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Refactor lookup_segment_selector to accept SegmentSelector instead of raw

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This commit is contained in:
Fabian 2021-03-30 12:12:40 -05:00
parent 4344954da3
commit 827b9f3741
2 changed files with 106 additions and 94 deletions
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180
src/rust/cpu/cpu.rs
View file

@ -295,6 +295,7 @@ impl LastJump {
}
pub static mut debug_last_jump: LastJump = LastJump::None;
#[derive(Copy, Clone)]
pub struct SegmentSelector {
raw: u16,
}
@ -518,8 +519,9 @@ pub unsafe fn iret(is_16: bool) {
// protected mode return
let (cs_descriptor, cs_selector) = match return_on_pagefault!(lookup_segment_selector(new_cs)) {
Ok((desc, sel, _)) => (desc, sel),
let cs_selector = SegmentSelector::of_u16(new_cs as u16);
let cs_descriptor = match return_on_pagefault!(lookup_segment_selector(cs_selector)) {
Ok((desc, _)) => desc,
Err(selector_unusable) => match selector_unusable {
SelectorNullOrInvalid::IsNull => {
panic!("Unimplemented: CS selector is null");
@ -570,23 +572,23 @@ pub unsafe fn iret(is_16: bool) {
)
};
let (ss_descriptor, ss_selector) =
match return_on_pagefault!(lookup_segment_selector(temp_ss)) {
Ok((desc, sel, _)) => (desc, sel),
Err(selector_unusable) => match selector_unusable {
SelectorNullOrInvalid::IsNull => {
dbg_log!("#GP for loading 0 in SS sel={:x}", temp_ss);
dbg_trace();
trigger_gp(0);
return;
},
SelectorNullOrInvalid::OutsideOfTableLimit => {
dbg_log!("#GP for loading invalid in SS sel={:x}", temp_ss);
trigger_gp(temp_ss & !3);
return;
},
let ss_selector = SegmentSelector::of_u16(temp_ss as u16);
let ss_descriptor = match return_on_pagefault!(lookup_segment_selector(ss_selector)) {
Ok((desc, _)) => desc,
Err(selector_unusable) => match selector_unusable {
SelectorNullOrInvalid::IsNull => {
dbg_log!("#GP for loading 0 in SS sel={:x}", temp_ss);
dbg_trace();
trigger_gp(0);
return;
},
};
SelectorNullOrInvalid::OutsideOfTableLimit => {
dbg_log!("#GP for loading invalid in SS sel={:x}", temp_ss);
trigger_gp(temp_ss & !3);
return;
},
},
};
let new_cpl = cs_selector.rpl();
if ss_descriptor.is_system()
@ -754,8 +756,10 @@ pub unsafe fn call_interrupt_vector(
panic!("Unimplemented: #GP handler");
}
let cs_segment_descriptor = match return_on_pagefault!(lookup_segment_selector(selector)) {
Ok((desc, _, _)) => desc,
let cs_segment_descriptor = match return_on_pagefault!(lookup_segment_selector(
SegmentSelector::of_u16(selector as u16)
)) {
Ok((desc, _)) => desc,
Err(selector_unusable) => match selector_unusable {
SelectorNullOrInvalid::IsNull => {
dbg_log!("is null");
@ -796,9 +800,10 @@ pub unsafe fn call_interrupt_vector(
let new_esp = read32s(tss_stack_addr);
let new_ss = read16(tss_stack_addr + if *tss_size_32 { 4 } else { 2 });
let (ss_segment_descriptor, ss_segment_selector) =
match return_on_pagefault!(lookup_segment_selector(new_ss)) {
Ok((desc, sel, _)) => (desc, sel),
let ss_segment_selector = SegmentSelector::of_u16(new_ss as u16);
let ss_segment_descriptor =
match return_on_pagefault!(lookup_segment_selector(ss_segment_selector)) {
Ok((desc, _)) => desc,
Err(_) => {
panic!("Unimplemented: #TS handler");
},
@ -1016,8 +1021,9 @@ pub unsafe fn far_jump(eip: i32, selector: i32, is_call: bool, is_osize_32: bool
return;
}
let (info, cs_selector) = match return_on_pagefault!(lookup_segment_selector(selector)) {
Ok((desc, sel, _)) => (desc, sel),
let cs_selector = SegmentSelector::of_u16(selector as u16);
let info = match return_on_pagefault!(lookup_segment_selector(cs_selector)) {
Ok((desc, _)) => desc,
Err(selector_unusable) => match selector_unusable {
SelectorNullOrInvalid::IsNull => {
dbg_log!("#gp null cs");
@ -1055,8 +1061,10 @@ pub unsafe fn far_jump(eip: i32, selector: i32, is_call: bool, is_osize_32: bool
let cs_selector = (info.raw >> 16) as i32;
let (cs_info, _) = match return_on_pagefault!(lookup_segment_selector(cs_selector)) {
Ok((desc, sel, _)) => (desc, sel),
let cs_info = match return_on_pagefault!(lookup_segment_selector(
SegmentSelector::of_u16(cs_selector as u16)
)) {
Ok((desc, _)) => desc,
Err(selector_unusable) => match selector_unusable {
SelectorNullOrInvalid::IsNull => {
dbg_log!("#gp null cs");
@ -1109,18 +1117,18 @@ pub unsafe fn far_jump(eip: i32, selector: i32, is_call: bool, is_osize_32: bool
new_ss = read16(tss_stack_addr + 2);
}
let (ss_info, ss_selector) =
match return_on_pagefault!(lookup_segment_selector(new_ss)) {
Ok((desc, sel, _)) => (desc, sel),
Err(selector_unusable) => match selector_unusable {
SelectorNullOrInvalid::IsNull => {
panic!("null ss: {}", new_ss);
},
SelectorNullOrInvalid::OutsideOfTableLimit => {
panic!("invalid ss: {}", new_ss);
},
let ss_selector = SegmentSelector::of_u16(new_ss as u16);
let ss_info = match return_on_pagefault!(lookup_segment_selector(ss_selector)) {
Ok((desc, _)) => desc,
Err(selector_unusable) => match selector_unusable {
SelectorNullOrInvalid::IsNull => {
panic!("null ss: {}", new_ss);
},
};
SelectorNullOrInvalid::OutsideOfTableLimit => {
panic!("invalid ss: {}", new_ss);
},
},
};
// Disabled: Incorrect handling of direction bit
// See http://css.csail.mit.edu/6.858/2014/readings/i386/s06_03.htm
@ -1352,8 +1360,9 @@ pub unsafe fn far_return(eip: i32, selector: i32, stack_adjust: i32, is_osize_32
return;
}
let (info, cs_selector) = match return_on_pagefault!(lookup_segment_selector(selector)) {
Ok((desc, sel, _)) => (desc, sel),
let cs_selector = SegmentSelector::of_u16(selector as u16);
let info = match return_on_pagefault!(lookup_segment_selector(cs_selector)) {
Ok((desc, _)) => desc,
Err(selector_unusable) => match selector_unusable {
SelectorNullOrInvalid::IsNull => {
dbg_log!("far return: #gp null cs");
@ -2090,10 +2099,8 @@ pub unsafe fn is_asize_32() -> bool {
}
pub unsafe fn lookup_segment_selector(
selector: i32,
) -> OrPageFault<Result<(SegmentDescriptor, SegmentSelector, i32), SelectorNullOrInvalid>> {
let selector = SegmentSelector::of_u16(selector as u16);
selector: SegmentSelector,
) -> OrPageFault<Result<(SegmentDescriptor, i32), SelectorNullOrInvalid>> {
if selector.is_null() {
return Ok(Err(SelectorNullOrInvalid::IsNull));
}
@ -2118,7 +2125,7 @@ pub unsafe fn lookup_segment_selector(
descriptor_address,
)?) as u64);
Ok(Ok((descriptor, selector, descriptor_address)))
Ok(Ok((descriptor, descriptor_address)))
}
pub unsafe fn switch_seg(reg: i32, selector_raw: i32) -> bool {
@ -2136,39 +2143,39 @@ pub unsafe fn switch_seg(reg: i32, selector_raw: i32) -> bool {
return true;
}
let (descriptor, selector) =
match return_on_pagefault!(lookup_segment_selector(selector_raw), false) {
Ok((desc, sel, _)) => (desc, sel),
Err(selector_unusable) => {
// The selector couldn't be used to fetch a descriptor, so we handle all of those
// cases
if selector_unusable == SelectorNullOrInvalid::IsNull {
if reg == SS {
dbg_log!("#GP for loading 0 in SS sel={:x}", selector_raw);
trigger_gp(0);
return false;
}
else if reg != CS {
// es, ds, fs, gs
*sreg.offset(reg as isize) = selector_raw as u16;
*segment_is_null.offset(reg as isize) = true;
return true;
}
}
else if selector_unusable == SelectorNullOrInvalid::OutsideOfTableLimit {
dbg_log!(
"#GP for loading invalid in seg={} sel={:x}",
reg,
selector_raw
);
trigger_gp(selector_raw & !3);
let selector = SegmentSelector::of_u16(selector_raw as u16);
let descriptor = match return_on_pagefault!(lookup_segment_selector(selector), false) {
Ok((desc, _)) => desc,
Err(selector_unusable) => {
// The selector couldn't be used to fetch a descriptor, so we handle all of those
// cases
if selector_unusable == SelectorNullOrInvalid::IsNull {
if reg == SS {
dbg_log!("#GP for loading 0 in SS sel={:x}", selector_raw);
trigger_gp(0);
return false;
}
dbg_assert!(false);
else if reg != CS {
// es, ds, fs, gs
*sreg.offset(reg as isize) = selector_raw as u16;
*segment_is_null.offset(reg as isize) = true;
return true;
}
}
else if selector_unusable == SelectorNullOrInvalid::OutsideOfTableLimit {
dbg_log!(
"#GP for loading invalid in seg={} sel={:x}",
reg,
selector_raw
);
trigger_gp(selector_raw & !3);
return false;
},
};
}
dbg_assert!(false);
return false;
},
};
if reg == SS {
if descriptor.is_system()
@ -2228,9 +2235,12 @@ pub unsafe fn switch_seg(reg: i32, selector_raw: i32) -> bool {
}
pub unsafe fn load_tr(selector: i32) {
let (descriptor, selector, descriptor_address) =
let selector = SegmentSelector::of_u16(selector as u16);
dbg_assert!(selector.is_gdt(), "TODO: TR can only be loaded from GDT");
let (descriptor, descriptor_address) =
match return_on_pagefault!(lookup_segment_selector(selector)) {
Ok((desc, sel, addr)) => (desc, sel, addr),
Ok((desc, addr)) => (desc, addr),
Err(SelectorNullOrInvalid::IsNull) => {
panic!("TODO: null TR");
},
@ -2239,15 +2249,13 @@ pub unsafe fn load_tr(selector: i32) {
},
};
dbg_log!(
"load tr: {:x} offset={:x} limit={:x} is32={}",
selector.raw,
descriptor.base(),
descriptor.effective_limit(),
descriptor.system_type() == 9,
);
dbg_assert!(selector.is_gdt(), "TODO: TR can only be loaded from GDT");
//dbg_log!(
// "load tr: {:x} offset={:x} limit={:x} is32={}",
// selector.raw,
// descriptor.base(),
// descriptor.effective_limit(),
// descriptor.system_type() == 9,
//);
if !descriptor.is_system() {
panic!("#GP | ltr: not a system entry (happens when running kvm-unit-test without ACPI)");

20
src/rust/cpu/misc_instr.rs
View file

@ -431,7 +431,8 @@ pub unsafe fn lar(selector: i32, original: i32) -> i32 {
const LAR_INVALID_TYPE: u32 =
1 << 0 | 1 << 6 | 1 << 7 | 1 << 8 | 1 << 0xA | 1 << 0xD | 1 << 0xE | 1 << 0xF;
match lookup_segment_selector(selector) {
let sel = SegmentSelector::of_u16(selector as u16);
match lookup_segment_selector(sel) {
Err(()) => {
// pagefault
return original;
@ -442,7 +443,7 @@ pub unsafe fn lar(selector: i32, original: i32) -> i32 {
dbg_log!("lar: invalid selector={:x}: null or invalid", selector);
return original;
},
Ok(Ok((desc, sel, _))) => {
Ok(Ok((desc, _))) => {
*flags_changed &= !FLAG_ZERO;
let dpl_bad = desc.dpl() < *cpl || desc.dpl() < sel.rpl();
@ -486,7 +487,8 @@ pub unsafe fn lsl(selector: i32, original: i32) -> i32 {
| 1 << 0xE
| 1 << 0xF;
match lookup_segment_selector(selector) {
let sel = SegmentSelector::of_u16(selector as u16);
match lookup_segment_selector(sel) {
Err(()) => {
// pagefault
return original;
@ -497,7 +499,7 @@ pub unsafe fn lsl(selector: i32, original: i32) -> i32 {
dbg_log!("lsl: invalid selector={:x}: null or invalid", selector);
return original;
},
Ok(Ok((desc, sel, _))) => {
Ok(Ok((desc, _))) => {
*flags_changed &= !FLAG_ZERO;
let dpl_bad = desc.dpl() < *cpl || desc.dpl() < sel.rpl();
@ -526,12 +528,13 @@ pub unsafe fn lsl(selector: i32, original: i32) -> i32 {
pub unsafe fn verr(selector: i32) {
*flags_changed &= !FLAG_ZERO;
match return_on_pagefault!(lookup_segment_selector(selector)) {
let sel = SegmentSelector::of_u16(selector as u16);
match return_on_pagefault!(lookup_segment_selector(sel)) {
Err(_) => {
*flags &= !FLAG_ZERO;
dbg_log!("verr -> invalid. selector={:x}", selector);
},
Ok((desc, sel, _)) => {
Ok((desc, _)) => {
if desc.is_system()
|| !desc.is_readable()
|| (!desc.is_conforming_executable()
@ -550,12 +553,13 @@ pub unsafe fn verr(selector: i32) {
pub unsafe fn verw(selector: i32) {
*flags_changed &= !FLAG_ZERO;
match return_on_pagefault!(lookup_segment_selector(selector)) {
let sel = SegmentSelector::of_u16(selector as u16);
match return_on_pagefault!(lookup_segment_selector(sel)) {
Err(_) => {
*flags &= !FLAG_ZERO;
dbg_log!("verw -> invalid. selector={:x}", selector);
},
Ok((desc, sel, _)) => {
Ok((desc, _)) => {
if desc.is_system()
|| !desc.is_writable()
|| desc.dpl() < *cpl