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c901c3e764
The relationship between the thread pointer and the rseq area is made explicit. The constant offset can be used by JIT compilers to optimize rseq access (e.g., for really fast sched_getcpu). Extensibility is provided through __rseq_size and __rseq_flags. (In the future, the kernel could request a different rseq size via the auxiliary vector.) Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
135 lines
4.3 KiB
C
135 lines
4.3 KiB
C
/* Completion of TCB initialization after TLS_INIT_TP. NPTL version.
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Copyright (C) 2020-2021 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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#include <kernel-features.h>
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#include <ldsodefs.h>
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#include <list.h>
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#include <pthreadP.h>
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#include <tls.h>
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#include <rseq-internal.h>
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#include <thread_pointer.h>
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#define TUNABLE_NAMESPACE pthread
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#include <dl-tunables.h>
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#ifndef __ASSUME_SET_ROBUST_LIST
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bool __nptl_set_robust_list_avail;
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rtld_hidden_data_def (__nptl_set_robust_list_avail)
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#endif
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bool __nptl_initial_report_events;
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rtld_hidden_def (__nptl_initial_report_events)
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#ifdef SHARED
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/* Dummy implementation. See __rtld_mutex_init. */
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static int
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rtld_mutex_dummy (pthread_mutex_t *lock)
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{
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return 0;
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}
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#endif
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const unsigned int __rseq_flags;
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const unsigned int __rseq_size attribute_relro;
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const int __rseq_offset attribute_relro;
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void
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__tls_pre_init_tp (void)
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{
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/* The list data structures are not consistent until
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initialized. */
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INIT_LIST_HEAD (&GL (dl_stack_used));
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INIT_LIST_HEAD (&GL (dl_stack_user));
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INIT_LIST_HEAD (&GL (dl_stack_cache));
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#ifdef SHARED
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___rtld_mutex_lock = rtld_mutex_dummy;
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___rtld_mutex_unlock = rtld_mutex_dummy;
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#endif
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}
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void
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__tls_init_tp (void)
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{
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struct pthread *pd = THREAD_SELF;
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/* Set up thread stack list management. */
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list_add (&pd->list, &GL (dl_stack_user));
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/* Early initialization of the TCB. */
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pd->tid = INTERNAL_SYSCALL_CALL (set_tid_address, &pd->tid);
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THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
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THREAD_SETMEM (pd, user_stack, true);
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/* Before initializing GL (dl_stack_user), the debugger could not
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find us and had to set __nptl_initial_report_events. Propagate
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its setting. */
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THREAD_SETMEM (pd, report_events, __nptl_initial_report_events);
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/* Initialize the robust mutex data. */
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{
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#if __PTHREAD_MUTEX_HAVE_PREV
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pd->robust_prev = &pd->robust_head;
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#endif
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pd->robust_head.list = &pd->robust_head;
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pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
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- offsetof (pthread_mutex_t,
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__data.__list.__next));
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int res = INTERNAL_SYSCALL_CALL (set_robust_list, &pd->robust_head,
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sizeof (struct robust_list_head));
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if (!INTERNAL_SYSCALL_ERROR_P (res))
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{
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#ifndef __ASSUME_SET_ROBUST_LIST
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__nptl_set_robust_list_avail = true;
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#endif
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}
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}
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{
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bool do_rseq = true;
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#if HAVE_TUNABLES
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do_rseq = TUNABLE_GET (rseq, int, NULL);
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#endif
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if (rseq_register_current_thread (pd, do_rseq))
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{
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/* We need a writable view of the variables. They are in
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.data.relro and are not yet write-protected. */
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extern unsigned int size __asm__ ("__rseq_size");
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size = sizeof (pd->rseq_area);
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}
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#ifdef RSEQ_SIG
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/* This should be a compile-time constant, but the current
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infrastructure makes it difficult to determine its value. Not
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all targets support __thread_pointer, so set __rseq_offset only
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if thre rseq registration may have happened because RSEQ_SIG is
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defined. */
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extern int offset __asm__ ("__rseq_offset");
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offset = (char *) &pd->rseq_area - (char *) __thread_pointer ();
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#endif
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}
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/* Set initial thread's stack block from 0 up to __libc_stack_end.
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It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
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purposes this is good enough. */
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THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
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THREAD_SETMEM (pd, cancelstate, PTHREAD_CANCEL_ENABLE);
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THREAD_SETMEM (pd, canceltype, PTHREAD_CANCEL_DEFERRED);
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}
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