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-rw-r--r--arch/arm/probes/decode.c60
1 files changed, 54 insertions, 6 deletions
diff --git a/arch/arm/probes/decode.c b/arch/arm/probes/decode.c
index 3b05d5742359..c7d442018902 100644
--- a/arch/arm/probes/decode.c
+++ b/arch/arm/probes/decode.c
@@ -342,6 +342,31 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
[DECODE_TYPE_REJECT] = sizeof(struct decode_reject)
};
+static int run_checkers(const struct decode_checker *checkers[],
+ int action, probes_opcode_t insn,
+ struct arch_probes_insn *asi,
+ const struct decode_header *h)
+{
+ const struct decode_checker **p;
+
+ if (!checkers)
+ return INSN_GOOD;
+
+ p = checkers;
+ while (*p != NULL) {
+ int retval;
+ probes_check_t *checker_func = (*p)[action].checker;
+
+ retval = INSN_GOOD;
+ if (checker_func)
+ retval = checker_func(insn, asi, h);
+ if (retval == INSN_REJECTED)
+ return retval;
+ p++;
+ }
+ return INSN_GOOD;
+}
+
/*
* probes_decode_insn operates on data tables in order to decode an ARM
* architecture instruction onto which a kprobe has been placed.
@@ -388,11 +413,17 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
int __kprobes
probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
const union decode_item *table, bool thumb,
- bool emulate, const union decode_action *actions)
+ bool emulate, const union decode_action *actions,
+ const struct decode_checker *checkers[])
{
const struct decode_header *h = (struct decode_header *)table;
const struct decode_header *next;
bool matched = false;
+ /*
+ * @insn can be modified by decode_regs. Save its original
+ * value for checkers.
+ */
+ probes_opcode_t origin_insn = insn;
if (emulate)
insn = prepare_emulated_insn(insn, asi, thumb);
@@ -422,24 +453,41 @@ probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi,
}
case DECODE_TYPE_CUSTOM: {
+ int err;
struct decode_custom *d = (struct decode_custom *)h;
- return actions[d->decoder.action].decoder(insn, asi, h);
+ int action = d->decoder.action;
+
+ err = run_checkers(checkers, action, origin_insn, asi, h);
+ if (err == INSN_REJECTED)
+ return INSN_REJECTED;
+ return actions[action].decoder(insn, asi, h);
}
case DECODE_TYPE_SIMULATE: {
+ int err;
struct decode_simulate *d = (struct decode_simulate *)h;
- asi->insn_handler = actions[d->handler.action].handler;
+ int action = d->handler.action;
+
+ err = run_checkers(checkers, action, origin_insn, asi, h);
+ if (err == INSN_REJECTED)
+ return INSN_REJECTED;
+ asi->insn_handler = actions[action].handler;
return INSN_GOOD_NO_SLOT;
}
case DECODE_TYPE_EMULATE: {
+ int err;
struct decode_emulate *d = (struct decode_emulate *)h;
+ int action = d->handler.action;
+
+ err = run_checkers(checkers, action, origin_insn, asi, h);
+ if (err == INSN_REJECTED)
+ return INSN_REJECTED;
if (!emulate)
- return actions[d->handler.action].decoder(insn,
- asi, h);
+ return actions[action].decoder(insn, asi, h);
- asi->insn_handler = actions[d->handler.action].handler;
+ asi->insn_handler = actions[action].handler;
set_emulated_insn(insn, asi, thumb);
return INSN_GOOD;
}