1 files changed, 13 insertions, 5 deletions

diff --git a/arch/arm/kernel/probes.c b/arch/arm/kernel/probes.c
index b6d9b855273c..f9dff12cf85c 100644
--- a/arch/arm/kernel/probes.c
+++ b/arch/arm/kernel/probes.c
@@ -257,7 +257,7 @@ set_emulated_insn(probes_opcode_t insn, struct arch_specific_insn *asi,
  * non-zero value, the corresponding nibble in pinsn is validated and modified
  * according to the type.
  */
-static bool __kprobes decode_regs(probes_opcode_t *pinsn, u32 regs)
+static bool __kprobes decode_regs(probes_opcode_t *pinsn, u32 regs, bool modify)
 {
         probes_opcode_t insn = *pinsn;
         probes_opcode_t mask = 0xf; /* Start at least significant nibble */
@@ -323,7 +323,9 @@ static bool __kprobes decode_regs(probes_opcode_t *pinsn, u32 regs)
                 insn |= new_bits & mask;
         }
 
-        *pinsn = insn;
+        if (modify)
+                *pinsn = insn;
+
         return true;
 
 reject:
@@ -385,13 +387,14 @@ static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
 int __kprobes
 probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi,
                    const union decode_item *table, bool thumb,
-                   const union decode_action *actions)
+                   bool emulate, const union decode_action *actions)
 {
         const struct decode_header *h = (struct decode_header *)table;
         const struct decode_header *next;
         bool matched = false;
 
-        insn = prepare_emulated_insn(insn, asi, thumb);
+        if (emulate)
+                insn = prepare_emulated_insn(insn, asi, thumb);
 
         for (;; h = next) {
                 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
@@ -406,7 +409,7 @@ probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi,
                 if (!matched && (insn & h->mask.bits) != h->value.bits)
                         continue;
 
-                if (!decode_regs(&insn, regs))
+                if (!decode_regs(&insn, regs, emulate))
                         return INSN_REJECTED;
 
                 switch (type) {
@@ -430,6 +433,11 @@ probes_decode_insn(probes_opcode_t insn, struct arch_specific_insn *asi,
 
                 case DECODE_TYPE_EMULATE: {
                         struct decode_emulate *d = (struct decode_emulate *)h;
+
+                        if (!emulate)
+                                return actions[d->handler.action].decoder(insn,
+                                        asi, h);
+
                         asi->insn_handler = actions[d->handler.action].handler;
                         set_emulated_insn(insn, asi, thumb);
                         return INSN_GOOD;