Fix libcr gdb integration?

1 files changed, 52 insertions, 8 deletions

diff --git a/libcr/coroutine.c b/libcr/coroutine.c
index c446276..a947ae9 100644
--- a/libcr/coroutine.c
+++ b/libcr/coroutine.c
@@ -135,6 +135,8 @@
 #define ARRAY_LEN(arr)          (sizeof(arr)/sizeof((arr)[0]))
 #define NEXT_POWER_OF_2(x)      ((1ULL)<<((sizeof(unsigned long long)*8)-__builtin_clzll(x)))
 
+#define UNUSED(name)
+
 #define ALWAYS_INLINE           [[gnu::always_inline]] inline
 #define NEVER_INLINE            [[gnu::noinline]]
 
@@ -158,7 +160,10 @@
 	/* For a signal to be *in* the mask means that the signal is
 	 * *blocked*.  */
 
-	#define _CR_SIG_SENTINEL SIGHUP
+	#define _CR_SIG_SENTINEL SIGURG
+	#if CONFIG_COROUTINE_GDB
+	#define _CR_SIG_GDB      SIGWINCH
+	#endif
 
 	bool cr_is_in_intrhandler(void) {
 		sigset_t cur_mask;
@@ -205,6 +210,19 @@
 		sigemptyset(&zero);
 		sigprocmask(SIG_SETMASK, &zero, NULL);
 	}
+	#if CONFIG_COROUTINE_GDB
+	static void _cr_gdb_intrhandler(int UNUSED(sig)) {}
+	#endif
+	static void cr_plat_init(void) {
+	#if CONFIG_COROUTINE_GDB
+		int r;
+		struct sigaction action = {
+			.sa_handler = _cr_gdb_intrhandler,
+		};
+		r = sigaction(_CR_SIG_GDB, &action, NULL);
+		assert(r == 0);
+	#endif
+	}
 #elif __ARM_ARCH_6M__ && __ARM_EABI__
 	bool cr_is_in_intrhandler(void) {
 		uint32_t isr_number;
@@ -242,6 +260,7 @@
 		assert(!_cr_plat_are_interrupts_enabled());
 		asm volatile ("cpsie i");
 	}
+	static void cr_plat_init(void) {}
 #else
 	#error unsupported platform (not __unix__, not __ARM_ARCH_6M__ && __ARM_EABI__)
 #endif
@@ -327,14 +346,7 @@
 		uintptr_t                      sp;
 	#endif
 	} cr_plat_jmp_buf;
-	#if CONIG_COROUTINE_GDB
-	NEVER_INLINE
-	#endif
 	static void _cr_plat_setjmp_pre(cr_plat_jmp_buf *env [[gnu::unused]]) {
-	#if CONIG_COROUTINE_GDB
-		/* Prevent the call from being optimized away. */
-		asm ("");
-	#endif
 	#if CONFIG_COROUTINE_MEASURE_STACK
 		env->sp = cr_plat_get_sp();
 	#endif
@@ -415,8 +427,12 @@ static const uint8_t stack_pattern[] = {
 
 /* global variables ***********************************************************/
 
+static bool            coroutine_initialized = false;
 static cr_plat_jmp_buf coroutine_add_env;
 static cr_plat_jmp_buf coroutine_main_env;
+#if CONFIG_COROUTINE_GDB
+static cr_plat_jmp_buf coroutine_gdb_env;
+#endif
 
 /*
  * Invariants (and non-invariants):
@@ -471,7 +487,26 @@ static inline cid_t coroutine_ringbuf_pop(void) {
 	return coroutine_ringbuf.buf[coroutine_ringbuf.tail++ % ARRAY_LEN(coroutine_ringbuf.buf)];
 }
 
+#if CONFIG_COROUTINE_GDB
+NEVER_INLINE void cr_gdb_breakpoint(void) {
+	/* Prevent the call from being optimized away. */
+	asm ("");
+}
+NEVER_INLINE void cr_gdb_readjmp(cr_plat_jmp_buf *env) {
+	if (!cr_plat_setjmp(&coroutine_gdb_env))
+		cr_plat_longjmp(env, 2);
+}
+#define cr_setjmp(env) ({                                               \
+			int val = cr_plat_setjmp(env);                  \
+			if (val == 2) {                                 \
+				cr_gdb_breakpoint();                    \
+				cr_plat_longjmp(&coroutine_gdb_env, 1); \
+			}                                               \
+			val;                                            \
+		})
+#else
 #define cr_setjmp(env)  cr_plat_setjmp(env)
+#endif
 #define cr_longjmp(env) cr_plat_longjmp(env, 1)
 
 static inline void assert_cid(cid_t cid) {
@@ -511,6 +546,11 @@ cid_t coroutine_add_with_stack_size(size_t stack_size,
 	debugf("coroutine_add_with_stack_size(%zu, \"%s\", %p, %p)...",
 	       stack_size, name, fn, args);
 
+	if (!coroutine_initialized) {
+		cr_plat_init();
+		coroutine_initialized = true;
+	}
+
 	cid_t child;
 	{
 		size_t base = last_created;
@@ -587,6 +627,10 @@ cid_t coroutine_add(const char *name, cr_fn_t fn, void *args) {
 
 void coroutine_main(void) {
 	debugf("coroutine_main()");
+	if (!coroutine_initialized) {
+		cr_plat_init();
+		coroutine_initialized = true;
+	}
 	bool saved = cr_save_and_disable_interrupts();
 	assert(saved);
 	assert(!cr_is_in_intrhandler());