go/build, runtime/cgo: cgo support for NetBSD/ARM

R=golang-dev, rsc, dave
CC=golang-dev
https://golang.org/cl/7229082

diff --git a/src/pkg/go/build/build.go b/src/pkg/go/build/build.go
index 4dedee6caa66190411dc9b6c4924a7729752e74c..16c3da45858e0bcd24dcf90079fad64f1ca68192 100644 (file)
--- a/src/pkg/go/build/build.go
+++ b/src/pkg/go/build/build.go
@@ -251,6 +251,7 @@ var cgoEnabled = map[string]bool{
        "linux/arm":     true,
        "netbsd/386":    true,
        "netbsd/amd64":  true,
+       "netbsd/arm":    true,
        "openbsd/386":   true,
        "openbsd/amd64": true,
        "windows/386":   true,

diff --git a/src/pkg/runtime/cgo/gcc_netbsd_arm.c b/src/pkg/runtime/cgo/gcc_netbsd_arm.c
new file mode 100644 (file)
index 0000000..0adcac6
--- /dev/null
+++ b/src/pkg/runtime/cgo/gcc_netbsd_arm.c
@@ -0,0 +1,117 @@
+// Copyright 2013 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 <sys/types.h>
+#include <pthread.h>
+#include <signal.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) {
+       // this function is only allowed to clobber r0
+       __asm__ __volatile__ (
+               "mrc p15, 0, r0, c13, c0, 3\n\t"
+               "cmp r0, #0\n\t"
+               "movne pc, lr\n\t"
+               "push {r1,r2,r3,r12}\n\t"
+               "svc 0x00a0013c\n\t" // _lwp_getprivate
+               "pop {r1,r2,r3,r12}\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;
+       sigset_t ign, oset;
+       pthread_t p;
+       size_t size;
+       int err;
+
+       sigfillset(&ign);
+       sigprocmask(SIG_SETMASK, &ign, &oset);
+
+       pthread_attr_init(&attr);
+       pthread_attr_getstacksize(&attr, &size);
+       ts->g->stackguard = size;
+       err = pthread_create(&p, &attr, threadentry, ts);
+
+       sigprocmask(SIG_SETMASK, &oset, nil);
+
+       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;
+}