diff options
Diffstat (limited to 'src/bits64/segmentation.rs')
| -rw-r--r-- | src/bits64/segmentation.rs | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/src/bits64/segmentation.rs b/src/bits64/segmentation.rs index 2c83f3c..c4420d8 100644 --- a/src/bits64/segmentation.rs +++ b/src/bits64/segmentation.rs @@ -26,10 +26,12 @@ impl Descriptor64 { pub(crate) fn apply_builder_settings(&mut self, builder: &DescriptorBuilder) { self.desc32.apply_builder_settings(builder); - if let Some((base, limit)) = builder - .base_limit { self.set_base_limit(base, limit) } - if let Some((selector, offset)) = builder - .selector_offset { self.set_selector_offset(selector, offset) } + if let Some((base, limit)) = builder.base_limit { + self.set_base_limit(base, limit) + } + if let Some((selector, offset)) = builder.selector_offset { + self.set_selector_offset(selector, offset) + } } /// Create a new segment, TSS or LDT descriptor @@ -129,10 +131,14 @@ impl BuildDescriptor<Descriptor64> for DescriptorBuilder { } /// 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:. +/// +/// # Safety +/// Can cause a GP-fault with a bad `sel` value. #[cfg(target_arch = "x86_64")] pub unsafe fn load_cs(sel: SegmentSelector) { llvm_asm!("pushq $0; \ @@ -143,6 +149,8 @@ pub unsafe fn load_cs(sel: SegmentSelector) { } /// Write GS Segment Base +/// +/// # Safety /// Needs FSGSBASE-Enable Bit (bit 16 of CR4) set. #[cfg(target_arch = "x86_64")] pub unsafe fn wrgsbase(base: u64) { @@ -150,6 +158,8 @@ pub unsafe fn wrgsbase(base: u64) { } /// Write FS Segment Base +/// +/// # Safety /// Needs FSGSBASE-Enable Bit (bit 16 of CR4) set. #[cfg(target_arch = "x86_64")] pub unsafe fn wrfsbase(base: u64) { @@ -157,6 +167,8 @@ pub unsafe fn wrfsbase(base: u64) { } /// Read GS Segment Base +/// +/// # Safety /// Needs FSGSBASE-Enable Bit (bit 16 of CR4) set. #[cfg(target_arch = "x86_64")] pub unsafe fn rdgsbase() -> u64 { @@ -166,6 +178,8 @@ pub unsafe fn rdgsbase() -> u64 { } /// Read FS Segment Base +/// +/// # Safety /// Needs FSGSBASE-Enable Bit (bit 16 of CR4) set. #[cfg(target_arch = "x86_64")] pub unsafe fn rdfsbase() -> u64 { @@ -175,6 +189,9 @@ pub unsafe fn rdfsbase() -> u64 { } /// "Dereferences" the fs register at offset 0. +/// +/// # Safety +/// fs needs to point to valid address. #[cfg(target_arch = "x86_64")] pub unsafe fn fs_deref() -> u64 { let fs: u64; @@ -183,6 +200,9 @@ pub unsafe fn fs_deref() -> u64 { } /// "Dereferences" the gs register at offset 0. +/// +/// # Safety +/// gs needs to point to valid address. #[cfg(target_arch = "x86_64")] pub unsafe fn gs_deref() -> u64 { let gs: u64; @@ -197,7 +217,7 @@ pub unsafe fn gs_deref() -> u64 { /// /// The SWAPGS instruction is available only in 64-bit mode. /// -/// # Unsafe +/// # Safety /// The SWAPGS instruction is a privileged instruction intended for use by system software. #[cfg(target_arch = "x86_64")] pub unsafe fn swapgs() { |