64 lines
2.2 KiB
C++
64 lines
2.2 KiB
C++
/*
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* Instruction Patching
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*
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* Copyright (C) 2019-2025 Udo Steinberg, BlueRock Security, Inc.
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*
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* This file is part of the NOVA microhypervisor.
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*
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* NOVA is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* NOVA 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
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* GNU General Public License version 2 for more details.
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*/
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#pragma once
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#include "patch_arch.hpp"
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/*
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* Portability note: Some x86 assemblers (e.g., on MacOS) don't recognize
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* '/' as division operator by default and instead treat it as comment.
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* Passing --divide on the assembler command line fixes that behavior.
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*/
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#define PATCH(O, N, T) .set F, (904f - 903f) - (901f - 900f); \
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900: O; \
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901: .fill -(F > 0) * F / NOP_LEN, NOP_LEN, NOP_OPC; \
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902: .pushsection .patch.code, "a"; \
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903: N; \
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904: .popsection; \
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.pushsection .patch.data, "a"; \
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.balign 4; \
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905: .long 900b - 905b; \
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.long 903b - 905b; \
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.byte 902b - 900b; \
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.byte 904b - 903b; \
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.word T; \
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.popsection;
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#ifndef __ASSEMBLER__
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#include "types.hpp"
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class Patch final
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{
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private:
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int32_t off_old;
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int32_t off_new;
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uint8_t len_old;
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uint8_t len_new;
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uint16_t tag;
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public:
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static inline constinit uint32_t applied { 0 };
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static void detect();
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static void init();
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};
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#endif
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