runtime/cgo, go/build: re-enable cgo for FreeBSD/ARM.

R=dave, rsc
CC=golang-dev
https://golang.org/cl/7970043

diff --git a/src/pkg/go/build/build.go b/src/pkg/go/build/build.go
index f4a84b8a7f1b20d8ced8e5b618510d976a185024..dc3669c1df57522d6ad322506dbdc05d1aac096f 100644 (file)
--- a/src/pkg/go/build/build.go
+++ b/src/pkg/go/build/build.go
@@ -262,6 +262,7 @@ var cgoEnabled = map[string]bool{
        "darwin/amd64":  true,
        "freebsd/386":   true,
        "freebsd/amd64": true,
+       "freebsd/arm":   true,
        "linux/386":     true,
        "linux/amd64":   true,
        "linux/arm":     true,

diff --git a/src/pkg/runtime/cgo/gcc_freebsd_arm.c b/src/pkg/runtime/cgo/gcc_freebsd_arm.c
index 3bcb0b270119d56b0cb700e65faedffd864d6055..73c990c28faeab88f99b9afa9ccbf0fb30a1af64 100644 (file)
--- a/src/pkg/runtime/cgo/gcc_freebsd_arm.c
+++ b/src/pkg/runtime/cgo/gcc_freebsd_arm.c
@@ -2,6 +2,8 @@
 // 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 <machine/sysarch.h>
 #include <pthread.h>
 #include <string.h>
 #include "libcgo.h"
@@ -22,10 +24,20 @@ void x_cgo_load_gm(void) __attribute__((naked));
 void
 __aeabi_read_tp(void)
 {
-       // read @ 0xffff1000
        __asm__ __volatile__ (
+#ifdef ARM_TP_ADDRESS
+               // ARM_TP_ADDRESS is (ARM_VECTORS_HIGH + 0x1000) or 0xffff1000
+               // GCC inline asm doesn't provide a way to provide a constant
+               // to "ldr r0, =??" pseudo instruction, so we hardcode the value
+               // and check it with cpp.
+#if ARM_TP_ADDRESS != 0xffff1000
+#error Wrong ARM_TP_ADDRESS!
+#endif
                "ldr r0, =0xffff1000\n\t"
                "ldr r0, [r0]\n\t"
+#else
+               "mrc p15, 0, r0, c13, c0, 3\n\t"
+#endif
                "mov pc, lr\n\t"
        );
 }