[PATCH v2 2/4] target/ppc: Ensure stcx size matches larx

[Nicholas Piggin <npiggin@gmail.com>]

Differently-sized larx/stcx. pairs can succeed if the starting address
matches. Add a check to require the size of stcx. exactly match the larx
that established the reservation. Use the term "reserve_length" for this
state, which matches the terminology used in the ISA.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
v2:
- Changed lqarx/stqcx. reservation size to 16 [Richard]
- Changed name to reserve_length [Richard]

 target/ppc/cpu.h       | 5 +++--
 target/ppc/cpu_init.c  | 4 ++--
 target/ppc/translate.c | 9 +++++++++
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 7959bfed0a..45d84ce06a 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -1123,8 +1123,9 @@ struct CPUArchState {
     target_ulong ov32;
     target_ulong ca32;
 
-    target_ulong reserve_addr; /* Reservation address */
-    target_ulong reserve_val;  /* Reservation value */
+    target_ulong reserve_addr;   /* Reservation address */
+    target_ulong reserve_length; /* Reservation larx op size (bytes) */
+    target_ulong reserve_val;    /* Reservation value */
     target_ulong reserve_val2;
 
     /* These are used in supervisor mode only */
diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index 944a74befe..c3dd7052a3 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -7421,8 +7421,8 @@ void ppc_cpu_dump_state(CPUState *cs, FILE *f, int flags)
         }
         qemu_fprintf(f, " %c%c", a, env->crf[i] & 0x01 ? 'O' : ' ');
     }
-    qemu_fprintf(f, " ]             RES " TARGET_FMT_lx "\n",
-                 env->reserve_addr);
+    qemu_fprintf(f, " ]     RES %03x@" TARGET_FMT_lx "\n",
+                 (int)env->reserve_length, env->reserve_addr);
 
     if (flags & CPU_DUMP_FPU) {
         for (i = 0; i < 32; i++) {
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index 7a5bf1d820..538f757dec 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -71,6 +71,7 @@ static TCGv cpu_cfar;
 #endif
 static TCGv cpu_xer, cpu_so, cpu_ov, cpu_ca, cpu_ov32, cpu_ca32;
 static TCGv cpu_reserve;
+static TCGv cpu_reserve_length;
 static TCGv cpu_reserve_val;
 static TCGv cpu_reserve_val2;
 static TCGv cpu_fpscr;
@@ -141,6 +142,10 @@ void ppc_translate_init(void)
     cpu_reserve = tcg_global_mem_new(cpu_env,
                                      offsetof(CPUPPCState, reserve_addr),
                                      "reserve_addr");
+    cpu_reserve_length = tcg_global_mem_new(cpu_env,
+                                            offsetof(CPUPPCState,
+                                                     reserve_length),
+                                            "reserve_length");
     cpu_reserve_val = tcg_global_mem_new(cpu_env,
                                          offsetof(CPUPPCState, reserve_val),
                                          "reserve_val");
@@ -3585,6 +3590,7 @@ static void gen_load_locked(DisasContext *ctx, MemOp memop)
     gen_addr_reg_index(ctx, t0);
     tcg_gen_qemu_ld_tl(gpr, t0, ctx->mem_idx, memop | MO_ALIGN);
     tcg_gen_mov_tl(cpu_reserve, t0);
+    tcg_gen_movi_tl(cpu_reserve_length, memop_size(memop));
     tcg_gen_mov_tl(cpu_reserve_val, gpr);
     tcg_gen_mb(TCG_MO_ALL | TCG_BAR_LDAQ);
 }
@@ -3816,6 +3822,7 @@ static void gen_conditional_store(DisasContext *ctx, MemOp memop)
     gen_set_access_type(ctx, ACCESS_RES);
     gen_addr_reg_index(ctx, t0);
     tcg_gen_brcond_tl(TCG_COND_NE, t0, cpu_reserve, l1);
+    tcg_gen_brcondi_tl(TCG_COND_NE, cpu_reserve_length, memop_size(memop), l1);
 
     t0 = tcg_temp_new();
     tcg_gen_atomic_cmpxchg_tl(t0, cpu_reserve, cpu_reserve_val,
@@ -3882,6 +3889,7 @@ static void gen_lqarx(DisasContext *ctx)
     tcg_gen_extr_i128_i64(lo, hi, t16);
 
     tcg_gen_mov_tl(cpu_reserve, EA);
+    tcg_gen_movi_tl(cpu_reserve_length, 16);
     tcg_gen_st_tl(hi, cpu_env, offsetof(CPUPPCState, reserve_val));
     tcg_gen_st_tl(lo, cpu_env, offsetof(CPUPPCState, reserve_val2));
 }
@@ -3907,6 +3915,7 @@ static void gen_stqcx_(DisasContext *ctx)
     gen_addr_reg_index(ctx, EA);
 
     tcg_gen_brcond_tl(TCG_COND_NE, EA, cpu_reserve, lab_fail);
+    tcg_gen_brcondi_tl(TCG_COND_NE, cpu_reserve_length, 16, lab_fail);
 
     cmp = tcg_temp_new_i128();
     val = tcg_temp_new_i128();
-- 
2.40.1