Kernel/x86_64 - Unbroke user stack creation

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

diff --git a/Kernel/arch/x86_64/proc.asm b/Kernel/arch/x86_64/proc.asm
index 664ad21..e6db3ce 100644 (file)
--- a/Kernel/arch/x86_64/proc.asm
+++ b/Kernel/arch/x86_64/proc.asm
@@ -47,6 +47,29 @@ NewTaskHeader:
 .hlt:
        jmp .hlt
 
+[extern MM_Clone]
+[extern MM_DumpTables]
+[global Proc_CloneInt]
+Proc_CloneInt:
+       PUSH_GPR
+       ; Save RSP
+       mov [rdi], rsp
+       call MM_Clone
+       ; Save CR3
+       mov rsi, [rsp+0x30]     ; Saved version of RSI
+       mov [rsi], rax
+       ; Undo the PUSH_GPR
+       add rsp, 0x80
+       mov rax, .newTask
+       ret
+.newTask:
+;      mov rdi, 0
+;      mov rsi, 0x800000000000
+;      call MM_DumpTables
+       POP_GPR
+       xor eax, eax
+       ret
+
 [global SaveState]
 SaveState:
        ; Save regs to RSI
@@ -69,4 +92,39 @@ SaveState:
        mov [rsp], rax  ; Restore return address
        xor eax, eax
        ret
+
+[global SwitchTasks]
+; rdi = New RSP
+; rsi = Old RSP save loc
+; rdx = New RIP
+; rcx = Old RIP save loc
+; r8 = CR3
+SwitchTasks:
+       PUSH_GPR
        
+       ; Save state RIP and RSP
+       lea rax, [rel .restore]
+       mov [rcx], rax
+       mov [rsi], rsp
+
+       ; Change CR3 if requested
+       test r8, r8
+       jz .setState
+       mov cr3, r8
+       
+       ; Make sure the stack is valid before jumping
+       invlpg [rdi]
+       invlpg [rdi+0x1000]
+       
+       ; Go to new state
+.setState:
+       mov rsp, rdi
+       jmp rdx
+
+       ; Restore point for saved state
+.restore:
+       POP_GPR
+       xor eax, eax    ; Return zero
+       ret
+
+; vim: ft=nasm