target/arm: Add MO_128 entry to pred_esz_masks[]

In commit 7390e0e9ab, we added support for SME loads and stores.
Unlike SVE loads and stores, these include handling of 128-bit
elements.  The SME load/store functions call down into the existing
sve_cont_ldst_elements() function, which uses the element size MO_*
value as an index into the pred_esz_masks[] array.  Because this code
path now has to handle MO_128, we need to add an extra element to the
array.

This bug was spotted by Coverity because it meant we were reading off
the end of the array.

Resolves: Coverity CID 1490539, 1490541, 1490543, 1490544, 1490545,
 1490546, 1490548, 1490549, 1490550, 1490551, 1490555, 1490557,
 1490558, 1490560, 1490561, 1490563
Fixes: 7390e0e9ab ("target/arm: Implement SME LD1, ST1")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220718100144.3248052-1-peter.maydell@linaro.org

target/arm/cpu.h

@@ -3387,7 +3387,7 @@ static inline uint64_t *aa64_vfp_qreg(CPUARMState *env, unsigned regno)
 }
 
 /* Shared between translate-sve.c and sve_helper.c.  */
-extern const uint64_t pred_esz_masks[4];
+extern const uint64_t pred_esz_masks[5];
 
 /* Helper for the macros below, validating the argument type. */
 static inline MemTxAttrs *typecheck_memtxattrs(MemTxAttrs *x)

target/arm/translate-sve.c

@@ -529,9 +529,10 @@ static void do_predtest(DisasContext *s, int dofs, int gofs, int words)
 }
 
 /* For each element size, the bits within a predicate word that are active.  */
-const uint64_t pred_esz_masks[4] = {
+const uint64_t pred_esz_masks[5] = {
     0xffffffffffffffffull, 0x5555555555555555ull,
-    0x1111111111111111ull, 0x0101010101010101ull
+    0x1111111111111111ull, 0x0101010101010101ull,
+    0x0001000100010001ull,
 };
 
 static bool trans_INVALID(DisasContext *s, arg_INVALID *a)