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8e78a2e1d1
Properly differentiate between setting up the real TLS with
TLS_INIT_TP, and setting up the early TLS (__init1_tcbhead) in static
builds. In the latter case, don't yet migrate the reply port into the
TCB, and don't yet set __libc_tls_initialized to 1.
This also lets us move the __init1_desc assignment inside
_hurd_tls_init ().
Fixes cd019ddd89
"hurd: Don't leak __hurd_reply_port0"
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
229 lines
7.6 KiB
C
229 lines
7.6 KiB
C
/* Definitions for thread-local data handling. Hurd/x86_64 version.
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Copyright (C) 2003-2023 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, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _X86_64_TLS_H
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#define _X86_64_TLS_H
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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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#ifndef __ASSEMBLER__
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# include <dl-dtv.h>
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# include <mach/machine/thread_status.h>
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# include <errno.h>
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# include <assert.h>
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/* Type of the TCB. */
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typedef struct
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{
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void *tcb; /* Points to this structure. */
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dtv_t *dtv; /* Vector of pointers to TLS data. */
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thread_t self; /* This thread's control port. */
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int __glibc_padding1;
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int multiple_threads;
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int gscope_flag;
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uintptr_t sysinfo;
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uintptr_t stack_guard;
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uintptr_t pointer_guard;
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long __glibc_padding2[2];
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int private_futex;
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int __glibc_padding3;
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/* Reservation of some values for the TM ABI. */
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void *__private_tm[4];
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/* GCC split stack support. */
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void *__private_ss;
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/* The lowest address of shadow stack. */
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unsigned long long int ssp_base;
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/* Keep these fields last, so offsets of fields above can continue being
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compatible with the x86_64 NPTL version. */
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mach_port_t reply_port; /* This thread's reply port. */
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struct hurd_sigstate *_hurd_sigstate;
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/* Used by the exception handling implementation in the dynamic loader. */
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struct rtld_catch *rtld_catch;
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} tcbhead_t;
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/* GCC generates %fs:0x28 to access the stack guard. */
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_Static_assert (offsetof (tcbhead_t, stack_guard) == 0x28,
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"stack guard offset");
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/* libgcc uses %fs:0x70 to access the split stack pointer. */
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_Static_assert (offsetof (tcbhead_t, __private_ss) == 0x70,
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"split stack pointer offset");
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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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# define TLS_DTV_AT_TP 0
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/* Alignment requirement for TCB.
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Some processors such as Intel Atom pay a big penalty on every
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access using a segment override if that segment's base is not
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aligned to the size of a cache line. (See Intel 64 and IA-32
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Architectures Optimization Reference Manual, section 13.3.3.3,
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"Segment Base".) On such machines, a cache line is 64 bytes. */
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# define TCB_ALIGNMENT 64
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# define THREAD_SELF \
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(*(tcbhead_t * __seg_fs *) offsetof (tcbhead_t, tcb))
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/* Read member of the thread descriptor directly. */
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# define THREAD_GETMEM(descr, member) \
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(*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member))
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/* Write member of the thread descriptor directly. */
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# define THREAD_SETMEM(descr, member, value) \
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(*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member) = value)
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/* Return the TCB address of a thread given its state.
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Note: this is expensive. */
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static inline tcbhead_t * __attribute__ ((unused))
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THREAD_TCB (thread_t thread,
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const void *all_state __attribute__ ((unused)))
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{
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error_t err;
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/* Fetch the target thread's state. */
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struct i386_fsgs_base_state state;
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mach_msg_type_number_t state_count = i386_FSGS_BASE_STATE_COUNT;
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err = __thread_get_state (thread, i386_FSGS_BASE_STATE,
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(thread_state_t) &state,
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&state_count);
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assert_perror (err);
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assert (state_count == i386_FSGS_BASE_STATE_COUNT);
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return (tcbhead_t *) state.fs_base;
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}
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/* Install new dtv for current thread. */
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# define INSTALL_NEW_DTV(dtvp) THREAD_SETMEM (THREAD_SELF, dtv, dtvp)
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/* Return the address of the dtv for the current thread. */
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# define THREAD_DTV() THREAD_GETMEM (THREAD_SELF, dtv)
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/* Set the stack guard field in TCB head. */
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# define THREAD_SET_STACK_GUARD(value) \
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THREAD_SETMEM (THREAD_SELF, stack_guard, value)
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# define THREAD_COPY_STACK_GUARD(descr) \
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((descr)->stack_guard \
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= THREAD_GETMEM (THREAD_SELF, stack_guard))
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/* Set the pointer guard field in the TCB head. */
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# define THREAD_SET_POINTER_GUARD(value) \
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THREAD_SETMEM (THREAD_SELF, pointer_guard, value)
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# define THREAD_COPY_POINTER_GUARD(descr) \
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((descr)->pointer_guard \
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= THREAD_GETMEM (THREAD_SELF, pointer_guard))
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/* Set up TLS in the new thread of a fork child, copying from the original. */
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static inline kern_return_t __attribute__ ((unused))
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_hurd_tls_fork (thread_t child, thread_t orig,
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void *machine_state __attribute__ ((unused)))
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{
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error_t err;
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struct i386_fsgs_base_state state;
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mach_msg_type_number_t state_count = i386_FSGS_BASE_STATE_COUNT;
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err = __thread_get_state (orig, i386_FSGS_BASE_STATE,
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(thread_state_t) &state,
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&state_count);
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if (err)
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return err;
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assert (state_count == i386_FSGS_BASE_STATE_COUNT);
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return __thread_set_state (child, i386_FSGS_BASE_STATE,
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(thread_state_t) &state,
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state_count);
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}
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static inline kern_return_t __attribute__ ((unused))
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_hurd_tls_new (thread_t child, tcbhead_t *tcb)
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{
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struct i386_fsgs_base_state state;
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tcb->tcb = tcb;
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tcb->self = child;
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/* Install the TCB address into FS base. */
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state.fs_base = (uintptr_t) tcb;
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state.gs_base = 0;
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return __thread_set_state (child, i386_FSGS_BASE_STATE,
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(thread_state_t) &state,
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i386_FSGS_BASE_STATE_COUNT);
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}
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# if !defined (SHARED) || IS_IN (rtld)
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extern unsigned char __libc_tls_initialized;
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# define __LIBC_NO_TLS() __builtin_expect (!__libc_tls_initialized, 0)
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static inline bool __attribute__ ((unused))
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_hurd_tls_init (tcbhead_t *tcb, bool full)
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{
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error_t err;
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thread_t self = __mach_thread_self ();
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extern mach_port_t __hurd_reply_port0;
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/* We always at least start the sigthread anyway. */
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tcb->multiple_threads = 1;
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if (full)
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/* Take over the reply port we've been using. */
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tcb->reply_port = __hurd_reply_port0;
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err = _hurd_tls_new (self, tcb);
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if (err == 0 && full)
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{
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__libc_tls_initialized = 1;
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/* This port is now owned by the TCB. */
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__hurd_reply_port0 = MACH_PORT_NULL;
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}
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__mach_port_deallocate (__mach_task_self (), self);
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return err == 0;
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}
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# define TLS_INIT_TP(descr) _hurd_tls_init ((tcbhead_t *) (descr), 1)
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# else /* defined (SHARED) && !IS_IN (rtld) */
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# define __LIBC_NO_TLS() 0
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# endif
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/* Global scope switch support. */
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# define THREAD_GSCOPE_FLAG_UNUSED 0
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# define THREAD_GSCOPE_FLAG_USED 1
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# define THREAD_GSCOPE_FLAG_WAIT 2
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# define THREAD_GSCOPE_SET_FLAG() \
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THREAD_SETMEM (THREAD_SELF, gscope_flag, THREAD_GSCOPE_FLAG_USED)
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# define THREAD_GSCOPE_RESET_FLAG() \
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({ \
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int __flag; \
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asm volatile ("xchgl %0, %%fs:%P1" \
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: "=r" (__flag) \
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: "i" (offsetof (tcbhead_t, gscope_flag)), \
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"0" (THREAD_GSCOPE_FLAG_UNUSED)); \
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if (__flag == THREAD_GSCOPE_FLAG_WAIT) \
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lll_wake (THREAD_SELF->gscope_flag, LLL_PRIVATE); \
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})
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#endif /* __ASSEMBLER__ */
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#endif /* x86_64/tls.h */
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