[Qemu-devel] [PATCH 04/13] target-arm: Handle UNDEF cases for Neon "2 regs and shift" insns

[Peter Maydell]

Correctly handle all the UNDEF cases for Neon instructions of the
"2 registers and shift" form, and make sure that we check for these
cases early enough not to leak TCG temporaries.

Signed-off-by: Peter Maydell <address@hidden>
---
 target-arm/translate.c |   41 ++++++++++++++++++++++-------------------
 1 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/target-arm/translate.c b/target-arm/translate.c
index 0cf933d..c0ffa9f 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -4744,7 +4744,10 @@ static int disas_neon_data_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
             /* Two registers and shift.  */
             op = (insn >> 8) & 0xf;
             if (insn & (1 << 7)) {
-                /* 64-bit shift.   */
+                /* 64-bit shift. */
+                if (op > 7) {
+                    return 1;
+                }
                 size = 3;
             } else {
                 size = 2;
@@ -4757,6 +4760,12 @@ static int disas_neon_data_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
             if (op < 8) {
                 /* Shift by immediate:
                    VSHR, VSRA, VRSHR, VRSRA, VSRI, VSHL, VQSHL, VQSHLU.  */
+                if (q && ((rd | rm) & 1)) {
+                    return 1;
+                }
+                if (!u && (op == 4 || op == 6)) {
+                    return 1;
+                }
                 /* Right shifts are encoded as N - shift, where N is the
                    element size in bits.  */
                 if (op <= 4)
@@ -4804,20 +4813,13 @@ static int disas_neon_data_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
                                 gen_helper_neon_rshl_s64(cpu_V0, cpu_V0, 
cpu_V1);
                             break;
                         case 4: /* VSRI */
-                            if (!u)
-                                return 1;
                             gen_helper_neon_shl_u64(cpu_V0, cpu_V0, cpu_V1);
                             break;
                         case 5: /* VSHL, VSLI */
                             gen_helper_neon_shl_u64(cpu_V0, cpu_V0, cpu_V1);
                             break;
                         case 6: /* VQSHLU */
-                            if (u) {
-                                gen_helper_neon_qshlu_s64(cpu_V0,
-                                                          cpu_V0, cpu_V1);
-                            } else {
-                                return 1;
-                            }
+                            gen_helper_neon_qshlu_s64(cpu_V0, cpu_V0, cpu_V1);
                             break;
                         case 7: /* VQSHL */
                             if (u) {
@@ -4865,8 +4867,6 @@ static int disas_neon_data_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
                             GEN_NEON_INTEGER_OP(rshl);
                             break;
                         case 4: /* VSRI */
-                            if (!u)
-                                return 1;
                             GEN_NEON_INTEGER_OP(shl);
                             break;
                         case 5: /* VSHL, VSLI */
@@ -4874,13 +4874,10 @@ static int disas_neon_data_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
                             case 0: gen_helper_neon_shl_u8(tmp, tmp, tmp2); 
break;
                             case 1: gen_helper_neon_shl_u16(tmp, tmp, tmp2); 
break;
                             case 2: gen_helper_neon_shl_u32(tmp, tmp, tmp2); 
break;
-                            default: return 1;
+                            default: abort();
                             }
                             break;
                         case 6: /* VQSHLU */
-                            if (!u) {
-                                return 1;
-                            }
                             switch (size) {
                             case 0:
                                 gen_helper_neon_qshlu_s8(tmp, tmp, tmp2);
@@ -4892,7 +4889,7 @@ static int disas_neon_data_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
                                 gen_helper_neon_qshlu_s32(tmp, tmp, tmp2);
                                 break;
                             default:
-                                return 1;
+                                abort();
                             }
                             break;
                         case 7: /* VQSHL */
@@ -4950,7 +4947,9 @@ static int disas_neon_data_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
                 /* Shift by immediate and narrow:
                    VSHRN, VRSHRN, VQSHRN, VQRSHRN.  */
                 int input_unsigned = (op == 8) ? !u : u;
-
+                if (rm & 1) {
+                    return 1;
+                }
                 shift = shift - (1 << (size + 3));
                 size++;
                 if (size == 3) {
@@ -5018,9 +5017,10 @@ static int disas_neon_data_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
                     tcg_temp_free_i32(tmp2);
                 }
             } else if (op == 10) {
-                /* VSHLL */
-                if (q || size == 3)
+                /* VSHLL, VMOVL */
+                if (q || (rd & 1)) {
                     return 1;
+                }
                 tmp = neon_load_reg(rm, 0);
                 tmp2 = neon_load_reg(rm, 1);
                 for (pass = 0; pass < 2; pass++) {
@@ -5061,6 +5061,9 @@ static int disas_neon_data_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
                 }
             } else if (op >= 14) {
                 /* VCVT fixed-point.  */
+                if (!(insn & (1 << 21)) || (q && ((rd | rm) & 1))) {
+                    return 1;
+                }
                 /* We have already masked out the must-be-1 top bit of imm6,
                  * hence this 32-shift where the ARM ARM has 64-imm6.
                  */
-- 
1.7.1