target/arm: Restore SPSEL to correct CONTROL register on exception return
On exception return for v8M, the SPSEL bit in the EXC_RETURN magic
value should be restored to the SPSEL bit in the CONTROL register
banked specified by the EXC_RETURN.ES bit.
Add write_v7m_control_spsel_for_secstate() which behaves like
write_v7m_control_spsel() but allows the caller to specify which
CONTROL bank to use, reimplement write_v7m_control_spsel() in
terms of it, and use it in exception return.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 1506092407-26985-6-git-send-email-peter.maydell@linaro.org
diff --git a/target/arm/helper.c b/target/arm/helper.c
index b82fc9f..1bab86c 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -6059,26 +6059,40 @@
env->v7m.control[env->v7m.secure] & R_V7M_CONTROL_SPSEL_MASK;
}
+/* Write to v7M CONTROL.SPSEL bit for the specified security bank.
+ * This may change the current stack pointer between Main and Process
+ * stack pointers if it is done for the CONTROL register for the current
+ * security state.
+ */
+static void write_v7m_control_spsel_for_secstate(CPUARMState *env,
+ bool new_spsel,
+ bool secstate)
+{
+ bool old_is_psp = v7m_using_psp(env);
+
+ env->v7m.control[secstate] =
+ deposit32(env->v7m.control[secstate],
+ R_V7M_CONTROL_SPSEL_SHIFT,
+ R_V7M_CONTROL_SPSEL_LENGTH, new_spsel);
+
+ if (secstate == env->v7m.secure) {
+ bool new_is_psp = v7m_using_psp(env);
+ uint32_t tmp;
+
+ if (old_is_psp != new_is_psp) {
+ tmp = env->v7m.other_sp;
+ env->v7m.other_sp = env->regs[13];
+ env->regs[13] = tmp;
+ }
+ }
+}
+
/* Write to v7M CONTROL.SPSEL bit. This may change the current
* stack pointer between Main and Process stack pointers.
*/
static void write_v7m_control_spsel(CPUARMState *env, bool new_spsel)
{
- uint32_t tmp;
- bool new_is_psp, old_is_psp = v7m_using_psp(env);
-
- env->v7m.control[env->v7m.secure] =
- deposit32(env->v7m.control[env->v7m.secure],
- R_V7M_CONTROL_SPSEL_SHIFT,
- R_V7M_CONTROL_SPSEL_LENGTH, new_spsel);
-
- new_is_psp = v7m_using_psp(env);
-
- if (old_is_psp != new_is_psp) {
- tmp = env->v7m.other_sp;
- env->v7m.other_sp = env->regs[13];
- env->regs[13] = tmp;
- }
+ write_v7m_control_spsel_for_secstate(env, new_spsel, env->v7m.secure);
}
void write_v7m_exception(CPUARMState *env, uint32_t new_exc)
@@ -6379,7 +6393,7 @@
* Handler mode (and will be until we write the new XPSR.Interrupt
* field) this does not switch around the current stack pointer.
*/
- write_v7m_control_spsel(env, return_to_sp_process);
+ write_v7m_control_spsel_for_secstate(env, return_to_sp_process, exc_secure);
switch_v7m_security_state(env, return_to_secure);