implement arch-generic version of __unmapself

[musl] / src / thread / __unmapself.c

diff --git a/src/thread/__unmapself.c b/src/thread/__unmapself.c
index e69de29..1d3bee1 100644 (file)
--- a/src/thread/__unmapself.c
+++ b/src/thread/__unmapself.c
@@ -0,0 +1,29 @@
+#include "pthread_impl.h"
+#include "atomic.h"
+#include "syscall.h"
+/* cheat and reuse CRTJMP macro from dynlink code */
+#include "dynlink.h"
+
+static volatile int lock;
+static void *unmap_base;
+static size_t unmap_size;
+static char shared_stack[256];
+
+static void do_unmap()
+{
+       __syscall(SYS_munmap, unmap_base, unmap_size);
+       __syscall(SYS_exit);
+}
+
+void __unmapself(void *base, size_t size)
+{
+       int tid=__pthread_self()->tid;
+       char *stack = shared_stack + sizeof shared_stack;
+       stack -= (uintptr_t)stack % 16;
+       while (lock || a_cas(&lock, 0, tid))
+               a_spin();
+       __syscall(SYS_set_tid_address, &lock);
+       unmap_base = base;
+       unmap_size = size;
+       CRTJMP(do_unmap, stack);
+}