ARM: kprobes: Fix emulation of SXTB16, SXTB, SXTH, UXTB16, UXTB and UXTH instructions
These sign extension instructions are encoded as extend-and-add
instructions where the register to add is specified as r15. The decoding
routines weren't checking for this and were using the incorrect
emulation code, giving incorrect results.
Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c
index f0ca7f4..1e413a9 100644
--- a/arch/arm/kernel/kprobes-decode.c
+++ b/arch/arm/kernel/kprobes-decode.c
@@ -1390,18 +1390,28 @@
return prep_emulate_rd12rn16rm0_wflags(insn, asi);
/* SXTAB16 : cccc 0110 1000 xxxx xxxx xxxx 0111 xxxx : */
- /* SXTB : cccc 0110 1010 xxxx xxxx xxxx 0111 xxxx : */
+ /* SXTB16 : cccc 0110 1000 1111 xxxx xxxx 0111 xxxx : */
/* ??? : cccc 0110 1001 xxxx xxxx xxxx 0111 xxxx : */
/* SXTAB : cccc 0110 1010 xxxx xxxx xxxx 0111 xxxx : */
+ /* SXTB : cccc 0110 1010 1111 xxxx xxxx 0111 xxxx : */
/* SXTAH : cccc 0110 1011 xxxx xxxx xxxx 0111 xxxx : */
+ /* SXTH : cccc 0110 1011 1111 xxxx xxxx 0111 xxxx : */
/* UXTAB16 : cccc 0110 1100 xxxx xxxx xxxx 0111 xxxx : */
+ /* UXTB16 : cccc 0110 1100 1111 xxxx xxxx 0111 xxxx : */
/* ??? : cccc 0110 1101 xxxx xxxx xxxx 0111 xxxx : */
/* UXTAB : cccc 0110 1110 xxxx xxxx xxxx 0111 xxxx : */
+ /* UXTB : cccc 0110 1110 1111 xxxx xxxx 0111 xxxx : */
/* UXTAH : cccc 0110 1111 xxxx xxxx xxxx 0111 xxxx : */
+ /* UXTH : cccc 0110 1111 1111 xxxx xxxx 0111 xxxx : */
if ((insn & 0x0f8000f0) == 0x06800070) {
if ((insn & 0x00300000) == 0x00100000)
return INSN_REJECTED; /* Unallocated space */
- return prep_emulate_rd12rn16rm0_wflags(insn, asi);
+
+ if ((insn & 0x000f0000) == 0x000f0000) {
+ return prep_emulate_rd12rm0(insn, asi);
+ } else {
+ return prep_emulate_rd12rn16rm0_wflags(insn, asi);
+ }
}
/* Other instruction encodings aren't yet defined */