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/* Definitions for thread-local data handling. Hurd/i386 version.
Copyright (C) 2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _I386_TLS_H
#define _I386_TLS_H
#if defined HAVE_TLS_SUPPORT
/* Some things really need not be machine-dependent. */
# include <sysdeps/mach/hurd/tls.h>
/* Indiciate that TLS support is available. */
# define USE_TLS 1
/* Use i386-specific RPCs to arrange that %gs segment register prefix
addresses the TCB in each thread. */
# include <mach/i386/mach_i386.h>
#ifndef HAVE_I386_SET_GDT
# define __i386_set_gdt(thr, sel, desc) ((thr), (sel), (desc), MIG_BAD_ID)
#endif
static inline int _hurd_tls_init (tcbhead_t *, int secondcall)
__attribute__ ((unused));
static inline const char *
_hurd_tls_init (tcbhead_t *tcb, int secondcall)
{
const unsigned int base = (unsigned int) tcb;
const struct descriptor desc =
{ /* low word: */
0xffff /* limit 0..15 */
| (base << 16) /* base 0..15 */
, /* high word: */
((base >> 16) & 0xff) /* base 16..23 */
| ((0x12 | 0x60 | 0x80) << 8) /* access = ACC_DATA_W|ACC_PL_U|ACC_P */
| (0xf << 16) /* limit 16..19 */
| ((4 | 8) << 20) /* granularity = SZ_32|SZ_G */
| (base & 0xff000000) /* base 24..31 */
};
if (!secondcall)
{
/* Cache our thread port. */
tcb->self = __mach_thread_self ();
/* Get the first available selector. */
int sel = -1;
error_t err = __i386_set_gdt (tcb->self, &sel, &desc);
if (err == MIG_BAD_ID)
{
/* Old kernel, use a per-thread LDT. */
sel = 0x27;
err = __i386_set_ldt (tcb->self, sel, &desc, 1);
assert_perror (err);
return "i386_set_ldt failed";
}
else
{
assert_perror (err); /* Separate from above with different line #. */
return "i386_set_gdt failed";
}
/* Now install the new selector. */
asm volatile ("mov %w0, %%gs" :: "q" (sel));
}
else
{
/* Fetch the selector set by the first call. */
int sel;
asm ("mov %%gs, %w0" : "=q" (sel));
if (__builtin_expect (sel, 0x50) & 4) /* LDT selector */
{
error_t err = __i386_set_ldt (tcb->self, sel, &desc, 1);
assert_perror (err);
return "i386_set_ldt failed";
}
else
{
error_t err = __i386_set_gdt (tcb->self, &sel, &desc);
assert_perror (err);
return "i386_set_gdt failed";
}
}
return 0;
}
/* Code to initially initialize the thread pointer. This might need
special attention since 'errno' is not yet available and if the
operation can cause a failure 'errno' must not be touched. */
# define TLS_INIT_TP(descr, secondcall) \
_hurd_tls_init ((tcbhead_t *) (descr), (secondcall))
/* Install new dtv for current thread. */
# define INSTALL_NEW_DTV(dtv) \
({ __asm__ ("movl %0, %%gs:0" : : "r" (dtv)); })
/* Return the address of the dtv for the current thread. */
# define THREAD_DTV() \
({ void *_dtv; __asm__ ("movl %%gs:0, %0" : "=r" (_dtv)); _dtv; })
#endif /* HAVE_TLS_SUPPORT */
#endif /* i386/tls.h */
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