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c813c1490d
Get the rseq feature size and alignment requirement from the auxiliary vector for use inside the dynamic loader. Use '__rseq_size' directly to store the feature size. If the main thread registration fails or is disabled by tunable, reset the value to 0. This will be used in the TLS block allocator to compute the size and alignment of the rseq area block for the extended ABI support. Signed-off-by: Michael Jeanson <mjeanson@efficios.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Florian Weimer <fweimer@redhat.com>
127 lines
4.2 KiB
C
127 lines
4.2 KiB
C
/* Completion of TCB initialization after TLS_INIT_TP. NPTL version.
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Copyright (C) 2020-2025 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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size_t _rseq_align attribute_hidden;
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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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/* If the registration fails or is disabled by tunable, the public
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'__rseq_size' will be set to '0' regardless of the feature size of the
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allocated rseq area. An rseq area of at least 32 bytes is always
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allocated since application code is allowed to check the status of the
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rseq registration by reading the content of the 'cpu_id' field. */
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bool do_rseq = TUNABLE_GET (rseq, int, NULL);
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if (!rseq_register_current_thread (pd, do_rseq))
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_rseq_size = 0;
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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 the rseq registration may have happened because RSEQ_SIG is
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defined. */
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_rseq_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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}
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