libthread: use mmap to allocate OpenBSD stacks

Should fix faults on OpenBSD.

Fixes #218.
Fixes #226.

1 files changed, 25 insertions, 0 deletions

diff --git a/src/libthread/stkmmap.c b/src/libthread/stkmmap.c
new file mode 100644
index 00000000..f4a24630
--- /dev/null
+++ b/src/libthread/stkmmap.c
@@ -0,0 +1,25 @@
+#include <u.h>
+#include <sys/mman.h>
+#include "threadimpl.h"
+
+#ifndef MAP_STACK
+#define MAP_STACK 0
+#endif
+
+void*
+_threadstkalloc(int n)
+{
+	void *p;
+
+	p = mmap(nil, n, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON|MAP_STACK, -1, 0);
+	if(p == (void*)-1)
+		return nil;
+	return p;
+}
+
+void
+_threadstkfree(void *v, int n)
+{
+	if(n > 0)
+		munmap(v, n);
+}