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convert 386 to use %gs instead of %fs for extern register.

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required for nacl and may be nicer for ffi,
because %gs is the standard register for thread-local storage.

R=ken
OCL=34861
CL=34866
This commit is contained in:
Russ Cox 2009-09-21 15:46:50 -07:00
parent a95ee61aea
commit bbcb91a3a7
6 changed files with 29 additions and 37 deletions
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2
src/cmd/8c/txt.c
View File

@ -450,7 +450,7 @@ naddr(Node *n, Adr *a)
break;
case OEXREG:
a->type = D_INDIR + D_FS;
a->type = D_INDIR + D_GS;
a->offset = n->reg - 1;
break;

3
src/cmd/8l/pass.c
View File

@ -464,6 +464,7 @@ dostkoff(void)
int a, f, curframe, curbecome, maxbecome;
Prog *pmorestack;
Sym *symmorestack;
static int fsreg;
pmorestack = P;
symmorestack = lookup("sys·morestack", 0);
@ -565,7 +566,7 @@ dostkoff(void)
if(!(p->from.scale & NOSPLIT)) {
p = appendp(p); // load g into CX
p->as = AMOVL;
p->from.type = D_INDIR+D_FS;
p->from.type = D_INDIR+D_GS;
p->from.offset = 0;
p->to.type = D_CX;

6
src/pkg/runtime/386/asm.s
View File

@ -15,12 +15,12 @@ TEXT _rt0_386(SB),7,$0
CALL ldt0setup(SB)
// set up %fs to refer to that ldt entry
// set up %gs to refer to that ldt entry
MOVL $(7*8+7), AX
MOVW AX, FS
MOVW AX, GS
// store through it, to make sure it works
MOVL $0x123, 0(FS)
MOVL $0x123, 0(GS)
MOVL tls0(SB), AX
CMPL AX, $0x123
JEQ ok

2
src/pkg/runtime/darwin/386/sys.s
View File

@ -139,7 +139,7 @@ TEXT bsdthread_start(SB),7,$0
POPAL
SHLL $3, DI // segment# is ldt*8 + 7.
ADDL $7, DI
MOVW DI, FS
MOVW DI, GS
// Now segment is established. Initialize m, g.
MOVL AX, g

49
src/pkg/runtime/linux/386/sys.s
View File

@ -8,20 +8,6 @@
#include "386/asm.h"
TEXT syscall(SB),7,$0
MOVL 4(SP), AX // syscall number
MOVL 8(SP), BX // arg1
MOVL 12(SP), CX // arg2
MOVL 16(SP), DX // arg3
MOVL 20(SP), SI // arg4
MOVL 24(SP), DI // arg5
MOVL 28(SP), BP // arg6
INT $0x80
CMPL AX, $0xfffff001
JLS 2(PC)
INT $3 // not reached
RET
TEXT exit(SB),7,$0
MOVL $252, AX // syscall number
MOVL 4(SP), BX
@ -159,7 +145,7 @@ TEXT clone(SB),7,$0
POPAL
SHLL $3, DI // segment# is ldt*8 + 7 (different 7 than above)
ADDL $7, DI
MOVW DI, FS
MOVW DI, GS
// Now segment is established. Initialize m, g.
MOVL DX, g
@ -190,15 +176,15 @@ TEXT sigaltstack(SB),7,$-8
// <asm-i386/ldt.h>
// struct user_desc {
// unsigned int entry_number;
// unsigned long base_addr;
// unsigned int limit;
// unsigned int seg_32bit:1;
// unsigned int contents:2;
// unsigned int read_exec_only:1;
// unsigned int limit_in_pages:1;
// unsigned int seg_not_present:1;
// unsigned int useable:1;
// unsigned int entry_number;
// unsigned long base_addr;
// unsigned int limit;
// unsigned int seg_32bit:1;
// unsigned int contents:2;
// unsigned int read_exec_only:1;
// unsigned int limit_in_pages:1;
// unsigned int seg_not_present:1;
// unsigned int useable:1;
// };
#define SEG_32BIT 0x01
// contents are the 2 bits 0x02 and 0x04.
@ -223,10 +209,15 @@ TEXT setldt(SB),7,$32
MOVL $(SEG_32BIT|USEABLE|CONTENTS_DATA), 12(AX) // flag bits
// call modify_ldt
MOVL $123, 0(SP) // syscall - modify_ldt
MOVL $1, 4(SP) // func = 1 (write)
MOVL AX, 8(SP) // user_desc
MOVL $16, 12(SP) // sizeof(user_desc)
CALL syscall(SB)
MOVL $1, BX // func = 1 (write)
MOVL AX, CX // user_desc
MOVL $16, DX // sizeof(user_desc)
MOVL $123, AX // syscall - modify_ldt
INT $0x80
// breakpoint on error
CMPL AX, $0xfffff001
JLS 2(PC)
INT $3
RET

4
src/pkg/runtime/mkasmh.sh
View File

@ -13,8 +13,8 @@ EOF
case "$GOARCH" in
386)
echo '#define g 0(FS)'
echo '#define m 4(FS)'
echo '#define g 0(GS)'
echo '#define m 4(GS)'
;;
amd64)
echo '#define g R15'