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Add variable privilege to gdt #68

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Add variable privilege to gdt #68

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c3f353a
Add variable privilege to gdt
Restioson Apr 26, 2019
2ebfa60
BREAKING: allow use of io permissions bitmap with tss
Restioson Apr 26, 2019
a271078
-2 -> -1
Restioson Apr 26, 2019
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8 changes: 4 additions & 4 deletions src/structures/gdt.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -70,15 +70,15 @@ impl GlobalDescriptorTable {
///
/// Panics if the GDT has no free entries left.
pub fn add_entry(&mut self, entry: Descriptor) -> SegmentSelector {
let index = match entry {
Descriptor::UserSegment(value) => self.push(value),
let (index, privilege) = match entry {
Descriptor::UserSegment(value) => (self.push(value), (value >> 45) & 0b11),
Descriptor::SystemSegment(value_low, value_high) => {
let index = self.push(value_low);
self.push(value_high);
index
(index, (value_low >> 45) & 0b11)
}
};
SegmentSelector::new(index as u16, PrivilegeLevel::Ring0)
SegmentSelector::new(index as u16, PrivilegeLevel::from_u16(privilege as u16))
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@phil-opp phil-opp Apr 28, 2019

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How about adding a privilege_level(&self) -> PrivilegeLevel method to Descriptor? Then we could keep the bit shifts at one place. Also, we could use the get_bits method instead of doing the shift and logical AND ourselves.

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@Restioson Restioson Apr 28, 2019

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Cool, will do.

}

/// Loads the GDT in the CPU using the `lgdt` instruction.
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