From patchwork Thu Mar 19 14:41:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathieu Desnoyers X-Patchwork-Id: 38583 Return-Path: X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail.efficios.com (mail.efficios.com [167.114.26.124]) by sourceware.org (Postfix) with ESMTPS id 63BD2381DCE3 for ; Thu, 19 Mar 2020 14:41:39 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 63BD2381DCE3 Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 11BE8278651; Thu, 19 Mar 2020 10:41:39 -0400 (EDT) Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id cmCjFOI-kJzD; Thu, 19 Mar 2020 10:41:36 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 407CF27864E; Thu, 19 Mar 2020 10:41:34 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 407CF27864E X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 4qLBzaWrd1Qg; Thu, 19 Mar 2020 10:41:34 -0400 (EDT) Received: from localhost.localdomain (192-222-181-218.qc.cable.ebox.net [192.222.181.218]) by mail.efficios.com (Postfix) with ESMTPSA id 86F80278792; Thu, 19 Mar 2020 10:41:29 -0400 (EDT) From: Mathieu Desnoyers To: Carlos O'Donell Cc: Florian Weimer , Joseph Myers , Szabolcs Nagy , libc-alpha@sourceware.org, Mathieu Desnoyers , Thomas Gleixner , Ben Maurer , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Will Deacon , Dave Watson , Paul Turner , Rich Felker , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Subject: [RFC PATCH glibc 4/8] glibc: Perform rseq(2) registration at C startup and thread creation (v15) Date: Thu, 19 Mar 2020 10:41:06 -0400 Message-Id: <20200319144110.3733-5-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200319144110.3733-1-mathieu.desnoyers@efficios.com> References: <20200319144110.3733-1-mathieu.desnoyers@efficios.com> X-Spam-Status: No, score=-25.2 required=5.0 tests=DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, SPF_HELO_NONE, SPF_PASS 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-List-Received-Date: Thu, 19 Mar 2020 14:41:44 -0000 Register rseq(2) TLS for each thread (including main), and unregister for each thread (excluding main). "rseq" stands for Restartable Sequences. See the rseq(2) man page proposed here: https://lkml.org/lkml/2018/9/19/647 This patch depends on three patches from Florian Weimer: - Introduce - Implement __libc_early_init - nptl: Start new threads with all signals blocked [BZ #25098] those are based on glibc master branch commit 1fabdb99084df004f7f4cdc7068d1be209a258be. The rseq(2) system call was merged into Linux 4.18. * NEWS: Add Restartable Sequences feature description. * elf/libc_early_init.c: Perform rseq(2) registration at C startup. startup for shared libc. * nptl/pthread_create.c: Perform rseq(2) registration at thread creation. * manual/threads.texi: Document __rseq_abi, RSEQ_SIG, sys/rseq.h. * sysdeps/unix/sysv/linux/kernel-features.h: Add __ASSUME_RSEQ. * sysdeps/unix/sysv/linux/Makefile: Add rseq-sym, sys/rseq.h, bits/rseq.h. * sysdeps/unix/sysv/linux/Versions: Export __rseq_abi from libc. * sysdeps/unix/sysv/linux/aarch64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/arm/be/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/arm/le/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/csky/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/hppa/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/i386/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/ia64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/microblaze/be/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/microblaze/le/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/nios2/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/sh/be/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/sh/le/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise. * misc/rseq-internal.h: New file. * sysdeps/unix/sysv/linux/rseq-internal.h: Likewise. * sysdeps/unix/sysv/linux/rseq-sym.c: Likewise. * sysdeps/unix/sysv/linux/sys/rseq.h: Likewise. * sysdeps/unix/sysv/linux/bits/rseq.h: Likewise. * sysdeps/unix/sysv/linux/aarch64/bits/rseq.h: Likewise. * sysdeps/unix/sysv/linux/arm/bits/rseq.h: Likewise. * sysdeps/unix/sysv/linux/mips/bits/rseq.h: Likewise. * sysdeps/unix/sysv/linux/powerpc/bits/rseq.h: Likewise. * sysdeps/unix/sysv/linux/s390/bits/rseq.h: Likewise. * sysdeps/unix/sysv/linux/x86/bits/rseq.h: Likewise. Signed-off-by: Mathieu Desnoyers CC: Carlos O'Donell CC: Florian Weimer CC: Joseph Myers CC: Szabolcs Nagy CC: Thomas Gleixner CC: Ben Maurer CC: Peter Zijlstra CC: "Paul E. McKenney" CC: Boqun Feng CC: Will Deacon CC: Dave Watson CC: Paul Turner CC: Rich Felker CC: libc-alpha@sourceware.org CC: linux-kernel@vger.kernel.org CC: linux-api@vger.kernel.org --- Changes since v1: - Move __rseq_refcount to an extra field at the end of __rseq_abi to eliminate one symbol. All libraries/programs which try to register rseq (glibc, early-adopter applications, early-adopter libraries) should use the rseq refcount. It becomes part of the ABI within a user-space process, but it's not part of the ABI shared with the kernel per se. - Restructure how this code is organized so glibc keeps building on non-Linux targets. - Use non-weak symbol for __rseq_abi. - Move rseq registration/unregistration implementation into its own nptl/rseq.c compile unit. - Move __rseq_abi symbol under GLIBC_2.29. Changes since v2: - Move __rseq_refcount to its own symbol, which is less ugly than trying to play tricks with the rseq uapi. - Move __rseq_abi from nptl to csu (C start up), so it can be used across glibc, including memory allocator and sched_getcpu(). The __rseq_refcount symbol is kept in nptl, because there is no reason to use it elsewhere in glibc. Changes since v3: - Set __rseq_refcount TLS to 1 on register/set to 0 on unregister because glibc is the first/last user. - Unconditionally register/unregister rseq at thread start/exit, because glibc is the first/last user. - Add missing abilist items. - Rebase on glibc master commit a502c5294. - Add NEWS entry. Changes since v4: - Do not use "weak" symbols for __rseq_abi and __rseq_refcount. Based on "System V Application Binary Interface", weak only affects the link editor, not the dynamic linker. - Install a new sys/rseq.h system header on Linux, which contains the RSEQ_SIG definition, __rseq_abi declaration and __rseq_refcount declaration. Move those definition/declarations from rseq-internal.h to the installed sys/rseq.h header. - Considering that rseq is only available on Linux, move csu/rseq.c to sysdeps/unix/sysv/linux/rseq-sym.c. - Move __rseq_refcount from nptl/rseq.c to sysdeps/unix/sysv/linux/rseq-sym.c, so it is only defined on Linux. - Move both ABI definitions for __rseq_abi and __rseq_refcount to sysdeps/unix/sysv/linux/Versions, so they only appear on Linux. - Document __rseq_abi and __rseq_refcount volatile. - Document the RSEQ_SIG signature define. - Move registration functions from rseq.c to rseq-internal.h static inline functions. Introduce empty stubs in misc/rseq-internal.h, which can be overridden by architecture code in sysdeps/unix/sysv/linux/rseq-internal.h. - Rename __rseq_register_current_thread and __rseq_unregister_current_thread to rseq_register_current_thread and rseq_unregister_current_thread, now that those are only visible as internal static inline functions. - Invoke rseq_register_current_thread() from libc-start.c LIBC_START_MAIN rather than nptl init, so applications not linked against libpthread.so have rseq registered for their main() thread. Note that it is invoked separately for SHARED and !SHARED builds. Changes since v5: - Replace __rseq_refcount by __rseq_lib_abi, which contains two uint32_t: register_state and refcount. The "register_state" field allows inhibiting rseq registration from signal handlers nested on top of glibc registration and occuring after rseq unregistration by glibc. - Introduce enum rseq_register_state, which contains the states allowed for the struct rseq_lib_abi register_state field. Changes since v6: - Introduce bits/rseq.h to define RSEQ_SIG for each architecture. The generic bits/rseq.h does not define RSEQ_SIG, meaning that each architecture implementing rseq needs to implement bits/rseq.h. - Rename enum item RSEQ_REGISTER_NESTED to RSEQ_REGISTER_ONGOING. - Port to glibc-2.29. Changes since v7: - Remove __rseq_lib_abi symbol, including refcount and register_state fields. - Remove reference counting and nested signals handling from registration/unregistration functions. - Introduce new __rseq_handled exported symbol, which is set to 1 by glibc on C startup when it handles restartable sequences. This allows glibc to coexist with early adopter libraries and applications wishing to register restartable sequences when it is not handled by glibc. - Introduce rseq_init (), which sets __rseq_handled to 1 from C startup. - Update NEWS entry. - Update comments at the beginning of new files. - Registration depends on both __NR_rseq and RSEQ_SIG. - Remove ARM, powerpc, MIPS RSEQ_SIG until we agree with maintainers on the signature choice. - Update x86, s390 RSEQ_SIG based on discussion with arch maintainers. - Remove rseq-internal.h from headers list of misc/Makefile, so it it not installed by make install. Changes since v8: - Introduce RSEQ_SIG_CODE and RSEQ_SIG_DATA on aarch64 to handle compiling with -mbig-endian. Changes since v9: - Update Changelog. - Remove unneeded new file comment header newlines. Changes since v10: - Remove volatile from __rseq_abi declaration. - Document that __rseq_handled is about library managing rseq registration, independently of whether rseq is available or not. - Move __rseq_handled symbol to ld.so, initialize this symbol within the dynamic linker initialization for both shared (rtld.c) and static (dl-support.c) builds. - Only register the rseq TLS on initialization once in multiple-libc scenarios. Use rtld_active () for this purpose. - In the static libc case, register the rseq TLS after LD_PRELOAD constructors are run, so it matches the order of this initialization vs LD_PRELOAD contructors execution for the shared libc. - Agreed on signature choice with powerpc and MIPS maintainers, re-adding those signatures, - The main architecture still left out signature-wise is ARM32. Changes since v11: - Rebase on glibc 2.30. - Re-introduce ARM RSEQ_SIG following feedback from Will Deacon. Changes since v12: - Remove __rseq_handled, - Rely on OS implicit rseq unregistration on thread teardown, - Register main thread in __libc_early_init (). - Add Restartable Sequences entry to threads manual. Changes since v13: - Update following be/le abilist split for arm, microblaze, and sh. - Update manual to add the __rseq_abi variable and RSEQ_SIG macro to generate manual index entries, and add missing "Restartable Sequences" menu entry to the threads chapter. Changes since v14: - Update copyright range to include 2020. - Introduce __ASSUME_RSEQ defined for --enable-kernel=4.18.0 and higher. - Use ifdef __ASSUME_RSEQ rather than ifdef __NR_rseq to discover rseq availability. This is necessary now that the system call numbers are integrated within glibc. Signed-off-by: Mathieu Desnoyers CC: Carlos O'Donell CC: Florian Weimer CC: Joseph Myers CC: Szabolcs Nagy CC: Thomas Gleixner CC: Ben Maurer CC: Peter Zijlstra CC: "Paul E. McKenney" CC: Boqun Feng CC: Will Deacon CC: Dave Watson CC: Paul Turner CC: Rich Felker CC: libc-alpha@sourceware.org CC: linux-kernel@vger.kernel.org CC: linux-api@vger.kernel.org --- NEWS | 10 +++ elf/libc_early_init.c | 3 + manual/threads.texi | 30 ++++++- misc/rseq-internal.h | 33 ++++++++ nptl/pthread_create.c | 12 +++ sysdeps/unix/sysv/linux/Makefile | 5 +- sysdeps/unix/sysv/linux/Versions | 3 + sysdeps/unix/sysv/linux/aarch64/bits/rseq.h | 43 ++++++++++ sysdeps/unix/sysv/linux/aarch64/libc.abilist | 1 + sysdeps/unix/sysv/linux/alpha/libc.abilist | 1 + sysdeps/unix/sysv/linux/arm/be/libc.abilist | 1 + sysdeps/unix/sysv/linux/arm/bits/rseq.h | 83 +++++++++++++++++++ sysdeps/unix/sysv/linux/arm/le/libc.abilist | 1 + sysdeps/unix/sysv/linux/bits/rseq.h | 29 +++++++ sysdeps/unix/sysv/linux/csky/libc.abilist | 1 + sysdeps/unix/sysv/linux/hppa/libc.abilist | 1 + sysdeps/unix/sysv/linux/i386/libc.abilist | 1 + sysdeps/unix/sysv/linux/ia64/libc.abilist | 1 + sysdeps/unix/sysv/linux/kernel-features.h | 5 ++ .../sysv/linux/m68k/coldfire/libc.abilist | 1 + .../unix/sysv/linux/m68k/m680x0/libc.abilist | 1 + .../sysv/linux/microblaze/be/libc.abilist | 1 + .../sysv/linux/microblaze/le/libc.abilist | 1 + sysdeps/unix/sysv/linux/mips/bits/rseq.h | 62 ++++++++++++++ .../sysv/linux/mips/mips32/fpu/libc.abilist | 1 + .../sysv/linux/mips/mips32/nofpu/libc.abilist | 1 + .../sysv/linux/mips/mips64/n32/libc.abilist | 1 + .../sysv/linux/mips/mips64/n64/libc.abilist | 1 + sysdeps/unix/sysv/linux/nios2/libc.abilist | 1 + sysdeps/unix/sysv/linux/powerpc/bits/rseq.h | 37 +++++++++ .../linux/powerpc/powerpc32/fpu/libc.abilist | 1 + .../powerpc/powerpc32/nofpu/libc.abilist | 1 + .../linux/powerpc/powerpc64/be/libc.abilist | 1 + .../linux/powerpc/powerpc64/le/libc.abilist | 1 + .../unix/sysv/linux/riscv/rv64/libc.abilist | 1 + sysdeps/unix/sysv/linux/rseq-internal.h | 76 +++++++++++++++++ sysdeps/unix/sysv/linux/rseq-sym.c | 44 ++++++++++ sysdeps/unix/sysv/linux/s390/bits/rseq.h | 37 +++++++++ .../unix/sysv/linux/s390/s390-32/libc.abilist | 1 + .../unix/sysv/linux/s390/s390-64/libc.abilist | 1 + sysdeps/unix/sysv/linux/sh/be/libc.abilist | 1 + sysdeps/unix/sysv/linux/sh/le/libc.abilist | 1 + .../sysv/linux/sparc/sparc32/libc.abilist | 1 + .../sysv/linux/sparc/sparc64/libc.abilist | 1 + sysdeps/unix/sysv/linux/sys/rseq.h | 30 +++++++ sysdeps/unix/sysv/linux/x86/bits/rseq.h | 30 +++++++ .../unix/sysv/linux/x86_64/64/libc.abilist | 1 + .../unix/sysv/linux/x86_64/x32/libc.abilist | 1 + 48 files changed, 598 insertions(+), 4 deletions(-) create mode 100644 misc/rseq-internal.h create mode 100644 sysdeps/unix/sysv/linux/aarch64/bits/rseq.h create mode 100644 sysdeps/unix/sysv/linux/arm/bits/rseq.h create mode 100644 sysdeps/unix/sysv/linux/bits/rseq.h create mode 100644 sysdeps/unix/sysv/linux/mips/bits/rseq.h create mode 100644 sysdeps/unix/sysv/linux/powerpc/bits/rseq.h create mode 100644 sysdeps/unix/sysv/linux/rseq-internal.h create mode 100644 sysdeps/unix/sysv/linux/rseq-sym.c create mode 100644 sysdeps/unix/sysv/linux/s390/bits/rseq.h create mode 100644 sysdeps/unix/sysv/linux/sys/rseq.h create mode 100644 sysdeps/unix/sysv/linux/x86/bits/rseq.h diff --git a/NEWS b/NEWS index e0379fc53c..abc62ae5f5 100644 --- a/NEWS +++ b/NEWS @@ -61,6 +61,16 @@ Major new features: responses, indicating a lack of DNSSEC validation. (Therefore, the name servers and the network path to them are treated as untrusted.) +* Support for automatically registering threads with the Linux rseq(2) + system call has been added. This system call is implemented starting + from Linux 4.18. The Restartable Sequences ABI accelerates user-space + operations on per-cpu data. It allows user-space to perform updates + on per-cpu data without requiring heavy-weight atomic operations. + Automatically registering threads allows all libraries, including libc, + to make immediate use of the rseq(2) support by using the documented ABI. + See 'man 2 rseq' for the details of the ABI shared between libc and the + kernel. + Deprecated and removed features, and other changes affecting compatibility: * The totalorder and totalordermag functions, and the corresponding diff --git a/elf/libc_early_init.c b/elf/libc_early_init.c index 1ac66d895d..30466afea0 100644 --- a/elf/libc_early_init.c +++ b/elf/libc_early_init.c @@ -18,10 +18,13 @@ #include #include +#include void __libc_early_init (void) { /* Initialize ctype data. */ __ctype_init (); + /* Register rseq ABI to the kernel. */ + (void) rseq_register_current_thread (); } diff --git a/manual/threads.texi b/manual/threads.texi index 0858ef8f92..59f634e432 100644 --- a/manual/threads.texi +++ b/manual/threads.texi @@ -9,8 +9,10 @@ This chapter describes functions used for managing threads. POSIX threads. @menu -* ISO C Threads:: Threads based on the ISO C specification. -* POSIX Threads:: Threads based on the POSIX specification. +* ISO C Threads:: Threads based on the ISO C specification. +* POSIX Threads:: Threads based on the POSIX specification. +* Restartable Sequences:: Linux-specific Restartable Sequences + integration. @end menu @@ -881,3 +883,27 @@ Behaves like @code{pthread_timedjoin_np} except that the absolute time in @c pthread_spin_unlock @c pthread_testcancel @c pthread_yield + +@node Restartable Sequences +@section Restartable Sequences +@cindex rseq + +This section describes @theglibc{} Restartable Sequences integration. + +@deftypevar {struct rseq} __rseq_abi +@standards{GNU, sys/rseq.h} +@Theglibc{} implements a @code{__rseq_abi} TLS symbol to interact with the +Restartable Sequences system call (Linux-specific). The layout of this +structure is defined by the Linux kernel @file{linux/rseq.h} UAPI. +Registration of each thread's @code{__rseq_abi} is performed by +@theglibc{} at libc initialization and pthread creation. +@end deftypevar + +@deftypevr Macro int RSEQ_SIG +@standards{GNU, sys/rseq.h} +Each supported architecture provide a @code{RSEQ_SIG} macro in +@file{sys/rseq.h} which contains a signature. That signature is expected to be +present in the code before each Restartable Sequences abort handler. Failure +to provide the expected signature may terminate the process with a Segmentation +fault. +@end deftypevr diff --git a/misc/rseq-internal.h b/misc/rseq-internal.h new file mode 100644 index 0000000000..d564cf1bc3 --- /dev/null +++ b/misc/rseq-internal.h @@ -0,0 +1,33 @@ +/* Restartable Sequences internal API. Stub version. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef RSEQ_INTERNAL_H +#define RSEQ_INTERNAL_H + +static inline int +rseq_register_current_thread (void) +{ + return -1; +} + +static inline int +rseq_unregister_current_thread (void) +{ + return -1; +} + +#endif /* rseq-internal.h */ diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c index afd379e89a..1ff248042e 100644 --- a/nptl/pthread_create.c +++ b/nptl/pthread_create.c @@ -33,6 +33,7 @@ #include #include #include +#include #include "libioP.h" #include @@ -384,6 +385,9 @@ START_THREAD_DEFN /* Initialize pointers to locale data. */ __ctype_init (); + /* Register rseq TLS to the kernel. */ + (void) rseq_register_current_thread (); + #ifndef __ASSUME_SET_ROBUST_LIST if (__set_robust_list_avail >= 0) #endif @@ -578,6 +582,14 @@ START_THREAD_DEFN process is really dead since 'clone' got passed the CLONE_CHILD_CLEARTID flag. The 'tid' field in the TCB will be set to zero. + rseq TLS is still registered at this point. Rely on implicit unregistration + performed by the kernel on thread teardown. This is not a problem because the + rseq TLS lives on the stack, and the stack outlives the thread. If TCB + allocation is ever changed, additional steps may be required, such as + performing explicit rseq unregistration before reclaiming the rseq TLS area + memory. It is NOT sufficient to block signals because the kernel may write + to the rseq area even without signals. + The exit code is zero since in case all threads exit by calling 'pthread_exit' the exit status must be 0 (zero). */ __exit_thread (); diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index 60dc5cf9e5..6c6f669d21 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -41,7 +41,7 @@ update-syscall-lists: arch-syscall.h endif ifeq ($(subdir),csu) -sysdep_routines += errno-loc +sysdep_routines += errno-loc rseq-sym endif ifeq ($(subdir),assert) @@ -92,7 +92,8 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ bits/termios-baud.h bits/termios-c_cflag.h \ bits/termios-c_lflag.h bits/termios-tcflow.h \ bits/termios-misc.h \ - bits/ipc-perm.h + bits/ipc-perm.h \ + sys/rseq.h bits/rseq.h tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \ diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions index d385085c61..7f0da50580 100644 --- a/sysdeps/unix/sysv/linux/Versions +++ b/sysdeps/unix/sysv/linux/Versions @@ -177,6 +177,9 @@ libc { GLIBC_2.30 { getdents64; gettid; tgkill; } + GLIBC_2.31 { + __rseq_abi; + } GLIBC_PRIVATE { # functions used in other libraries __syscall_rt_sigqueueinfo; diff --git a/sysdeps/unix/sysv/linux/aarch64/bits/rseq.h b/sysdeps/unix/sysv/linux/aarch64/bits/rseq.h new file mode 100644 index 0000000000..e272c30446 --- /dev/null +++ b/sysdeps/unix/sysv/linux/aarch64/bits/rseq.h @@ -0,0 +1,43 @@ +/* Restartable Sequences Linux aarch64 architecture header. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef _SYS_RSEQ_H +# error "Never use directly; include instead." +#endif + +/* RSEQ_SIG is a signature required before each abort handler code. + + It is a 32-bit value that maps to actual architecture code compiled + into applications and libraries. It needs to be defined for each + architecture. When choosing this value, it needs to be taken into + account that generating invalid instructions may have ill effects on + tools like objdump, and may also have impact on the CPU speculative + execution efficiency in some cases. + + aarch64 -mbig-endian generates mixed endianness code vs data: + little-endian code and big-endian data. Ensure the RSEQ_SIG signature + matches code endianness. */ + +#define RSEQ_SIG_CODE 0xd428bc00 /* BRK #0x45E0. */ + +#ifdef __AARCH64EB__ +#define RSEQ_SIG_DATA 0x00bc28d4 /* BRK #0x45E0. */ +#else +#define RSEQ_SIG_DATA RSEQ_SIG_CODE +#endif + +#define RSEQ_SIG RSEQ_SIG_DATA diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist index a4c31932cb..6784f13c09 100644 --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist @@ -2145,3 +2145,4 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist index e7f2174ac2..71db8422a2 100644 --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist @@ -2225,6 +2225,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _IO_fprintf F GLIBC_2.4 _IO_printf F GLIBC_2.4 _IO_sprintf F diff --git a/sysdeps/unix/sysv/linux/arm/be/libc.abilist b/sysdeps/unix/sysv/linux/arm/be/libc.abilist index b152c0e24a..eecebc908f 100644 --- a/sysdeps/unix/sysv/linux/arm/be/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/be/libc.abilist @@ -133,6 +133,7 @@ GLIBC_2.30 twalk_r F GLIBC_2.31 msgctl F GLIBC_2.31 semctl F GLIBC_2.31 shmctl F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 GLIBC_2.4 _IO_2_1_stdin_ D 0xa0 diff --git a/sysdeps/unix/sysv/linux/arm/bits/rseq.h b/sysdeps/unix/sysv/linux/arm/bits/rseq.h new file mode 100644 index 0000000000..45a2118dbc --- /dev/null +++ b/sysdeps/unix/sysv/linux/arm/bits/rseq.h @@ -0,0 +1,83 @@ +/* Restartable Sequences Linux arm architecture header. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef _SYS_RSEQ_H +# error "Never use directly; include instead." +#endif + +/* + RSEQ_SIG is a signature required before each abort handler code. + + It is a 32-bit value that maps to actual architecture code compiled + into applications and libraries. It needs to be defined for each + architecture. When choosing this value, it needs to be taken into + account that generating invalid instructions may have ill effects on + tools like objdump, and may also have impact on the CPU speculative + execution efficiency in some cases. + + - ARM little endian + + RSEQ_SIG uses the udf A32 instruction with an uncommon immediate operand + value 0x5de3. This traps if user-space reaches this instruction by mistake, + and the uncommon operand ensures the kernel does not move the instruction + pointer to attacker-controlled code on rseq abort. + + The instruction pattern in the A32 instruction set is: + + e7f5def3 udf #24035 ; 0x5de3 + + This translates to the following instruction pattern in the T16 instruction + set: + + little endian: + def3 udf #243 ; 0xf3 + e7f5 b.n <7f5> + + - ARMv6+ big endian (BE8): + + ARMv6+ -mbig-endian generates mixed endianness code vs data: little-endian + code and big-endian data. The data value of the signature needs to have its + byte order reversed to generate the trap instruction: + + Data: 0xf3def5e7 + + Translates to this A32 instruction pattern: + + e7f5def3 udf #24035 ; 0x5de3 + + Translates to this T16 instruction pattern: + + def3 udf #243 ; 0xf3 + e7f5 b.n <7f5> + + - Prior to ARMv6 big endian (BE32): + + Prior to ARMv6, -mbig-endian generates big-endian code and data + (which match), so the endianness of the data representation of the + signature should not be reversed. However, the choice between BE32 + and BE8 is done by the linker, so we cannot know whether code and + data endianness will be mixed before the linker is invoked. So rather + than try to play tricks with the linker, the rseq signature is simply + data (not a trap instruction) prior to ARMv6 on big endian. This is + why the signature is expressed as data (.word) rather than as + instruction (.inst) in assembler. */ + +#ifdef __ARMEB__ +#define RSEQ_SIG 0xf3def5e7 /* udf #24035 ; 0x5de3 (ARMv6+) */ +#else +#define RSEQ_SIG 0xe7f5def3 /* udf #24035 ; 0x5de3 */ +#endif diff --git a/sysdeps/unix/sysv/linux/arm/le/libc.abilist b/sysdeps/unix/sysv/linux/arm/le/libc.abilist index 9371927927..3e7434d3d5 100644 --- a/sysdeps/unix/sysv/linux/arm/le/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/le/libc.abilist @@ -130,6 +130,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 GLIBC_2.4 _IO_2_1_stdin_ D 0xa0 diff --git a/sysdeps/unix/sysv/linux/bits/rseq.h b/sysdeps/unix/sysv/linux/bits/rseq.h new file mode 100644 index 0000000000..b8a63ed26d --- /dev/null +++ b/sysdeps/unix/sysv/linux/bits/rseq.h @@ -0,0 +1,29 @@ +/* Restartable Sequences architecture header. Stub version. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef _SYS_RSEQ_H +# error "Never use directly; include instead." +#endif + +/* RSEQ_SIG is a signature required before each abort handler code. + + It is a 32-bit value that maps to actual architecture code compiled + into applications and libraries. It needs to be defined for each + architecture. When choosing this value, it needs to be taken into + account that generating invalid instructions may have ill effects on + tools like objdump, and may also have impact on the CPU speculative + execution efficiency in some cases. */ diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist index 9b3cee65bb..b7ed346b1c 100644 --- a/sysdeps/unix/sysv/linux/csky/libc.abilist +++ b/sysdeps/unix/sysv/linux/csky/libc.abilist @@ -2089,3 +2089,4 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist index df6d96fbae..d55b153c48 100644 --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist @@ -2046,6 +2046,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist index fcb625b6bf..c9061600f6 100644 --- a/sysdeps/unix/sysv/linux/i386/libc.abilist +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist @@ -2212,6 +2212,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist index cb556c5998..f794303f0e 100644 --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist @@ -2078,6 +2078,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h index 32533e94cf..2c15da9389 100644 --- a/sysdeps/unix/sysv/linux/kernel-features.h +++ b/sysdeps/unix/sysv/linux/kernel-features.h @@ -121,6 +121,11 @@ # define __ASSUME_STATX 1 #endif +/* Support for rseq was added in kernel 4.18. */ +#if __LINUX_KERNEL_VERSION >= 0x041200 +# define __ASSUME_RSEQ 1 +#endif + /* Support for clone call used on fork. The signature varies across the architectures with current 4 different variants: diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist index 5e3cdea246..e5e545f3af 100644 --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist @@ -134,6 +134,7 @@ GLIBC_2.30 twalk_r F GLIBC_2.31 msgctl F GLIBC_2.31 semctl F GLIBC_2.31 shmctl F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0x98 GLIBC_2.4 _IO_2_1_stdin_ D 0x98 diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist index ea5e7a41af..3fc1223e2c 100644 --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist @@ -2158,6 +2158,7 @@ GLIBC_2.30 twalk_r F GLIBC_2.31 msgctl F GLIBC_2.31 semctl F GLIBC_2.31 shmctl F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist index ac55b0acd7..81db30b543 100644 --- a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist +++ b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist @@ -2140,3 +2140,4 @@ GLIBC_2.30 twalk_r F GLIBC_2.31 msgctl F GLIBC_2.31 semctl F GLIBC_2.31 shmctl F +GLIBC_2.31 __rseq_abi T 0x20 diff --git a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist index f7ced487f7..a2ce147dde 100644 --- a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist +++ b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist @@ -2137,3 +2137,4 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 diff --git a/sysdeps/unix/sysv/linux/mips/bits/rseq.h b/sysdeps/unix/sysv/linux/mips/bits/rseq.h new file mode 100644 index 0000000000..4eee59265a --- /dev/null +++ b/sysdeps/unix/sysv/linux/mips/bits/rseq.h @@ -0,0 +1,62 @@ +/* Restartable Sequences Linux mips architecture header. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef _SYS_RSEQ_H +# error "Never use directly; include instead." +#endif + +/* RSEQ_SIG is a signature required before each abort handler code. + + It is a 32-bit value that maps to actual architecture code compiled + into applications and libraries. It needs to be defined for each + architecture. When choosing this value, it needs to be taken into + account that generating invalid instructions may have ill effects on + tools like objdump, and may also have impact on the CPU speculative + execution efficiency in some cases. + + RSEQ_SIG uses the break instruction. The instruction pattern is: + + On MIPS: + 0350000d break 0x350 + + On nanoMIPS: + 00100350 break 0x350 + + On microMIPS: + 0000d407 break 0x350 + + For nanoMIPS32 and microMIPS, the instruction stream is encoded as + 16-bit halfwords, so the signature halfwords need to be swapped + accordingly for little-endian. */ + +#if defined(__nanomips__) +# ifdef __MIPSEL__ +# define RSEQ_SIG 0x03500010 +# else +# define RSEQ_SIG 0x00100350 +# endif +#elif defined(__mips_micromips) +# ifdef __MIPSEL__ +# define RSEQ_SIG 0xd4070000 +# else +# define RSEQ_SIG 0x0000d407 +# endif +#elif defined(__mips__) +# define RSEQ_SIG 0x0350000d +#else +/* Unknown MIPS architecture. */ +#endif diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist index 06c2e64edd..c0040ddd4e 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist @@ -2129,6 +2129,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist index bdfd073b86..61f19076eb 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist @@ -2127,6 +2127,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist index 3d61d4974a..df4f3a3c04 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist @@ -2135,6 +2135,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist index 675acca5db..a96de2e467 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist @@ -2129,6 +2129,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist index 7fec0c9670..7b2ccbe953 100644 --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist @@ -2178,3 +2178,4 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 diff --git a/sysdeps/unix/sysv/linux/powerpc/bits/rseq.h b/sysdeps/unix/sysv/linux/powerpc/bits/rseq.h new file mode 100644 index 0000000000..9d10000a6e --- /dev/null +++ b/sysdeps/unix/sysv/linux/powerpc/bits/rseq.h @@ -0,0 +1,37 @@ +/* Restartable Sequences Linux powerpc architecture header. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef _SYS_RSEQ_H +# error "Never use directly; include instead." +#endif + +/* RSEQ_SIG is a signature required before each abort handler code. + + It is a 32-bit value that maps to actual architecture code compiled + into applications and libraries. It needs to be defined for each + architecture. When choosing this value, it needs to be taken into + account that generating invalid instructions may have ill effects on + tools like objdump, and may also have impact on the CPU speculative + execution efficiency in some cases. + + RSEQ_SIG uses the following trap instruction: + + powerpc-be: 0f e5 00 0b twui r5,11 + powerpc64-le: 0b 00 e5 0f twui r5,11 + powerpc64-be: 0f e5 00 0b twui r5,11 */ + +#define RSEQ_SIG 0x0fe5000b diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist index 1e8ff6f83e..6f4c6515dc 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist @@ -2185,6 +2185,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _IO_fprintf F GLIBC_2.4 _IO_printf F GLIBC_2.4 _IO_sprintf F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist index b5a0751d90..f9875b4e22 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist @@ -2218,6 +2218,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _IO_fprintf F GLIBC_2.4 _IO_printf F GLIBC_2.4 _IO_sprintf F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist index 0c86217fc6..db06080db8 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist @@ -2048,6 +2048,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _IO_fprintf F GLIBC_2.4 _IO_printf F GLIBC_2.4 _IO_sprintf F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist index 2229a1dcc0..608ad49593 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist @@ -2247,3 +2247,4 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist index 31010e6cf7..c7657ce7f6 100644 --- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist +++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist @@ -2107,3 +2107,4 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 diff --git a/sysdeps/unix/sysv/linux/rseq-internal.h b/sysdeps/unix/sysv/linux/rseq-internal.h new file mode 100644 index 0000000000..3502c109b0 --- /dev/null +++ b/sysdeps/unix/sysv/linux/rseq-internal.h @@ -0,0 +1,76 @@ +/* Restartable Sequences internal API. Linux implementation. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef RSEQ_INTERNAL_H +#define RSEQ_INTERNAL_H + +#include +#include +#include + +#ifdef __ASSUME_RSEQ +#include +#endif + +#if defined __ASSUME_RSEQ && defined RSEQ_SIG + +static inline int +rseq_register_current_thread (void) +{ + int rc, ret = 0; + + if (__rseq_abi.cpu_id == RSEQ_CPU_ID_REGISTRATION_FAILED) + return -1; + rc = INTERNAL_SYSCALL_CALL (rseq, &__rseq_abi, sizeof (struct rseq), + 0, RSEQ_SIG); + if (!rc) + goto end; + if (INTERNAL_SYSCALL_ERRNO (rc) != EBUSY) + __rseq_abi.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED; + ret = -1; +end: + return ret; +} + +static inline int +rseq_unregister_current_thread (void) +{ + int rc, ret = 0; + + rc = INTERNAL_SYSCALL_CALL (rseq, &__rseq_abi, sizeof (struct rseq), + RSEQ_FLAG_UNREGISTER, RSEQ_SIG); + if (!rc) + goto end; + ret = -1; +end: + return ret; +} +#else +static inline int +rseq_register_current_thread (void) +{ + return -1; +} + +static inline int +rseq_unregister_current_thread (void) +{ + return -1; +} +#endif + +#endif /* rseq-internal.h */ diff --git a/sysdeps/unix/sysv/linux/rseq-sym.c b/sysdeps/unix/sysv/linux/rseq-sym.c new file mode 100644 index 0000000000..2234bd62af --- /dev/null +++ b/sysdeps/unix/sysv/linux/rseq-sym.c @@ -0,0 +1,44 @@ +/* Restartable Sequences exported symbols. Linux Implementation. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + +#ifdef __ASSUME_RSEQ +#include +#else + +enum rseq_cpu_id_state { + RSEQ_CPU_ID_UNINITIALIZED = -1, + RSEQ_CPU_ID_REGISTRATION_FAILED = -2, +}; + +/* linux/rseq.h defines struct rseq as aligned on 32 bytes. The kernel ABI + size is 20 bytes. */ +struct rseq { + uint32_t cpu_id_start; + uint32_t cpu_id; + uint64_t rseq_cs; + uint32_t flags; +} __attribute__ ((aligned(4 * sizeof(uint64_t)))); + +#endif + +__thread struct rseq __rseq_abi = { + .cpu_id = RSEQ_CPU_ID_UNINITIALIZED, +}; diff --git a/sysdeps/unix/sysv/linux/s390/bits/rseq.h b/sysdeps/unix/sysv/linux/s390/bits/rseq.h new file mode 100644 index 0000000000..c25ee67ee7 --- /dev/null +++ b/sysdeps/unix/sysv/linux/s390/bits/rseq.h @@ -0,0 +1,37 @@ +/* Restartable Sequences Linux s390 architecture header. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef _SYS_RSEQ_H +# error "Never use directly; include instead." +#endif + +/* RSEQ_SIG is a signature required before each abort handler code. + + It is a 32-bit value that maps to actual architecture code compiled + into applications and libraries. It needs to be defined for each + architecture. When choosing this value, it needs to be taken into + account that generating invalid instructions may have ill effects on + tools like objdump, and may also have impact on the CPU speculative + execution efficiency in some cases. + + RSEQ_SIG uses the trap4 instruction. As Linux does not make use of the + access-register mode nor the linkage stack this instruction will always + cause a special-operation exception (the trap-enabled bit in the DUCT + is and will stay 0). The instruction pattern is + b2 ff 0f ff trap4 4095(%r0) */ + +#define RSEQ_SIG 0xB2FF0FFF diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist index 4feca641b0..9c29ec0d2d 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist @@ -2183,6 +2183,7 @@ GLIBC_2.30 twalk_r F GLIBC_2.31 msgctl F GLIBC_2.31 semctl F GLIBC_2.31 shmctl F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _IO_fprintf F GLIBC_2.4 _IO_printf F GLIBC_2.4 _IO_sprintf F diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist index efe588a072..99424ceac9 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist @@ -2084,6 +2084,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _IO_fprintf F GLIBC_2.4 _IO_printf F GLIBC_2.4 _IO_sprintf F diff --git a/sysdeps/unix/sysv/linux/sh/be/libc.abilist b/sysdeps/unix/sysv/linux/sh/be/libc.abilist index 6bfc2b7439..80198de5d6 100644 --- a/sysdeps/unix/sysv/linux/sh/be/libc.abilist +++ b/sysdeps/unix/sysv/linux/sh/be/libc.abilist @@ -2053,6 +2053,7 @@ GLIBC_2.30 twalk_r F GLIBC_2.31 msgctl F GLIBC_2.31 semctl F GLIBC_2.31 shmctl F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/sh/le/libc.abilist b/sysdeps/unix/sysv/linux/sh/le/libc.abilist index 4b057bf4a2..916aa0b7f0 100644 --- a/sysdeps/unix/sysv/linux/sh/le/libc.abilist +++ b/sysdeps/unix/sysv/linux/sh/le/libc.abilist @@ -2050,6 +2050,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist index 49cd597fd6..9a27df8e43 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist @@ -2174,6 +2174,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 _IO_fprintf F GLIBC_2.4 _IO_printf F GLIBC_2.4 _IO_sprintf F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist index 95e68e0ba1..32908666c4 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist @@ -2101,6 +2101,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/sys/rseq.h b/sysdeps/unix/sysv/linux/sys/rseq.h new file mode 100644 index 0000000000..eb64fd41d7 --- /dev/null +++ b/sysdeps/unix/sysv/linux/sys/rseq.h @@ -0,0 +1,30 @@ +/* Restartable Sequences exported symbols. Linux header. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef _SYS_RSEQ_H +#define _SYS_RSEQ_H 1 + +/* We use the structures declarations from the kernel headers. */ +#include +/* Architecture-specific rseq signature. */ +#include +#include + +extern __thread struct rseq __rseq_abi +__attribute__ ((tls_model ("initial-exec"))); + +#endif /* sys/rseq.h */ diff --git a/sysdeps/unix/sysv/linux/x86/bits/rseq.h b/sysdeps/unix/sysv/linux/x86/bits/rseq.h new file mode 100644 index 0000000000..75f52d9788 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86/bits/rseq.h @@ -0,0 +1,30 @@ +/* Restartable Sequences Linux x86 architecture header. + Copyright (C) 2019-2020 Free Software Foundation, Inc. + + 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 + . */ + +#ifndef _SYS_RSEQ_H +# error "Never use directly; include instead." +#endif + +/* RSEQ_SIG is a signature required before each abort handler code. + + RSEQ_SIG is used with the following reserved undefined instructions, which + trap in user-space: + + x86-32: 0f b9 3d 53 30 05 53 ud1 0x53053053,%edi + x86-64: 0f b9 3d 53 30 05 53 ud1 0x53053053(%rip),%edi */ + +#define RSEQ_SIG 0x53053053 diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist index 1f2dbd1451..7366565608 100644 --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist @@ -2059,6 +2059,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20 GLIBC_2.4 __confstr_chk F GLIBC_2.4 __fgets_chk F GLIBC_2.4 __fgets_unlocked_chk F diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist index 59da85a5d8..c1aa86f06e 100644 --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist @@ -2158,3 +2158,4 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.31 __rseq_abi T 0x20