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a364304718
Compiler generates the following instruction sequence for GNU2 dynamic
TLS access:
leaq tls_var@TLSDESC(%rip), %rax
call *tls_var@TLSCALL(%rax)
or
leal tls_var@TLSDESC(%ebx), %eax
call *tls_var@TLSCALL(%eax)
CALL instruction is transparent to compiler which assumes all registers,
except for EFLAGS and RAX/EAX, are unchanged after CALL. When
_dl_tlsdesc_dynamic is called, it calls __tls_get_addr on the slow
path. __tls_get_addr is a normal function which doesn't preserve any
caller-saved registers. _dl_tlsdesc_dynamic saved and restored integer
caller-saved registers, but didn't preserve any other caller-saved
registers. Add _dl_tlsdesc_dynamic IFUNC functions for FNSAVE, FXSAVE,
XSAVE and XSAVEC to save and restore all caller-saved registers. This
fixes BZ #31372.
Add GLRO(dl_x86_64_runtime_resolve) with GLRO(dl_x86_tlsdesc_dynamic)
to optimize elf_machine_runtime_setup.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
(cherry picked from commit 0aac205a81)
123 lines
3.0 KiB
C
123 lines
3.0 KiB
C
/* Test TLSDESC relocation.
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Copyright (C) 2024 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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<http://www.gnu.org/licenses/>. */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <dlfcn.h>
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#include <pthread.h>
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#include <support/xdlfcn.h>
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#include <support/xthread.h>
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#include <support/check.h>
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#include <support/test-driver.h>
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#include "tst-gnu2-tls2.h"
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#ifndef IS_SUPPORTED
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# define IS_SUPPORTED() true
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#endif
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/* An architecture can define it to clobber caller-saved registers in
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malloc below to verify that the implicit TLSDESC call won't change
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caller-saved registers. */
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#ifndef PREPARE_MALLOC
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# define PREPARE_MALLOC()
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#endif
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extern void * __libc_malloc (size_t);
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size_t malloc_counter = 0;
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void *
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malloc (size_t n)
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{
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PREPARE_MALLOC ();
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malloc_counter++;
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return __libc_malloc (n);
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}
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static void *mod[3];
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#ifndef MOD
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# define MOD(i) "tst-gnu2-tls2mod" #i ".so"
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#endif
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static const char *modname[3] = { MOD(0), MOD(1), MOD(2) };
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#undef MOD
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static void
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open_mod (int i)
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{
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mod[i] = xdlopen (modname[i], RTLD_LAZY);
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printf ("open %s\n", modname[i]);
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}
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static void
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close_mod (int i)
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{
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xdlclose (mod[i]);
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mod[i] = NULL;
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printf ("close %s\n", modname[i]);
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}
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static void
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access_mod (int i, const char *sym)
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{
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struct tls var = { -1, -1, -1, -1 };
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struct tls *(*f) (struct tls *) = xdlsym (mod[i], sym);
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/* Check that our malloc is called. */
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malloc_counter = 0;
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struct tls *p = f (&var);
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TEST_VERIFY (malloc_counter != 0);
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printf ("access %s: %s() = %p\n", modname[i], sym, p);
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TEST_VERIFY_EXIT (memcmp (p, &var, sizeof (var)) == 0);
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++(p->a);
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}
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static void *
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start (void *arg)
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{
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/* The DTV generation is at the last dlopen of mod0 and the
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entry for mod1 is NULL. */
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open_mod (1); /* Reuse modid of mod1. Uses dynamic TLS. */
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/* Force the slow path in GNU2 TLS descriptor call. */
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access_mod (1, "apply_tls");
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return arg;
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}
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static int
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do_test (void)
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{
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if (!IS_SUPPORTED ())
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return EXIT_UNSUPPORTED;
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open_mod (0);
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open_mod (1);
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open_mod (2);
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close_mod (0);
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close_mod (1); /* Create modid gap at mod1. */
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open_mod (0); /* Reuse modid of mod0, bump generation count. */
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/* Create a thread where DTV of mod1 is NULL. */
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pthread_t t = xpthread_create (NULL, start, NULL);
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xpthread_join (t);
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return 0;
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}
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#include <support/test-driver.c>
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