[Qemu-devel] [PATCH] target/arm: Set strict alignment for ARMv6-M load/store

[Julia Suvorova <jusual@mail.ru>]

Unlike ARMv7-M, ARMv6-M only supports naturally aligned memory accesses
for 16-bit halfword and 32-bit word accesses using the LDR, LDRH,
LDRSH, STR and STRH instructions.

Signed-off-by: Julia Suvorova <jusual@mail.ru>
---
 target/arm/translate.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/target/arm/translate.c b/target/arm/translate.c
index b988d379e7..d923cbe98e 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -1100,7 +1100,14 @@ static inline TCGv gen_aa32_addr(DisasContext *s, TCGv_i32 a32, TCGMemOp op)
 static void gen_aa32_ld_i32(DisasContext *s, TCGv_i32 val, TCGv_i32 a32,
                             int index, TCGMemOp opc)
 {
-    TCGv addr = gen_aa32_addr(s, a32, opc);
+    TCGv addr;
+
+    if (arm_dc_feature(s, ARM_FEATURE_M) &&
+        !arm_dc_feature(s, ARM_FEATURE_V7)) {
+        opc |= MO_ALIGN;
+    }
+
+    addr = gen_aa32_addr(s, a32, opc);
     tcg_gen_qemu_ld_i32(val, addr, index, opc);
     tcg_temp_free(addr);
 }
@@ -1108,7 +1115,14 @@ static void gen_aa32_ld_i32(DisasContext *s, TCGv_i32 val, TCGv_i32 a32,
 static void gen_aa32_st_i32(DisasContext *s, TCGv_i32 val, TCGv_i32 a32,
                             int index, TCGMemOp opc)
 {
-    TCGv addr = gen_aa32_addr(s, a32, opc);
+    TCGv addr;
+
+    if (arm_dc_feature(s, ARM_FEATURE_M) &&
+        !arm_dc_feature(s, ARM_FEATURE_V7)) {
+        opc |= MO_ALIGN;
+    }
+
+    addr = gen_aa32_addr(s, a32, opc);
     tcg_gen_qemu_st_i32(val, addr, index, opc);
     tcg_temp_free(addr);
 }
-- 
2.17.0