From 31f8b07e55d6f712315eea021ee84bff73f87c51 Mon Sep 17 00:00:00 2001 From: Shenghou Ma Date: Sat, 3 Nov 2012 02:22:37 +0800 Subject: [PATCH] runtime/cgo, go/build: cgo support for FreeBSD/ARM This is the last CL for FreeBSD/ARM support. Also update cmd/ld/doc.go for 5l support of -Hfreebsd. R=rsc CC=golang-dev https://golang.org/cl/6650051 --- src/cmd/ld/doc.go | 2 +- src/pkg/go/build/build.go | 1 + src/pkg/runtime/cgo/gcc_freebsd_arm.c | 109 ++++++++++++++++++++++++++ 3 files changed, 111 insertions(+), 1 deletion(-) create mode 100644 src/pkg/runtime/cgo/gcc_freebsd_arm.c diff --git a/src/cmd/ld/doc.go b/src/cmd/ld/doc.go index a4977d581c..7fc22983db 100644 --- a/src/cmd/ld/doc.go +++ b/src/cmd/ld/doc.go @@ -33,7 +33,7 @@ Options new in this version: Write Apple Mach-O binaries (default when $GOOS is darwin) -Hlinux Write Linux ELF binaries (default when $GOOS is linux) - -Hfreebsd (only in 6l/8l) + -Hfreebsd Write FreeBSD ELF binaries (default when $GOOS is freebsd) -Hnetbsd (only in 6l/8l) Write NetBSD ELF binaries (default when $GOOS is netbsd) diff --git a/src/pkg/go/build/build.go b/src/pkg/go/build/build.go index d32afc31db..e65d8453bc 100644 --- a/src/pkg/go/build/build.go +++ b/src/pkg/go/build/build.go @@ -216,6 +216,7 @@ 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 new file mode 100644 index 0000000000..70f4b571e0 --- /dev/null +++ b/src/pkg/runtime/cgo/gcc_freebsd_arm.c @@ -0,0 +1,109 @@ +// 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 +#include +#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; +} -- 2.48.1