qiurui
/
asterinas
mirror of https://github.com/asterinas/asterinas.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Remove the x86 kernel page fault handler

This commit is contained in:
Zhang Junyang 2025-11-25 15:46:55 +08:00 committed by Tate, Hongliang Tian
parent 3f3838d3a3
commit d516bdedeb
1 changed files with 8 additions and 79 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

87
ostd/src/arch/x86/trap/mod.rs
View File

@ -20,27 +20,19 @@ pub(super) mod gdt;
mod idt;
mod syscall;
use align_ext::AlignExt;
use cfg_if::cfg_if;
use log::debug;
use spin::Once;
use super::cpu::context::GeneralRegs;
use crate::{
arch::{
cpu::context::{CpuException, PageFaultErrorCode, RawPageFaultInfo},
if_tdx_enabled,
cpu::context::CpuException,
irq::{disable_local, enable_local, HwIrqLine},
},
cpu::PrivilegeLevel,
ex_table::ExTable,
irq::call_irq_callback_functions,
mm::{
kspace::{KERNEL_PAGE_TABLE, LINEAR_MAPPING_BASE_VADDR, LINEAR_MAPPING_VADDR_RANGE},
page_prop::{CachePolicy, PageProperty},
PageFlags, PrivilegedPageFlags as PrivFlags, MAX_USERSPACE_VADDR, PAGE_SIZE,
},
task::disable_preempt,
mm::MAX_USERSPACE_VADDR,
};
cfg_if! {
@ -177,14 +169,17 @@ extern "sysv64" fn trap_handler(f: &mut TrapFrame) {
if (0..MAX_USERSPACE_VADDR).contains(&raw_page_fault_info.addr) {
handle_user_page_fault(f, cpu_exception.as_ref().unwrap());
} else {
handle_kernel_page_fault(raw_page_fault_info);
panic!(
"Cannot handle kernel page fault: {:#x?}; trapframe: {:#x?}",
raw_page_fault_info, f
);
}
disable_local_if(was_irq_enabled);
}
Some(exception) => {
enable_local_if(was_irq_enabled);
panic!(
"cannot handle kernel CPU exception: {:?}, trapframe: {:?}",
"Cannot handle kernel CPU exception: {:#x?}; trapframe: {:#x?}",
exception, f
);
}
@ -227,72 +222,6 @@ fn handle_user_page_fault(f: &mut TrapFrame, exception: &CpuException) {
if let Some(addr) = ExTable::find_recovery_inst_addr(f.rip) {
f.rip = addr;
} else {
panic!("Cannot handle user page fault; Trapframe:{:#x?}.", f);
panic!("Cannot handle user page fault; trapframe: {:#x?}", f);
}
}
/// FIXME: this is a hack because we don't allocate kernel space for IO memory. We are currently
/// using the linear mapping for IO memory. This is not a good practice.
fn handle_kernel_page_fault(info: RawPageFaultInfo) {
let preempt_guard = disable_preempt();
let RawPageFaultInfo {
error_code,
addr: page_fault_vaddr,
} = info;
debug!(
"kernel page fault: address {:?}, error code {:?}",
page_fault_vaddr as *const (), error_code
);
assert!(
LINEAR_MAPPING_VADDR_RANGE.contains(&page_fault_vaddr),
"kernel page fault: the address is outside the range of the linear mapping",
);
const SUPPORTED_ERROR_CODES: PageFaultErrorCode = PageFaultErrorCode::PRESENT
.union(PageFaultErrorCode::WRITE)
.union(PageFaultErrorCode::INSTRUCTION);
assert!(
SUPPORTED_ERROR_CODES.contains(error_code),
"kernel page fault: the error code is not supported",
);
assert!(
!error_code.contains(PageFaultErrorCode::INSTRUCTION),
"kernel page fault: the direct mapping cannot be executed",
);
assert!(
!error_code.contains(PageFaultErrorCode::PRESENT),
"kernel page fault: the direct mapping already exists",
);
// Do the mapping
let page_table = KERNEL_PAGE_TABLE
.get()
.expect("kernel page fault: the kernel page table is not initialized");
let vaddr = page_fault_vaddr.align_down(PAGE_SIZE);
let paddr = vaddr - LINEAR_MAPPING_BASE_VADDR;
let priv_flags = if_tdx_enabled!({
PrivFlags::SHARED | PrivFlags::GLOBAL
} else {
PrivFlags::GLOBAL
});
let prop = PageProperty {
flags: PageFlags::RW,
cache: CachePolicy::Uncacheable,
priv_flags,
};
let mut cursor = page_table
.cursor_mut(&preempt_guard, &(vaddr..vaddr + PAGE_SIZE))
.unwrap();
// SAFETY:
// 1. We have checked that the page fault address falls within the address range of the direct
// mapping of physical memory.
// 2. We map the address to the correct physical page with the correct flags, where the
// correctness follows the semantics of the direct mapping of physical memory.
unsafe { cursor.map(crate::mm::kspace::MappedItem::Untracked(paddr, 1, prop)) }.unwrap();
}