From patchwork Thu Feb 13 17:08:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 38048 Received: (qmail 53588 invoked by alias); 13 Feb 2020 17:08:52 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 53506 invoked by uid 89); 13 Feb 2020 17:08:51 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-19.0 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.1 spammy= X-HELO: us-smtp-delivery-1.mimecast.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581613726; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=USUB1nUYzZ9Bn2cld3AHDvlxi6gIunuQ2UYPqdRn22Q=; b=DjlMILdJm/JQPwlbprzpTxec11Rgih/tLJHpuH8O+z8C79No8gZxqr7KotrgwML+IFIRbH mZe5tV9fla7OOfbOss6xquSrBCD/MdRpC4q3+Tn4P/FSHVDzYHn5fN+r9GvOOTmFCzDLQY LyVhrckSCzllJ5mWjyW2K/QPpZsNuWQ= From: Florian Weimer To: libc-alpha@sourceware.org Subject: [PATCH 11/11] nptl: Use for accessing the libgcc_s unwinder In-Reply-To: References: X-From-Line: f76766bb3e960981c0e2ccadafaea916174cf86c Mon Sep 17 00:00:00 2001 Message-Id: Date: Thu, 13 Feb 2020 18:08:32 +0100 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com --- nptl/nptlfreeres.c | 1 - nptl/pthreadP.h | 6 +- nptl/pthread_cancel.c | 3 +- sysdeps/arm/nptl/unwind-forcedunwind.c | 25 ++++ sysdeps/arm/pt-arm-unwind-resume.S | 30 +---- sysdeps/nptl/unwind-forcedunwind.c | 115 +++--------------- .../sysv/linux/ia64/unwind-forcedunwind.c | 16 +-- 7 files changed, 50 insertions(+), 146 deletions(-) create mode 100644 sysdeps/arm/nptl/unwind-forcedunwind.c diff --git a/nptl/nptlfreeres.c b/nptl/nptlfreeres.c index dda11e5922..644d196ab4 100644 --- a/nptl/nptlfreeres.c +++ b/nptl/nptlfreeres.c @@ -27,5 +27,4 @@ __libpthread_freeres (void) { call_function_static_weak (__nptl_stacks_freeres); call_function_static_weak (__shm_directory_freeres); - call_function_static_weak (__nptl_unwind_freeres); } diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index 7e0ab8ef42..2f370ae0ae 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -290,9 +290,11 @@ hidden_proto (__pthread_unwind_next) hidden_proto (__pthread_register_cancel) hidden_proto (__pthread_unregister_cancel) # ifdef SHARED -extern void attribute_hidden pthread_cancel_init (void); +/* The difference from __libc_unwind_link_get is that here, errors + terminate the process. */ +struct unwind_link ; +struct unwind_link *__pthread_unwind_link_get (void) attribute_hidden; # endif -extern void __nptl_unwind_freeres (void) attribute_hidden; #endif diff --git a/nptl/pthread_cancel.c b/nptl/pthread_cancel.c index 8e7be996e9..42b58b7034 100644 --- a/nptl/pthread_cancel.c +++ b/nptl/pthread_cancel.c @@ -35,7 +35,8 @@ __pthread_cancel (pthread_t th) return ESRCH; #ifdef SHARED - pthread_cancel_init (); + /* Trigger an error if libgcc_s cannot be loaded. */ + __pthread_unwind_link_get (); #endif int result = 0; int oldval; diff --git a/sysdeps/arm/nptl/unwind-forcedunwind.c b/sysdeps/arm/nptl/unwind-forcedunwind.c new file mode 100644 index 0000000000..ae64e61b85 --- /dev/null +++ b/sysdeps/arm/nptl/unwind-forcedunwind.c @@ -0,0 +1,25 @@ +/* Unwinder function forwarders for libpthread. Arm version. + Copyright (C) 2020 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; see the file COPYING.LIB. If + not, see . */ + +#include + +void * +__unwind_link_get_resume (void) +{ + return UNWIND_LINK_PTR (__pthread_unwind_link_get (), _Unwind_Resume); +} diff --git a/sysdeps/arm/pt-arm-unwind-resume.S b/sysdeps/arm/pt-arm-unwind-resume.S index 86ff5cbeea..d01e129cf4 100644 --- a/sysdeps/arm/pt-arm-unwind-resume.S +++ b/sysdeps/arm/pt-arm-unwind-resume.S @@ -16,31 +16,5 @@ License along with the GNU C Library. If not, see . */ -#include - -/* This is just implementing exactly what the C version does. - We do it in assembly just to ensure that we get an unmolested tail - call to the libgcc function, which is necessary for the ARM unwinder. */ - -ENTRY (_Unwind_Resume) - LDR_HIDDEN (ip, ip, __libgcc_s_resume, 0) - cmp ip, #0 - beq 1f -0: PTR_DEMANGLE (ip, ip, r2, r3) - bx ip - - /* We need to save and restore LR (for our own return address) - and R0 (for the argument to _Unwind_Resume) around the call. */ -1: push {r0, lr} - cfi_adjust_cfa_offset (8) - cfi_rel_offset (r0, 0) - cfi_rel_offset (lr, 4) - bl pthread_cancel_init - pop {r0, lr} - cfi_adjust_cfa_offset (-8) - cfi_restore (r0) - cfi_restore (lr) - - LDR_HIDDEN (ip, ip, __libgcc_s_resume, 0) - b 0b -END (_Unwind_Resume) +/* The implementation in libpthread is identical to the one in libc. */ +#include diff --git a/sysdeps/nptl/unwind-forcedunwind.c b/sysdeps/nptl/unwind-forcedunwind.c index 50a089282b..f57a3d0c18 100644 --- a/sysdeps/nptl/unwind-forcedunwind.c +++ b/sysdeps/nptl/unwind-forcedunwind.c @@ -16,134 +16,49 @@ License along with the GNU C Library; see the file COPYING.LIB. If not, see . */ -#include #include -#include +#include #include #include #include #include -static void *libgcc_s_handle; -void (*__libgcc_s_resume) (struct _Unwind_Exception *exc) - attribute_hidden __attribute__ ((noreturn)); -static _Unwind_Reason_Code (*libgcc_s_personality) PERSONALITY_PROTO; -static _Unwind_Reason_Code (*libgcc_s_forcedunwind) - (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *); -static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *); - -void -__attribute_noinline__ -pthread_cancel_init (void) +struct unwind_link * +__pthread_unwind_link_get (void) { - void *resume; - void *personality; - void *forcedunwind; - void *getcfa; - void *handle; - - if (__glibc_likely (libgcc_s_handle != NULL)) - { - /* Force gcc to reload all values. */ - asm volatile ("" ::: "memory"); - return; - } - - /* See include/dlfcn.h. Use of __libc_dlopen requires RTLD_NOW. */ - handle = __libc_dlopen (LIBGCC_S_SO); - - if (handle == NULL - || (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL - || (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL - || (forcedunwind = __libc_dlsym (handle, "_Unwind_ForcedUnwind")) - == NULL - || (getcfa = __libc_dlsym (handle, "_Unwind_GetCFA")) == NULL -#ifdef ARCH_CANCEL_INIT - || ARCH_CANCEL_INIT (handle) -#endif - ) - __libc_fatal (LIBGCC_S_SO " must be installed for pthread_cancel to work\n"); - - PTR_MANGLE (resume); - __libgcc_s_resume = resume; - PTR_MANGLE (personality); - libgcc_s_personality = personality; - PTR_MANGLE (forcedunwind); - libgcc_s_forcedunwind = forcedunwind; - PTR_MANGLE (getcfa); - libgcc_s_getcfa = getcfa; - /* Make sure libgcc_s_handle is written last. Otherwise, - pthread_cancel_init might return early even when the pointer the - caller is interested in is not initialized yet. */ - atomic_write_barrier (); - libgcc_s_handle = handle; -} - -/* Register for cleanup in libpthread.so. */ -void -__nptl_unwind_freeres (void) -{ - void *handle = libgcc_s_handle; - if (handle != NULL) - { - libgcc_s_handle = NULL; - __libc_dlclose (handle); - } + struct unwind_link *unwind_link = __libc_unwind_link_get (); + if (unwind_link == NULL) + __libc_fatal (LIBGCC_S_SO + " must be installed for pthread_cancel to work\n"); + return unwind_link; } #if !HAVE_ARCH_UNWIND_RESUME void _Unwind_Resume (struct _Unwind_Exception *exc) { - if (__glibc_unlikely (libgcc_s_handle == NULL)) - pthread_cancel_init (); - else - atomic_read_barrier (); - - void (*resume) (struct _Unwind_Exception *exc) = __libgcc_s_resume; - PTR_DEMANGLE (resume); - resume (exc); + UNWIND_LINK_PTR (__pthread_unwind_link_get (), _Unwind_Resume) (exc); } #endif _Unwind_Reason_Code __gcc_personality_v0 PERSONALITY_PROTO { - if (__glibc_unlikely (libgcc_s_handle == NULL)) - pthread_cancel_init (); - else - atomic_read_barrier (); - - __typeof (libgcc_s_personality) personality = libgcc_s_personality; - PTR_DEMANGLE (personality); - return (*personality) PERSONALITY_ARGS; + return UNWIND_LINK_PTR (__pthread_unwind_link_get (), personality) + PERSONALITY_ARGS; } _Unwind_Reason_Code _Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop, void *stop_argument) { - if (__glibc_unlikely (libgcc_s_handle == NULL)) - pthread_cancel_init (); - else - atomic_read_barrier (); - - _Unwind_Reason_Code (*forcedunwind) - (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *) - = libgcc_s_forcedunwind; - PTR_DEMANGLE (forcedunwind); - return forcedunwind (exc, stop, stop_argument); + return UNWIND_LINK_PTR (__pthread_unwind_link_get (), _Unwind_ForcedUnwind) + (exc, stop, stop_argument); } _Unwind_Word _Unwind_GetCFA (struct _Unwind_Context *context) { - if (__glibc_unlikely (libgcc_s_handle == NULL)) - pthread_cancel_init (); - else - atomic_read_barrier (); - - _Unwind_Word (*getcfa) (struct _Unwind_Context *) = libgcc_s_getcfa; - PTR_DEMANGLE (getcfa); - return getcfa (context); + return UNWIND_LINK_PTR (__pthread_unwind_link_get (), _Unwind_GetCFA) + (context); } diff --git a/sysdeps/unix/sysv/linux/ia64/unwind-forcedunwind.c b/sysdeps/unix/sysv/linux/ia64/unwind-forcedunwind.c index 4c953bf63c..17c35aa68a 100644 --- a/sysdeps/unix/sysv/linux/ia64/unwind-forcedunwind.c +++ b/sysdeps/unix/sysv/linux/ia64/unwind-forcedunwind.c @@ -16,23 +16,11 @@ License along with the GNU C Library; if not, see . */ -#include -#include -#include -#include - -static _Unwind_Word (*libgcc_s_getbsp) (struct _Unwind_Context *); - -#define ARCH_CANCEL_INIT(handle) \ - ((libgcc_s_getbsp = __libc_dlsym (handle, "_Unwind_GetBSP")) == NULL) - #include _Unwind_Word _Unwind_GetBSP (struct _Unwind_Context *context) { - if (__builtin_expect (libgcc_s_getbsp == NULL, 0)) - pthread_cancel_init (); - - return libgcc_s_getbsp (context); + return UNWIND_LINK_PTR (__pthread_unwind_link_get (), _Unwind_GetBSP) + (context); }