mirror of
https://github.com/RGBCube/serenity
synced 2025-05-31 19:08:10 +00:00
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.
57 lines
2.2 KiB
C++
57 lines
2.2 KiB
C++
/*
|
|
* Copyright (c) 2023, Liav A. <liavalb@hotmail.co.il>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#include <Kernel/Arch/x86_64/Firmware/PCBIOS/Mapper.h>
|
|
#include <Kernel/Firmware/ACPI/StaticParsing.h>
|
|
#include <Kernel/Memory/MemoryManager.h>
|
|
|
|
namespace Kernel::ACPI::StaticParsing {
|
|
|
|
// https://uefi.org/specs/ACPI/6.4/05_ACPI_Software_Programming_Model/ACPI_Software_Programming_Model.html#finding-the-rsdp-on-ia-pc-systems
|
|
ErrorOr<Optional<PhysicalAddress>> find_rsdp_in_platform_specific_memory_locations()
|
|
{
|
|
constexpr auto signature = "RSD PTR "sv;
|
|
auto ebda_or_error = map_ebda();
|
|
if (!ebda_or_error.is_error()) {
|
|
auto rsdp = ebda_or_error.value().find_chunk_starting_with(signature, 16);
|
|
if (rsdp.has_value())
|
|
return rsdp;
|
|
}
|
|
auto bios_or_error = map_bios();
|
|
if (!bios_or_error.is_error()) {
|
|
auto rsdp = bios_or_error.value().find_chunk_starting_with(signature, 16);
|
|
if (rsdp.has_value())
|
|
return rsdp;
|
|
}
|
|
|
|
// On some systems the RSDP may be located in ACPI NVS or reclaimable memory regions
|
|
Optional<PhysicalAddress> rsdp;
|
|
MM.for_each_physical_memory_range([&](auto& memory_range) {
|
|
if (!(memory_range.type == Memory::PhysicalMemoryRangeType::ACPI_NVS || memory_range.type == Memory::PhysicalMemoryRangeType::ACPI_Reclaimable))
|
|
return IterationDecision::Continue;
|
|
|
|
Memory::MappedROM mapping;
|
|
auto region_size_or_error = Memory::page_round_up(memory_range.length);
|
|
if (region_size_or_error.is_error())
|
|
return IterationDecision::Continue;
|
|
auto region_or_error = MM.allocate_kernel_region(memory_range.start, region_size_or_error.value(), {}, Memory::Region::Access::Read);
|
|
if (region_or_error.is_error())
|
|
return IterationDecision::Continue;
|
|
mapping.region = region_or_error.release_value();
|
|
mapping.offset = memory_range.start.offset_in_page();
|
|
mapping.size = memory_range.length;
|
|
mapping.paddr = memory_range.start;
|
|
|
|
rsdp = mapping.find_chunk_starting_with(signature, 16);
|
|
if (rsdp.has_value())
|
|
return IterationDecision::Break;
|
|
|
|
return IterationDecision::Continue;
|
|
});
|
|
return rsdp;
|
|
}
|
|
|
|
}
|