ARM: kprobes: Decode 32-bit Thumb multiply and absolute difference instructions

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

1 files changed, 49 insertions, 0 deletions

diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c
index 4ef12d13c7d0..902ca59e8b11 100644
--- a/arch/arm/kernel/kprobes-thumb.c
+++ b/arch/arm/kernel/kprobes-thumb.c
@@ -315,6 +315,10 @@ t32_emulate_rdlo12rdhi8rn16rm0_noflags(struct kprobe *p, struct pt_regs *regs)
         regs->uregs[rdhi] = rdhiv;
 }
 
+/* These emulation encodings are functionally equivalent... */
+#define t32_emulate_rd8rn16rm0ra12_noflags \
+                t32_emulate_rdlo12rdhi8rn16rm0_noflags
+
 static const union decode_item t32_table_1110_100x_x0xx[] = {
         /* Load/store multiple instructions */
 
@@ -789,6 +793,45 @@ static const union decode_item t32_table_1111_1010___1111[] = {
         DECODE_END
 };
 
+static const union decode_item t32_table_1111_1011_0[] = {
+        /* Multiply, multiply accumulate, and absolute difference       */
+
+        /* ???                  1111 1011 0000 xxxx 1111 xxxx 0001 xxxx */
+        DECODE_REJECT   (0xfff0f0f0, 0xfb00f010),
+        /* ???                  1111 1011 0111 xxxx 1111 xxxx 0001 xxxx */
+        DECODE_REJECT   (0xfff0f0f0, 0xfb70f010),
+
+        /* SMULxy               1111 1011 0001 xxxx 1111 xxxx 00xx xxxx */
+        DECODE_OR       (0xfff0f0c0, 0xfb10f000),
+        /* MUL                  1111 1011 0000 xxxx 1111 xxxx 0000 xxxx */
+        /* SMUAD{X}             1111 1011 0010 xxxx 1111 xxxx 000x xxxx */
+        /* SMULWy               1111 1011 0011 xxxx 1111 xxxx 000x xxxx */
+        /* SMUSD{X}             1111 1011 0100 xxxx 1111 xxxx 000x xxxx */
+        /* SMMUL{R}             1111 1011 0101 xxxx 1111 xxxx 000x xxxx */
+        /* USAD8                1111 1011 0111 xxxx 1111 xxxx 0000 xxxx */
+        DECODE_EMULATEX (0xff80f0e0, 0xfb00f000, t32_emulate_rd8rn16rm0_rwflags,
+                                                 REGS(NOSPPC, 0, NOSPPC, 0, NOSPPC)),
+
+        /* ???                  1111 1011 0111 xxxx xxxx xxxx 0001 xxxx */
+        DECODE_REJECT   (0xfff000f0, 0xfb700010),
+
+        /* SMLAxy               1111 1011 0001 xxxx xxxx xxxx 00xx xxxx */
+        DECODE_OR       (0xfff000c0, 0xfb100000),
+        /* MLA                  1111 1011 0000 xxxx xxxx xxxx 0000 xxxx */
+        /* MLS                  1111 1011 0000 xxxx xxxx xxxx 0001 xxxx */
+        /* SMLAD{X}             1111 1011 0010 xxxx xxxx xxxx 000x xxxx */
+        /* SMLAWy               1111 1011 0011 xxxx xxxx xxxx 000x xxxx */
+        /* SMLSD{X}             1111 1011 0100 xxxx xxxx xxxx 000x xxxx */
+        /* SMMLA{R}             1111 1011 0101 xxxx xxxx xxxx 000x xxxx */
+        /* SMMLS{R}             1111 1011 0110 xxxx xxxx xxxx 000x xxxx */
+        /* USADA8               1111 1011 0111 xxxx xxxx xxxx 0000 xxxx */
+        DECODE_EMULATEX (0xff8000c0, 0xfb000000, t32_emulate_rd8rn16rm0ra12_noflags,
+                                                 REGS(NOSPPC, NOSPPCX, NOSPPC, 0, NOSPPC)),
+
+        /* Other unallocated instructions...                            */
+        DECODE_END
+};
+
 static const union decode_item t32_table_1111_1011_1[] = {
         /* Long multiply, long multiply accumulate, and divide          */
 
@@ -883,6 +926,12 @@ const union decode_item kprobe_decode_thumb32_table[] = {
         DECODE_TABLE    (0xff00f000, 0xfa00f000, t32_table_1111_1010___1111),
 
         /*
+         * Multiply, multiply accumulate, and absolute difference
+         *                      1111 1011 0xxx xxxx xxxx xxxx xxxx xxxx
+         */
+        DECODE_TABLE    (0xff800000, 0xfb000000, t32_table_1111_1011_0),
+
+        /*
          * Long multiply, long multiply accumulate, and divide
          *                      1111 1011 1xxx xxxx xxxx xxxx xxxx xxxx
          */