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-rw-r--r--target/arm/helper.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 559065131a..8b07bf214e 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -7162,6 +7162,22 @@ static void do_v7m_exception_exit(ARMCPU *cpu)
return;
}
+ /*
+ * Tailchaining: if there is currently a pending exception that
+ * is high enough priority to preempt execution at the level we're
+ * about to return to, then just directly take that exception now,
+ * avoiding an unstack-and-then-stack. Note that now we have
+ * deactivated the previous exception by calling armv7m_nvic_complete_irq()
+ * our current execution priority is already the execution priority we are
+ * returning to -- none of the state we would unstack or set based on
+ * the EXCRET value affects it.
+ */
+ if (armv7m_nvic_can_take_pending_exception(env->nvic)) {
+ qemu_log_mask(CPU_LOG_INT, "...tailchaining to pending exception\n");
+ v7m_exception_taken(cpu, excret, true, false);
+ return;
+ }
+
switch_v7m_security_state(env, return_to_secure);
{