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glibc/linuxthreads/sysdeps/i386/useldt.h
Ulrich Drepper 2626ed6c9c Update. 
* sysdeps/i386/useldt.h (DO_SET_THREAD_AREA): Make sure the
	compiler knows we use the ldt_entry variable and that the syscall
	modifies the memory.
2003-04-20 08:25:06 +00:00

315 lines
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/* Special definitions for ix86 machine using segment register based
thread descriptor.
Copyright (C) 1998, 2000, 2001, 2002 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 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; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#ifndef __ASSEMBLER__
#include <stddef.h> /* For offsetof. */
#include <stdlib.h> /* For abort(). */
#include <sysdep.h>
/* 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_header.data.self))); \
__self; \
})
/* Initialize the thread-unique value. Two possible ways to do it. */
#define DO_MODIFY_LDT(descr, nr) \
({ \
struct modify_ldt_ldt_s ldt_entry = \
{ nr, (unsigned long int) (descr), 0xfffff /* 4GB in pages */, \
1, 0, 0, 1, 0, 1, 0 }; \
if (__modify_ldt (1, &ldt_entry, sizeof (ldt_entry)) != 0) \
abort (); \
asm ("movw %w0, %%gs" : : "q" (nr * 8 + 7)); \
})
#ifdef __PIC__
# define USETLS_EBX_ARG "r"
# define USETLS_LOAD_EBX "xchgl %1, %%ebx\n\t"
#else
# define USETLS_EBX_ARG "b"
# define USETLS_LOAD_EBX
#endif
/* When using the new set_thread_area call, we don't need to change %gs
because we inherited the value set up in the main thread by TLS setup.
We need to extract that value and set up the same segment in this
thread. */
#if USE_TLS
# define DO_SET_THREAD_AREA_REUSE(nr) 1
#else
/* Without TLS, we do the initialization of the main thread, where NR == 0. */
# define DO_SET_THREAD_AREA_REUSE(nr) (!__builtin_constant_p (nr) || (nr))
#endif
#define DO_SET_THREAD_AREA(descr, nr) \
({ \
int __gs; \
if (DO_SET_THREAD_AREA_REUSE (nr)) \
{ \
asm ("movw %%gs, %w0" : "=q" (__gs)); \
struct modify_ldt_ldt_s ldt_entry = \
{ (__gs & 0xffff) >> 3, \
(unsigned long int) (descr), 0xfffff /* 4GB in pages */, \
1, 0, 0, 1, 0, 1, 0 }; \
\
int __result; \
__asm (USETLS_LOAD_EBX \
"movl %2, %%eax\n\t" \
"int $0x80\n\t" \
USETLS_LOAD_EBX \
: "=&a" (__result) \
: USETLS_EBX_ARG (&ldt_entry), "i" (__NR_set_thread_area), \
"m" (ldt_entry) \
: "memory"); \
if (__result == 0) \
asm ("movw %w0, %%gs" :: "q" (__gs)); \
else \
__gs = -1; \
} \
else \
{ \
struct modify_ldt_ldt_s ldt_entry = \
{ -1, \
(unsigned long int) (descr), 0xfffff /* 4GB in pages */, \
1, 0, 0, 1, 0, 1, 0 }; \
int __result; \
__asm (USETLS_LOAD_EBX \
"movl %2, %%eax\n\t" \
"int $0x80\n\t" \
USETLS_LOAD_EBX \
: "=&a" (__result) \
: USETLS_EBX_ARG (&ldt_entry), "i" (__NR_set_thread_area), \
"m" (ldt_entry) \
: "memory"); \
if (__result == 0) \
{ \
__gs = (ldt_entry.entry_number << 3) + 3; \
asm ("movw %w0, %%gs" : : "q" (__gs)); \
} \
else \
__gs = -1; \
} \
__gs; \
})
#if defined __ASSUME_SET_THREAD_AREA_SYSCALL
# define INIT_THREAD_SELF(descr, nr) DO_SET_THREAD_AREA (descr, nr)
#elif defined __NR_set_thread_area
# define INIT_THREAD_SELF(descr, nr) \
({ \
if (__builtin_expect (__have_no_set_thread_area, 0) \
|| (DO_SET_THREAD_AREA (descr, DO_SET_THREAD_AREA_REUSE (nr)) == -1 \
&& (__have_no_set_thread_area = 1))) \
DO_MODIFY_LDT (descr, nr); \
})
/* Defined in pspinlock.c. */
extern int __have_no_set_thread_area;
#else
# define INIT_THREAD_SELF(descr, nr) DO_MODIFY_LDT (descr, nr)
#endif
/* Free resources associated with thread descriptor. */
#ifdef __ASSUME_SET_THREAD_AREA_SYSCALL
#define FREE_THREAD(descr, nr) do { } while (0)
#elif defined __NR_set_thread_area
#define FREE_THREAD(descr, nr) \
{ \
int __gs; \
__asm__ __volatile__ ("movw %%gs, %w0" : "=q" (__gs)); \
if (__builtin_expect (__gs & 4, 0)) \
{ \
struct modify_ldt_ldt_s ldt_entry = \
{ nr, 0, 0, 0, 0, 1, 0, 1, 0, 0 }; \
__modify_ldt (1, &ldt_entry, sizeof (ldt_entry)); \
} \
}
#else
#define FREE_THREAD(descr, nr) \
{ \
struct modify_ldt_ldt_s ldt_entry = \
{ nr, 0, 0, 0, 0, 1, 0, 1, 0, 0 }; \
__modify_ldt (1, &ldt_entry, sizeof (ldt_entry)); \
}
#endif
/* Read member of the thread descriptor directly. */
#define THREAD_GETMEM(descr, member) \
({ \
__typeof__ (descr->member) __value; \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %%gs:%P2,%b0" \
: "=q" (__value) \
: "0" (0), \
"i" (offsetof (struct _pthread_descr_struct, \
member))); \
else if (sizeof (__value) == 4) \
__asm__ __volatile__ ("movl %%gs:%P1,%0" \
: "=r" (__value) \
: "i" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 8) \
/* There should not be any value with a size other than 1, 4 or 8. */\
abort (); \
\
__asm__ __volatile__ ("movl %%gs:%P1,%%eax\n\t" \
"movl %%gs:%P2,%%edx" \
: "=A" (__value) \
: "i" (offsetof (struct _pthread_descr_struct, \
member)), \
"i" (offsetof (struct _pthread_descr_struct, \
member) + 4)); \
} \
__value; \
})
/* Same as THREAD_GETMEM, but the member offset can be non-constant. */
#define THREAD_GETMEM_NC(descr, member) \
({ \
__typeof__ (descr->member) __value; \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %%gs:(%2),%b0" \
: "=q" (__value) \
: "0" (0), \
"r" (offsetof (struct _pthread_descr_struct, \
member))); \
else if (sizeof (__value) == 4) \
__asm__ __volatile__ ("movl %%gs:(%1),%0" \
: "=r" (__value) \
: "r" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 8) \
/* There should not be any value with a size other than 1, 4 or 8. */\
abort (); \
\
__asm__ __volatile__ ("movl %%gs:(%1),%%eax\n\t" \
"movl %%gs:4(%1),%%edx" \
: "=&A" (__value) \
: "r" (offsetof (struct _pthread_descr_struct, \
member))); \
} \
__value; \
})
/* Same as THREAD_SETMEM, but the member offset can be non-constant. */
#define THREAD_SETMEM(descr, member, value) \
({ \
__typeof__ (descr->member) __value = (value); \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %0,%%gs:%P1" : \
: "q" (__value), \
"i" (offsetof (struct _pthread_descr_struct, \
member))); \
else if (sizeof (__value) == 4) \
__asm__ __volatile__ ("movl %0,%%gs:%P1" : \
: "r" (__value), \
"i" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 8) \
/* There should not be any value with a size other than 1, 4 or 8. */\
abort (); \
\
__asm__ __volatile__ ("movl %%eax,%%gs:%P1\n\n" \
"movl %%edx,%%gs:%P2" : \
: "A" (__value), \
"i" (offsetof (struct _pthread_descr_struct, \
member)), \
"i" (offsetof (struct _pthread_descr_struct, \
member) + 4)); \
} \
})
/* Set member of the thread descriptor directly. */
#define THREAD_SETMEM_NC(descr, member, value) \
({ \
__typeof__ (descr->member) __value = (value); \
if (sizeof (__value) == 1) \
__asm__ __volatile__ ("movb %0,%%gs:(%1)" : \
: "q" (__value), \
"r" (offsetof (struct _pthread_descr_struct, \
member))); \
else if (sizeof (__value) == 4) \
__asm__ __volatile__ ("movl %0,%%gs:(%1)" : \
: "r" (__value), \
"r" (offsetof (struct _pthread_descr_struct, \
member))); \
else \
{ \
if (sizeof (__value) != 8) \
/* There should not be any value with a size other than 1, 4 or 8. */\
abort (); \
\
__asm__ __volatile__ ("movl %%eax,%%gs:(%1)\n\t" \
"movl %%edx,%%gs:4(%1)" : \
: "A" (__value), \
"r" (offsetof (struct _pthread_descr_struct, \
member))); \
} \
})
#endif
#if __ASSUME_LDT_WORKS > 0
/* We want the OS to assign stack addresses. */
#define FLOATING_STACKS 1
/* Maximum size of the stack if the rlimit is unlimited. */
#define ARCH_STACK_MAX_SIZE 8*1024*1024
#endif
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