target-ppc: fix vcipher, vcipherlast, vncipherlast and vpermxor

For vector instructions, the helpers get pointers to the vector register
in arguments. Some operands might point to the same register, including
the operand holding the result.

When emulating instructions which access the vector elements in a
non-linear way, we need to store the result in an temporary variable.

This fixes openssl when emulating a POWER8 CPU.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Alexander Graf <agraf@suse.de>

target-ppc/int_helper.c

@@ -2327,24 +2327,28 @@ void helper_vsbox(ppc_avr_t *r, ppc_avr_t *a)
 
 void helper_vcipher(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
 {
+    ppc_avr_t result;
     int i;
 
     VECTOR_FOR_INORDER_I(i, u32) {
-        r->AVRW(i) = b->AVRW(i) ^
+        result.AVRW(i) = b->AVRW(i) ^
             (AES_Te0[a->AVRB(AES_shifts[4*i + 0])] ^
              AES_Te1[a->AVRB(AES_shifts[4*i + 1])] ^
              AES_Te2[a->AVRB(AES_shifts[4*i + 2])] ^
              AES_Te3[a->AVRB(AES_shifts[4*i + 3])]);
     }
+    *r = result;
 }
 
 void helper_vcipherlast(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
 {
+    ppc_avr_t result;
     int i;
 
     VECTOR_FOR_INORDER_I(i, u8) {
-        r->AVRB(i) = b->AVRB(i) ^ (AES_sbox[a->AVRB(AES_shifts[i])]);
+        result.AVRB(i) = b->AVRB(i) ^ (AES_sbox[a->AVRB(AES_shifts[i])]);
     }
+    *r = result;
 }
 
 void helper_vncipher(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
@@ -2369,11 +2373,13 @@ void helper_vncipher(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
 
 void helper_vncipherlast(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
 {
+    ppc_avr_t result;
     int i;
 
     VECTOR_FOR_INORDER_I(i, u8) {
-        r->AVRB(i) = b->AVRB(i) ^ (AES_isbox[a->AVRB(AES_ishifts[i])]);
+        result.AVRB(i) = b->AVRB(i) ^ (AES_isbox[a->AVRB(AES_ishifts[i])]);
     }
+    *r = result;
 }
 
 #define ROTRu32(v, n) (((v) >> (n)) | ((v) << (32-n)))
@@ -2460,16 +2466,19 @@ void helper_vshasigmad(ppc_avr_t *r,  ppc_avr_t *a, uint32_t st_six)
 
 void helper_vpermxor(ppc_avr_t *r,  ppc_avr_t *a, ppc_avr_t *b, ppc_avr_t *c)
 {
+    ppc_avr_t result;
     int i;
+
     VECTOR_FOR_INORDER_I(i, u8) {
         int indexA = c->u8[i] >> 4;
         int indexB = c->u8[i] & 0xF;
 #if defined(HOST_WORDS_BIGENDIAN)
-        r->u8[i] = a->u8[indexA] ^ b->u8[indexB];
+        result.u8[i] = a->u8[indexA] ^ b->u8[indexB];
 #else
-        r->u8[i] = a->u8[15-indexA] ^ b->u8[15-indexB];
+        result.u8[i] = a->u8[15-indexA] ^ b->u8[15-indexB];
 #endif
     }
+    *r = result;
 }
 
 #undef VECTOR_FOR_INORDER_I