100 lines
3.1 KiB
C
100 lines
3.1 KiB
C
/* $OpenBSD: codepatch.h,v 1.15 2023/07/10 03:32:10 guenther Exp $ */
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/*
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* Copyright (c) 2014-2015 Stefan Fritsch <sf@sfritsch.de>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef _MACHINE_CODEPATCH_H_
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#define _MACHINE_CODEPATCH_H_
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#include <machine/param.h>
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#ifndef _LOCORE
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/* code in this section will be unmapped after boot */
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#define __cptext __attribute__((section(".cptext")))
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__cptext void *codepatch_maprw(vaddr_t *nva, vaddr_t dest);
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__cptext void codepatch_unmaprw(vaddr_t nva);
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__cptext void codepatch_fill_nop(void *caddr, uint16_t len);
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__cptext void codepatch_nop(uint16_t tag);
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__cptext void codepatch_replace(uint16_t tag, void *code, size_t len);
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__cptext void codepatch_call(uint16_t _tag, void *_func);
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__cptext void codepatch_jmp(uint16_t _tag, void *_func);
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void codepatch_disable(void);
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#endif /* !_LOCORE */
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/*
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* Mark the start of some code snippet to be patched.
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*/
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#define CODEPATCH_START 998:
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/*
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* Mark the end of some code to be patched, and assign the given tag.
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*/
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#define CODEPATCH_END2(startnum,tag) \
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999: \
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.section .codepatch, "a" ;\
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.quad startnum##b ;\
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.short (999b - startnum##b) ;\
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.short tag ;\
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.int 0 ;\
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.previous
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#define CODEPATCH_END(tag) CODEPATCH_END2(998,tag)
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#define CPTAG_STAC 1
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#define CPTAG_CLAC 2
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#define CPTAG_EOI 3
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#define CPTAG_XRSTOR 4
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#define CPTAG_XSAVE 5
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#define CPTAG_MELTDOWN_NOP 6
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#define CPTAG_MELTDOWN_ALLTRAPS 7
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#define CPTAG_PCID_SET_REUSE 8
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#define CPTAG_MDS 9
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#define CPTAG_MDS_VMM 10
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#define CPTAG_FENCE_SWAPGS_MIS_TAKEN 11
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#define CPTAG_FENCE_NO_SAFE_SMAP 12
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#define CPTAG_XRSTORS 13
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/*
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* stac/clac SMAP instructions have lfence like semantics. Let's
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* guarantee those semantics on older cpus.
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*/
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#define SMAP_NOP lfence
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#define SMAP_STAC CODEPATCH_START ;\
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SMAP_NOP ;\
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CODEPATCH_END(CPTAG_STAC)
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#define SMAP_CLAC CODEPATCH_START ;\
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SMAP_NOP ;\
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CODEPATCH_END(CPTAG_CLAC)
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/* CVE-2019-1125: block speculation after swapgs */
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#define FENCE_SWAPGS_MIS_TAKEN \
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CODEPATCH_START ; \
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lfence ; \
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CODEPATCH_END(CPTAG_FENCE_SWAPGS_MIS_TAKEN)
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/* block speculation when a correct SMAP impl would have been enough */
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#define FENCE_NO_SAFE_SMAP \
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CODEPATCH_START ; \
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lfence ; \
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CODEPATCH_END(CPTAG_FENCE_NO_SAFE_SMAP)
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#define PCID_SET_REUSE_SIZE 12
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#define PCID_SET_REUSE_NOP \
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997: ;\
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.byte 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 ;\
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.byte 0x0f, 0x1f, 0x40, 0x00 ;\
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CODEPATCH_END2(997, CPTAG_PCID_SET_REUSE)
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#endif /* _MACHINE_CODEPATCH_H_ */
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