Hi Adhemerval, Siddhesh > 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 > > >> 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 > >> + . */ > >> + > >> +#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 > >> + . */ > >> + > >> +/* 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. Unfortunately this patch caused regression on my ARMv7 32 bit setup. Please find filled in bugzilla entry: https://sourceware.org/bugzilla/show_bug.cgi?id=25352 Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de