ARM: kprobes: Add Thumb instruction decoding stubs
Extend arch_prepare_kprobe to support probing of Thumb code. For
the actual decoding of Thumb instructions, stub functions are
added which currently just reject the probe.
Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c
index 0e47d3d..0df2d6d 100644
--- a/arch/arm/kernel/kprobes.c
+++ b/arch/arm/kernel/kprobes.c
@@ -51,16 +51,32 @@
kprobe_opcode_t insn;
kprobe_opcode_t tmp_insn[MAX_INSN_SIZE];
unsigned long addr = (unsigned long)p->addr;
+ kprobe_decode_insn_t *decode_insn;
int is;
- if (addr & 0x3 || in_exception_text(addr))
+ if (in_exception_text(addr))
return -EINVAL;
+#ifdef CONFIG_THUMB2_KERNEL
+ addr &= ~1; /* Bit 0 would normally be set to indicate Thumb code */
+ insn = ((u16 *)addr)[0];
+ if (is_wide_instruction(insn)) {
+ insn <<= 16;
+ insn |= ((u16 *)addr)[1];
+ decode_insn = thumb32_kprobe_decode_insn;
+ } else
+ decode_insn = thumb16_kprobe_decode_insn;
+#else /* !CONFIG_THUMB2_KERNEL */
+ if (addr & 0x3)
+ return -EINVAL;
insn = *p->addr;
+ decode_insn = arm_kprobe_decode_insn;
+#endif
+
p->opcode = insn;
p->ainsn.insn = tmp_insn;
- switch (arm_kprobe_decode_insn(insn, &p->ainsn)) {
+ switch ((*decode_insn)(insn, &p->ainsn)) {
case INSN_REJECTED: /* not supported */
return -EINVAL;