--- /dev/null
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include <pthread.h>
+#include <string.h>
+#include "libcgo.h"
+
+static void *threadentry(void*);
+
+// We have to resort to TLS variable to save g(R10) and
+// m(R9). One reason is that external code might trigger
+// SIGSEGV, and our runtime.sigtramp don't even know we
+// are in external code, and will continue to use R10/R9,
+// this might as well result in another SIGSEGV.
+// Note: all three functions will clobber R0, and the last
+// two can be called from 5c ABI code.
+void __aeabi_read_tp(void) __attribute__((naked));
+void cgo_tls_set_gm(void) __attribute__((naked));
+void cgo_tls_get_gm(void) __attribute__((naked));
+void __aeabi_read_tp(void) {
+ // read @ 0xffff1000
+ __asm__ __volatile__ (
+ "ldr r0, =0xffff1000\n\t"
+ "ldr r0, [r0]\n\t"
+ "mov pc, lr\n\t"
+ );
+}
+// g (R10) at 8(TP), m (R9) at 12(TP)
+void cgo_tls_get_gm(void) {
+ __asm__ __volatile__ (
+ "push {lr}\n\t"
+ "bl __aeabi_read_tp\n\t"
+ "ldr r10, [r0, #8]\n\t"
+ "ldr r9, [r0, #12]\n\t"
+ "pop {pc}\n\t"
+ );
+}
+void cgo_tls_set_gm(void) {
+ __asm__ __volatile__ (
+ "push {lr}\n\t"
+ "bl __aeabi_read_tp\n\t"
+ "str r10, [r0, #8]\n\t"
+ "str r9, [r0, #12]\n\t"
+ "pop {pc}\n\t"
+ );
+}
+// both cgo_tls_{get,set}_gm can be called from runtime
+void (*cgo_load_gm)(void) = cgo_tls_get_gm;
+void (*cgo_save_gm)(void) = cgo_tls_set_gm;
+
+static void
+xinitcgo(G *g)
+{
+ pthread_attr_t attr;
+ size_t size;
+ cgo_tls_set_gm(); // save g and m for the initial thread
+
+ pthread_attr_init(&attr);
+ pthread_attr_getstacksize(&attr, &size);
+ g->stackguard = (uintptr)&attr - size + 4096;
+ pthread_attr_destroy(&attr);
+}
+
+void (*initcgo)(G*) = xinitcgo;
+
+void
+libcgo_sys_thread_start(ThreadStart *ts)
+{
+ pthread_attr_t attr;
+ pthread_t p;
+ size_t size;
+ int err;
+
+ // Not sure why the memset is necessary here,
+ // but without it, we get a bogus stack size
+ // out of pthread_attr_getstacksize. C'est la Linux.
+ memset(&attr, 0, sizeof attr);
+ pthread_attr_init(&attr);
+ size = 0;
+ pthread_attr_getstacksize(&attr, &size);
+ ts->g->stackguard = size;
+ err = pthread_create(&p, &attr, threadentry, ts);
+ if (err != 0) {
+ fprintf(stderr, "runtime/cgo: pthread_create failed: %s\n", strerror(err));
+ abort();
+ }
+}
+
+extern void crosscall_arm2(void (*fn)(void), void *g, void *m);
+static void*
+threadentry(void *v)
+{
+ ThreadStart ts;
+
+ ts = *(ThreadStart*)v;
+ free(v);
+
+ ts.g->stackbase = (uintptr)&ts;
+
+ /*
+ * libcgo_sys_thread_start set stackguard to stack size;
+ * change to actual guard pointer.
+ */
+ ts.g->stackguard = (uintptr)&ts - ts.g->stackguard + 4096 * 2;
+
+ crosscall_arm2(ts.fn, (void *)ts.g, (void *)ts.m);
+ return nil;
+}