bjorn3
87 lines
2.3 KiB
Rust
87 lines
2.3 KiB
Rust
#[cfg(feature = "pti")]
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use core::ptr;
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#[cfg(feature = "pti")]
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use crate::memory::Frame;
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#[cfg(feature = "pti")]
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use crate::paging::ActivePageTable;
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#[cfg(feature = "pti")]
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#[thread_local]
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pub static mut PTI_CPU_STACK: [u8; 256] = [0; 256];
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#[cfg(feature = "pti")]
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#[thread_local]
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pub static mut PTI_CONTEXT_STACK: usize = 0;
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#[cfg(feature = "pti")]
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#[inline(always)]
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unsafe fn switch_stack(old: usize, new: usize) {
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let old_rsp: usize;
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asm!("", out("rsp") old_rsp);
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let offset_rsp = old - old_rsp;
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let new_rsp = new - offset_rsp;
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ptr::copy_nonoverlapping(old_rsp as *const u8, new_rsp as *mut u8, offset_rsp);
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asm!("", out("rsp") new_rsp);
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}
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#[cfg(feature = "pti")]
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#[inline(always)]
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pub unsafe fn map() {
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// {
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// let mut active_table = unsafe { ActivePageTable::new() };
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//
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// // Map kernel heap
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// let address = active_table.p4()[::KERNEL_HEAP_PML4].address();
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// let frame = Frame::containing(address);
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// let mut flags = active_table.p4()[::KERNEL_HEAP_PML4].flags();
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// flags.remove(EntryFlags::PRESENT);
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// active_table.p4_mut()[::KERNEL_HEAP_PML4].set(frame, flags);
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//
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// // Reload page tables
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// active_table.flush_all();
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// }
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// Switch to per-context stack
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switch_stack(
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PTI_CPU_STACK.as_ptr() as usize + PTI_CPU_STACK.len(),
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PTI_CONTEXT_STACK,
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);
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}
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#[cfg(feature = "pti")]
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#[inline(always)]
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pub unsafe extern "C" fn unmap() {
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// Switch to per-CPU stack
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switch_stack(
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PTI_CONTEXT_STACK,
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PTI_CPU_STACK.as_ptr() as usize + PTI_CPU_STACK.len(),
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);
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// {
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// let mut active_table = unsafe { ActivePageTable::new() };
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//
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// // Unmap kernel heap
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// let address = active_table.p4()[::KERNEL_HEAP_PML4].address();
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// let frame = Frame::containing(address);
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// let mut flags = active_table.p4()[::KERNEL_HEAP_PML4].flags();
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// flags.insert(EntryFlags::PRESENT);
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// active_table.p4_mut()[::KERNEL_HEAP_PML4].set(frame, flags);
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//
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// // Reload page tables
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// active_table.flush_all();
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// }
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}
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#[cfg(not(feature = "pti"))]
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#[inline(always)]
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pub unsafe fn map() {}
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#[cfg(not(feature = "pti"))]
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#[inline(always)]
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pub unsafe extern "C" fn unmap() {}
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