ARM: kprobes: Decode 32-bit Thumb load/store multiple instructions

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c
index 27f83a32a038..d25e5cbdd736 100644
--- a/arch/arm/kernel/kprobes-thumb.c
+++ b/arch/arm/kernel/kprobes-thumb.c
@@ -37,6 +37,48 @@ static inline unsigned long __kprobes thumb_probe_pc(struct kprobe *p)
         return (unsigned long)p->addr - 1 + 4;
 }
 
+static enum kprobe_insn __kprobes
+t32_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi)
+{
+        enum kprobe_insn ret = kprobe_decode_ldmstm(insn, asi);
+
+        /* Fixup modified instruction to have halfwords in correct order...*/
+        insn = asi->insn[0];
+        ((u16 *)asi->insn)[0] = insn >> 16;
+        ((u16 *)asi->insn)[1] = insn & 0xffff;
+
+        return ret;
+}
+
+static const union decode_item t32_table_1110_100x_x0xx[] = {
+        /* Load/store multiple instructions */
+
+        /* Rn is PC             1110 100x x0xx 1111 xxxx xxxx xxxx xxxx */
+        DECODE_REJECT   (0xfe4f0000, 0xe80f0000),
+
+        /* SRS                  1110 1000 00x0 xxxx xxxx xxxx xxxx xxxx */
+        /* RFE                  1110 1000 00x1 xxxx xxxx xxxx xxxx xxxx */
+        DECODE_REJECT   (0xffc00000, 0xe8000000),
+        /* SRS                  1110 1001 10x0 xxxx xxxx xxxx xxxx xxxx */
+        /* RFE                  1110 1001 10x1 xxxx xxxx xxxx xxxx xxxx */
+        DECODE_REJECT   (0xffc00000, 0xe9800000),
+
+        /* STM Rn, {...pc}      1110 100x x0x0 xxxx 1xxx xxxx xxxx xxxx */
+        DECODE_REJECT   (0xfe508000, 0xe8008000),
+        /* LDM Rn, {...lr,pc}   1110 100x x0x1 xxxx 11xx xxxx xxxx xxxx */
+        DECODE_REJECT   (0xfe50c000, 0xe810c000),
+        /* LDM/STM Rn, {...sp}  1110 100x x0xx xxxx xx1x xxxx xxxx xxxx */
+        DECODE_REJECT   (0xfe402000, 0xe8002000),
+
+        /* STMIA                1110 1000 10x0 xxxx xxxx xxxx xxxx xxxx */
+        /* LDMIA                1110 1000 10x1 xxxx xxxx xxxx xxxx xxxx */
+        /* STMDB                1110 1001 00x0 xxxx xxxx xxxx xxxx xxxx */
+        /* LDMDB                1110 1001 00x1 xxxx xxxx xxxx xxxx xxxx */
+        DECODE_CUSTOM   (0xfe400000, 0xe8000000, t32_decode_ldmstm),
+
+        DECODE_END
+};
+
 static const union decode_item t32_table_1111_0xxx___1[] = {
         /* Branches and miscellaneous control                           */
 
@@ -55,6 +97,12 @@ static const union decode_item t32_table_1111_0xxx___1[] = {
 const union decode_item kprobe_decode_thumb32_table[] = {
 
         /*
+         * Load/store multiple instructions
+         *                      1110 100x x0xx xxxx xxxx xxxx xxxx xxxx
+         */
+        DECODE_TABLE    (0xfe400000, 0xe8000000, t32_table_1110_100x_x0xx),
+
+        /*
          * Branches and miscellaneous control
          *                      1111 0xxx xxxx xxxx 1xxx xxxx xxxx xxxx
          */