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848746e88e
Add ELF_DYNAMIC_AFTER_RELOC to allow target specific processing after relocation. For x86-64, add #define DT_X86_64_PLT (DT_LOPROC + 0) #define DT_X86_64_PLTSZ (DT_LOPROC + 1) #define DT_X86_64_PLTENT (DT_LOPROC + 3) 1. DT_X86_64_PLT: The address of the procedure linkage table. 2. DT_X86_64_PLTSZ: The total size, in bytes, of the procedure linkage table. 3. DT_X86_64_PLTENT: The size, in bytes, of a procedure linkage table entry. With the r_addend field of the R_X86_64_JUMP_SLOT relocation set to the memory offset of the indirect branch instruction. Define ELF_DYNAMIC_AFTER_RELOC for x86-64 to rewrite the PLT section with direct branch after relocation when the lazy binding is disabled. PLT rewrite is disabled by default since SELinux may disallow modifying code pages and ld.so can't detect it in all cases. Use $ export GLIBC_TUNABLES=glibc.cpu.plt_rewrite=1 to enable PLT rewrite with 32-bit direct jump at run-time or $ export GLIBC_TUNABLES=glibc.cpu.plt_rewrite=2 to enable PLT rewrite with 32-bit direct jump and on APX processors with 64-bit absolute jump at run-time. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
78 lines
2.2 KiB
C
78 lines
2.2 KiB
C
/* Data for processor runtime information. x86 version.
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Copyright (C) 2018-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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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/* This information must be kept in sync with the _DL_HWCAP_COUNT,
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HWCAP_PLATFORMS_START and HWCAP_PLATFORMS_COUNT definitions in
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dl-hwcap.h.
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If anything should be added here check whether the size of each string
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is still ok with the given array size.
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All the #ifdefs in the definitions are quite irritating but
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necessary if we want to avoid duplicating the information. There
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are three different modes:
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- PROCINFO_DECL is defined. This means we are only interested in
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declarations.
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- PROCINFO_DECL is not defined:
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+ if SHARED is defined the file is included in an array
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initializer. The .element = { ... } syntax is needed.
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+ if SHARED is not defined a normal array initialization is
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needed.
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*/
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#ifndef PROCINFO_CLASS
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# define PROCINFO_CLASS
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#endif
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#if !IS_IN (ldconfig)
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# if !defined PROCINFO_DECL && defined SHARED
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._dl_x86_feature_1
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# else
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PROCINFO_CLASS unsigned int _dl_x86_feature_1
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# endif
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# ifndef PROCINFO_DECL
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= 0
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# endif
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# if !defined SHARED || defined PROCINFO_DECL
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;
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# else
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,
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# endif
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# if !defined PROCINFO_DECL && defined SHARED
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._dl_x86_feature_control
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# else
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PROCINFO_CLASS struct dl_x86_feature_control _dl_x86_feature_control
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# endif
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# ifndef PROCINFO_DECL
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= {
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.ibt = DEFAULT_DL_X86_CET_CONTROL,
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.shstk = DEFAULT_DL_X86_CET_CONTROL,
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.plt_rewrite = plt_rewrite_none,
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}
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# endif
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# if !defined SHARED || defined PROCINFO_DECL
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;
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# else
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,
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# endif
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#endif
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