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#[allow(unused_imports)]
use crate::segmentation::SegmentSelector;
use crate::segmentation::{
BuildDescriptor, Descriptor, DescriptorBuilder, DescriptorType, GateDescriptorBuilder,
LdtDescriptorBuilder, SystemDescriptorTypes64,
};
#[derive(Copy, Clone, Debug, Default)]
#[repr(C, packed)]
pub struct Descriptor64 {
desc32: Descriptor,
lower: u32,
upper: u32,
}
impl Descriptor64 {
pub const NULL: Descriptor64 = Descriptor64 {
desc32: Descriptor::NULL,
lower: 0,
upper: 0,
};
pub(crate) fn apply_builder_settings(&mut self, builder: &DescriptorBuilder) {
self.desc32.apply_builder_settings(builder);
builder
.base_limit
.map(|(base, limit)| self.set_base_limit(base, limit));
builder
.selector_offset
.map(|(selector, offset)| self.set_selector_offset(selector, offset));
}
pub fn set_base_limit(&mut self, base: u64, limit: u64) {
self.desc32.set_base_limit(base as u32, limit as u32);
self.lower = (base >> 32) as u32;
}
pub fn set_selector_offset(&mut self, selector: SegmentSelector, offset: u64) {
self.desc32.set_selector_offset(selector, offset as u32);
self.lower = (offset >> 32) as u32;
}
pub fn set_ist(&mut self, index: u8) {
assert!(index <= 0b111);
self.desc32.upper |= index as u32;
}
}
impl GateDescriptorBuilder<u64> for DescriptorBuilder {
fn tss_descriptor(base: u64, limit: u64, available: bool) -> DescriptorBuilder {
let typ = if available {
DescriptorType::System64(SystemDescriptorTypes64::TssAvailable)
} else {
DescriptorType::System64(SystemDescriptorTypes64::TssBusy)
};
DescriptorBuilder::with_base_limit(base, limit).set_type(typ)
}
fn call_gate_descriptor(selector: SegmentSelector, offset: u64) -> DescriptorBuilder {
DescriptorBuilder::with_selector_offset(selector, offset)
.set_type(DescriptorType::System64(SystemDescriptorTypes64::CallGate))
}
fn interrupt_descriptor(selector: SegmentSelector, offset: u64) -> DescriptorBuilder {
DescriptorBuilder::with_selector_offset(selector, offset).set_type(
DescriptorType::System64(SystemDescriptorTypes64::InterruptGate),
)
}
fn trap_gate_descriptor(selector: SegmentSelector, offset: u64) -> DescriptorBuilder {
DescriptorBuilder::with_selector_offset(selector, offset)
.set_type(DescriptorType::System64(SystemDescriptorTypes64::TrapGate))
}
}
impl LdtDescriptorBuilder<u64> for DescriptorBuilder {
fn ldt_descriptor(base: u64, limit: u64) -> DescriptorBuilder {
DescriptorBuilder::with_base_limit(base, limit)
.set_type(DescriptorType::System64(SystemDescriptorTypes64::LDT))
}
}
impl BuildDescriptor<Descriptor64> for DescriptorBuilder {
fn finish(&self) -> Descriptor64 {
let mut desc: Descriptor64 = Default::default();
desc.apply_builder_settings(self);
let typ = match self.typ {
Some(DescriptorType::System64(typ)) => {
assert!(!self.l);
if typ == SystemDescriptorTypes64::LDT
|| typ == SystemDescriptorTypes64::TssAvailable
|| typ == SystemDescriptorTypes64::TssBusy
{
assert!(!self.db);
}
if typ == SystemDescriptorTypes64::InterruptGate {
desc.set_ist(self.ist);
}
typ as u8
}
Some(DescriptorType::System32(_typ)) => {
panic!("Can't build a 64-bit version of this type.")
}
Some(DescriptorType::Data(_typ)) => {
panic!("Can't build a 64-bit version of this type.")
}
Some(DescriptorType::Code(_typ)) => {
panic!("Can't build a 64-bit version of this type.")
}
None => unreachable!("Type not set, this is a library bug in x86."),
};
desc.desc32.set_type(typ);
desc
}
}
#[cfg(target_arch = "x86_64")]
pub unsafe fn load_cs(sel: SegmentSelector) {
llvm_asm!("pushq $0; \
leaq 1f(%rip), %rax; \
pushq %rax; \
lretq; \
1:" :: "ri" (sel.bits() as usize) : "rax" "memory");
}
#[cfg(target_arch = "x86_64")]
pub unsafe fn wrgsbase(base: u64) {
llvm_asm!("wrgsbase $0" :: "r" (base) : "memory");
}
#[cfg(target_arch = "x86_64")]
pub unsafe fn wrfsbase(base: u64) {
llvm_asm!("wrfsbase $0" :: "r" (base) : "memory");
}
#[cfg(target_arch = "x86_64")]
pub unsafe fn rdgsbase() -> u64 {
let gs_base: u64;
llvm_asm!("rdgsbase $0" : "=r" (gs_base) );
gs_base
}
#[cfg(target_arch = "x86_64")]
pub unsafe fn rdfsbase() -> u64 {
let fs_base: u64;
llvm_asm!("rdfsbase $0" : "=r" (fs_base) );
fs_base
}
#[cfg(target_arch = "x86_64")]
pub unsafe fn fs_deref() -> u64 {
let fs: u64;
llvm_asm!("movq %fs:0x0, $0" : "=r" (fs) );
fs
}
#[cfg(target_arch = "x86_64")]
pub unsafe fn gs_deref() -> u64 {
let gs: u64;
llvm_asm!("movq %gs:0x0, $0" : "=r" (gs) );
gs
}
#[cfg(target_arch = "x86_64")]
pub unsafe fn swapgs() {
llvm_asm!("swapgs" ::: "gs");
}