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Redo the macro stuff for incrementing and decrementing counters.
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@kitlith
kitlith committed Nov 9, 2019
1 parent a203fb5 commit d854a1f
Showing 1 changed file with 116 additions and 67 deletions.
183 changes: 116 additions & 67 deletions kernel/src/i386/interrupt_service_routines.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -336,7 +336,7 @@ macro_rules! trap_gate_asm {
/// kernel_fault_strategy: panic, // what to do if we were in kernelspace when this interruption happened.
/// user_fault_strategy: panic, // what to do if we were in userspace when this interruption happened, and feature "panic-on-exception" is enabled.
/// handler_strategy: kill, // what to for this interrupt otherwise
/// interrupts_disabled: true // OPTIONAL: are IRQs disabled. True by default, false used for syscalls.
/// type: exception // what "type" of interrupt this is
///);
/// ```
///
Expand All @@ -349,6 +349,10 @@ macro_rules! trap_gate_asm {
/// * `ignore`: don't do anything for this interrupt.
/// * `kill`: kills the process in which this interrupt originated.
/// * `my_handler_func`: calls `my_handler_func` to handle this interrupt. Useful if you want to override a standard strategy.
/// * The possible values for `type` are:
/// * `syscall`: interrupts and usage of regular SpinLocks are allowed.
/// * `exception`: interrupts are disabled, but regular SpinLocks can be accessed if coming from userspace.
/// * `interrupt`: interrupts and usage of regular SpinLocks are disabled.
///
/// When providing a custom function as strategy, the function must be of signature:
///
Expand All @@ -374,6 +378,12 @@ macro_rules! trap_gate_asm {
///
/// extern "C" fn $wrapper_rust_fnname(userspace_context: &mut UserspaceHardwareContext) {
///
/// disable_interrupts() //
/// // type
/// if coming from Ring == 0 { // (here: exception)
/// disable_spinlocks() //
/// } //
///
/// if coming from Ring == 0 {
///
/// kernel_panic(&PanicOrigin::KernelFault { //
Expand Down Expand Up @@ -410,6 +420,12 @@ macro_rules! trap_gate_asm {
/// ProcessStruct::kill_current_process(); //
/// }
///
/// enable_interrupts() //
/// // type
/// if coming from Ring == 0 { // (here: exception)
/// enable_spinlocks() //
/// } //
///
/// // if we're returning to userspace, check we haven't been killed
/// if comming from Ring == 3 {
/// check_thread_killed();
Expand Down Expand Up @@ -527,26 +543,53 @@ macro_rules! generate_trap_gate_handler {
}
};

// handle optional argument interrupts_disabled.
(
name: $exception_name:literal,
has_errcode: $has_errcode:ident,
wrapper_asm_fnname: $wrapper_asm_fnname:ident,
wrapper_rust_fnname: $wrapper_rust_fnname:ident,
kernel_fault_strategy: $kernel_fault_strategy:ident,
user_fault_strategy: $user_fault_strategy:ident,
handler_strategy: $handler_strategy:ident
) => {
generate_trap_gate_handler!(
name: $exception_name,
has_errcode: $has_errcode,
wrapper_asm_fnname: $wrapper_asm_fnname,
wrapper_rust_fnname: $wrapper_rust_fnname,
kernel_fault_strategy: $kernel_fault_strategy,
user_fault_strategy: $user_fault_strategy,
handler_strategy: $handler_strategy,
interrupts_disabled: true
);
/* Counter manipulation */

// syscall
(__gen increment syscall; $_privlvl:path) => {
/* ignored -- interrupts are enabled, spinlocks are enabled */
};
(__gen decrement syscall; $_privlvl:path) => {
/* ignored -- interrupts are enabled, spinlocks are enabled */
};

// exception
(__gen increment exception; $privlvl:path) => {
unsafe {
// Safety: Paired with decrement_lock_count in (__gen decrement exception; _)
crate::sync::spin_lock_irq::disable_interrupts();
}
if $privlvl == PrivilegeLevel::Ring0 {
crate::i386::interrupt_service_routines::INSIDE_INTERRUPT_COUNT.fetch_add(1, core::sync::atomic::Ordering::SeqCst);
}

};
(__gen decrement exception; $privlvl:path) => {
unsafe {
// Safety: Paired with disable_interrupts in (__gen increment exception; _)
// Additionally, this is called shortly before an iret occurs, inside the asm wrapper.
crate::sync::spin_lock_irq::decrement_lock_count();
}
if $privlvl == PrivilegeLevel::Ring0 {
crate::i386::interrupt_service_routines::INSIDE_INTERRUPT_COUNT.fetch_sub(1, core::sync::atomic::Ordering::SeqCst);
}
};

// interrupt
(__gen increment interrupt; $_privlvl:path) => {
unsafe {
// Safety: Paired with decrement_lock_count in (__gen decrement interrupt; _)
crate::sync::spin_lock_irq::disable_interrupts();
}
crate::i386::interrupt_service_routines::INSIDE_INTERRUPT_COUNT.fetch_add(1, core::sync::atomic::Ordering::SeqCst);
};
(__gen decrement interrupt; $_privlvl:path) => {
unsafe {
// Safety: Paired with disable_interrupts in (__gen increment interrupt; _)
// Additionally, this is called shortly before an iret occurs, inside the asm wrapper.
crate::sync::spin_lock_irq::decrement_lock_count();
}
crate::i386::interrupt_service_routines::INSIDE_INTERRUPT_COUNT.fetch_sub(1, core::sync::atomic::Ordering::SeqCst);
};

/* The full wrapper */
Expand All @@ -560,29 +603,21 @@ macro_rules! generate_trap_gate_handler {
kernel_fault_strategy: $kernel_fault_strategy:ident,
user_fault_strategy: $user_fault_strategy:ident,
handler_strategy: $handler_strategy:ident,
interrupts_disabled: $interrupts_disabled:literal
type: $type:ident
) => {

generate_trap_gate_handler!(__gen asm_wrapper; $wrapper_asm_fnname, $wrapper_rust_fnname, $has_errcode);

/// Auto generated function. See [generate_trap_gate_handler].
extern "C" fn $wrapper_rust_fnname(userspace_context: &mut UserspaceHardwareContext) {

use crate::i386::structures::gdt::SegmentSelector;
use crate::i386::interrupt_service_routines::INSIDE_INTERRUPT_COUNT;
use crate::sync::spin_lock_irq::{disable_interrupts, decrement_lock_count};
use core::sync::atomic::Ordering;

if $interrupts_disabled {
// Lets SpinLockIrq know that we are an interrupt; interrupts should not be re-enabled.
unsafe {
// Safety: Paired with decrement_lock_count, which is called before exiting the interrupt.
disable_interrupts();
}
}

if let PrivilegeLevel::Ring0 = SegmentSelector(userspace_context.cs as u16).rpl() {
let _ = INSIDE_INTERRUPT_COUNT.fetch_add(1, Ordering::SeqCst);
let privilege_level = SegmentSelector(userspace_context.cs as u16).rpl();

// mark interrupts and spinlocks disabled as apporpriate
generate_trap_gate_handler!(__gen increment $type; privilege_level);

if let PrivilegeLevel::Ring0 = privilege_level {
generate_trap_gate_handler!(__gen kernel_fault; name: $exception_name, userspace_context, errcode: $has_errcode, strategy: $kernel_fault_strategy);
} else {
// we come from userspace, backup the hardware context in the thread struct
Expand All @@ -599,18 +634,12 @@ macro_rules! generate_trap_gate_handler {
// call the handler
generate_trap_gate_handler!(__gen handler; name: $exception_name, userspace_context, errcode: $has_errcode, strategy: $handler_strategy);

if $interrupts_disabled {
unsafe {
// Safety: Paired with disable_interrupts, which was called earlier in this wrapper function.
// Additionally, this is called shortly before an iret occurs, inside the asm wrapper.
decrement_lock_count();
}
}
// re-enable interrupts and spinlocks as appropriate
generate_trap_gate_handler!(__gen decrement $type; privilege_level);

// if we're returning to userspace, check we haven't been killed
match SegmentSelector(userspace_context.cs as u16).rpl() {
PrivilegeLevel::Ring3 => check_thread_killed(),
PrivilegeLevel::Ring0 => INSIDE_INTERRUPT_COUNT.fetch_sub(1, Ordering::SeqCst)
if let PrivilegeLevel::Ring3 = SegmentSelector(userspace_context.cs as u16).rpl() {
check_thread_killed()
}
}
};
Expand All @@ -626,7 +655,8 @@ generate_trap_gate_handler!(name: "Divide Error Exception",
wrapper_rust_fnname: divide_by_zero_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "Debug Exception",
Expand All @@ -635,7 +665,8 @@ generate_trap_gate_handler!(name: "Debug Exception",
wrapper_rust_fnname: debug_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: panic
handler_strategy: panic,
type: exception
);

generate_trap_gate_handler!(name: "An unexpected non-maskable (but still kinda maskable) interrupt occurred",
Expand All @@ -644,7 +675,8 @@ generate_trap_gate_handler!(name: "An unexpected non-maskable (but still kinda m
wrapper_rust_fnname: nmi_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: panic
handler_strategy: panic,
type: exception
);

generate_trap_gate_handler!(name: "Breakpoint Exception",
Expand All @@ -653,7 +685,8 @@ generate_trap_gate_handler!(name: "Breakpoint Exception",
wrapper_rust_fnname: breakpoint_exception_rust_wrapper,
kernel_fault_strategy: ignore,
user_fault_strategy: ignore,
handler_strategy: panic
handler_strategy: panic,
type: exception
);

generate_trap_gate_handler!(name: "Overflow Exception",
Expand All @@ -662,7 +695,8 @@ generate_trap_gate_handler!(name: "Overflow Exception",
wrapper_rust_fnname: overflow_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "BOUND Range Exceeded Exception",
Expand All @@ -671,7 +705,8 @@ generate_trap_gate_handler!(name: "BOUND Range Exceeded Exception",
wrapper_rust_fnname: bound_range_exceeded_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "Invalid opcode Exception",
Expand All @@ -680,7 +715,8 @@ generate_trap_gate_handler!(name: "Invalid opcode Exception",
wrapper_rust_fnname: invalid_opcode_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "Device Not Available Exception",
Expand All @@ -689,7 +725,8 @@ generate_trap_gate_handler!(name: "Device Not Available Exception",
wrapper_rust_fnname: device_not_available_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

/// Double fault handler. Panics the kernel unconditionally.
Expand All @@ -705,7 +742,8 @@ generate_trap_gate_handler!(name: "Invalid TSS Exception",
wrapper_rust_fnname: invalid_tss_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: panic
handler_strategy: panic,
type: exception
);

generate_trap_gate_handler!(name: "Segment Not Present Exception",
Expand All @@ -714,7 +752,8 @@ generate_trap_gate_handler!(name: "Segment Not Present Exception",
wrapper_rust_fnname: segment_not_present_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "Stack Fault Exception",
Expand All @@ -723,7 +762,8 @@ generate_trap_gate_handler!(name: "Stack Fault Exception",
wrapper_rust_fnname: stack_fault_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "General Protection Fault Exception",
Expand All @@ -732,7 +772,8 @@ generate_trap_gate_handler!(name: "General Protection Fault Exception",
wrapper_rust_fnname: general_protection_fault_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "Page Fault Exception",
Expand All @@ -741,7 +782,8 @@ generate_trap_gate_handler!(name: "Page Fault Exception",
wrapper_rust_fnname: page_fault_exception_rust_wrapper,
kernel_fault_strategy: kernel_page_fault_panic,
user_fault_strategy: user_page_fault_panic,
handler_strategy: user_page_fault_handler
handler_strategy: user_page_fault_handler,
type: exception
);

/// Overriding the default panic strategy so we can display cr2
Expand Down Expand Up @@ -786,7 +828,8 @@ generate_trap_gate_handler!(name: "x87 FPU floating-point error",
wrapper_rust_fnname: x87_floating_point_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "Alignment Check Exception",
Expand All @@ -795,7 +838,8 @@ generate_trap_gate_handler!(name: "Alignment Check Exception",
wrapper_rust_fnname: alignment_check_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "Machine-Check Exception",
Expand All @@ -804,7 +848,8 @@ generate_trap_gate_handler!(name: "Machine-Check Exception",
wrapper_rust_fnname: machinee_check_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: panic
handler_strategy: panic,
type: exception
);

generate_trap_gate_handler!(name: "SIMD Floating-Point Exception",
Expand All @@ -813,7 +858,8 @@ generate_trap_gate_handler!(name: "SIMD Floating-Point Exception",
wrapper_rust_fnname: simd_floating_point_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "Virtualization Exception",
Expand All @@ -822,7 +868,8 @@ generate_trap_gate_handler!(name: "Virtualization Exception",
wrapper_rust_fnname: virtualization_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: kill
handler_strategy: kill,
type: exception
);

generate_trap_gate_handler!(name: "Security Exception",
Expand All @@ -831,7 +878,8 @@ generate_trap_gate_handler!(name: "Security Exception",
wrapper_rust_fnname: security_exception_rust_wrapper,
kernel_fault_strategy: panic,
user_fault_strategy: panic,
handler_strategy: panic
handler_strategy: panic,
type: exception
);

generate_trap_gate_handler!(name: "Syscall Interrupt",
Expand All @@ -841,7 +889,7 @@ generate_trap_gate_handler!(name: "Syscall Interrupt",
kernel_fault_strategy: panic, // you aren't expected to syscall from the kernel
user_fault_strategy: ignore, // don't worry it's fine ;)
handler_strategy: syscall_interrupt_dispatcher,
interrupts_disabled: false
type: syscall
);

impl UserspaceHardwareContext {
Expand Down Expand Up @@ -1055,7 +1103,8 @@ macro_rules! irq_handler {
wrapper_rust_fnname: $rust_wrapper_name,
kernel_fault_strategy: ignore, // irqs can happen while we're in kernel mode, don't worry, it's fine ;)
user_fault_strategy: ignore, // don't worry it's fine ;)
handler_strategy: $handler_name
handler_strategy: $handler_name,
type: interrupt
);
)*

Expand Down

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