From patchwork Thu Feb 13 17:08:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 38047 Received: (qmail 52356 invoked by alias); 13 Feb 2020 17:08:40 -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 52128 invoked by uid 89); 13 Feb 2020 17:08:38 -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 autolearn=ham version=3.3.1 spammy= X-HELO: us-smtp-1.mimecast.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581613714; 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=HpES1XHE1nVfAjpO21pNudPaI4AhymaHK3WErPq6JdE=; b=LVL/y1fBU7UUyMgLcoih4tp/INtd6T9NWBuxDosDVUPLuuCn0wQhdFzqzt0p+XCUn1MgD/ 5Y0sL47l7wC0I8TD6Xd7TMapbhcTvNdtSle0IWCrjDe2lo3lKeRdL3Z/PH0e7GYf2rIQm4 NX2CiKnv45B0T+rCSSH5mjg11IJ4jhQ= From: Florian Weimer To: libc-alpha@sourceware.org Subject: [PATCH 10/11] Implement _Unwind_Resume in libc on top of In-Reply-To: References: X-From-Line: 2072b946f9c666fc1970976ccdec477ec3260789 Mon Sep 17 00:00:00 2001 Message-Id: <2072b946f9c666fc1970976ccdec477ec3260789.1581613260.git.fweimer@redhat.com> Date: Thu, 13 Feb 2020 18:08:28 +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 Temporarily move the arm _Unwind_Resume implementation to the file used by libpthread. It will be ported next. --- sysdeps/arm/arch-unwind-link.h | 4 +++ sysdeps/arm/arm-unwind-resume.S | 26 +++++++------- sysdeps/arm/pt-arm-unwind-resume.S | 48 ++++++++++++++++++++++++-- sysdeps/arm/unwind-resume.c | 25 ++++++++++++++ sysdeps/generic/unwind-resume.c | 55 +++++------------------------- 5 files changed, 97 insertions(+), 61 deletions(-) create mode 100644 sysdeps/arm/unwind-resume.c diff --git a/sysdeps/arm/arch-unwind-link.h b/sysdeps/arm/arch-unwind-link.h index b16a94e02a..abb3ba28d6 100644 --- a/sysdeps/arm/arch-unwind-link.h +++ b/sysdeps/arm/arch-unwind-link.h @@ -31,4 +31,8 @@ assert (local.ptr__Unwind_VRS_Get != NULL); \ PTR_MANGLE (local.ptr__Unwind_VRS_Get); +/* This is used by the _Unwind_Resume assembler implementation to + obtain the address to jump to. */ +void *__unwind_link_get_resume (void) attribute_hidden; + #endif /* _ARCH_UNWIND_LINK_H */ diff --git a/sysdeps/arm/arm-unwind-resume.S b/sysdeps/arm/arm-unwind-resume.S index 60df9aac46..48059475e4 100644 --- a/sysdeps/arm/arm-unwind-resume.S +++ b/sysdeps/arm/arm-unwind-resume.S @@ -18,29 +18,29 @@ #include -/* This is just implementing exactly what the C version does. +/* This is equivalent to the following C implementation: + + void + _Unwind_Resume (struct _Unwind_Exception *exc) + { + __unwind_link_get_resume () (exc); + } + 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} + push {r0, lr} cfi_adjust_cfa_offset (8) cfi_rel_offset (r0, 0) cfi_rel_offset (lr, 4) - bl __libgcc_s_init + bl __unwind_link_get_resume + mov r3, r0 pop {r0, lr} cfi_adjust_cfa_offset (-8) - cfi_restore (r0) + cfi_restore (r4) cfi_restore (lr) - - LDR_HIDDEN (ip, ip, __libgcc_s_resume, 0) - b 0b + bx r3 END (_Unwind_Resume) diff --git a/sysdeps/arm/pt-arm-unwind-resume.S b/sysdeps/arm/pt-arm-unwind-resume.S index 7cb555c02b..86ff5cbeea 100644 --- a/sysdeps/arm/pt-arm-unwind-resume.S +++ b/sysdeps/arm/pt-arm-unwind-resume.S @@ -1,2 +1,46 @@ -#define __libgcc_s_init pthread_cancel_init -#include +/* _Unwind_Resume wrapper for ARM EABI. + Copyright (C) 2015-2020 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. 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) diff --git a/sysdeps/arm/unwind-resume.c b/sysdeps/arm/unwind-resume.c new file mode 100644 index 0000000000..ea0bf8998a --- /dev/null +++ b/sysdeps/arm/unwind-resume.c @@ -0,0 +1,25 @@ +/* Unwinder function forwarders for libc. 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 (link (), _Unwind_Resume); +} diff --git a/sysdeps/generic/unwind-resume.c b/sysdeps/generic/unwind-resume.c index 42593c3f61..539b2b3574 100644 --- a/sysdeps/generic/unwind-resume.c +++ b/sysdeps/generic/unwind-resume.c @@ -16,68 +16,31 @@ License along with the GNU C Library; see the file COPYING.LIB. If not, see . */ -#include #include -#include #include +#include #include #include - -void (*__libgcc_s_resume) (struct _Unwind_Exception *exc) - attribute_hidden __attribute__ ((noreturn)); - -static _Unwind_Reason_Code (*libgcc_s_personality) PERSONALITY_PROTO; - -void attribute_hidden __attribute__ ((cold)) -__libgcc_s_init (void) +static struct unwind_link * +link (void) { - void *resume, *personality; - void *handle; - - /* 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) - __libc_fatal (LIBGCC_S_SO - " must be installed for unwinding to work\n"); - -#ifdef PTR_MANGLE - PTR_MANGLE (resume); -#endif - __libgcc_s_resume = resume; -#ifdef PTR_MANGLE - PTR_MANGLE (personality); -#endif - libgcc_s_personality = personality; + struct unwind_link *unwind_link = __libc_unwind_link_get (); + if (unwind_link == NULL) + __libc_fatal (LIBGCC_S_SO " must be installed for unwinding to work\n"); + return unwind_link; } #if !HAVE_ARCH_UNWIND_RESUME void _Unwind_Resume (struct _Unwind_Exception *exc) { - if (__glibc_unlikely (__libgcc_s_resume == NULL)) - __libgcc_s_init (); - - __typeof (__libgcc_s_resume) resume = __libgcc_s_resume; -#ifdef PTR_DEMANGLE - PTR_DEMANGLE (resume); -#endif - (*resume) (exc); + UNWIND_LINK_PTR (link (), _Unwind_Resume) (exc); } #endif _Unwind_Reason_Code __gcc_personality_v0 PERSONALITY_PROTO { - if (__glibc_unlikely (libgcc_s_personality == NULL)) - __libgcc_s_init (); - - __typeof (libgcc_s_personality) personality = libgcc_s_personality; -#ifdef PTR_DEMANGLE - PTR_DEMANGLE (personality); -#endif - return (*personality) PERSONALITY_ARGS; + return UNWIND_LINK_PTR (link (), personality) PERSONALITY_ARGS; }