forked from AbleOS/ableos
94 lines
3.3 KiB
Rust
94 lines
3.3 KiB
Rust
mod memory;
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use core::{arch::{asm, global_asm}, fmt::Write};
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use alloc::boxed::Box;
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use sbi::system_reset::{ResetType, ResetReason, system_reset};
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use spin::{Mutex, Once};
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use uart_16550::MmioSerialPort;
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use crate::{allocator, memory::PhysicalAddress, arch::riscv64::memory::{PAGE_TABLE, PageEntryFlags, PageSize, PageTable}};
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global_asm!(include_str!("entry.s"));
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global_asm!(include_str!("memory_regions.s"));
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pub const PAGE_SIZE: usize = 4096;
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extern {
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static TEXT_START: PhysicalAddress;
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static TEXT_END: PhysicalAddress;
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static RODATA_START: PhysicalAddress;
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static RODATA_END: PhysicalAddress;
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static DATA_START: PhysicalAddress;
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static DATA_END: PhysicalAddress;
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static SDATA_START: PhysicalAddress;
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static SDATA_END: PhysicalAddress;
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static BSS_START: PhysicalAddress;
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static BSS_END: PhysicalAddress;
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static INITIAL_KERNEL_HEAP_START: PhysicalAddress;
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static INITIAL_KERNEL_HEAP_SIZE: usize;
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static USABLE_MEMORY_START: PhysicalAddress;
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static USABLE_MEMORY_SIZE: usize;
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}
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static SERIAL_CONSOLE: Once<Mutex<MmioSerialPort>> = Once::new();
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#[no_mangle]
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unsafe extern fn _kernel_start() -> ! {
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SERIAL_CONSOLE.call_once(|| Mutex::new(unsafe { MmioSerialPort::new(0x1000_0000) }));
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crate::logger::init().expect("failed to set logger");
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log::info!("Initialising AKern {}", crate::VERSION);
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allocator::init(INITIAL_KERNEL_HEAP_START.as_mut_ptr::<u8>(), INITIAL_KERNEL_HEAP_SIZE);
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memory::init(USABLE_MEMORY_START.into(), USABLE_MEMORY_SIZE / PAGE_SIZE);
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let mut page_table_addr = PAGE_TABLE.get().unwrap().lock();
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let mut page_table = page_table_addr.as_mut_ptr::<PageTable>().as_mut().unwrap();
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// Map text (executable) section
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page_table.identity_map_range(TEXT_START, TEXT_END, PageEntryFlags::ReadExecute);
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// Map rodata section
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page_table.identity_map_range(RODATA_END, RODATA_END, PageEntryFlags::Read);
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// Map data section
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page_table.identity_map_range(DATA_START, DATA_END, PageEntryFlags::ReadWrite);
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// Map sdata section
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page_table.identity_map_range(SDATA_START, SDATA_END, PageEntryFlags::ReadWrite);
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// Map bss section (includes stack and initial kernel heap)
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page_table.identity_map_range(BSS_START, BSS_END, PageEntryFlags::ReadWrite);
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// Map usable memory range (as rw so not executable)
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page_table.identity_map_range(USABLE_MEMORY_START, USABLE_MEMORY_START + USABLE_MEMORY_SIZE.into(), PageEntryFlags::ReadWrite);
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// Map Uart so we can continue using serial
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page_table.identity_map(0x1000_0000_usize.into(), PageEntryFlags::ReadWrite, PageSize::Size4KiB);
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let table_ppn = page_table_addr.as_addr() as usize >> 12;
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let satp_value = 8 << 60 | table_ppn;
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log::info!("Enabling the MMU...");
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asm!(
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"csrw satp, {}",
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"sfence.vma",
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in(reg) satp_value,
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);
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log::info!("We're in PAGING LAND!");
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#[allow(unreachable_code)]
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match system_reset(ResetType::Shutdown, ResetReason::NoReason).unwrap() {}
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}
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/// Spin loop
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pub fn sloop() -> ! {
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loop {
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unsafe { asm!("wfi") }
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}
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}
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pub fn log(args: core::fmt::Arguments<'_>) -> core::fmt::Result {
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SERIAL_CONSOLE.get().unwrap().lock().write_fmt(args)
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}
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