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