Kernel/x86_64 - Implemented COW, fixed PMM bugs

[tpg/acess2.git] / Kernel / arch / x86_64 / start64.asm

diff --git a/Kernel/arch/x86_64/start64.asm b/Kernel/arch/x86_64/start64.asm
index 5027a1e..b63b63a 100644 (file)
--- a/Kernel/arch/x86_64/start64.asm
+++ b/Kernel/arch/x86_64/start64.asm
@@ -1,6 +1,7 @@
 ;
 ; Acess2 x86_64 Port
 ;
+%include "arch/x86_64/include/common.inc.asm"
 [bits 64]
 ;KERNEL_BASE   equ     0xFFFF800000000000
 KERNEL_BASE    equ     0xFFFFFFFF80000000
@@ -35,7 +36,7 @@ start64:
        rep stosq
        
        ; Set kernel stack
-       mov rsp, 0xFFFFA00000000000 + 0x10000
+       mov rsp, 0xFFFFA00000000000 + INITIAL_KSTACK_SIZE*0x1000
        
        ; Call main
        mov edi, [gMultibootMagic - KERNEL_BASE]
@@ -55,45 +56,35 @@ GetCPUNum:
        shr ax, 4       ; One 16-byte TSS per CPU
        ret
 
-KSTACK_USERSTATE_SIZE  equ     (16+1+5)*8      ; GPRegs, CPU, IRET
+KSTACK_USERSTATE_SIZE  equ     (5+2+16+2)*8    ; IRET, ErrorNum, ErrorCode, GPRs, FS&GS
 [global Proc_ReturnToUser]
-[extern Proc_GetCurThread]
 Proc_ReturnToUser:
-       ; RBP is the handler to use
-       
-       call Proc_GetCurThread
-       
-       ; EAX is the current thread
-       mov rbx, rax
-       mov rax, [rbx+40]       ; Get Kernel Stack
-       sub rax, KSTACK_USERSTATE_SIZE
+       ; RDI - Handler
+       ; RSI - Kernel Stack
+       ; RDX - Signal num
        
        ;
        ; NOTE: This can cause corruption if the signal happens while the user
        ;       has called a kernel operation.
        ; Good thing this can only be called on a user fault.
        ;
-       
+
+       xchg bx, bx     
        ; Get and alter User SP
-       mov rcx, [rax+KSTACK_USERSTATE_SIZE-3*8]
-       mov rdx, [rbx+60]       ; Get Signal Number
-       mov [rcx-8], rdx
-       mov rax, User_Syscall_RetAndExit
+       mov rcx, [rsi-0x20]     ; Get user SP
+       xor eax, eax
        mov [rcx-16], rax
        sub rcx, 16
        
-       ; Restore Segment Registers
-       mov ax, 0x23
-       mov ds, ax
-       mov es, ax
-       
-       push 0x23       ; SS
-       push rcx        ; RSP
-       push 0x202      ; RFLAGS (IF and Rsvd)
-       push 0x1B       ; CS
-       push rbp        ; RIP
+       ; Drop down to user mode
+       cli
+       mov rsp, rcx    ; Set SP
+       mov rcx, rdi    ; SYSRET IP
        
-       iret
+       mov rdi, rdx    ; Argument for handler
+       mov r11, 0x202  ; RFlags
+       db 0x48
+       sysret
 
 ; int CallWithArgArray(void *Ptr, int NArgs, Uint *Args)
 ; Call a function passing the array as arguments
@@ -152,12 +143,4 @@ CallWithArgArray:
        pop rbp
        ret
 
-[section .usertext]
-User_Syscall_RetAndExit:
-       mov rdi, rax
-       jmp User_Syscall_Exit
-User_Syscall_Exit:
-       xor rax, rax
-       ; RDI: Return Value
-       int 0xAC
-
+; vim: ft=nasm