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DO_SYSCALL(class::method, &classInstance);
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[GLOBAL fastSyscall]
fastSyscall:
mov ecx, ebp ; Current stack frame start.
mov ebx, ebp ; ebx = stack frame size
sub ebx, esp ; = (ebp-esp)
mov eax, .syscall_end ; eax = EIP to return to.
sysenter ; Make syscall.
.syscall_end:
ret
; Takes one argument - esp0 - the start (upper limit) of the kernel stack.
[GLOBAL fastSysexit]
fastSysexit:
mov esp, [esp-4] ; Dereference parameter - esp = *(esp0) - go back to the
; beginning of our stack frame and dereference what we
; find, which will be the esp pushed in the handler.
pop ebp ; Return ebp to what it was before we were called.
pop edx ; EDX = EIP return pointer
mov ecx, esp ; Return ESP
jmp $
sysexit
[GLOBAL fastSyscallHandler]
fastSyscallHandler:
push ecx ; Push the old stack pointer on the new stack.
mov esi, 0x20
add ecx, 0x20
.loop: ; copy some of the stack before the stack frame base
mov edx, [ecx] ; to make sure we copy any arguments passed to the
mov [esp], edx ; function.
sub esp, 0x4
sub ecx, 0x4
sub esi, 0x4
jnz .loop
mov ebp, esp ; Set up our new base pointer
mov edx, ebx ; store the frame size.
mov ebx, ebp ; EBX = stack base ptr -stack frame size.
sub ebx, edx ; do the subtraction.
.loop2:
mov edx, [ecx] ; Copy [ecx] to [esp] ( copying stack frame to kernelspace )
mov [esp], edx
sub esp, 0x4 ; Next word, working down the stack.
sub ecx, 0x4 ; Next work, working down the stack.
cmp esp, ebx ; do while esp < frame size + base ptr
jnz .loop2
mov edx, [ecx] ; copy one more.
mov [esp], edx
jmp eax
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class C
{
int a_member_func(int a)
{
START_KERNEL;
bleh
END_KERNEL;
}
}