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https://github.com/RGBCube/serenity
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84b7bc5e14
This patch adds a MappedROM abstraction to the Kernel VM subsystem. It's basically the read-only byte buffer equivalent of a TypedMapping. We use this in the ACPI and MP table parsers to scan for interesting stuff in low memory instead of doing a bunch of address arithmetic.
59 lines
2.3 KiB
C++
59 lines
2.3 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/StringView.h>
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#include <Kernel/Arch/PC/BIOS.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/TypedMapping.h>
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namespace Kernel {
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MappedROM map_bios()
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{
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MappedROM mapping;
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mapping.size = 128 * KB;
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mapping.paddr = PhysicalAddress(0xe0000);
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mapping.region = MM.allocate_kernel_region(mapping.paddr, PAGE_ROUND_UP(mapping.size), {}, Region::Access::Read);
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return mapping;
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}
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MappedROM map_ebda()
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{
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auto ebda_segment_ptr = map_typed<u16>(PhysicalAddress(0x40e));
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auto ebda_length_ptr = map_typed<u16>(PhysicalAddress(0x413));
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PhysicalAddress ebda_paddr(*ebda_segment_ptr << 4);
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size_t ebda_size = *ebda_length_ptr;
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MappedROM mapping;
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mapping.region = MM.allocate_kernel_region(ebda_paddr.page_base(), PAGE_ROUND_UP(ebda_size), {}, Region::Access::Read);
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mapping.offset = ebda_paddr.offset_in_page();
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mapping.size = ebda_size;
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mapping.paddr = ebda_paddr;
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return mapping;
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}
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}
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