From 9fdf87f7291fb4aa0fc2705d8f6d6e6bcf581a27 Mon Sep 17 00:00:00 2001
From: graham sanderson <graham.sanderson@raspberrypi.com>
Date: Wed, 17 Feb 2021 14:54:46 -0600
Subject: [PATCH] panic in debug mode if sleep methods are called in an
 exception handler (unless PICO_ALLOW_SLEEP_IN_EXCEPTION is set)

---
 src/common/pico_time/time.c                          | 5 +++++
 src/rp2_common/hardware_irq/irq.c                    | 1 -
 src/rp2_common/pico_platform/include/pico/platform.h | 6 ++++++
 src/rp2_common/pico_runtime/runtime.c                | 4 +---
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/common/pico_time/time.c b/src/common/pico_time/time.c
index 32f11e6..33e66a4 100644
--- a/src/common/pico_time/time.c
+++ b/src/common/pico_time/time.c
@@ -325,6 +325,11 @@ static int64_t sev_callback(__unused alarm_id_t id, __unused void *user_data) {
 #endif
 
 void sleep_until(absolute_time_t t) {
+#if PICO_ON_DEVICE && !PICO_ALLOW_SLEEP_IN_EXCEPTION && !defined(NDEBUG)
+    if (__get_current_exception()) {
+        panic("Attempted to sleep inside of an exception handler");
+    }
+#endif
 #if !PICO_TIME_DEFAULT_ALARM_POOL_DISABLED
     uint64_t t_us = to_us_since_boot(t);
     uint64_t t_before_us = t_us - PICO_TIME_SLEEP_OVERHEAD_ADJUST_US;
diff --git a/src/rp2_common/hardware_irq/irq.c b/src/rp2_common/hardware_irq/irq.c
index 54b1125..e47b68d 100644
--- a/src/rp2_common/hardware_irq/irq.c
+++ b/src/rp2_common/hardware_irq/irq.c
@@ -13,7 +13,6 @@
 #include "pico/assert.h"
 
 extern void __unhandled_user_irq(void);
-extern uint __get_current_exception(void);
 
 static inline irq_handler_t *get_vtable(void) {
     return (irq_handler_t *) scb_hw->vtor;
diff --git a/src/rp2_common/pico_platform/include/pico/platform.h b/src/rp2_common/pico_platform/include/pico/platform.h
index ef013d5..7da3103 100644
--- a/src/rp2_common/pico_platform/include/pico/platform.h
+++ b/src/rp2_common/pico_platform/include/pico/platform.h
@@ -163,6 +163,12 @@ return a;
 
 #define __check_type_compatible(type_a, type_b) static_assert(__builtin_types_compatible_p(type_a, type_b), __STRING(type_a) " is not compatible with " __STRING(type_b));
 
+/**
+ * Get the current exception level on this core
+ * \return the exception number if the CPU is handling an exception, or 0 otherwise
+ */
+extern uint __get_current_exception(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/rp2_common/pico_runtime/runtime.c b/src/rp2_common/pico_runtime/runtime.c
index c6a5830..796284e 100644
--- a/src/rp2_common/pico_runtime/runtime.c
+++ b/src/rp2_common/pico_runtime/runtime.c
@@ -124,9 +124,7 @@ void runtime_init(void) {
 #endif
 
 #ifndef NDEBUG
-    uint32_t xpsr;
-    __asm volatile ("mrs %0, XPSR" : "=r" (xpsr)::);
-    if (xpsr & 0xffu) {
+    if (__get_current_exception()) {
         // crap; started in exception handler
         __asm ("bkpt #0");
     }