X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Farch%2Fx86_64%2Fproc.asm;h=90eb3dca0f357a23a1dff0586b2de5fb834b7cca;hb=90311ae923051afa0db6554679e7389d1c95e4f2;hp=664ad21916fb8785748ad9f1649831a2512372e3;hpb=a59083b859599aeee6ab3e4fd6a0113faa5fddf5;p=tpg%2Facess2.git

diff --git a/Kernel/arch/x86_64/proc.asm b/Kernel/arch/x86_64/proc.asm
index 664ad219..90eb3dca 100644
--- a/Kernel/arch/x86_64/proc.asm
+++ b/Kernel/arch/x86_64/proc.asm
@@ -47,6 +47,25 @@ NewTaskHeader:
 .hlt:
 	jmp .hlt
 
+[extern MM_Clone]
+[global Proc_CloneInt]
+Proc_CloneInt:
+	PUSH_GPR
+	; Save RSP
+	mov [rdi], rsp
+	call MM_Clone
+	; Save CR3
+	mov rsi, [rsp+0x30]
+	mov [rsi], rax
+	; Undo the PUSH_GPR
+	add rsp, 0x80
+	mov rax, .newTask
+	ret
+.newTask:
+	POP_GPR
+	xor eax, eax
+	ret
+
 [global SaveState]
 SaveState:
 	; Save regs to RSI
@@ -69,4 +88,38 @@ 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
+