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#![allow(non_upper_case_globals)]
pub use self::x86_shared::*;
use core::mem::size_of;
mod x86_shared;
bitflags! {
pub flags GdtAccess: u8 {
const Accessed = 1 << 0,
const Writable = 1 << 1,
const Direction = 1 << 2,
const Executable = 1 << 3,
const NotTss = 1 << 4,
}
}
#[derive(Copy, Clone, Debug)]
#[repr(C, packed)]
pub struct GdtEntry {
limit: u16,
base1: u16,
base2: u8,
access: u8,
flags: u8,
base3: u8,
}
#[derive(Copy, Clone)]
#[repr(C, packed)]
pub struct IdtEntry {
offset1: u16,
selector: u16,
reserved: u8,
flags: u8,
offset2: u16
}
impl GdtEntry {
pub const NULL: GdtEntry = GdtEntry {
base1: 0,
base2: 0,
base3: 0,
access: 0,
limit: 0,
flags: 0
};
pub fn new(base: *const (), limit: usize, access: GdtAccess, dpl: PrivilegeLevel) -> GdtEntry {
let (limit, flags) = if limit < 0x100000 {
((limit & 0xFFFF) as u16, ((limit & 0xF0000) >> 16) as u8 | 0x40u8)
} else {
if ((limit - 0xFFF) & 0xFFF) > 0 {
panic!("bad segment limit for GDT entry");
}
(((limit & 0xFFFF000) >> 12) as u16, ((limit & 0xF0000000) >> 28) as u8 | 0xC0u8)
};
GdtEntry {
base1: base as u16,
base2: ((base as usize & 0xFF0000) >> 16) as u8,
base3: ((base as usize & 0xFF000000) >> 24) as u8,
access: access.bits() | ((dpl as u8) << 5) | 0x80,
limit: limit,
flags: flags
}
}
}
impl IdtEntry {
pub const NULL: IdtEntry = IdtEntry {
offset1: 0,
selector: 0,
reserved: 0,
flags: 0,
offset2: 0
};
pub fn new(f: unsafe extern "C" fn(), dpl: PrivilegeLevel, block: bool) -> IdtEntry {
IdtEntry {
offset1: f as u16,
offset2: ((f as usize & 0xFFFF0000) >> 16) as u16,
selector: 8,
reserved: 0,
flags: if block { 0x8E } else { 0x8F } | ((dpl as u8) << 5)
}
}
}
#[derive(Copy, Clone, Debug)]
#[repr(C, packed)]
pub struct Tss {
pub link: u16,
reserved0: u16,
pub esp0: u32,
pub ss0: u16,
reserved1: u16,
pub esp1: u32,
pub ss1: u16,
reserved2: u16,
pub esp2: u32,
pub ss2: u16,
reserved3: u16,
pub cr3: u32,
pub eip: u32,
pub eflags: u32,
pub eax: u32,
pub ecx: u32,
pub edx: u32,
pub ebx: u32,
pub esp: u32,
pub ebp: u32,
pub esi: u32,
pub edi: u32,
pub es: u16,
reserved4: u16,
pub cs: u16,
reserved5: u16,
pub ss: u16,
reserved6: u16,
pub ds: u16,
reserved7: u16,
pub fs: u16,
reserved8: u16,
pub gs: u16,
reserved9: u16,
pub ldtr: u16,
reserved10: u32,
pub iobp_offset: u16
}
impl Tss {
pub fn new() -> Tss {
Tss {
link: 0,
reserved0: 0,
esp0: 0,
ss0: 0,
reserved1: 0,
esp1: 0,
ss1: 0,
reserved2: 0,
esp2: 0,
ss2: 0,
reserved3: 0,
cr3: 0,
eip: 0,
eflags: 0,
eax: 0,
ecx: 0,
edx: 0,
ebx: 0,
esp: 0,
ebp: 0,
esi: 0,
edi: 0,
es: 0,
reserved4: 0,
cs: 0,
reserved5: 0,
ss: 0,
reserved6: 0,
ds: 0,
reserved7: 0,
fs: 0,
reserved8: 0,
gs: 0,
reserved9: 0,
ldtr: 0,
reserved10: 0,
iobp_offset: size_of::<Tss>() as u16
}
}
}
#[inline(always)]
pub fn get_flags() -> Flags {
unsafe {
let r: usize;
asm!("pushfd; pop $0" : "=r"(r) ::: "intel");
Flags::from_bits_truncate(r)
}
}
#[inline(always)]
pub unsafe fn set_flags(val: Flags) {
asm!("push $0; popfd" :: "r"(val.bits()) : "flags" : "volatile", "intel");
}
#[inline(always)]
pub unsafe fn set_gdt(gdt: &[GdtEntry]) {
#[repr(C, packed)]
struct GDTR {
limit: u16,
ptr: *const GdtEntry,
}
asm!("lgdtl $0" :: "*m"(&GDTR { ptr: gdt.as_ptr(), limit: (gdt.len()*size_of::<GdtEntry>() - 1) as u16 }) :: "volatile");
}
#[inline(always)]
pub unsafe fn set_idt(idt: &[IdtEntry]) {
#[repr(C, packed)]
struct IDTR {
limit: u16,
ptr: *const IdtEntry,
}
asm!("lidtl $0" :: "*m"(&IDTR { ptr: idt.as_ptr(), limit: idt.len() as u16 * 8 }) :: "volatile");
}
#[inline(always)]
pub unsafe fn stack_jmp(stack: *mut (), ip: *const ()) -> ! {
asm!("mov esp, $0; jmp $1" :: "rg"(stack), "r"(ip) :: "volatile", "intel");
loop { }
}
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