From b56cd2207ddd8acebdaca2d9e236869a6498c15b Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Thu, 6 Oct 2011 23:19:03 +0800
Subject: [PATCH] Kernel/x86_64 - Commenting and cleanup

---
 Kernel/arch/x86_64/proc.asm | 11 +++++++++--
 Kernel/arch/x86_64/proc.c   |  8 ++++----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/Kernel/arch/x86_64/proc.asm b/Kernel/arch/x86_64/proc.asm
index 4771e1b9..90eb3dca 100644
--- a/Kernel/arch/x86_64/proc.asm
+++ b/Kernel/arch/x86_64/proc.asm
@@ -98,21 +98,28 @@ SaveState:
 SwitchTasks:
 	PUSH_GPR
 	
+	; Save state RIP and RSP
 	lea rax, [rel .restore]
-	mov QWORD [rcx], rax
+	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
+	xor eax, eax	; Return zero
 	ret
 
diff --git a/Kernel/arch/x86_64/proc.c b/Kernel/arch/x86_64/proc.c
index 6ed99eea..2d07e1ac 100644
--- a/Kernel/arch/x86_64/proc.c
+++ b/Kernel/arch/x86_64/proc.c
@@ -16,7 +16,7 @@
 #include <hal_proc.h>
 
 // === FLAGS ===
-#define DEBUG_TRACE_SWITCH	1
+#define DEBUG_TRACE_SWITCH	0
 #define BREAK_ON_SWITCH 	0	// Break into bochs debugger on a task switch
 
 // === CONSTANTS ===
@@ -457,7 +457,7 @@ int Proc_NewKThread(void (*Fcn)(void*), void *Data)
 	
 	newThread->SavedState.RSP = rsp;
 	newThread->SavedState.RIP = (Uint)&NewTaskHeader;
-	Log("New (KThread) %p, rsp = %p\n", newThread->SavedState.RIP, newThread->SavedState.RSP);
+//	Log("New (KThread) %p, rsp = %p\n", newThread->SavedState.RIP, newThread->SavedState.RSP);
 	
 //	MAGIC_BREAK();	
 	Threads_AddActive(newThread);
@@ -495,7 +495,7 @@ int Proc_Clone(Uint Flags)
 	newThread->SavedState.RIP = rip;
 
 	// DEBUG	
-	Log("New (Clone) %p, rsp = %p, cr3 = %p", rip, newThread->SavedState.RSP, newThread->MemState.CR3);
+//	Log("New (Clone) %p, rsp = %p, cr3 = %p", rip, newThread->SavedState.RSP, newThread->MemState.CR3);
 	{
 		Uint cr3;
 		__asm__ __volatile__ ("mov %%cr3, %0" : "=r" (cr3));
@@ -543,7 +543,7 @@ int Proc_SpawnWorker(void (*Fcn)(void*), void *Data)
 	new->SavedState.RSP = new->KernelStack - sizeof(stack_contents);
 	new->SavedState.RIP = (Uint)&NewTaskHeader;
 	
-	Log("New (Worker) %p, rsp = %p\n", new->SavedState.RIP, new->SavedState.RSP);
+//	Log("New (Worker) %p, rsp = %p\n", new->SavedState.RIP, new->SavedState.RSP);
 	
 	// Mark as active
 	new->Status = THREAD_STAT_PREINIT;
-- 
2.20.1