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Use the i386_set_gsbase() syscall if it is implemented in the kernel.

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This is a little hairy here because the allocation and usage of this
functionality is split into two places in libpthread.
This commit is contained in:
Peter Wemm 2005-04-14 00:13:20 +00:00
parent 8a477e0a7a
commit 72a79166ea
4 changed files with 82 additions and 32 deletions
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47
lib/libkse/arch/i386/i386/pthread_md.c
View File

@ -42,6 +42,8 @@ __FBSDID("$FreeBSD$");
#include "rtld_tls.h"
#include "pthread_md.h"
int _thr_using_setbase;
struct tcb *
_tcb_ctor(struct pthread *thread, int initial)
{
@ -78,8 +80,10 @@ _kcb_ctor(struct kse *kse)
{
#ifndef COMPAT_32BIT
union descriptor ldt;
void *base;
#endif
struct kcb *kcb;
int error;
kcb = malloc(sizeof(struct kcb));
if (kcb != NULL) {
@ -87,20 +91,35 @@ _kcb_ctor(struct kse *kse)
kcb->kcb_self = kcb;
kcb->kcb_kse = kse;
#ifndef COMPAT_32BIT
ldt.sd.sd_hibase = (unsigned int)kcb >> 24;
ldt.sd.sd_lobase = (unsigned int)kcb & 0xFFFFFF;
ldt.sd.sd_hilimit = (sizeof(struct kcb) >> 16) & 0xF;
ldt.sd.sd_lolimit = sizeof(struct kcb) & 0xFFFF;
ldt.sd.sd_type = SDT_MEMRWA;
ldt.sd.sd_dpl = SEL_UPL;
ldt.sd.sd_p = 1;
ldt.sd.sd_xx = 0;
ldt.sd.sd_def32 = 1;
ldt.sd.sd_gran = 0; /* no more than 1M */
kcb->kcb_ldt = i386_set_ldt(LDT_AUTO_ALLOC, &ldt, 1);
if (kcb->kcb_ldt < 0) {
free(kcb);
return (NULL);
switch (_thr_using_setbase) {
case 1: /* use i386_set_gsbase() in _kcb_set */
kcb->kcb_ldt = -1;
break;
case 0: /* Untested, try the get/set_gsbase routines once */
error = i386_get_gsbase(&base);
if (error == 0) {
_thr_using_setbase = 1;
break;
}
/* fall through */
case 2: /* Use the user_ldt code, we must have an old kernel */
_thr_using_setbase = 2;
ldt.sd.sd_hibase = (unsigned int)kcb >> 24;
ldt.sd.sd_lobase = (unsigned int)kcb & 0xFFFFFF;
ldt.sd.sd_hilimit = (sizeof(struct kcb) >> 16) & 0xF;
ldt.sd.sd_lolimit = sizeof(struct kcb) & 0xFFFF;
ldt.sd.sd_type = SDT_MEMRWA;
ldt.sd.sd_dpl = SEL_UPL;
ldt.sd.sd_p = 1;
ldt.sd.sd_xx = 0;
ldt.sd.sd_def32 = 1;
ldt.sd.sd_gran = 0; /* no more than 1M */
kcb->kcb_ldt = i386_set_ldt(LDT_AUTO_ALLOC, &ldt, 1);
if (kcb->kcb_ldt < 0) {
free(kcb);
return (NULL);
}
break;
}
#endif
}

10
lib/libkse/arch/i386/include/pthread_md.h
View File

@ -40,6 +40,8 @@
extern int _thr_setcontext(mcontext_t *, intptr_t, intptr_t *);
extern int _thr_getcontext(mcontext_t *);
extern int _thr_using_setbase;
#define KSE_STACKSIZE 16384
#define DTV_OFFSET offsetof(struct tcb, tcb_dtv)
@ -155,8 +157,12 @@ _kcb_set(struct kcb *kcb)
#ifndef COMPAT_32BIT
int val;
val = (kcb->kcb_ldt << 3) | 7;
__asm __volatile("movl %0, %%gs" : : "r" (val));
if (_thr_using_setbase == 1) {
i386_set_gsbase(kcb);
} else {
val = (kcb->kcb_ldt << 3) | 7;
__asm __volatile("movl %0, %%gs" : : "r" (val));
}
#else
_amd64_set_gsbase(kcb);
#endif

47
lib/libpthread/arch/i386/i386/pthread_md.c
View File

@ -42,6 +42,8 @@ __FBSDID("$FreeBSD$");
#include "rtld_tls.h"
#include "pthread_md.h"
int _thr_using_setbase;
struct tcb *
_tcb_ctor(struct pthread *thread, int initial)
{
@ -78,8 +80,10 @@ _kcb_ctor(struct kse *kse)
{
#ifndef COMPAT_32BIT
union descriptor ldt;
void *base;
#endif
struct kcb *kcb;
int error;
kcb = malloc(sizeof(struct kcb));
if (kcb != NULL) {
@ -87,20 +91,35 @@ _kcb_ctor(struct kse *kse)
kcb->kcb_self = kcb;
kcb->kcb_kse = kse;
#ifndef COMPAT_32BIT
ldt.sd.sd_hibase = (unsigned int)kcb >> 24;
ldt.sd.sd_lobase = (unsigned int)kcb & 0xFFFFFF;
ldt.sd.sd_hilimit = (sizeof(struct kcb) >> 16) & 0xF;
ldt.sd.sd_lolimit = sizeof(struct kcb) & 0xFFFF;
ldt.sd.sd_type = SDT_MEMRWA;
ldt.sd.sd_dpl = SEL_UPL;
ldt.sd.sd_p = 1;
ldt.sd.sd_xx = 0;
ldt.sd.sd_def32 = 1;
ldt.sd.sd_gran = 0; /* no more than 1M */
kcb->kcb_ldt = i386_set_ldt(LDT_AUTO_ALLOC, &ldt, 1);
if (kcb->kcb_ldt < 0) {
free(kcb);
return (NULL);
switch (_thr_using_setbase) {
case 1: /* use i386_set_gsbase() in _kcb_set */
kcb->kcb_ldt = -1;
break;
case 0: /* Untested, try the get/set_gsbase routines once */
error = i386_get_gsbase(&base);
if (error == 0) {
_thr_using_setbase = 1;
break;
}
/* fall through */
case 2: /* Use the user_ldt code, we must have an old kernel */
_thr_using_setbase = 2;
ldt.sd.sd_hibase = (unsigned int)kcb >> 24;
ldt.sd.sd_lobase = (unsigned int)kcb & 0xFFFFFF;
ldt.sd.sd_hilimit = (sizeof(struct kcb) >> 16) & 0xF;
ldt.sd.sd_lolimit = sizeof(struct kcb) & 0xFFFF;
ldt.sd.sd_type = SDT_MEMRWA;
ldt.sd.sd_dpl = SEL_UPL;
ldt.sd.sd_p = 1;
ldt.sd.sd_xx = 0;
ldt.sd.sd_def32 = 1;
ldt.sd.sd_gran = 0; /* no more than 1M */
kcb->kcb_ldt = i386_set_ldt(LDT_AUTO_ALLOC, &ldt, 1);
if (kcb->kcb_ldt < 0) {
free(kcb);
return (NULL);
}
break;
}
#endif
}

10
lib/libpthread/arch/i386/include/pthread_md.h
View File

@ -40,6 +40,8 @@
extern int _thr_setcontext(mcontext_t *, intptr_t, intptr_t *);
extern int _thr_getcontext(mcontext_t *);
extern int _thr_using_setbase;
#define KSE_STACKSIZE 16384
#define DTV_OFFSET offsetof(struct tcb, tcb_dtv)
@ -155,8 +157,12 @@ _kcb_set(struct kcb *kcb)
#ifndef COMPAT_32BIT
int val;
val = (kcb->kcb_ldt << 3) | 7;
__asm __volatile("movl %0, %%gs" : : "r" (val));
if (_thr_using_setbase == 1) {
i386_set_gsbase(kcb);
} else {
val = (kcb->kcb_ldt << 3) | 7;
__asm __volatile("movl %0, %%gs" : : "r" (val));
}
#else
_amd64_set_gsbase(kcb);
#endif