From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Siddhesh Poyarekar <siddhesh@gotplt.org>, libc-alpha@sourceware.org
Subject: Re: [PATCH v3 09/16] elf: Move vDSO setup to rtld (BZ#24967)
Date: Thu, 2 Jan 2020 10:00:45 -0300 [thread overview]
Message-ID: <24cb9107-0d17-54c8-f169-fbfdebd0099a@linaro.org> (raw)
In-Reply-To: <d0cafb1b-d000-9ac7-af19-24a17e711384@gotplt.org>
On 02/01/2020 09:55, Siddhesh Poyarekar wrote:
> On 18/12/19 3:17 am, Adhemerval Zanella wrote:
>> Changes from previous version:
>>
>> - Do not GLRO access on ifunc resolver, ut rather call the vDSO
>> resolve function instead (dl_vdso_vsym).
>>
>> --
>>
>> This patch moves the vDSO setup from libc to loader code, just after
>> the vDSO link_map setup. For static case the initialization
>> is moved to _dl_non_dynamic_init instead.
>>
>> Instead of using the mangled pointer, the vDSO data is set as
>> attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for
>> static). It is read-only even with partial relro.
>>
>> It fixes BZ#24967 now that the vDSO pointer is setup earlier than
>> malloc interposition is called.
>>
>> Also, vDSO calls should not be a problem for static dlopen as
>> indicated by BZ#20802. The vDSO pointer would be zero-initialized
>> and the syscall will be issued instead.
>>
>> Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
>> arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu,
>> powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and
>> sparcv9-linux-gnu. I also run some tests on mips.
>> ---
>> csu/init-first.c | 4 -
>> elf/dl-support.c | 7 ++
>> elf/rtld.c | 7 +-
>> malloc/tst-interpose-aux.c | 5 ++
>> sysdeps/generic/dl-vdso-setup.c | 1 +
>> sysdeps/generic/dl-vdso-setup.h | 28 ++++++
>> sysdeps/generic/dl-vdso.h | 30 +++++++
>> sysdeps/generic/ldsodefs.h | 6 ++
>> sysdeps/powerpc/powerpc32/backtrace.c | 16 ++--
>> sysdeps/powerpc/powerpc64/backtrace.c | 8 +-
>> sysdeps/unix/sysv/linux/aarch64/Makefile | 1 -
>> sysdeps/unix/sysv/linux/arm/Makefile | 1 -
>> sysdeps/unix/sysv/linux/dl-vdso-setup.c | 81 +++++++++++++++++
>> sysdeps/unix/sysv/linux/dl-vdso-setup.h | 55 ++++++++++++
>> sysdeps/unix/sysv/linux/dl-vdso.c | 48 ----------
>> sysdeps/unix/sysv/linux/dl-vdso.h | 30 ++++---
>> sysdeps/unix/sysv/linux/gettimeofday.c | 3 +-
>> sysdeps/unix/sysv/linux/init-first.c | 90 -------------------
>> sysdeps/unix/sysv/linux/libc-vdso.h | 30 +------
>> sysdeps/unix/sysv/linux/mips/Makefile | 2 -
>> sysdeps/unix/sysv/linux/powerpc/Makefile | 1 -
>> .../sysv/linux/powerpc/get_timebase_freq.c | 5 +-
>> sysdeps/unix/sysv/linux/powerpc/init-first.c | 50 -----------
>> sysdeps/unix/sysv/linux/powerpc/libc-vdso.h | 10 ---
>> sysdeps/unix/sysv/linux/riscv/Makefile | 4 -
>> sysdeps/unix/sysv/linux/riscv/flush-icache.c | 2 +-
>> sysdeps/unix/sysv/linux/s390/Makefile | 4 -
>> sysdeps/unix/sysv/linux/sparc/Makefile | 4 -
>> sysdeps/unix/sysv/linux/sysdep-vdso.h | 6 +-
>> sysdeps/unix/sysv/linux/time.c | 3 +-
>> sysdeps/unix/sysv/linux/x86/Makefile | 4 -
>> 31 files changed, 257 insertions(+), 289 deletions(-)
>> create mode 100644 sysdeps/generic/dl-vdso-setup.c
>> create mode 100644 sysdeps/generic/dl-vdso-setup.h
>> create mode 100644 sysdeps/generic/dl-vdso.h
>> create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.c
>> create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.h
>> delete mode 100644 sysdeps/unix/sysv/linux/dl-vdso.c
>> delete mode 100644 sysdeps/unix/sysv/linux/init-first.c
>> delete mode 100644 sysdeps/unix/sysv/linux/powerpc/init-first.c
>>
>
> OK with some minor nits fixed, see below.
>
> Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
>> diff --git a/sysdeps/generic/dl-vdso-setup.h b/sysdeps/generic/dl-vdso-setup.h
>> new file mode 100644
>> index 0000000000..3d79bae317
>> --- /dev/null
>> +++ b/sysdeps/generic/dl-vdso-setup.h
>> @@ -0,0 +1,28 @@
>> +/* ELF symbol initialization functions for VDSO objects.
>> + Copyright (C) 2019 Free Software Foundation, Inc.
>
> Update copyright year.
Ack.
>
>> + 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
>> + <https://www.gnu.org/licenses/>. */
>> +
>> +#ifndef _DL_VDSO_INIT_H
>> +#define _DL_VDSO_INIT_H
>> +
>> +/* Initialize the VDSO functions pointers. */
>> +static inline void __attribute__ ((always_inline))
>> +setup_vdso_pointers (void)
>> +{
>> +}
>> +
>> +#endif
>> diff --git a/sysdeps/generic/dl-vdso.h b/sysdeps/generic/dl-vdso.h
>> new file mode 100644
>> index 0000000000..5651f49a1a
>> --- /dev/null
>> +++ b/sysdeps/generic/dl-vdso.h
>> @@ -0,0 +1,30 @@
>> +/* ELF symbol resolve functions for VDSO objects.
>> + Copyright (C) 2019 Free Software Foundation, Inc.
>
> Update copyright year.
Ack.
>> diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.c b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
>> new file mode 100644
>> index 0000000000..1069879f1a
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
>> @@ -0,0 +1,81 @@
>> +/* Data for vDSO support. Linux version.
>> + Copyright (C) 2019 Free Software Foundation, Inc.
>
> Update copyright year.
Ack.
>
>> + 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
>> + <https://www.gnu.org/licenses/>. */
>> +
>> +/* This file is included in three different modes for both static (libc.a)
>> + and shared (rtld) modes:
>> +
>> + 1. PROCINFO_DECL is defined, meaning we are only interested in
>> + declarations. For static it requires use the extern keywork along with
>> + the attribute_relro while for shared it will be embedded in the
>> + rtld_global_ro.
>> +
>> + 2. PROCINFO_DECL and SHARED are not defined. Nothing to do, the default
>> + zero initializion is suffice.
>> +
>> + 3. PROCINFO_DECL is not defined while SHARED is. Similar to 2., the zero
>> + initialization of rtld_global_ro is suffice. */
>> +
>> +#ifndef PROCINFO_CLASS
>> +# define PROCINFO_CLASS
>> +#endif
>> +
>> +#ifndef SHARED
>> +# define RELRO attribute_relro
>> +#else
>> +# define RELRO
>> +#endif
>> +
>> +#if defined PROCINFO_DECL || !defined SHARED
>> +# ifdef HAVE_CLOCK_GETTIME_VSYSCALL
>> +PROCINFO_CLASS int (*_dl_vdso_clock_gettime) (clockid_t,
>> + struct timespec *) RELRO;
>> +#endif
>
> Fix indentation.
Ack.
>
>> +# ifdef HAVE_GETTIMEOFDAY_VSYSCALL
>> +PROCINFO_CLASS int (*_dl_vdso_gettimeofday) (struct timeval *, void *) RELRO;
>> +#endif
>
> Fix indentation.
Ack.
next prev parent reply other threads:[~2020-01-02 13:01 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 21:47 [PATCH v2 01/16] linux: Fix vDSO macros build with time64 interfaces Adhemerval Zanella
2019-12-17 21:47 ` [PATCH v2 02/16] x86: Make x32 use x86 time implementation Adhemerval Zanella
2020-01-02 12:07 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 03/16] Remove vDSO support from make-syscall.sh Adhemerval Zanella
2020-01-02 12:07 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 04/16] linux: Update x86 vDSO symbols Adhemerval Zanella
2020-01-02 12:07 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 05/16] linux: Update mips " Adhemerval Zanella
2020-01-02 12:08 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 06/16] linux: Consolidate Linux gettimeofday Adhemerval Zanella
2019-12-18 8:46 ` Andreas Schwab
2019-12-18 14:50 ` Adhemerval Zanella
2020-01-02 12:07 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 07/16] linux: Consolidate time implementation Adhemerval Zanella
2020-01-02 12:51 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH v3 08/16] elf: Enable relro for static build Adhemerval Zanella
2020-01-02 12:07 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH v3 09/16] elf: Move vDSO setup to rtld (BZ#24967) Adhemerval Zanella
2020-01-02 12:55 ` Siddhesh Poyarekar
2020-01-02 13:00 ` Adhemerval Zanella [this message]
2020-01-07 16:13 ` [PATCH v3 09/16] elf: Move vDSO setup to rtld (BZ#24967) - regression found Lukasz Majewski
2020-01-07 19:40 ` Adhemerval Zanella
2019-12-17 21:47 ` [PATCH v2 10/16] linux: Add support for clock_gettime64 vDSO Adhemerval Zanella
2020-01-02 13:03 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 11/16] linux: Optimize fallback 32-bit clock_gettime Adhemerval Zanella
2019-12-18 8:53 ` Andreas Schwab
2019-12-18 14:58 ` Adhemerval Zanella
2020-01-02 13:07 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 12/16] linux: Enable vDSO clock_gettime64 for i386 Adhemerval Zanella
2020-01-02 13:08 ` Siddhesh Poyarekar
2020-01-02 13:08 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 13/16] linux: Enable vDSO clock_gettime64 for arm Adhemerval Zanella
2020-01-02 13:08 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 14/16] linux: Enable vDSO clock_gettime64 for mips Adhemerval Zanella
2019-12-18 15:33 ` Florian Weimer
2020-01-02 13:13 ` Siddhesh Poyarekar
2020-01-02 13:50 ` Adhemerval Zanella
2020-01-02 14:09 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH v2 15/16] linux: Add support for clock_getres64 vDSO Adhemerval Zanella
2020-01-02 13:15 ` Siddhesh Poyarekar
2019-12-17 21:47 ` [PATCH 16/16] linux: Optimize fallback 32-bit clock_getres Adhemerval Zanella
2019-12-18 8:56 ` Andreas Schwab
2019-12-18 14:58 ` Adhemerval Zanella
2019-12-18 15:02 ` Adhemerval Zanella
2020-01-02 13:16 ` Siddhesh Poyarekar
2020-01-02 12:07 ` [PATCH v2 01/16] linux: Fix vDSO macros build with time64 interfaces Siddhesh Poyarekar
2020-01-02 12:55 ` Adhemerval Zanella
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