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Returning from Exceptions: Take stack_frame as reference

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Philipp Oppermann
2016-10-30 18:44:49 +01:00
parent e129da8cc2
commit 67857bde2f
1 changed files with 14 additions and 14 deletions
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28
blog/post/11-returning-from-exceptions.md
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@@ -40,7 +40,7 @@ Let's start by defining a handler function for the breakpoint exception:
```rust ```rust
// in src/interrupts/mod.rs // in src/interrupts/mod.rs
extern "C" fn breakpoint_handler(stack_frame: *const ExceptionStackFrame) -> ! extern "C" fn breakpoint_handler(stack_frame: &ExceptionStackFrame) -> !
{ {
let stack_frame = unsafe { &*stack_frame }; let stack_frame = unsafe { &*stack_frame };
println!("\nEXCEPTION: BREAKPOINT at {:#x}\n{:#?}", println!("\nEXCEPTION: BREAKPOINT at {:#x}\n{:#?}",
@@ -157,7 +157,7 @@ macro_rules! handler {
sub rsp, 8 // align the stack pointer sub rsp, 8 // align the stack pointer
call $0" call $0"
:: "i"($name as extern "C" fn( :: "i"($name as extern "C" fn(
*const ExceptionStackFrame)) // no longer diverging &ExceptionStackFrame)) // no longer diverging
: "rdi" : "intel", "volatile"); : "rdi" : "intel", "volatile");
// new // new
@@ -180,16 +180,16 @@ We've changed the handler function type, so we need to adjust our existing excep
// in src/interrupts/mod.rs // in src/interrupts/mod.rs
extern "C" fn divide_by_zero_handler( extern "C" fn divide_by_zero_handler(
- stack_frame: *const ExceptionStackFrame) -> ! {...} - stack_frame: &ExceptionStackFrame) -> ! {...}
+ stack_frame: *const ExceptionStackFrame) {...} + stack_frame: &ExceptionStackFrame) {...}
extern "C" fn invalid_opcode_handler( extern "C" fn invalid_opcode_handler(
- stack_frame: *const ExceptionStackFrame) -> ! {...} - stack_frame: &ExceptionStackFrame) -> ! {...}
+ stack_frame: *const ExceptionStackFrame) {...} + stack_frame: &ExceptionStackFrame) {...}
extern "C" fn breakpoint_handler( extern "C" fn breakpoint_handler(
- stack_frame: *const ExceptionStackFrame) -> ! { - stack_frame: &ExceptionStackFrame) -> ! {
+ stack_frame: *const ExceptionStackFrame) { + stack_frame: &ExceptionStackFrame) {
println!(...); println!(...);
- loop {} - loop {}
} }
@@ -386,7 +386,7 @@ macro_rules! handler {
// sub rsp, 8 (stack is aligned already) // sub rsp, 8 (stack is aligned already)
call $0" call $0"
:: "i"($name as :: "i"($name as
extern "C" fn(*const ExceptionStackFrame)) extern "C" fn(&ExceptionStackFrame))
: "rdi" : "intel", "volatile"); : "rdi" : "intel", "volatile");
restore_scratch_registers!(); restore_scratch_registers!();
@@ -742,7 +742,7 @@ macro_rules! handler_with_error_code {
sub rsp, 8 // align the stack pointer sub rsp, 8 // align the stack pointer
call $0" call $0"
:: "i"($name as extern "C" fn( :: "i"($name as extern "C" fn(
*const ExceptionStackFrame, u64)) &ExceptionStackFrame, u64))
: "rdi","rsi" : "intel"); : "rdi","rsi" : "intel");
asm!("iretq" :::: "intel", "volatile"); asm!("iretq" :::: "intel", "volatile");
::core::intrinsics::unreachable(); ::core::intrinsics::unreachable();
@@ -760,7 +760,7 @@ Now we can make our `page_fault_handler` non-diverging:
```diff ```diff
// in src/interrupts/mod.rs // in src/interrupts/mod.rs
extern "C" fn page_fault_handler(stack_frame: *const ExceptionStackFrame, extern "C" fn page_fault_handler(stack_frame: &ExceptionStackFrame,
- error_code: u64) -> ! { ... } - error_code: u64) -> ! { ... }
+ error_code: u64) { ... } + error_code: u64) { ... }
``` ```
@@ -783,7 +783,7 @@ macro_rules! handler_with_error_code {
call $0 call $0
add rsp, 8 // undo stack pointer alignment add rsp, 8 // undo stack pointer alignment
" :: "i"($name as extern "C" fn( " :: "i"($name as extern "C" fn(
*const ExceptionStackFrame, u64)) &ExceptionStackFrame, u64))
: "rdi","rsi" : "intel"); : "rdi","rsi" : "intel");
restore_scratch_registers!(); restore_scratch_registers!();
asm!("iretq" :::: "intel", "volatile"); asm!("iretq" :::: "intel", "volatile");
@@ -816,7 +816,7 @@ macro_rules! handler_with_error_code {
call $0 call $0
add rsp, 8 // undo stack pointer alignment add rsp, 8 // undo stack pointer alignment
" :: "i"($name as extern "C" fn( " :: "i"($name as extern "C" fn(
*const ExceptionStackFrame, u64)) &ExceptionStackFrame, u64))
: "rdi","rsi" : "intel"); : "rdi","rsi" : "intel");
restore_scratch_registers!(); restore_scratch_registers!();
asm!("add rsp, 8 // pop error code asm!("add rsp, 8 // pop error code
@@ -872,7 +872,7 @@ Therefore we update our `page_fault_handler`:
{{< highlight rust "hl_lines=10 11 12 13 14 15 16" >}} {{< highlight rust "hl_lines=10 11 12 13 14 15 16" >}}
// in src/interrupts/mod.rs // in src/interrupts/mod.rs
extern "C" fn page_fault_handler(stack_frame: *const ExceptionStackFrame, extern "C" fn page_fault_handler(stack_frame: &ExceptionStackFrame,
error_code: u64) error_code: u64)
{ {
use x86::controlregs; use x86::controlregs;