This commit is contained in:
Timothy Warren 2019-09-24 16:59:20 -04:00
parent 13de97db85
commit 730df58cc8
6 changed files with 126 additions and 2 deletions

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@ -33,3 +33,7 @@ test-success-exit-code = 33 # (0x10 << 1) | 1
[[test]] [[test]]
name = "should_panic" name = "should_panic"
harness = false harness = false
[[test]]
name = "stack_overflow"
harness = false

45
src/gdt.rs Normal file
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@ -0,0 +1,45 @@
use lazy_static::lazy_static;
use x86_64::VirtAddr;
use x86_64::structures::gdt::{GlobalDescriptorTable, Descriptor, SegmentSelector};
use x86_64::structures::tss::TaskStateSegment;
pub const DOUBLE_FAULT_IST_INDEX: u16 = 0;
lazy_static!{
static ref TSS: TaskStateSegment = {
let mut tss = TaskStateSegment::new();
tss.interrupt_stack_table[DOUBLE_FAULT_IST_INDEX as usize] = {
const STACK_SIZE: usize = 4096;
static mut STACK: [u8; STACK_SIZE] = [0; STACK_SIZE];
let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
let stack_end = stack_start + STACK_SIZE;
stack_end
};
tss
};
}
lazy_static!{
static ref GDT: (GlobalDescriptorTable, Selectors) = {
let mut gdt = GlobalDescriptorTable::new();
let code_selector = gdt.add_entry(Descriptor::kernel_code_segment());
let tss_selector = gdt.add_entry(Descriptor::tss_segment(&TSS));
(gdt, Selectors { code_selector, tss_selector })
};
}
struct Selectors {
code_selector: SegmentSelector,
tss_selector: SegmentSelector,
}
pub fn init() {
use x86_64::instructions::segmentation::set_cs;
use x86_64::instructions::tables::load_tss;
GDT.0.load();
unsafe {
set_cs(GDT.1.code_selector);
load_tss(GDT.1.tss_selector);
}
}

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@ -1,6 +1,7 @@
use lazy_static::lazy_static; use lazy_static::lazy_static;
use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame}; use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
use crate::gdt;
use crate::println; use crate::println;
#[cfg(test)] #[cfg(test)]
@ -10,6 +11,11 @@ lazy_static!{
static ref IDT: InterruptDescriptorTable = { static ref IDT: InterruptDescriptorTable = {
let mut idt = InterruptDescriptorTable::new(); let mut idt = InterruptDescriptorTable::new();
idt.breakpoint.set_handler_fn(breakpoint_handler); idt.breakpoint.set_handler_fn(breakpoint_handler);
unsafe {
idt.double_fault.set_handler_fn(double_fault_handler)
.set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX);
}
idt idt
}; };
} }
@ -24,6 +30,12 @@ extern "x86-interrupt" fn breakpoint_handler(
println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame); println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame);
} }
extern "x86-interrupt" fn double_fault_handler(
stack_frame: &mut InterruptStackFrame, _error_code: u64
) {
panic!("EXCEPTION: DOUBLE FAULT\n{:#?}", stack_frame);
}
#[test_case] #[test_case]
fn test_breakpoint_exception() { fn test_breakpoint_exception() {
serial_print!("test_breakpoint_exception..."); serial_print!("test_breakpoint_exception...");

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@ -7,6 +7,7 @@
use core::panic::PanicInfo; use core::panic::PanicInfo;
pub mod gdt;
pub mod interrupts; pub mod interrupts;
pub mod serial; pub mod serial;
pub mod macros; pub mod macros;
@ -59,5 +60,6 @@ pub fn exit_qemu(exit_code: QemuExitCode) {
} }
pub fn init() { pub fn init() {
gdt::init();
interrupts::init_idt(); interrupts::init_idt();
} }

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@ -28,10 +28,9 @@ pub extern "C" fn _start() -> ! {
blog_os::init(); blog_os::init();
x86_64::instructions::interrupts::int3();
#[cfg(test)] #[cfg(test)]
test_main(); test_main();
println!("It did not crash!");
loop {} loop {}
} }

62
tests/stack_overflow.rs Normal file
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@ -0,0 +1,62 @@
// in tests/stack_overflow.rs
#![no_std]
#![no_main]
#![feature(abi_x86_interrupt)]
use core::panic::PanicInfo;
use lazy_static::lazy_static;
use x86_64::structures::idt::InterruptDescriptorTable;
use x86_64::structures::idt::InterruptStackFrame;
lazy_static! {
static ref TEST_IDT: InterruptDescriptorTable = {
let mut idt = InterruptDescriptorTable::new();
unsafe {
idt.double_fault
.set_handler_fn(test_double_fault_handler)
.set_stack_index(blog_os::gdt::DOUBLE_FAULT_IST_INDEX);
}
idt
};
}
use blog_os::{exit_qemu, QemuExitCode, serial_print, serial_println};
#[no_mangle]
pub extern "C" fn _start() -> ! {
serial_print!("stack_overflow... ");
blog_os::gdt::init();
init_test_idt();
// trigger a stack overflow
stack_overflow();
panic!("Execution continued after stack overflow");
}
#[panic_handler]
fn panic(info: &PanicInfo) -> ! {
blog_os::test_panic_handler(info)
}
#[allow(unconditional_recursion)]
fn stack_overflow() {
stack_overflow(); // for each recursion, the return address is pushed
}
pub fn init_test_idt() {
TEST_IDT.load();
}
extern "x86-interrupt" fn test_double_fault_handler(
_stack_frame: &mut InterruptStackFrame,
_error_code: u64,
) {
serial_println!("[ok]");
exit_qemu(QemuExitCode::Success);
loop {}
}