From 58986ed5316acc6d6077541b7b6e754390069d73 Mon Sep 17 00:00:00 2001
From: "Luke T. Shumaker" <lukeshu@lukeshu.com>
Date: Sun, 17 Nov 2024 21:58:14 -0700
Subject: libcr: Fixups

---
 libcr/coroutine.c | 47 ++++++++++++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/libcr/coroutine.c b/libcr/coroutine.c
index a468df0..252eca2 100644
--- a/libcr/coroutine.c
+++ b/libcr/coroutine.c
@@ -51,8 +51,9 @@
  * - It has a small bit of platform-specific code in the "platform
  *   support" section.  Other than this, it should be portable to
  *   other platforms CPUs.  It currently contains implementations for
- *   __x86_64__ (assumes POSIX) and __arm__ (assumes bare-metal), and
- *   should be fairly easy to add implementations for other platforms.
+ *   __unix__ and __ARM_EABI__ "operating systems" on __x86_64__ and
+ *   __ARM_ARCH_6M__ CPUs, and should be fairly easy to add
+ *   implementations for other platforms.
  *
  * - It uses setjmp()/longjmp() in "unsafe" ways.  POSIX-2017
  *   longjmp(3p) says
@@ -136,10 +137,10 @@
  * Wrappers for setjmp()/longjmp() that do *not* save the
  * interrupt mask.  */
 #if __unix__
-	/* On a *NIX OS, we use signals as interrupts.  POSIX leaves
-	 * it implementation-defined whether setjmp()/longjmp() save
-	 * the signal mask; while glibc does not save it, let's not
-	 * rely on that.  */
+	/* On __unix__, we use POSIX real-time signals as interrupts.
+	 * POSIX leaves it implementation-defined whether
+	 * setjmp()/longjmp() save the signal mask; while glibc does
+	 * not save it, let's not rely on that.  */
 	#define cr_plat_setjmp(env)             sigsetjmp(env, 0)
 	#define cr_plat_longjmp(env, val)       siglongjmp(env, val)
 #elif __NEWLIB__
@@ -159,10 +160,12 @@
 
 	/* For a signal to be *in* the mask means that the signal is
 	 * *blocked*.  */
+
 	static inline void cr_plat_wait_for_interrupt(void) {
 		sigset_t set;
 		sigemptyset(&set);
 		sigsuspend(&set);
+
 		sigfillset(&set);
 		sigprocmask(SIG_SETMASK, &set, NULL);
 	}
@@ -177,8 +180,7 @@
 		sigemptyset(&zero);
 		sigprocmask(SIG_SETMASK, &zero, NULL);
 	}
-#elif __arm__
-	/* Assume bare-metal if !__unix__.  */
+#elif __ARM_ARCH_6M__ && __ARM_EABI__
 	static ALWAYS_INLINE void cr_plat_wait_for_interrupt(void) {
 		asm volatile ("wfi":::"memory");
 	}
@@ -186,20 +188,20 @@
 		uint32_t primask;
 		asm volatile ("mrs %0, PRIMASK\n"
 		              "cpsid i"
-		              : /* %0 */"=r"(primask)
+		              : /* %0 */"=l"(primask)
 		              );
 		return primask == 0;
 	}
 	void _cr_plat_enable_interrupts(void) {
-		asm volatile ("cpsie i":::"memory");
+		asm volatile ("cpsie i");
 	}
 #else
-	#error unsupported platform (not __unix__, not bare-metal __arm__)
+	#error unsupported platform (not __unix__, not __ARM_ARCH_6M__ && __ARM_EABI__)
 #endif
 
 /*====================================================================
  * Stack management routines.  */
-#if __arm__
+#if __ARM_ARCH_6M__
 	#define CR_PLAT_STACK_GROWS_DOWNWARD 1
 
 	#if CONFIG_COROUTINE_MEASURE_STACK
@@ -225,9 +227,9 @@
 		              "mov sp, r0"     /* ] */
 		              :
 		              : /* %0 */"m"(saved_sp),
-		                /* %1 */"r"(stack),
-		                /* %2 */"r"(fn),
-		                /* %3 */"r"(args)
+		                /* %1 */"l"(stack),
+		                /* %2 */"l"(fn),
+		                /* %3 */"l"(args)
 		              : "r0"
 		              );
 	}
@@ -259,7 +261,7 @@
 		              );
 	}
 #else
-	#error unsupported platform (not __arm__, not __x86__)
+	#error unsupported CPU (not __ARM_ARCH_6M__, not __x86_64__)
 #endif
 
 #if 0
@@ -587,8 +589,7 @@ __attribute__ ((noreturn)) void cr_exit(void) {
 	cr_plat_longjmp(coroutine_main_env, 1); /* jump to point=b */
 }
 
-void cr_unpause_from_intrhandler(cid_t cid) {
-	debugf("cr_unpause(%zu)\n", cid);
+static void _cr_unpause(cid_t cid) {
 	assert_cid_state(cid, state == CR_PAUSED);
 
 	coroutine_table[cid-1].state = CR_RUNNABLE;
@@ -596,11 +597,19 @@ void cr_unpause_from_intrhandler(cid_t cid) {
 }
 
 void cr_unpause(cid_t cid) {
+	debugf("cr_unpause(%zu)\n", cid);
+	assert_cid_state(coroutine_running, state == CR_RUNNING);
 	bool saved = cr_save_and_disable_interrupts();
-	cr_unpause_from_intrhandler(cid);
+	_cr_unpause(cid);
 	cr_restore_interrupts(saved);
 }
 
+void cr_unpause_from_intrhandler(cid_t cid) {
+	debugf("cr_unpause_from_intrhandler(%zu)\n", cid);
+
+	_cr_unpause(cid);
+}
+
 cid_t cr_getcid(void) {
 	assert_cid_state(coroutine_running, state == CR_RUNNING);
 	return coroutine_running;
-- 
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