Messages in this thread Patch in this message | | | From | Wang Nan <> | Subject | [PATCH] ARM: probes: return directly when emulate not set | Date | Wed, 27 Aug 2014 13:08:29 +0800 |
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When kprobe decoding instruction, original code calls instruction specific decoder if emulate is set to false. However, instructions with DECODE_TYPE_EMULATE are in fact don't have their decoder. What in the action table are in fact handlers. For example:
/* LDRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1101 xxxx */ /* STRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1111 xxxx */ DECODE_EMULATEX (0x0e5000d0, 0x004000d0, PROBES_LDRSTRD, REGS(NOPCWB, NOPCX, 0, 0, 0)),
and
const union decode_action kprobes_arm_actions[NUM_PROBES_ARM_ACTIONS] = { ... [PROBES_LDRSTRD] = {.handler = emulate_ldrdstrd}, ...
In this situation, original code calls 'emulate_ldrdstrd' as a decoder, which is obviously incorrect.
This patch makes it returns INSN_GOOD directly when 'emulate' is not true.
Signed-off-by: Wang Nan <wangnan0@huawei.com> Cc: "David A. Long" <dave.long@linaro.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Jon Medhurst <tixy@linaro.org> Cc: Taras Kondratiuk <taras.kondratiuk@linaro.org> Cc: Ben Dooks <ben.dooks@codethink.co.uk> --- arch/arm/kernel/probes.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm/kernel/probes.c b/arch/arm/kernel/probes.c index a8ab540..1c77b8d 100644 --- a/arch/arm/kernel/probes.c +++ b/arch/arm/kernel/probes.c @@ -436,8 +436,7 @@ probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi, struct decode_emulate *d = (struct decode_emulate *)h; if (!emulate) - return actions[d->handler.action].decoder(insn, - asi, h); + return INSN_GOOD; asi->insn_handler = actions[d->handler.action].handler; set_emulated_insn(insn, asi, thumb); -- 1.8.4
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