[Qemu-devel] [PATCH v3 31/69] target/arm: Diagnose base == pc for LDM/STM

[Richard Henderson]

We have been using store_reg and not store_reg_for_load when writing
back a loaded value into the base register.  At first glance this is
incorrect when base == pc, however that case is UNPREDICTABLE.

Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
 target/arm/translate.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/target/arm/translate.c b/target/arm/translate.c
index bfc4508321..812ce5037f 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -9830,7 +9830,7 @@ static bool op_stm(DisasContext *s, arg_ldst_block *a, 
int min_n)
 
     list = a->list;
     n = ctpop16(list);
-    if (n < min_n) {
+    if (n < min_n || a->rn == 15) {
         unallocated_encoding(s);
         return true;
     }
@@ -9910,7 +9910,7 @@ static bool do_ldm(DisasContext *s, arg_ldst_block *a, 
int min_n)
 
     list = a->list;
     n = ctpop16(list);
-    if (n < min_n) {
+    if (n < min_n || a->rn == 15) {
         unallocated_encoding(s);
         return true;
     }
@@ -9950,6 +9950,7 @@ static bool do_ldm(DisasContext *s, arg_ldst_block *a, 
int min_n)
     op_addr_block_post(s, a, addr, n);
 
     if (loaded_base) {
+        /* Note that we reject base == pc above.  */
         store_reg(s, a->rn, loaded_var);
     }
 
-- 
2.17.1