[PATCH v1 04/19] target/arm: Use tcg_gen_qemu_st_i128 for STZG, STZ2G

[Richard Henderson]

This fixes a bug in that these two insns should have been using atomic
16-byte stores, since MTE is ARMv8.5 and LSE2 is mandatory from ARMv8.4.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/translate-a64.c | 18 +++++++++++-------
 tests/tcg/aarch64/mte-7.c  |  3 +--
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index edf92a728f..b42e5848cc 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -4207,16 +4207,20 @@ static void disas_ldst_tag(DisasContext *s, uint32_t 
insn)
 
     if (is_zero) {
         TCGv_i64 clean_addr = clean_data_tbi(s, addr);
-        TCGv_i64 tcg_zero = tcg_constant_i64(0);
+        TCGv_i64 zero64 = tcg_constant_i64(0);
+        TCGv_i128 zero128 = tcg_temp_new_i128();
         int mem_index = get_mem_index(s);
-        int i, n = (1 + is_pair) << LOG2_TAG_GRANULE;
+        MemOp mop = MO_128 | MO_ALIGN;
 
-        tcg_gen_qemu_st_i64(tcg_zero, clean_addr, mem_index,
-                            MO_UQ | MO_ALIGN_16);
-        for (i = 8; i < n; i += 8) {
-            tcg_gen_addi_i64(clean_addr, clean_addr, 8);
-            tcg_gen_qemu_st_i64(tcg_zero, clean_addr, mem_index, MO_UQ);
+        tcg_gen_concat_i64_i128(zero128, zero64, zero64);
+
+        /* This is 1 or 2 atomic 16-byte operations. */
+        tcg_gen_qemu_st_i128(zero128, clean_addr, mem_index, mop);
+        if (is_pair) {
+            tcg_gen_addi_i64(clean_addr, clean_addr, 16);
+            tcg_gen_qemu_st_i128(zero128, clean_addr, mem_index, mop);
         }
+        tcg_temp_free_i128(zero128);
     }
 
     if (index != 0) {
diff --git a/tests/tcg/aarch64/mte-7.c b/tests/tcg/aarch64/mte-7.c
index a981de62d4..04974f9ebb 100644
--- a/tests/tcg/aarch64/mte-7.c
+++ b/tests/tcg/aarch64/mte-7.c
@@ -19,8 +19,7 @@ int main(int ac, char **av)
     p = (void *)((unsigned long)p | (1ul << 56));
 
     /* Store tag in sequential granules. */
-    asm("stg %0, [%0]" : : "r"(p + 0x0ff0));
-    asm("stg %0, [%0]" : : "r"(p + 0x1000));
+    asm("stz2g %0, [%0]" : : "r"(p + 0x0ff0));
 
     /*
      * Perform an unaligned store with tag 1 crossing the pages.
-- 
2.34.1