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https://github.com/RGBCube/serenity
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d550b09871
All code that is related to PC BIOS should not be in the Kernel/Firmware directory as this directory is for abstracted and platform-agnostic code like ACPI (and device tree parsing in the future). This fixes a problem with the aarch64 architecure, as these machines don't have any PC-BIOS in them so actually trying to access these memory locations (EBDA, BIOS ROM) does not make any sense, as they're specific to x86 machines only.
41 lines
1.4 KiB
C++
41 lines
1.4 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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* Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/Arch/x86_64/Firmware/PCBIOS/Mapper.h>
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#include <Kernel/Memory/MemoryManager.h>
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#include <Kernel/Memory/TypedMapping.h>
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namespace Kernel {
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ErrorOr<Memory::MappedROM> map_bios()
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{
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Memory::MappedROM mapping;
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mapping.size = 128 * KiB;
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mapping.paddr = PhysicalAddress(0xe0000);
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auto region_size = TRY(Memory::page_round_up(mapping.size));
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mapping.region = TRY(MM.allocate_kernel_region(mapping.paddr, region_size, {}, Memory::Region::Access::Read));
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return mapping;
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}
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ErrorOr<Memory::MappedROM> map_ebda()
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{
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auto ebda_segment_ptr = TRY(Memory::map_typed<u16>(PhysicalAddress(0x40e)));
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PhysicalAddress ebda_paddr(PhysicalAddress(*ebda_segment_ptr).get() << 4);
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// The EBDA size is stored in the first byte of the EBDA in 1K units
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size_t ebda_size = *TRY(Memory::map_typed<u8>(ebda_paddr));
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ebda_size *= 1024;
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Memory::MappedROM mapping;
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auto region_size = TRY(Memory::page_round_up(ebda_size));
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mapping.region = TRY(MM.allocate_kernel_region(ebda_paddr.page_base(), region_size, {}, Memory::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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