diff options
author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2020-07-06 10:21:16 +0200 |
---|---|---|
committer | Florian Weimer <fweimer@redhat.com> | 2020-07-06 10:21:16 +0200 |
commit | 0c76fc3c2b346dc5401dc055d97d4279632b0fb3 (patch) | |
tree | 67d7a99ad801c38a137fbb9d08ac54137bb901b9 /sysdeps/unix/sysv/linux/aarch64 | |
parent | f9cf87353772ca370b7bb901d86365a564fba49f (diff) | |
download | glibc-0c76fc3c2b346dc5401dc055d97d4279632b0fb3.tar.gz glibc-0c76fc3c2b346dc5401dc055d97d4279632b0fb3.tar.xz glibc-0c76fc3c2b346dc5401dc055d97d4279632b0fb3.zip |
Linux: Perform rseq registration at C startup and thread creation
Register rseq 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 Those are based on glibc master branch commit 3ee1e0ec5c. The rseq system call was merged into Linux 4.18. The TLS_STATIC_SURPLUS define is increased to leave additional room for dlopen'd initial-exec TLS, which keeps elf/tst-auditmany working. The increase (76 bytes) is larger than 32 bytes because it has not been increased in quite a while. The cost in terms of additional TLS storage is quite significant, but it will also obscure some initial-exec-related dlopen failures.
Diffstat (limited to 'sysdeps/unix/sysv/linux/aarch64')
-rw-r--r-- | sysdeps/unix/sysv/linux/aarch64/bits/rseq.h | 43 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/aarch64/libc.abilist | 1 |
2 files changed, 44 insertions, 0 deletions
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..b6f6e536f4 --- /dev/null +++ b/sysdeps/unix/sysv/linux/aarch64/bits/rseq.h @@ -0,0 +1,43 @@ +/* Restartable Sequences Linux aarch64 architecture header. + Copyright (C) 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 + <https://www.gnu.org/licenses/>. */ + +#ifndef _SYS_RSEQ_H +# error "Never use <bits/rseq.h> directly; include <sys/rseq.h> 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 48c790b15d..e6e4f087eb 100644 --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist @@ -2149,6 +2149,7 @@ GLIBC_2.30 getdents64 F GLIBC_2.30 gettid F GLIBC_2.30 tgkill F GLIBC_2.30 twalk_r F +GLIBC_2.32 __rseq_abi T 0x20 GLIBC_2.32 pthread_attr_getsigmask_np F GLIBC_2.32 pthread_attr_setaffinity_np F GLIBC_2.32 pthread_attr_setsigmask_np F |