[PATCH v2] target/loongarch: Fix qemu-loongarch64 hang when executing 'll.d $t0, $t0, 0'

[PATCH v2] target/loongarch: Fix qemu-loongarch64 hang when executing 'll.d $t0, $t0, 0'

[Song Gao]

On gen_ll, if a->imm is zero, make_address_x return src1,
but the load to destination may clobber src1. We use a new
destination to fix this problem.

Fixes: c5af6628f4be (target/loongarch: Extract make_address_i() helper)
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Song Gao <gaosong@loongson.cn>
---
 target/loongarch/tcg/insn_trans/trans_atomic.c.inc | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/target/loongarch/tcg/insn_trans/trans_atomic.c.inc b/target/loongarch/tcg/insn_trans/trans_atomic.c.inc
index 80c2e286fd..974bc2a70f 100644
--- a/target/loongarch/tcg/insn_trans/trans_atomic.c.inc
+++ b/target/loongarch/tcg/insn_trans/trans_atomic.c.inc
@@ -5,14 +5,14 @@
 
 static bool gen_ll(DisasContext *ctx, arg_rr_i *a, MemOp mop)
 {
-    TCGv dest = gpr_dst(ctx, a->rd, EXT_NONE);
+    TCGv t1 = tcg_temp_new();
     TCGv src1 = gpr_src(ctx, a->rj, EXT_NONE);
     TCGv t0 = make_address_i(ctx, src1, a->imm);
 
-    tcg_gen_qemu_ld_i64(dest, t0, ctx->mem_idx, mop);
+    tcg_gen_qemu_ld_i64(t1, t0, ctx->mem_idx, mop);
     tcg_gen_st_tl(t0, tcg_env, offsetof(CPULoongArchState, lladdr));
-    tcg_gen_st_tl(dest, tcg_env, offsetof(CPULoongArchState, llval));
-    gen_set_gpr(a->rd, dest, EXT_NONE);
+    tcg_gen_st_tl(t1, tcg_env, offsetof(CPULoongArchState, llval));
+    gen_set_gpr(a->rd, t1, EXT_NONE);
 
     return true;
 }
-- 
2.25.1

Re: [PATCH v2] target/loongarch: Fix qemu-loongarch64 hang when executing 'll.d $t0,$t0, 0'

[Richard Henderson]

On 3/19/24 15:39, Song Gao wrote:
> On gen_ll, if a->imm is zero, make_address_x return src1,
> but the load to destination may clobber src1. We use a new
> destination to fix this problem.
> 
> Fixes: c5af6628f4be (target/loongarch: Extract make_address_i() helper)
> Suggested-by: Richard Henderson<richard.henderson@linaro.org>
> Signed-off-by: Song Gao<gaosong@loongson.cn>
> ---
>   target/loongarch/tcg/insn_trans/trans_atomic.c.inc | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~