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/* Special definitions for ix86 machine using segment register based
thread descriptor.
Copyright (C) 1998 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <stddef.h> /* For offsetof. */
/* We don't want to include the kernel header. So duplicate the
information. */
/* Structure passed on `modify_ldt' call. */
struct modify_ldt_ldt_s
{
unsigned int entry_number;
unsigned long int 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 empty:25;
};
/* System call to set LDT entry. */
extern int __modify_ldt (int, struct modify_ldt_ldt_s *, size_t);
/* Return the thread descriptor for the current thread.
The contained asm must *not* be marked volatile since otherwise
assignments like
pthread_descr self = thread_self();
do not get optimized away. */
#define THREAD_SELF \
({ \
register pthread_descr __self; \
__asm__ ("movl %%gs:%c1,%0" : "=r" (__self) \
: "i" (offsetof (struct _pthread_descr_struct, p_self))); \
__self; \
})
/* Initialize the thread-unique value. */
#define INIT_THREAD_SELF(descr, nr) \
{ \
struct modify_ldt_ldt_s ldt_entry = \
{ nr, (unsigned long int) descr, sizeof (*descr), 1, 0, 0, 0, 0, 1, 0 }; \
if (__modify_ldt (1, &ldt_entry, sizeof (ldt_entry)) != 0) \
abort (); \
__asm__ __volatile__ ("movw %w0, %%gs" : : "r" (nr * 8 + 7)); \
}
/* Free resources associated with thread descriptor. */
#define FREE_THREAD_SELF(descr, nr) \
{ \
struct modify_ldt_ldt_s ldt_entry = \
{ nr, 0, 0, 0, 0, 1, 0, 1, 0, 0 }; \
__asm__ __volatile__ ("movw %w0,%%gs" : : "r" (0)); \
__modify_ldt (1, &ldt_entry, sizeof (ldt_entry)); \
}
/* Read member of the thread descriptor directly. */
#define THREAD_GETMEM(descr, member) \
({ \
__typeof__ (descr->member) __value; \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %%gs:%c1,%b0" \
: "=r" (__value) \
: "0" (0), \
"i" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 4) \
/* There should not be any value with a size other than 1 or 4. */ \
abort (); \
\
__asm__ __volatile__ ("movl %%gs:%c1,%0" \
: "=r" (__value) \
: "i" (offsetof (struct _pthread_descr_struct, \
member))); \
} \
__value; \
})
/* Set member of the thread descriptor directly. */
#define THREAD_SETMEM(descr, member, value) \
({ \
__typeof__ (descr->member) __value = (value); \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %0,%%gs:%c1" : \
: "r" (__value), \
"i" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 4) \
/* There should not be any value with a size other than 1 or 4. */ \
abort (); \
\
__asm__ __volatile__ ("movl %0,%%gs:%c1" : \
: "r" (__value), \
"i" (offsetof (struct _pthread_descr_struct, \
member))); \
} \
})
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