More FreeBSD-touchups. Thundercats are GOOOOO!

R=rsc
CC=golang-dev
https://golang.org/cl/157074

misc/cgo/stdio/test.bash

@@ -3,8 +3,6 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-if [ "$(uname)" = "FreeBSD" ]; then exit 0; fi
-
 set -e
 gomake hello fib chain
 echo '*' hello >run.out

src/cmd/6l/obj.c

@@ -150,10 +150,9 @@ main(int argc, char *argv[])
 		if(strcmp(goos, "darwin") == 0)
 			HEADTYPE = 6;
 		else
-		if(strcmp(goos, "freebsd") == 0) {
-			debug['d'] = 1;	/* no dynamic syms for now */
+		if(strcmp(goos, "freebsd") == 0)
 			HEADTYPE = 9;
-		} else
+		else
 			print("goos is not known: %s\n", goos);
 	}
 

src/cmd/8l/obj.c

@@ -158,10 +158,9 @@ main(int argc, char *argv[])
 		if(strcmp(goos, "nacl") == 0)
 			HEADTYPE = 8;
 		else
-		if(strcmp(goos, "freebsd") == 0) {
-			debug['d'] = 1; /* no dynamic syms for now */
+		if(strcmp(goos, "freebsd") == 0)
 			HEADTYPE = 9;
-		} else
+		else
 			print("goos is not known: %sn", goos);
 	}
 
@@ -241,10 +240,7 @@ main(int argc, char *argv[])
 		 * Also known to ../../pkg/runtime/linux/386/sys.s
 		 * and ../../libcgo/linux_386.c.
 		 */
-		if (HEADTYPE == 7)
-			tlsoffset = -8;
-		else
-			tlsoffset = 0;
+		tlsoffset = -8;
 		elfinit();
 		HEADR = ELFRESERVE;
 		if(INITTEXT == -1)

src/libcgo/freebsd_386.c

@@ -6,15 +6,13 @@
 #include "libcgo.h"
 
 static void* threadentry(void*);
-static pthread_key_t k1, k2;
 
-/* gccism: arrange for inittls to be called at dynamic load time */
-static void inittls(void) __attribute__((constructor));
+char *environ[] = { 0 };
+char *__progname;
 
 static void
 inittls(void)
 {
-	/* unimplemented for now */
 }
 
 void
@@ -51,8 +49,16 @@ threadentry(void *v)
 	 */
 	ts.g->stackguard = (uintptr)&ts - ts.g->stackguard + 4096;
 
-	pthread_setspecific(k1, (void*)ts.g);
-	pthread_setspecific(k2, (void*)ts.m);
+	/*
+	 * Set specific keys.  On FreeBSD/ELF, the thread local storage
+	 * is just before %gs:0.  Our dynamic 8.out's reserve 8 bytes
+	 * for the two words g and m at %gs:-8 and %gs:-4.
+	 */
+	asm volatile (
+		"movl %0, %%gs:-8\n"	// MOVL g, -8(GS)
+		"movl %1, %%gs:-4\n"	// MOVL m, -4(GS)
+		:: "r"(ts.g), "r"(ts.m)
+	);
 
 	crosscall_386(ts.fn);
 	return nil;

src/libcgo/freebsd_amd64.c

@@ -7,6 +7,9 @@
 
 static void* threadentry(void*);
 
+char *environ[] = { 0 };
+char *__progname;
+
 void
 initcgo(void)
 {

src/pkg/runtime/freebsd/386/sys.s

@@ -19,8 +19,8 @@ TEXT thr_new(SB),7,$-4
 	RET
 
 TEXT thr_start(SB),7,$0
-	MOVL mm+0(FP), AX
-	MOVL m_g0(AX), BX
+	MOVL	mm+0(FP), AX
+	MOVL	m_g0(AX), BX
 	LEAL	m_tls(AX), BP
 	MOVL	0(BP), DI
 	ADDL	$7, DI
@@ -132,7 +132,8 @@ int i386_set_ldt(int, const union ldt_entry *, int);
 // setldt(int entry, int address, int limit)
 TEXT setldt(SB),7,$32
 	MOVL	address+4(FP), BX	// aka base
-	MOVL	limit+8(FP), CX
+	// see comment in linux/386/sys.s; freebsd is similar
+	ADDL	$0x8, BX
 
 	// set up data_desc
 	LEAL	16(SP), AX	// struct data_desc
@@ -145,11 +146,8 @@ TEXT setldt(SB),7,$32
 	SHRL	$8, BX
 	MOVB	BX, 7(AX)
 
-	MOVW	CX, 0(AX)
-	SHRL	$16, CX
-	ANDL	$0x0F, CX
-	ORL	$0x40, CX		// 32-bit operand size
-	MOVB	CX, 6(AX)
+	MOVW	$0xffff, 0(AX)
+	MOVB	$0xCF, 6(AX)	// 32-bit operand, 4k limit unit, 4 more bits of limit
 
 	MOVB	$0xF2, 5(AX)	// r/w data descriptor, dpl=3, present
 

src/pkg/runtime/proc.c

@@ -385,6 +385,8 @@ starttheworld(void)
 void
 mstart(void)
 {
+	if(g != m->g0)
+		throw("bad mstart");
 	if(m->mcache == nil)
 		m->mcache = allocmcache();
 	minit();