Kernel - Signals partially implimented

[tpg/acess2.git] / KernelLand / Kernel / arch / x86 / proc.asm

diff --git a/KernelLand/Kernel/arch/x86/proc.asm b/KernelLand/Kernel/arch/x86/proc.asm
index 8da7971..dcafc5f 100644 (file)
--- a/KernelLand/Kernel/arch/x86/proc.asm
+++ b/KernelLand/Kernel/arch/x86/proc.asm
@@ -215,9 +215,9 @@ scheduler_return:   ; Used by some hackery in Proc_DumpThreadCPUState
        
        mov al, 0x20
        out 0x20, al            ; ACK IRQ
+
        %if USE_MP
        jmp .ret
-       
 .sendEOI:
        mov eax, DWORD [gpMP_LocalAPIC]
        mov DWORD [eax+0x0B0], 0
@@ -225,15 +225,60 @@ scheduler_return: ; Used by some hackery in Proc_DumpThreadCPUState
 .ret:
        pop eax ; Debug Register 0, Current Thread
        mov dr0, eax
+       
+       jmp ReturnFromInterrupt
 
+;
+; Returns after an interrupt, restoring the user state
+; - Also handles signal handlers
+;
+[global ReturnFromInterrupt]
+[extern Threads_GetPendingSignal]
+[extern Threads_GetSignalHandler]
+[extern Proc_CallUser]
+ReturnFromInterrupt:
+       ; Check that we're returning to userland
+       test DWORD [esp+(4+8+2+1)*4], 0x07
+       jz .ret ; Kernel interrupted, return
+
+       call Threads_GetPendingSignal
+       ; eax: signal number
+       test eax, eax
+       jz .ret
+       
+       ; There's a signal pending, funtime
+       push eax
+       call Threads_GetSignalHandler
+       ; eax: signal handler
+       pop ecx
+       test eax, eax
+       jz .ret
+       cmp eax, -1
+       jz .default
+       
+       ; (some stack abuse)
+       push User_RestoreState
+       push ecx
+       mov ecx, esp
+       
+       push (2+4+8+2+2)*4      ; Up to and incl. CS
+       push ecx        ; User stack data base
+       push DWORD [ecx+(2+4+8+2+3)*4]  ; User SP
+       push eax        ; handler
+       call Proc_CallUser
+       ; Oh, ... it failed. Default time?
+       add esp, (4+2)*4
+.default:
+       
+
+       ; Fall through to return
+.ret:
        pop gs
        pop fs
        pop es
        pop ds
-       
        popa
-       add esp, 4*2    ; CPU ID + Dummy error code
-       ; No Error code / int num
+       add esp, 2*4    ; IRQ Num / CPU ID + error code
        iret
 
 [extern Proc_Clone]
@@ -286,52 +331,17 @@ Proc_ReturnToUser:
        ; Good thing this can only be called on a user fault.
        ;
        
-       ; Validate user ESP
-       ; - Page Table
-       mov edx, [eax+KSTACK_USERSTATE_SIZE-12] ; User ESP is at top of kstack - 3*4
-       mov ecx, edx
-       shr ecx, 22
-       test BYTE [0xFC3F0000+ecx*4], 1
-       jnz .justKillIt
-       ; - Page
-       mov ecx, edx
-       shr ecx, 12
-       test BYTE [0xFC000000+ecx*4], 1
-       jnz .justKillIt
-       ; Adjust
-       sub edx, 8
-       ; - Page Table
-       mov ecx, edx
-       shr ecx, 22
-       test BYTE [0xFC3F0000+ecx*4], 1
-       jnz .justKillIt
-       ; - Page
-       mov ecx, edx
-       shr ecx, 12
-       test BYTE [0xFC000000+ecx*4], 1
-       jnz .justKillIt
-       
-       ; Get and alter User SP
-       mov edi, edx
-       mov edx, [ebp+12]       ; Get parameter
-       mov [edi+4], edx        ; save to user stack
-       mov [edi], DWORD User_Syscall_RetAndExit        ; Return Address
-       
-       ; Restore Segment Registers
-       mov ax, 0x23
-       mov ds, ax
-       mov es, ax
-       mov fs, ax
-       mov gs, ax
-       
-       push 0x23       ; SS
-       push edi        ; ESP
-       push 0x202      ; EFLAGS (IP and Rsvd)
-       push 0x1B       ; CS
-       mov eax, [ebp+8]        ; Method to call
-       push eax        ; EIP
-       
-       iret
+       ; Create data to add to user stack
+       push DWORD [ebp+12]
+       push User_Syscall_RetAndExit
+       mov ecx, esp
+
+       ; Call user method      
+       push 2*4
+       push ecx
+       push DWORD [eax+KSTACK_USERSTATE_SIZE-12]       ; User ESP is at top of kstack - 3*4
+       push DWORD [ebp+8]
+       call Proc_CallUser      
        
        ; Just kill the bleeding thing
        ; (I know it calls int 0xAC in kernel mode, but meh)
@@ -363,6 +373,16 @@ User_Syscall:
        xchg bx, bx     ; MAGIC BREAKPOINT
        int 0xAC
 
+User_RestoreState:
+       pop gs
+       pop fs
+       pop es
+       pop ds
+       popa
+       add esp, 2*4    ; Kernel's error code and interrupt number
+       retf    ; EFLAGS/SS/ESP were not included in the state
+       
+
 ; A place to return to and exit
 User_Syscall_RetAndExit:
        push eax