From 0aac205a814a8511e98d02b91a8dc908f1c53cde Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 26 Feb 2024 06:37:03 -0800 Subject: x86: Update _dl_tlsdesc_dynamic to preserve caller-saved registers 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 --- elf/Makefile | 18 +++++++ elf/tst-gnu2-tls2.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++++ elf/tst-gnu2-tls2.h | 36 ++++++++++++++ elf/tst-gnu2-tls2mod0.c | 31 ++++++++++++ elf/tst-gnu2-tls2mod1.c | 31 ++++++++++++ elf/tst-gnu2-tls2mod2.c | 31 ++++++++++++ 6 files changed, 269 insertions(+) create mode 100644 elf/tst-gnu2-tls2.c create mode 100644 elf/tst-gnu2-tls2.h create mode 100644 elf/tst-gnu2-tls2mod0.c create mode 100644 elf/tst-gnu2-tls2mod1.c create mode 100644 elf/tst-gnu2-tls2mod2.c (limited to 'elf') diff --git a/elf/Makefile b/elf/Makefile index 36c04baf02..02dc476e27 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -424,6 +424,7 @@ tests += \ tst-glibc-hwcaps-prepend \ tst-global1 \ tst-global2 \ + tst-gnu2-tls2 \ tst-initfinilazyfail \ tst-initorder \ tst-initorder2 \ @@ -846,6 +847,9 @@ modules-names += \ tst-filterobj-flt \ tst-finilazyfailmod \ tst-globalmod2 \ + tst-gnu2-tls2mod0 \ + tst-gnu2-tls2mod1 \ + tst-gnu2-tls2mod2 \ tst-initlazyfailmod \ tst-initorder2a \ tst-initorder2b \ @@ -3044,8 +3048,22 @@ $(objpfx)tst-tlsgap.out: \ $(objpfx)tst-tlsgap-mod0.so \ $(objpfx)tst-tlsgap-mod1.so \ $(objpfx)tst-tlsgap-mod2.so + +$(objpfx)tst-gnu2-tls2: $(shared-thread-library) +$(objpfx)tst-gnu2-tls2.out: \ + $(objpfx)tst-gnu2-tls2mod0.so \ + $(objpfx)tst-gnu2-tls2mod1.so \ + $(objpfx)tst-gnu2-tls2mod2.so + ifeq (yes,$(have-mtls-dialect-gnu2)) +# This test fails if dl_tlsdesc_dynamic doesn't preserve all caller-saved +# registers. See https://sourceware.org/bugzilla/show_bug.cgi?id=31372 +test-xfail-tst-gnu2-tls2 = yes + CFLAGS-tst-tlsgap-mod0.c += -mtls-dialect=gnu2 CFLAGS-tst-tlsgap-mod1.c += -mtls-dialect=gnu2 CFLAGS-tst-tlsgap-mod2.c += -mtls-dialect=gnu2 +CFLAGS-tst-gnu2-tls2mod0.c += -mtls-dialect=gnu2 +CFLAGS-tst-gnu2-tls2mod1.c += -mtls-dialect=gnu2 +CFLAGS-tst-gnu2-tls2mod2.c += -mtls-dialect=gnu2 endif diff --git a/elf/tst-gnu2-tls2.c b/elf/tst-gnu2-tls2.c new file mode 100644 index 0000000000..7ac04d7f33 --- /dev/null +++ b/elf/tst-gnu2-tls2.c @@ -0,0 +1,122 @@ +/* Test TLSDESC relocation. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "tst-gnu2-tls2.h" + +#ifndef IS_SUPPORTED +# define IS_SUPPORTED() true +#endif + +/* An architecture can define it to clobber caller-saved registers in + malloc below to verify that the implicit TLSDESC call won't change + caller-saved registers. */ +#ifndef PREPARE_MALLOC +# define PREPARE_MALLOC() +#endif + +extern void * __libc_malloc (size_t); + +size_t malloc_counter = 0; + +void * +malloc (size_t n) +{ + PREPARE_MALLOC (); + malloc_counter++; + return __libc_malloc (n); +} + +static void *mod[3]; +#ifndef MOD +# define MOD(i) "tst-gnu2-tls2mod" #i ".so" +#endif +static const char *modname[3] = { MOD(0), MOD(1), MOD(2) }; +#undef MOD + +static void +open_mod (int i) +{ + mod[i] = xdlopen (modname[i], RTLD_LAZY); + printf ("open %s\n", modname[i]); +} + +static void +close_mod (int i) +{ + xdlclose (mod[i]); + mod[i] = NULL; + printf ("close %s\n", modname[i]); +} + +static void +access_mod (int i, const char *sym) +{ + struct tls var = { -1, -1, -1, -1 }; + struct tls *(*f) (struct tls *) = xdlsym (mod[i], sym); + /* Check that our malloc is called. */ + malloc_counter = 0; + struct tls *p = f (&var); + TEST_VERIFY (malloc_counter != 0); + printf ("access %s: %s() = %p\n", modname[i], sym, p); + TEST_VERIFY_EXIT (memcmp (p, &var, sizeof (var)) == 0); + ++(p->a); +} + +static void * +start (void *arg) +{ + /* The DTV generation is at the last dlopen of mod0 and the + entry for mod1 is NULL. */ + + open_mod (1); /* Reuse modid of mod1. Uses dynamic TLS. */ + + /* Force the slow path in GNU2 TLS descriptor call. */ + access_mod (1, "apply_tls"); + + return arg; +} + +static int +do_test (void) +{ + if (!IS_SUPPORTED ()) + return EXIT_UNSUPPORTED; + + open_mod (0); + open_mod (1); + open_mod (2); + close_mod (0); + close_mod (1); /* Create modid gap at mod1. */ + open_mod (0); /* Reuse modid of mod0, bump generation count. */ + + /* Create a thread where DTV of mod1 is NULL. */ + pthread_t t = xpthread_create (NULL, start, NULL); + xpthread_join (t); + return 0; +} + +#include diff --git a/elf/tst-gnu2-tls2.h b/elf/tst-gnu2-tls2.h new file mode 100644 index 0000000000..77964a57a3 --- /dev/null +++ b/elf/tst-gnu2-tls2.h @@ -0,0 +1,36 @@ +/* Test TLSDESC relocation. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +struct tls +{ + int64_t a, b, c, d; +}; + +extern struct tls *apply_tls (struct tls *); + +/* An architecture can define them to verify that clobber caller-saved + registers aren't changed by the implicit TLSDESC call. */ +#ifndef BEFORE_TLSDESC_CALL +# define BEFORE_TLSDESC_CALL() +#endif + +#ifndef AFTER_TLSDESC_CALL +# define AFTER_TLSDESC_CALL() +#endif diff --git a/elf/tst-gnu2-tls2mod0.c b/elf/tst-gnu2-tls2mod0.c new file mode 100644 index 0000000000..45556a0e17 --- /dev/null +++ b/elf/tst-gnu2-tls2mod0.c @@ -0,0 +1,31 @@ +/* DSO used by tst-gnu2-tls2. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include "tst-gnu2-tls2.h" + +__thread struct tls tls_var0 __attribute__ ((visibility ("hidden"))); + +struct tls * +apply_tls (struct tls *p) +{ + BEFORE_TLSDESC_CALL (); + tls_var0 = *p; + struct tls *ret = &tls_var0; + AFTER_TLSDESC_CALL (); + return ret; +} diff --git a/elf/tst-gnu2-tls2mod1.c b/elf/tst-gnu2-tls2mod1.c new file mode 100644 index 0000000000..e10b9dbc0a --- /dev/null +++ b/elf/tst-gnu2-tls2mod1.c @@ -0,0 +1,31 @@ +/* DSO used by tst-gnu2-tls2. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include "tst-gnu2-tls2.h" + +__thread struct tls tls_var1[100] __attribute__ ((visibility ("hidden"))); + +struct tls * +apply_tls (struct tls *p) +{ + BEFORE_TLSDESC_CALL (); + tls_var1[1] = *p; + struct tls *ret = &tls_var1[1]; + AFTER_TLSDESC_CALL (); + return ret; +} diff --git a/elf/tst-gnu2-tls2mod2.c b/elf/tst-gnu2-tls2mod2.c new file mode 100644 index 0000000000..141af51e55 --- /dev/null +++ b/elf/tst-gnu2-tls2mod2.c @@ -0,0 +1,31 @@ +/* DSO used by tst-gnu2-tls2. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include "tst-gnu2-tls2.h" + +__thread struct tls tls_var2 __attribute__ ((visibility ("hidden"))); + +struct tls * +apply_tls (struct tls *p) +{ + BEFORE_TLSDESC_CALL (); + tls_var2 = *p; + struct tls *ret = &tls_var2; + AFTER_TLSDESC_CALL (); + return ret; +} -- cgit 1.4.1