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0c76fc3c2b
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.
38 lines
1.6 KiB
C
38 lines
1.6 KiB
C
/* Restartable Sequences Linux powerpc architecture header.
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Copyright (C) 2020 Free Software Foundation, Inc.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _SYS_RSEQ_H
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# error "Never use <bits/rseq.h> directly; include <sys/rseq.h> instead."
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#endif
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/* RSEQ_SIG is a signature required before each abort handler code.
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It is a 32-bit value that maps to actual architecture code compiled
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into applications and libraries. It needs to be defined for each
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architecture. When choosing this value, it needs to be taken into
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account that generating invalid instructions may have ill effects on
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tools like objdump, and may also have impact on the CPU speculative
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execution efficiency in some cases.
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RSEQ_SIG uses the following trap instruction:
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powerpc-be: 0f e5 00 0b twui r5,11
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powerpc64-le: 0b 00 e5 0f twui r5,11
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powerpc64-be: 0f e5 00 0b twui r5,11 */
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#define RSEQ_SIG 0x0fe5000b
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