Excerpt from x86_64 OS kernel interrupt/trap handling

machine.rs

#[naked]
pub unsafe extern "C" fn irq0() {
    asm!{
        "push %rax
        movq $$0, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq1() {
    asm!{
        "push %rax
        movq $$1, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq2() {
    asm!{
        "push %rax
        movq $$2, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq3() {
    asm!{
        "push %rax
        movq $$3, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq4() {
    asm!{
        "push %rax
        movq $$4, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq5() {
    asm!{
        "push %rax
        movq $$5, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq6() {
    asm!{
        "push %rax
        movq $$6, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq7() {
    asm!{
        "push %rax
        movq $$7, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq8() {
    asm!{
        "push %rax
        movq $$8, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq9() {
    asm!{
        "push %rax
        movq $$9, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq10() {
    asm!{
        "push %rax
        movq $$10, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq11() {
    asm!{
        "push %rax
        movq $$11, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq12() {
    asm!{
        "push %rax
        movq $$12, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq13() {
    asm!{
        "push %rax
        movq $$13, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq14() {
    asm!{
        "push %rax
        movq $$14, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[naked]
pub unsafe extern "C" fn irq15() {
    asm!{
        "push %rax
        movq $$15, %rax "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rsp"
        : "volatile"
    };

    irq_common()
}

#[repr(C,packed)]
pub struct IrqContext {
    cr2: u64,
    r15: u64,
    r14: u64,
    r13: u64,
    r12: u64,
    r11: u64,
    r10: u64,
    r9: u64,
    r8: u64,
    rbp: u64,
    rdi: u64,
    rsi: u64,
    rdx: u64,
    rcx: u64,
    rbx: u64,
    rax: u64,
}

#[naked]
#[inline]
unsafe fn irq_common() -> ! {

    let irq: usize;
    let context_ptr: *mut IrqContext;

    // Save all registers
    asm!{
        "
        push %rbx
        push %rcx
        push %rdx
        push %rsi
        push %rdi
        push %rbp
        push %r8
        push %r9
        push %r10
        push %r11
        push %r12
        push %r13
        push %r14
        push %r15
        mov %cr2, %rbp
        push %rbp
        mov %rsp, $0
        mov %rax, $1
        "
        : "=r"(context_ptr), "=r"(irq)
        : /* No inputs */
        : "rbp"
        : "volatile"
    };

    // Handle interrupt
    pic_irq(irq, &mut *context_ptr);

    // Pop arguments and iretq
    asm!{
        "
        pop %rbp
        mov %rbp, %cr2
        pop %r15
        pop %r14
        pop %r13
        pop %r12
        pop %r11
        pop %r10
        pop %r9
        pop %r8
        pop %rbp
        pop %rdi
        pop %rsi
        pop %rdx
        pop %rcx
        pop %rbx
        pop %rax
        iretq
        "
        : /* No outputs */
        : /* No inputs */
        : "rax", "rbx", "rcx", "rdx", "rsi", "rdi", "rbp", "rsp", "r8",
          "r9", "r10", "r11", "r12", "r13", "r14", "r15"
        : "volatile"
    };

    panic!("Should never get here!");
}

#[naked]
pub unsafe extern "C" fn page_fault_handler() {
    use memory::handle_page_fault;

    let fault_addr: usize;

    asm!{
        "
        push %rax
        push %rbx
        push %rcx
        push %rdx
        push %rsi
        push %rdi
        push %rbp
        push %r8
        push %r9
        push %r10
        push %r11
        push %r12
        push %r13
        push %r14
        push %r15

        mov %cr2, $0   /* address */
        "
        : "=r"(fault_addr)
        : /* No inputs */
        : "rsp"
        : "volatile"
    };

    handle_page_fault(fault_addr);

    asm!{
        "
        pop %r15
        pop %r14
        pop %r13
        pop %r12
        pop %r11
        pop %r10
        pop %r9
        pop %r8
        pop %rbp
        pop %rdi
        pop %rsi
        pop %rdx
        pop %rcx
        pop %rbx
        pop %rax
        add $$8,%rsp   /* pop error */
        iret
        "
    };
}