Jeremy Soller
59 lines
1.7 KiB
Rust
59 lines
1.7 KiB
Rust
use memory::Frame;
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use paging::{ActivePageTable, Page, PhysicalAddress, VirtualAddress};
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use paging::entry::EntryFlags;
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/// RSDP
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#[derive(Copy, Clone, Debug)]
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#[repr(packed)]
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pub struct RSDP {
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signature: [u8; 8],
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checksum: u8,
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oemid: [u8; 6],
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revision: u8,
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rsdt_address: u32,
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length: u32,
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xsdt_address: u64,
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extended_checksum: u8,
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reserved: [u8; 3]
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}
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impl RSDP {
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/// Search for the RSDP
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pub fn get_rsdp(active_table: &mut ActivePageTable) -> Option<RSDP> {
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let start_addr = 0xE_0000;
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let end_addr = 0xF_FFFF;
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// Map all of the ACPI RSDP space
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{
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let start_frame = Frame::containing_address(PhysicalAddress::new(start_addr));
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let end_frame = Frame::containing_address(PhysicalAddress::new(end_addr));
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for frame in Frame::range_inclusive(start_frame, end_frame) {
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let page = Page::containing_address(VirtualAddress::new(frame.start_address().get()));
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let result = active_table.map_to(page, frame, EntryFlags::PRESENT | EntryFlags::NO_EXECUTE);
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result.flush(active_table);
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}
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}
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RSDP::search(start_addr, end_addr)
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}
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fn search(start_addr: usize, end_addr: usize) -> Option<RSDP> {
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for i in 0 .. (end_addr + 1 - start_addr)/16 {
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let rsdp = unsafe { &*((start_addr + i * 16) as *const RSDP) };
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if &rsdp.signature == b"RSD PTR " {
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return Some(*rsdp);
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}
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}
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None
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}
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/// Get the RSDT or XSDT address
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pub fn sdt_address(&self) -> usize {
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if self.revision >= 2 {
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self.xsdt_address as usize
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} else {
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self.rsdt_address as usize
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}
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}
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}
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