| 1 | /* x86-64 feature tuning. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | Copyright (C) 2018-2024 Free Software Foundation, Inc. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #ifndef _X86_64_FEATURE_CONTROL_H |
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| 20 | #define _X86_64_FEATURE_CONTROL_H |
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| 21 | |
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| 22 | /* For each CET feature, IBT and SHSTK, valid control values. */ |
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| 23 | enum dl_x86_cet_control |
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| 24 | { |
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| 25 | /* Enable CET features based on ELF property note. */ |
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| 26 | cet_elf_property = 0, |
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| 27 | /* Always enable CET features. */ |
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| 28 | cet_always_on, |
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| 29 | /* Always disable CET features. */ |
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| 30 | cet_always_off, |
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| 31 | /* Enable CET features permissively. */ |
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| 32 | cet_permissive |
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| 33 | }; |
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| 34 | |
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| 35 | /* PLT rewrite control. */ |
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| 36 | enum dl_plt_rewrite_control |
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| 37 | { |
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| 38 | /* No PLT rewrite. */ |
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| 39 | plt_rewrite_none, |
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| 40 | /* Rewrite PLT with JMP at run-time. */ |
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| 41 | plt_rewrite_jmp, |
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| 42 | /* Rewrite PLT with JMP and JMPABS at run-time. */ |
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| 43 | plt_rewrite_jmpabs |
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| 44 | }; |
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| 45 | |
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| 46 | struct dl_x86_feature_control |
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| 47 | { |
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| 48 | enum dl_x86_cet_control ibt : 2; |
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| 49 | enum dl_x86_cet_control shstk : 2; |
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| 50 | enum dl_plt_rewrite_control plt_rewrite : 2; |
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| 51 | }; |
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| 52 | |
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| 53 | #endif /* feature-control.h */ |
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| 54 | |
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