From patchwork Wed Feb 17 16:03:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 42085 X-Patchwork-Delegate: carlos@redhat.com Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 8E3FD39450ED; Wed, 17 Feb 2021 16:03:15 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8E3FD39450ED DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1613577795; bh=IKspne3hslJTjHDxzGvgS326KX01VfpI1em5GQfTiig=; h=To:Subject:In-Reply-To:References:Date:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=ZQpsN+eM+1P1vb+aMgowu1gQtCmaCn/ynJeL/rt8es1TouIlOHzfDwIAnBcz9CVEt yqPBpZAKjBUj1gG+x30a+a6pT4CLv4cL+/bqVByyMhs1jOfQdugaE+qbI3URwwzbu5 FsI5cRsiuMcu+GYVKrmR/2OwqzGIYs+ajyP60RR0= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id E18873834411 for ; Wed, 17 Feb 2021 16:03:12 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E18873834411 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-101-_3mfCuAvPY6hHJZjsGP58w-1; Wed, 17 Feb 2021 11:03:07 -0500 X-MC-Unique: _3mfCuAvPY6hHJZjsGP58w-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E7B70192D785 for ; Wed, 17 Feb 2021 16:03:06 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-113-131.ams2.redhat.com [10.36.113.131]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DBFE760D06 for ; Wed, 17 Feb 2021 16:03:05 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH 10/10] nptl: Use for accessing the libgcc_s unwinder In-Reply-To: References: Message-Id: <87938b5f4c53e2bd4f71274f7c61998ecb308cb6.1613577607.git.fweimer@redhat.com> Date: Wed, 17 Feb 2021 17:03:37 +0100 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" --- 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 Reviewed-by: Carlos O'Donell diff --git a/nptl/nptlfreeres.c b/nptl/nptlfreeres.c index d295bcb3c3..4833f04714 100644 --- a/nptl/nptlfreeres.c +++ b/nptl/nptlfreeres.c @@ -27,5 +27,4 @@ __libpthread_freeres (void) { call_function_static_weak (__default_pthread_attr_freeres); call_function_static_weak (__nptl_stacks_freeres); - call_function_static_weak (__nptl_unwind_freeres); } diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index d078128230..d2fd0826fe 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -287,9 +287,11 @@ 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 f88fa24e19..a011d72fa1 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..61db34c0b5 --- /dev/null +++ b/sysdeps/arm/nptl/unwind-forcedunwind.c @@ -0,0 +1,25 @@ +/* Unwinder function forwarders for libpthread. Arm version. + Copyright (C) 2021 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 d579848696..c056eb38d0 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 b70aae06ae..c0234670cf 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 e797ea22aa..eaed6cf2ef 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); }