[PATCH v4 17/17] target/ppc: Validate hflags with CONFIG_DEBUG_TCG

[Richard Henderson <richard.henderson@linaro.org>]

Verify that hflags was updated correctly whenever we change
cpu state that is used by hflags.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/ppc/cpu.h         |  5 +++++
 target/ppc/helper_regs.c | 29 +++++++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 2f8d7fa13c..7ee5c9a66e 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -2424,6 +2424,10 @@ void cpu_write_xer(CPUPPCState *env, target_ulong xer);
  */
 #define is_book3s_arch2x(ctx) (!!((ctx)->insns_flags & PPC_SEGMENT_64B))
 
+#ifdef CONFIG_DEBUG_TCG
+void cpu_get_tb_cpu_state(CPUPPCState *env, target_ulong *pc,
+                          target_ulong *cs_base, uint32_t *flags);
+#else
 static inline void cpu_get_tb_cpu_state(CPUPPCState *env, target_ulong *pc,
                                         target_ulong *cs_base, uint32_t *flags)
 {
@@ -2431,6 +2435,7 @@ static inline void cpu_get_tb_cpu_state(CPUPPCState *env, target_ulong *pc,
     *cs_base = 0;
     *flags = env->hflags;
 }
+#endif
 
 void QEMU_NORETURN raise_exception(CPUPPCState *env, uint32_t exception);
 void QEMU_NORETURN raise_exception_ra(CPUPPCState *env, uint32_t exception,
diff --git a/target/ppc/helper_regs.c b/target/ppc/helper_regs.c
index b28037ca24..9df1098fec 100644
--- a/target/ppc/helper_regs.c
+++ b/target/ppc/helper_regs.c
@@ -43,7 +43,7 @@ void hreg_swap_gpr_tgpr(CPUPPCState *env)
     env->tgpr[3] = tmp;
 }
 
-void hreg_compute_hflags(CPUPPCState *env)
+static uint32_t hreg_compute_hflags_value(CPUPPCState *env)
 {
     target_ulong msr = env->msr;
     uint32_t ppc_flags = env->flags;
@@ -147,9 +147,34 @@ void hreg_compute_hflags(CPUPPCState *env)
     hflags |= dmmu_idx << HFLAGS_DMMU_IDX;
 #endif
 
-    env->hflags = hflags | (msr & msr_mask);
+    return hflags | (msr & msr_mask);
 }
 
+void hreg_compute_hflags(CPUPPCState *env)
+{
+    env->hflags = hreg_compute_hflags_value(env);
+}
+
+#ifdef CONFIG_DEBUG_TCG
+void cpu_get_tb_cpu_state(CPUPPCState *env, target_ulong *pc,
+                          target_ulong *cs_base, uint32_t *flags)
+{
+    uint32_t hflags_current = env->hflags;
+    uint32_t hflags_rebuilt;
+
+    *pc = env->nip;
+    *cs_base = 0;
+    *flags = hflags_current;
+
+    hflags_rebuilt = hreg_compute_hflags_value(env);
+    if (unlikely(hflags_current != hflags_rebuilt)) {
+        cpu_abort(env_cpu(env),
+                  "TCG hflags mismatch (current:0x%08x rebuilt:0x%08x)\n",
+                  hflags_current, hflags_rebuilt);
+    }
+}
+#endif
+
 void cpu_interrupt_exittb(CPUState *cs)
 {
     if (!kvm_enabled()) {
-- 
2.25.1