target/arm: Introduce raise_exception_ra

This path uses cpu_loop_exit_restore to unwind current processor state.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20190108223129.5570-5-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 24 insertions, 2 deletions

diff --git a/target/arm/internals.h b/target/arm/internals.h
index 78e026d6e9..c01a3f8c96 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -104,6 +104,13 @@ void QEMU_NORETURN raise_exception(CPUARMState *env, uint32_t excp,
                                    uint32_t syndrome, uint32_t target_el);
 
 /*
+ * Similarly, but also use unwinding to restore cpu state.
+ */
+void QEMU_NORETURN raise_exception_ra(CPUARMState *env, uint32_t excp,
+                                      uint32_t syndrome, uint32_t target_el,
+                                      uintptr_t ra);
+
+/*
  * For AArch64, map a given EL to an index in the banked_spsr array.
  * Note that this mapping and the AArch32 mapping defined in bank_number()
  * must agree such that the AArch64<->AArch32 SPSRs have the architecturally
diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c
index ef72361a36..8b31c6a13b 100644
--- a/target/arm/op_helper.c
+++ b/target/arm/op_helper.c
@@ -28,8 +28,8 @@
 #define SIGNBIT (uint32_t)0x80000000
 #define SIGNBIT64 ((uint64_t)1 << 63)
 
-void raise_exception(CPUARMState *env, uint32_t excp,
-                     uint32_t syndrome, uint32_t target_el)
+static CPUState *do_raise_exception(CPUARMState *env, uint32_t excp,
+                                    uint32_t syndrome, uint32_t target_el)
 {
     CPUState *cs = CPU(arm_env_get_cpu(env));
 
@@ -50,9 +50,24 @@ void raise_exception(CPUARMState *env, uint32_t excp,
     cs->exception_index = excp;
     env->exception.syndrome = syndrome;
     env->exception.target_el = target_el;
+
+    return cs;
+}
+
+void raise_exception(CPUARMState *env, uint32_t excp,
+                     uint32_t syndrome, uint32_t target_el)
+{
+    CPUState *cs = do_raise_exception(env, excp, syndrome, target_el);
     cpu_loop_exit(cs);
 }
 
+void raise_exception_ra(CPUARMState *env, uint32_t excp, uint32_t syndrome,
+                        uint32_t target_el, uintptr_t ra)
+{
+    CPUState *cs = do_raise_exception(env, excp, syndrome, target_el);
+    cpu_loop_exit_restore(cs, ra);
+}
+
 static int exception_target_el(CPUARMState *env)
 {
     int target_el = MAX(1, arm_current_el(env));