From b1873b4cff47aae8ada8cc303ea01b475cc7ccc8 Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Sat, 7 May 2011 21:20:34 +0800
Subject: [PATCH] Kernel - Instruction tracing support

---
 Kernel/arch/x86/desctab.asm | 20 ++++++++++++++++++--
 Kernel/arch/x86/errors.c    | 12 ++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/Kernel/arch/x86/desctab.asm b/Kernel/arch/x86/desctab.asm
index f6cc14e1..dc064f57 100644
--- a/Kernel/arch/x86/desctab.asm
+++ b/Kernel/arch/x86/desctab.asm
@@ -210,7 +210,7 @@ DEF_SYSCALL	0xAC	; Acess System Call
 [extern SchedulerBase]
 ; AP's Timer Interrupt
 Isr0xEE:
-	push 0
+	push 0	; Line up with interrupt number
 	xchg bx, bx	; MAGIC BREAK
 	jmp SchedulerBase
 ; Spurious Interrupt
@@ -227,7 +227,8 @@ Isr0xEF:
 [extern SchedulerBase]
 [extern SetAPICTimerCount]
 Isr240:
-	push 0
+	push 0	; Line up with Argument in errors
+	push 0	; CPU Number
 	;xchg bx, bx	; MAGIC BREAK
 Isr240.jmp:
 	%if USE_MP
@@ -287,6 +288,18 @@ SyscallCommon:
 	call SyscallHandler
 	add esp, 4
 	
+	; Pass changes to TF on to the user
+	; EFLAGS is stored at ESP[4+8+2+2]
+	; 4 Segment Registers
+	; 8 GPRs
+	; 2 Error Code / Interrupt ID
+	; 2 CS/EIP
+	pushf
+	pop eax
+	and eax, 0x100	; 0x100 = Trace Flag
+	and WORD [esp+(4+8+2+2)*4], ~0x100	; Clear
+	or DWORD [esp+(4+8+2+2)*4], eax	; Set for user
+	
 	pop gs
 	pop fs
 	pop es
@@ -300,6 +313,8 @@ SyscallCommon:
 ; ------------
 [extern IRQ_Handler]
 [global IRQCommon]
+[global IRQCommon_handled]
+IRQCommon_handled equ IRQCommon.handled
 IRQCommon:
 	pusha
 	push ds
@@ -315,6 +330,7 @@ IRQCommon:
 	
 	push esp
 	call IRQ_Handler
+.handled:
 	add esp, 4
 	
 	pop gs
diff --git a/Kernel/arch/x86/errors.c b/Kernel/arch/x86/errors.c
index 1e0278b6..22ad1a39 100644
--- a/Kernel/arch/x86/errors.c
+++ b/Kernel/arch/x86/errors.c
@@ -60,6 +60,18 @@ void ErrorHandler(tRegs *Regs)
 	
 	__asm__ __volatile__ ("cli");
 	
+	// Debug exception (used for single-stepping)
+	if(Regs->int_num == 1)
+	{
+		static Uint32	lastEIP = 0;
+		tThread	*thread = Proc_GetCurThread();
+		if( Regs->eip == lastEIP )
+			return;
+		Log("%p(%i %s) IP=%08x", thread, thread->TID, thread->ThreadName, Regs->eip);
+		lastEIP = Regs->eip;
+		return ;
+	}
+	
 	// Page Fault
 	if(Regs->int_num == 14)
 	{
-- 
2.20.1