | 21 +++++++++++++++++++-- 1 file 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; }