From patchwork Tue Feb 6 16:27:55 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Jeanson X-Patchwork-Id: 85359 X-Patchwork-Delegate: dj@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 0AD123857C55 for ; Tue, 6 Feb 2024 16:30:33 +0000 (GMT) X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from smtpout.efficios.com (smtpout.efficios.com [IPv6:2607:5300:203:b2ee::31e5]) by sourceware.org (Postfix) with ESMTPS id 5C1DE3858C53 for ; Tue, 6 Feb 2024 16:28:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 5C1DE3858C53 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=efficios.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 5C1DE3858C53 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=2607:5300:203:b2ee::31e5 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1707236897; cv=none; b=QQLkoUkbywXNrOEd7kUaNsG4bJD2tVdT17YNtdSc9ltyARuGAjr6HYyM/P2Q5M7koe083e61w9ojqxUpajRRmBBwvNGjxpGTi/B5axgpMYWRoOsBvmfvfPrmXsFDoUA3R6SsQU0OYJQYP2P7jC8vwebimvqs8BjHaZ5h+VRTRuI= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1707236897; c=relaxed/simple; bh=R3DO+wtfmzyaO7b/HFRFeuDKSmbWi28zw+onA+KdRGU=; h=DKIM-Signature:From:To:Subject:Date:Message-Id:MIME-Version; b=ZKGd08X8AQNSHHQB2MtH+XnK9qm6y2BlMoAqTiHHM2/GlhRf9S7Owylg3pb4L+JPx8/MX87J/NLkR61c2hCRdOyaInJrHMwx743YRq0Um7ydaahtobqmcfts4tTIP7ivJUav2v500boLE4QjJymnoRmH/OnLcRhLxm3Gt/YQVA8= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=efficios.com; s=smtpout1; t=1707236891; bh=R3DO+wtfmzyaO7b/HFRFeuDKSmbWi28zw+onA+KdRGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zv08jYr6dSYPQxZUd1Z5Uhr5ZVQbhnOm+JrqZmmSNhicJrU983+Tvm4zblub97Y1u 95O6WTOkhPqY+V3SkixLa1YPe0+pXWwAcQwNovPSBR3ogQwC7QjY5t5i1wyZiZuTZS FRcCBBCddsrTVRFuVJflp5xeSKjSDO64BOsJ0j71EZ5yFUKrGrK6OBjyqctOYcntSP /gJmrekAZUXbORLuBEztI2i/Ibx+Ea+m5NSw1Jo5O15mv6+k4+ozux5Xh+ynrSLN9b nVBY9WCX6UoGI/oVQontEhr8nHAbpvIRcz6MJe/T6tk/gCjxmywUqi1ceP14lvq5QT BPTWq2aUCN8Tg== Received: from laptop-mjeanson.internal.efficios.com (192-222-143-198.qc.cable.ebox.net [192.222.143.198]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4TTpZf6XRyzXSK; Tue, 6 Feb 2024 11:28:10 -0500 (EST) From: Michael Jeanson To: libc-alpha@sourceware.org Cc: Michael Jeanson , Mathieu Desnoyers Subject: [PATCH v8 2/8] Add rseq extensible ABI support Date: Tue, 6 Feb 2024 11:27:55 -0500 Message-Id: <20240206162801.882585-3-mjeanson@efficios.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240206162801.882585-1-mjeanson@efficios.com> References: <20240206162801.882585-1-mjeanson@efficios.com> MIME-Version: 1.0 X-Spam-Status: No, score=-12.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Introduced in Linux v6.3 the rseq extensible ABI [1] will allow adding rseq features past the initial 32 bytes of the original ABI. While the rseq features in the latest kernel still fit within the original ABI size, there are currently only 4 bytes left. It would thus be a good time to add support for the extensible ABI so that when new features are added, they are immediately available to GNU libc users. We use the ELF auxiliary vectors to query the kernel for the size and alignment of the rseq area, if this fails we default to the original fixed size and alignment of '32' which the kernel will accept as a compatibility mode with the original ABI. This makes the size of the rseq area variable and thus requires to relocate it out of 'struct pthread'. We chose to move it after (in block allocation order) the last TLS block since it required a fairly small modification to the TLS block allocator and did not interfere with the main executable TLS block which must always be first. [1] https://lore.kernel.org/all/20221122203932.231377-4-mathieu.desnoyers@efficios.com/ Signed-off-by: Michael Jeanson Co-Authored-By: Mathieu Desnoyers Signed-off-By: Mathieu Desnoyers --- Changes since RFC v1: - Insert the rseq area after the last TLS block - Add proper support for TLS_TCB_AT_TP variant Changes since RFC v2: - Set __rseq_size even when the registration fails - Adjust rseq tests to the new ABI - Added support for statically linked executables Changes since RFC v3: - Fix RSEQ_SETMEM for rseq disabled - Replace sys/auxv.h usage with dl-parse_auxv.h - Fix offset for TLS_TCB_AT_TP with statically linked executables - Zero the rseq area before registration Changes since RFC v4: - Move dynamic linker defines to a header file - Fix alignment when tls block align is smaller than rseq align with statically linked executables - Add statically linked rseq tests - Revert: Set __rseq_size even when the registration fails - Use minimum size when rseq is disabled by tunable Changes since v5: - Fix TLS_DTV_AT_TP rseq offset with statically linked executables Changes since v6: - Fix tst-rseq for feature size over 32 bytes - Rebased on 'nptl: fix potential merge of __rseq_* relro symbols' --- csu/libc-tls.c | 66 ++++++++++++++++--- elf/dl-tls.c | 62 +++++++++++++++++ elf/rtld_static_init.c | 12 ++++ nptl/descr.h | 20 +----- nptl/pthread_create.c | 2 +- sysdeps/generic/dl-rseq.h | 26 ++++++++ sysdeps/generic/ldsodefs.h | 12 ++++ sysdeps/i386/nptl/tcb-access.h | 56 ++++++++++++++++ sysdeps/nptl/dl-tls_init_tp.c | 4 +- sysdeps/nptl/tcb-access.h | 5 ++ sysdeps/unix/sysv/linux/Makefile | 10 +++ sysdeps/unix/sysv/linux/dl-parse_auxv.h | 6 ++ sysdeps/unix/sysv/linux/rseq-internal.h | 29 ++++++-- sysdeps/unix/sysv/linux/sched_getcpu.c | 3 +- .../unix/sysv/linux/tst-rseq-disable-static.c | 1 + sysdeps/unix/sysv/linux/tst-rseq-disable.c | 19 +++--- .../unix/sysv/linux/tst-rseq-nptl-static.c | 1 + sysdeps/unix/sysv/linux/tst-rseq-static.c | 1 + sysdeps/unix/sysv/linux/tst-rseq.c | 22 +++++-- sysdeps/unix/sysv/linux/tst-rseq.h | 9 ++- sysdeps/x86_64/nptl/tcb-access.h | 56 ++++++++++++++++ 21 files changed, 375 insertions(+), 47 deletions(-) create mode 100644 sysdeps/generic/dl-rseq.h create mode 100644 sysdeps/unix/sysv/linux/tst-rseq-disable-static.c create mode 100644 sysdeps/unix/sysv/linux/tst-rseq-nptl-static.c create mode 100644 sysdeps/unix/sysv/linux/tst-rseq-static.c diff --git a/csu/libc-tls.c b/csu/libc-tls.c index b7682bdf43..9c70f53284 100644 --- a/csu/libc-tls.c +++ b/csu/libc-tls.c @@ -26,6 +26,8 @@ #include #include #include +#include +#include #ifdef SHARED #error makefile bug, this file is for static only @@ -62,6 +64,18 @@ size_t _dl_tls_static_surplus; dynamic TLS access (e.g. with TLSDESC). */ size_t _dl_tls_static_optional; +/* Size of the features present in the rseq area. */ +size_t _dl_tls_rseq_feature_size; + +/* Alignment requirement of the rseq area. */ +size_t _dl_tls_rseq_align; + +/* Size of the rseq area in the static TLS block. */ +size_t _dl_tls_rseq_size; + +/* Offset of the rseq area from the thread pointer. */ +ptrdiff_t _dl_tls_rseq_offset; + /* Generation counter for the dtv. */ size_t _dl_tls_generation; @@ -110,6 +124,7 @@ __libc_setup_tls (void) size_t filesz = 0; void *initimage = NULL; size_t align = 0; + size_t tls_blocks_size = 0; size_t max_align = TCB_ALIGNMENT; size_t tcb_offset; const ElfW(Phdr) *phdr; @@ -135,22 +150,61 @@ __libc_setup_tls (void) /* Calculate the size of the static TLS surplus, with 0 auditors. */ _dl_tls_static_surplus_init (0); + /* Default to the rseq ABI minimum sizes, this will reduce TLS usage to 32 + bytes when rseq is disabled by tunables. */ + size_t rseq_size = TLS_DL_RSEQ_MIN_SIZE; + size_t rseq_align = TLS_DL_RSEQ_MIN_ALIGN; + bool do_rseq = true; + do_rseq = TUNABLE_GET_FULL (glibc, pthread, rseq, int, NULL); + if (do_rseq) + { + rseq_align = GLRO(dl_tls_rseq_align); + /* Make sure the rseq area size is at least the minimum ABI size and a + multiple of the requested aligment. */ + rseq_size = roundup (MAX (GLRO(dl_tls_rseq_feature_size), + TLS_DL_RSEQ_MIN_SIZE), rseq_align); + } + + /* Increase the max_align if necessary. */ + max_align = MAX (max_align, rseq_align); + + /* Record the rseq_area block size. */ + GLRO (dl_tls_rseq_size) = rseq_size; + /* We have to set up the TCB block which also (possibly) contains 'errno'. Therefore we avoid 'malloc' which might touch 'errno'. Instead we use 'sbrk' which would only uses 'errno' if it fails. In this case we are right away out of memory and the user gets what she/he deserves. */ #if TLS_TCB_AT_TP + /* Before the the thread pointer, add the aligned tls block size and then + align the rseq area block on top. */ + tls_blocks_size = roundup (roundup (memsz, align ?: 1) + rseq_size, rseq_align); + + /* Record the rseq_area offset. The offset is negative with TLS_TCB_AT_TP + because the TLS blocks are located before the thread pointer. */ + GLRO (dl_tls_rseq_offset) = -tls_blocks_size; + /* Align the TCB offset to the maximum alignment, as _dl_allocate_tls_storage (in elf/dl-tls.c) does using __libc_memalign and dl_tls_static_align. */ - tcb_offset = roundup (memsz + GLRO(dl_tls_static_surplus), max_align); + tcb_offset = roundup (tls_blocks_size + GLRO(dl_tls_static_surplus), max_align); tlsblock = _dl_early_allocate (tcb_offset + TLS_INIT_TCB_SIZE + max_align); if (tlsblock == NULL) _startup_fatal_tls_error (); #elif TLS_DTV_AT_TP + /* Align memsz on top of the initial tcb. */ tcb_offset = roundup (TLS_INIT_TCB_SIZE, align ?: 1); - tlsblock = _dl_early_allocate (tcb_offset + memsz + max_align + + /* After the thread pointer, add the initial tcb plus the tls block size and + then align the rseq area block on top. */ + tls_blocks_size = roundup (tcb_offset + memsz + rseq_size, rseq_align); + + /* Record the rseq_area offset. The offset is positive with TLS_DTV_AT_TP + because the TLS blocks are located after the thread pointer. */ + GLRO (dl_tls_rseq_offset) = tls_blocks_size - rseq_size; + + tlsblock = _dl_early_allocate (tls_blocks_size + max_align + TLS_PRE_TCB_SIZE + GLRO(dl_tls_static_surplus)); if (tlsblock == NULL) @@ -209,11 +263,5 @@ __libc_setup_tls (void) /* static_slotinfo.slotinfo[1].gen = 0; -- Already zero. */ static_slotinfo.slotinfo[1].map = main_map; - memsz = roundup (memsz, align ?: 1); - -#if TLS_DTV_AT_TP - memsz += tcb_offset; -#endif - - init_static_tls (memsz, MAX (TCB_ALIGNMENT, max_align)); + init_static_tls (tls_blocks_size, MAX (TCB_ALIGNMENT, max_align)); } diff --git a/elf/dl-tls.c b/elf/dl-tls.c index 7b3dd9ab60..70fbe7095f 100644 --- a/elf/dl-tls.c +++ b/elf/dl-tls.c @@ -27,6 +27,7 @@ #include #include +#include #include #if PTHREAD_IN_LIBC @@ -298,6 +299,35 @@ _dl_determine_tlsoffset (void) slotinfo[cnt].map->l_tls_offset = off; } + /* Insert the rseq area block after the last TLS block. */ + + /* Default to the rseq ABI minimum sizes, this will reduce TLS usage to 32 + bytes when rseq is disabled by tunables. */ + size_t rseq_size = TLS_DL_RSEQ_MIN_SIZE; + size_t rseq_align = TLS_DL_RSEQ_MIN_ALIGN; + bool do_rseq = true; + do_rseq = TUNABLE_GET_FULL (glibc, pthread, rseq, int, NULL); + if (do_rseq) + { + rseq_align = GLRO(dl_tls_rseq_align); + /* Make sure the rseq area size is at least the minimum ABI size and a + multiple of the requested aligment. */ + rseq_size = roundup (MAX (GLRO(dl_tls_rseq_feature_size), + TLS_DL_RSEQ_MIN_SIZE), rseq_align); + } + + /* Add the rseq area block to the global offset. */ + offset = roundup (offset, rseq_align) + rseq_size; + + /* Increase the max_align if necessary. */ + max_align = MAX (max_align, rseq_align); + + /* Record the rseq_area block size and offset. The offset is negative + with TLS_TCB_AT_TP because the TLS blocks are located before the + thread pointer. */ + GLRO (dl_tls_rseq_offset) = -offset; + GLRO (dl_tls_rseq_size) = rseq_size; + GL(dl_tls_static_used) = offset; GLRO (dl_tls_static_size) = (roundup (offset + GLRO(dl_tls_static_surplus), max_align) @@ -343,6 +373,38 @@ _dl_determine_tlsoffset (void) offset = off + slotinfo[cnt].map->l_tls_blocksize - firstbyte; } + /* Insert the rseq area block after the last TLS block. */ + + /* Default to the rseq ABI minimum sizes, this will reduce TLS usage to 32 + bytes when rseq is disabled by tunables. */ + size_t rseq_size = TLS_DL_RSEQ_MIN_SIZE; + size_t rseq_align = TLS_DL_RSEQ_MIN_ALIGN; + bool do_rseq = true; + do_rseq = TUNABLE_GET_FULL (glibc, pthread, rseq, int, NULL); + if (do_rseq) + { + rseq_align = GLRO(dl_tls_rseq_align); + /* Make sure the rseq area size is at least the minimum ABI size and a + multiple of the requested aligment. */ + rseq_size = roundup (MAX (GLRO(dl_tls_rseq_feature_size), + TLS_DL_RSEQ_MIN_SIZE), rseq_align); + } + + /* Align the global offset to the beginning of the rseq area. */ + offset = roundup (offset, rseq_align); + + /* Record the rseq_area block size and offset. The offset is positive + with TLS_DTV_AT_TP because the TLS blocks are located after the + thread pointer. */ + GLRO (dl_tls_rseq_size) = rseq_size; + GLRO (dl_tls_rseq_offset) = offset; + + /* Add the rseq area block to the global offset. */ + offset += rseq_size; + + /* Increase the max_align if necessary. */ + max_align = MAX (max_align, rseq_align); + GL(dl_tls_static_used) = offset; GLRO (dl_tls_static_size) = roundup (offset + GLRO(dl_tls_static_surplus), TCB_ALIGNMENT); diff --git a/elf/rtld_static_init.c b/elf/rtld_static_init.c index e918e4ebdf..0606317b8c 100644 --- a/elf/rtld_static_init.c +++ b/elf/rtld_static_init.c @@ -78,6 +78,18 @@ __rtld_static_init (struct link_map *map) extern __typeof (dl->_dl_tls_static_size) _dl_tls_static_size attribute_hidden; dl->_dl_tls_static_size = _dl_tls_static_size; + extern __typeof (dl->_dl_tls_rseq_feature_size) _dl_tls_rseq_feature_size + attribute_hidden; + dl->_dl_tls_rseq_feature_size = _dl_tls_rseq_feature_size; + extern __typeof (dl->_dl_tls_rseq_align) _dl_tls_rseq_align + attribute_hidden; + dl->_dl_tls_rseq_align = _dl_tls_rseq_align; + extern __typeof (dl->_dl_tls_rseq_size) _dl_tls_rseq_size + attribute_hidden; + dl->_dl_tls_rseq_size = _dl_tls_rseq_size; + extern __typeof (dl->_dl_tls_rseq_offset) _dl_tls_rseq_offset + attribute_hidden; + dl->_dl_tls_rseq_offset = _dl_tls_rseq_offset; dl->_dl_find_object = _dl_find_object; __rtld_static_init_arch (map, dl); diff --git a/nptl/descr.h b/nptl/descr.h index 8cef95810c..cdc3c82d9a 100644 --- a/nptl/descr.h +++ b/nptl/descr.h @@ -404,25 +404,11 @@ struct pthread /* Used on strsignal. */ struct tls_internal_t tls_state; - /* rseq area registered with the kernel. Use a custom definition - here to isolate from kernel struct rseq changes. The - implementation of sched_getcpu needs acccess to the cpu_id field; - the other fields are unused and not included here. */ - union - { - struct - { - uint32_t cpu_id_start; - uint32_t cpu_id; - }; - char pad[32]; /* Original rseq area size. */ - } rseq_area __attribute__ ((aligned (32))); - /* Amount of end padding, if any, in this structure. - This definition relies on rseq_area being last. */ + This definition relies on tls_state being last. */ #define PTHREAD_STRUCT_END_PADDING \ - (sizeof (struct pthread) - offsetof (struct pthread, rseq_area) \ - + sizeof ((struct pthread) {}.rseq_area)) + (sizeof (struct pthread) - offsetof (struct pthread, tls_state) \ + + sizeof ((struct pthread) {}.tls_state)) } __attribute ((aligned (TCB_ALIGNMENT))); static inline bool diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c index 1d3665d5ed..9b49ee7121 100644 --- a/nptl/pthread_create.c +++ b/nptl/pthread_create.c @@ -691,7 +691,7 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr, /* Inherit rseq registration state. Without seccomp filters, rseq registration will either always fail or always succeed. */ - if ((int) THREAD_GETMEM_VOLATILE (self, rseq_area.cpu_id) >= 0) + if ((int) RSEQ_GETMEM_VOLATILE (rseq_get_area(), cpu_id) >= 0) pd->flags |= ATTR_FLAG_DO_RSEQ; /* Initialize the field for the ID of the thread which is waiting diff --git a/sysdeps/generic/dl-rseq.h b/sysdeps/generic/dl-rseq.h new file mode 100644 index 0000000000..0855981c89 --- /dev/null +++ b/sysdeps/generic/dl-rseq.h @@ -0,0 +1,26 @@ +/* RSEQ defines for the dynamic linker. Generic version. + Copyright (C) 2023 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 + . */ + +/* Minimum size of the rseq area. */ +#define TLS_DL_RSEQ_MIN_SIZE 32 + +/* Minimum feature size of the rseq area. */ +#define TLS_DL_RSEQ_MIN_FEATURE_SIZE 20 + +/* Minimum size of the rseq area alignment. */ +#define TLS_DL_RSEQ_MIN_ALIGN 32 diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index 117c901ccc..53a0a208d8 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -610,6 +610,18 @@ struct rtld_global_ro See comments in elf/dl-tls.c where it is initialized. */ EXTERN size_t _dl_tls_static_surplus; + /* Size of the features present in the rseq area. */ + EXTERN size_t _dl_tls_rseq_feature_size; + + /* Alignment requirement of the rseq area. */ + EXTERN size_t _dl_tls_rseq_align; + + /* Size of the rseq area in the static TLS block. */ + EXTERN size_t _dl_tls_rseq_size; + + /* Offset of the rseq area from the thread pointer. */ + EXTERN ptrdiff_t _dl_tls_rseq_offset; + /* Name of the shared object to be profiled (if any). */ EXTERN const char *_dl_profile; /* Filename of the output file. */ diff --git a/sysdeps/i386/nptl/tcb-access.h b/sysdeps/i386/nptl/tcb-access.h index 4b6221e103..e6988186d0 100644 --- a/sysdeps/i386/nptl/tcb-access.h +++ b/sysdeps/i386/nptl/tcb-access.h @@ -123,3 +123,59 @@ "i" (offsetof (struct pthread, member)), \ "r" (idx)); \ }}) + + +/* Read member of the RSEQ area directly. */ +#define RSEQ_GETMEM_VOLATILE(descr, member) \ + ({ __typeof (descr->member) __value; \ + ptrdiff_t _rseq_offset = GLRO (dl_tls_rseq_offset); \ + _Static_assert (sizeof (__value) == 1 \ + || sizeof (__value) == 4 \ + || sizeof (__value) == 8, \ + "size of per-thread data"); \ + if (sizeof (__value) == 1) \ + asm volatile ("movb %%gs:%P2(%3),%b0" \ + : "=q" (__value) \ + : "0" (0), "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + else if (sizeof (__value) == 4) \ + asm volatile ("movl %%gs:%P1(%2),%0" \ + : "=r" (__value) \ + : "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + else /* 8 */ \ + { \ + asm volatile ("movl %%gs:%P1(%2),%%eax\n\t" \ + "movl %%gs:4+%P1(%2),%%edx" \ + : "=&A" (__value) \ + : "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + } \ + __value; }) + +/* Set member of the RSEQ area directly. */ +#define RSEQ_SETMEM(descr, member, value) \ + ({ \ + ptrdiff_t _rseq_offset = GLRO (dl_tls_rseq_offset); \ + _Static_assert (sizeof (descr->member) == 1 \ + || sizeof (descr->member) == 4 \ + || sizeof (descr->member) == 8, \ + "size of per-thread data"); \ + if (sizeof (descr->member) == 1) \ + asm volatile ("movb %b0,%%gs:%P1(%2)" : \ + : "iq" (value), \ + "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + else if (sizeof (descr->member) == 4) \ + asm volatile ("movl %0,%%gs:%P1(%2)" : \ + : "ir" (value), \ + "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + else /* 8 */ \ + { \ + asm volatile ("movl %%eax,%%gs:%P1(%2)\n\t" \ + "movl %%edx,%%gs:4+%P1(%2)" : \ + : "A" ((uint64_t) cast_to_integer (value)), \ + "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + }}) diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c index 80eb0107b5..7aa15558e6 100644 --- a/sysdeps/nptl/dl-tls_init_tp.c +++ b/sysdeps/nptl/dl-tls_init_tp.c @@ -107,7 +107,7 @@ __tls_init_tp (void) do_rseq = TUNABLE_GET (rseq, int, NULL); if (rseq_register_current_thread (pd, do_rseq)) { - _rseq_size = sizeof (pd->rseq_area); + _rseq_size = GLRO (dl_tls_rseq_size); } #ifdef RSEQ_SIG @@ -116,7 +116,7 @@ __tls_init_tp (void) all targets support __thread_pointer, so set __rseq_offset only if the rseq registration may have happened because RSEQ_SIG is defined. */ - _rseq_offset = (char *) &pd->rseq_area - (char *) __thread_pointer (); + _rseq_offset = GLRO (dl_tls_rseq_offset); #endif } diff --git a/sysdeps/nptl/tcb-access.h b/sysdeps/nptl/tcb-access.h index 600433766f..9532f30022 100644 --- a/sysdeps/nptl/tcb-access.h +++ b/sysdeps/nptl/tcb-access.h @@ -30,3 +30,8 @@ descr->member = (value) #define THREAD_SETMEM_NC(descr, member, idx, value) \ descr->member[idx] = (value) + +#define RSEQ_GETMEM_VOLATILE(descr, member) \ + THREAD_GETMEM_VOLATILE(descr, member) +#define RSEQ_SETMEM(descr, member, value) \ + THREAD_SETMEM(descr, member, value) diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index 415aa1f14d..6bcf81461b 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -261,6 +261,11 @@ tests-internal += \ tst-rseq-disable \ # tests-internal +tests-static += \ + tst-rseq-disable-static \ + tst-rseq-static \ + # tests-static + tests-time64 += \ tst-adjtimex-time64 \ tst-clock_adjtime-time64 \ @@ -394,6 +399,7 @@ $(objpfx)tst-mount-compile.out: ../sysdeps/unix/sysv/linux/tst-mount-compile.py $(objpfx)tst-mount-compile.out: $(sysdeps-linux-python-deps) tst-rseq-disable-ENV = GLIBC_TUNABLES=glibc.pthread.rseq=0 +tst-rseq-disable-static-ENV = GLIBC_TUNABLES=glibc.pthread.rseq=0 endif # $(subdir) == misc @@ -655,4 +661,8 @@ tests += \ tests-internal += \ tst-rseq-nptl \ # tests-internal + +tests-static += \ + tst-rseq-nptl-static \ + # tests-static endif diff --git a/sysdeps/unix/sysv/linux/dl-parse_auxv.h b/sysdeps/unix/sysv/linux/dl-parse_auxv.h index e3d758b163..fbc90fc786 100644 --- a/sysdeps/unix/sysv/linux/dl-parse_auxv.h +++ b/sysdeps/unix/sysv/linux/dl-parse_auxv.h @@ -21,6 +21,7 @@ #include #include #include +#include typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1]; @@ -57,5 +58,10 @@ void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values) GLRO(dl_sysinfo) = auxv_values[AT_SYSINFO]; #endif + GLRO(dl_tls_rseq_feature_size) = MAX (auxv_values[AT_RSEQ_FEATURE_SIZE], + TLS_DL_RSEQ_MIN_FEATURE_SIZE); + GLRO(dl_tls_rseq_align) = MAX (auxv_values[AT_RSEQ_ALIGN], + TLS_DL_RSEQ_MIN_ALIGN); + DL_PLATFORM_AUXV } diff --git a/sysdeps/unix/sysv/linux/rseq-internal.h b/sysdeps/unix/sysv/linux/rseq-internal.h index 48eebc1e16..b6c9deea6b 100644 --- a/sysdeps/unix/sysv/linux/rseq-internal.h +++ b/sysdeps/unix/sysv/linux/rseq-internal.h @@ -24,6 +24,24 @@ #include #include #include +#include +#include + +/* rseq area registered with the kernel. Use a custom definition + here to isolate from kernel struct rseq changes. The + implementation of sched_getcpu needs acccess to the cpu_id field; + the other fields are unused and not included here. */ +struct rseq_area +{ + uint32_t cpu_id_start; + uint32_t cpu_id; +}; + +static inline struct rseq_area * +rseq_get_area(void) +{ + return (struct rseq_area *) ((char *) __thread_pointer() + GLRO (dl_tls_rseq_offset)); +} #ifdef RSEQ_SIG static inline bool @@ -31,20 +49,23 @@ rseq_register_current_thread (struct pthread *self, bool do_rseq) { if (do_rseq) { - int ret = INTERNAL_SYSCALL_CALL (rseq, &self->rseq_area, - sizeof (self->rseq_area), + /* The kernel expects 'rseq_area->rseq_cs == NULL' on registration, zero + the whole rseq area. */ + memset(rseq_get_area(), 0, GLRO (dl_tls_rseq_size)); + int ret = INTERNAL_SYSCALL_CALL (rseq, rseq_get_area(), + GLRO (dl_tls_rseq_size), 0, RSEQ_SIG); if (!INTERNAL_SYSCALL_ERROR_P (ret)) return true; } - THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); + RSEQ_SETMEM (rseq_get_area(), cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); return false; } #else /* RSEQ_SIG */ static inline bool rseq_register_current_thread (struct pthread *self, bool do_rseq) { - THREAD_SETMEM (self, rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); + RSEQ_SETMEM (rseq_get_area(), cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); return false; } #endif /* RSEQ_SIG */ diff --git a/sysdeps/unix/sysv/linux/sched_getcpu.c b/sysdeps/unix/sysv/linux/sched_getcpu.c index dfb884568d..4f7cd499d3 100644 --- a/sysdeps/unix/sysv/linux/sched_getcpu.c +++ b/sysdeps/unix/sysv/linux/sched_getcpu.c @@ -19,6 +19,7 @@ #include #include #include +#include static int vsyscall_sched_getcpu (void) @@ -37,7 +38,7 @@ vsyscall_sched_getcpu (void) int sched_getcpu (void) { - int cpu_id = THREAD_GETMEM_VOLATILE (THREAD_SELF, rseq_area.cpu_id); + int cpu_id = RSEQ_GETMEM_VOLATILE (rseq_get_area(), cpu_id); return __glibc_likely (cpu_id >= 0) ? cpu_id : vsyscall_sched_getcpu (); } #else /* RSEQ_SIG */ diff --git a/sysdeps/unix/sysv/linux/tst-rseq-disable-static.c b/sysdeps/unix/sysv/linux/tst-rseq-disable-static.c new file mode 100644 index 0000000000..2687d13d3d --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-rseq-disable-static.c @@ -0,0 +1 @@ +#include "tst-rseq-disable.c" diff --git a/sysdeps/unix/sysv/linux/tst-rseq-disable.c b/sysdeps/unix/sysv/linux/tst-rseq-disable.c index bbc655bec4..ae4143916b 100644 --- a/sysdeps/unix/sysv/linux/tst-rseq-disable.c +++ b/sysdeps/unix/sysv/linux/tst-rseq-disable.c @@ -26,27 +26,30 @@ #include #ifdef RSEQ_SIG +# include +# include "tst-rseq.h" + +static __thread struct rseq local_rseq; /* Check that rseq can be registered and has not been taken by glibc. */ static void check_rseq_disabled (void) { - struct pthread *pd = THREAD_SELF; + struct rseq *rseq_area = (struct rseq *) ((char *) __thread_pointer () + __rseq_offset); TEST_COMPARE (__rseq_flags, 0); - TEST_VERIFY ((char *) __thread_pointer () + __rseq_offset - == (char *) &pd->rseq_area); TEST_COMPARE (__rseq_size, 0); - TEST_COMPARE ((int) pd->rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); + TEST_COMPARE ((int) rseq_area->cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED); + + TEST_COMPARE (sizeof (local_rseq), RSEQ_TEST_MIN_SIZE); - int ret = syscall (__NR_rseq, &pd->rseq_area, sizeof (pd->rseq_area), - 0, RSEQ_SIG); + int ret = syscall (__NR_rseq, &local_rseq, RSEQ_TEST_MIN_SIZE, 0, RSEQ_SIG); if (ret == 0) { - ret = syscall (__NR_rseq, &pd->rseq_area, sizeof (pd->rseq_area), + ret = syscall (__NR_rseq, &local_rseq, RSEQ_TEST_MIN_SIZE, RSEQ_FLAG_UNREGISTER, RSEQ_SIG); TEST_COMPARE (ret, 0); - pd->rseq_area.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED; + rseq_area->cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED; } else { diff --git a/sysdeps/unix/sysv/linux/tst-rseq-nptl-static.c b/sysdeps/unix/sysv/linux/tst-rseq-nptl-static.c new file mode 100644 index 0000000000..6e2c923bb9 --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-rseq-nptl-static.c @@ -0,0 +1 @@ +#include "tst-rseq-nptl.c" diff --git a/sysdeps/unix/sysv/linux/tst-rseq-static.c b/sysdeps/unix/sysv/linux/tst-rseq-static.c new file mode 100644 index 0000000000..1d97f3bd3d --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-rseq-static.c @@ -0,0 +1 @@ +#include "tst-rseq.c" diff --git a/sysdeps/unix/sysv/linux/tst-rseq.c b/sysdeps/unix/sysv/linux/tst-rseq.c index 2c90409ba0..c8c0518a5d 100644 --- a/sysdeps/unix/sysv/linux/tst-rseq.c +++ b/sysdeps/unix/sysv/linux/tst-rseq.c @@ -31,18 +31,32 @@ # include # include # include +# include # include "tst-rseq.h" static void do_rseq_main_test (void) { - struct pthread *pd = THREAD_SELF; + size_t rseq_align = MAX (getauxval (AT_RSEQ_ALIGN), RSEQ_TEST_MIN_ALIGN); + size_t rseq_size = roundup (MAX (getauxval (AT_RSEQ_FEATURE_SIZE), RSEQ_TEST_MIN_SIZE), rseq_align); + struct rseq *rseq = __thread_pointer () + __rseq_offset; TEST_VERIFY_EXIT (rseq_thread_registered ()); TEST_COMPARE (__rseq_flags, 0); - TEST_VERIFY ((char *) __thread_pointer () + __rseq_offset - == (char *) &pd->rseq_area); - TEST_COMPARE (__rseq_size, sizeof (pd->rseq_area)); + TEST_COMPARE (__rseq_size, rseq_size); + /* The size of the rseq area must be a multiple of the alignment. */ + TEST_VERIFY ((__rseq_size % rseq_align) == 0); + /* The rseq area address must be aligned. */ + TEST_VERIFY (((unsigned long) rseq % rseq_align) == 0); +#if TLS_TCB_AT_TP + /* The rseq area block should come before the thread pointer and be at least 32 bytes. */ + TEST_VERIFY (__rseq_offset <= RSEQ_TEST_MIN_SIZE); +#elif TLS_DTV_AT_TP + /* The rseq area block should come after the thread pointer. */ + TEST_VERIFY (__rseq_offset >= 0); +#else +# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" +#endif } static void diff --git a/sysdeps/unix/sysv/linux/tst-rseq.h b/sysdeps/unix/sysv/linux/tst-rseq.h index dc603327d3..4931aa3d14 100644 --- a/sysdeps/unix/sysv/linux/tst-rseq.h +++ b/sysdeps/unix/sysv/linux/tst-rseq.h @@ -23,11 +23,18 @@ #include #include #include +#include + +#define RSEQ_TEST_MIN_SIZE 32 +#define RSEQ_TEST_MIN_FEATURE_SIZE 20 +#define RSEQ_TEST_MIN_ALIGN 32 static inline bool rseq_thread_registered (void) { - return THREAD_GETMEM_VOLATILE (THREAD_SELF, rseq_area.cpu_id) >= 0; + struct rseq_area *rseq = (struct rseq_area *) ((char *) __thread_pointer () + __rseq_offset); + + return __atomic_load_n (&rseq->cpu_id, __ATOMIC_RELAXED) >= 0; } static inline int diff --git a/sysdeps/x86_64/nptl/tcb-access.h b/sysdeps/x86_64/nptl/tcb-access.h index d35948f111..75ba4b3ce9 100644 --- a/sysdeps/x86_64/nptl/tcb-access.h +++ b/sysdeps/x86_64/nptl/tcb-access.h @@ -130,3 +130,59 @@ "i" (offsetof (struct pthread, member[0])), \ "r" (idx)); \ }}) + +/* Read member of the RSEQ area directly. */ +# define RSEQ_GETMEM_VOLATILE(descr, member) \ + ({ __typeof (descr->member) __value; \ + ptrdiff_t _rseq_offset = GLRO (dl_tls_rseq_offset); \ + _Static_assert (sizeof (__value) == 1 \ + || sizeof (__value) == 4 \ + || sizeof (__value) == 8, \ + "size of per-thread data"); \ + if (sizeof (__value) == 1) \ + asm volatile ("movb %%fs:%P2(%q3),%b0" \ + : "=q" (__value) \ + : "0" (0), "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + else if (sizeof (__value) == 4) \ + asm volatile ("movl %%fs:%P1(%q2),%0" \ + : "=r" (__value) \ + : "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + else /* 8 */ \ + { \ + asm volatile ("movq %%fs:%P1(%q2),%q0" \ + : "=r" (__value) \ + : "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + } \ + __value; }) + +/* Set member of the RSEQ area directly. */ +# define RSEQ_SETMEM(descr, member, value) \ + ({ \ + ptrdiff_t _rseq_offset = GLRO (dl_tls_rseq_offset); \ + _Static_assert (sizeof (descr->member) == 1 \ + || sizeof (descr->member) == 4 \ + || sizeof (descr->member) == 8, \ + "size of per-thread data"); \ + if (sizeof (descr->member) == 1) \ + asm volatile ("movb %b0,%%fs:%P1(%q2)" : \ + : "iq" (value), \ + "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + else if (sizeof (descr->member) == 4) \ + asm volatile ("movl %0,%%fs:%P1(%q2)" : \ + : IMM_MODE (value), \ + "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + else /* 8 */ \ + { \ + /* Since movq takes a signed 32-bit immediate or a register source \ + operand, use "er" constraint for 32-bit signed integer constant \ + or register. */ \ + asm volatile ("movq %q0,%%fs:%P1(%q2)" : \ + : "er" ((uint64_t) cast_to_integer (value)), \ + "i" (offsetof (struct rseq_area, member)), \ + "r" (_rseq_offset)); \ + }})