/* 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, see <http://www.gnu.org/licenses/>. */ #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. */ #ifdef __UCLIBC_HAS_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