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use core::mem::size_of;
use ::descriptor;
use ::PrivilegeLevel;
pub use ::segmentation::*;
use bits64::task::*;
/// Reload code segment register.
/// Note this is special since we can not directly move
/// to %cs. Instead we push the new segment selector
/// and return value on the stack and use lretq
/// to reload cs and continue at 1:.
#[cfg(target_arch="x86-64")]
pub unsafe fn set_cs(sel: SegmentSelector) {
asm!("pushq $0; \
leaq 1f(%rip), %rax; \
pushq %rax; \
lretq; \
1:" :: "ri" (sel.bits() as usize) : "rax" "memory");
}
pub enum SegmentBitness {
Bits32,
Bits64,
}
impl SegmentBitness {
pub fn pack(self) -> Flags {
match self {
SegmentBitness::Bits32 => FLAGS_DB,
SegmentBitness::Bits64 => FLAGS_L,
}
}
}
impl SegmentDescriptor {
pub fn new_memory64(base: u32, limit: u32, ty: Type, accessed: bool, dpl: PrivilegeLevel, bitness: SegmentBitness) -> SegmentDescriptor {
let ty1 = descriptor::Type::SegmentDescriptor {
ty: ty,
accessed: accessed,
};
let flags = bitness.pack();
let seg = SegmentDescriptor::memory_or_tss(base, limit, ty1, dpl, flags);
seg
}
pub fn new_tss64(tss: &TaskStateSegment, dpl: PrivilegeLevel) -> [SegmentDescriptor; 2] {
let tss_ptr = tss as *const TaskStateSegment;
let ty1 = descriptor::Type::SystemDescriptor {
size: true,
ty: descriptor::SystemType::TssAvailable,
};
let seg1 = SegmentDescriptor::memory_or_tss(tss_ptr as u32, size_of::<TaskStateSegment>() as u32, ty1, dpl, Flags::empty());
let seg2 = SegmentDescriptor::high(tss_ptr as u64);
[seg1, seg2]
}
}
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