TempleOSTS_130315.ISO

TempleOS/Demo/Lectures/Ring3.CPP

@@ -0,0 +1,83 @@
+/*
+TempleOS runs exclusively in ring 0.
+Ring 0 is part of the $LK,"Charter","FI:::/TempleOS/Doc/Charter.TXT"$.
+This demo is for you to play around
+with ring 3.  TempleOS is for
+recreational programming, after all.
+
+This redirects the general protection
+fault, switches to ring 3, and generates
+a fault to switch back.
+*/
+
+U8 *old_stk,*new_rip;
+
+asm {
+	IMPORT	SYS_PROGRESS1,old_stk,new_rip;
+TO_RING0::	//Set to handle general protection 0xD fault temporarily.
+	INC	U64 [SYS_PROGRESS1]
+	PUSH	U32 GDT_ZERO_DS_SEL	//STKSEG
+	MOV	RAX,U64 [&old_stk]
+	PUSH	RAX
+	PUSH	U32 0		//FLAGS--interrupts off
+	PUSH	U32 GDT_CS64_SEL
+	MOV	RAX,U64 [&new_rip]
+	PUSH	RAX
+	IRET
+}
+
+
+
+U0 Ring3Demo()
+{
+  U8 *old_pf;
+  "Progress1 Before:%X\n",progress1;
+  Cli;
+  old_pf=IntEntrySet(0x0D,TO_RING0,IDTET_TRAP,0);
+
+  TSSBusy(Gs->tss->tr_ring3,OFF);
+  SetRAX(Gs->tss->tr_ring3+3);
+asm {	LTR	AX}
+
+
+asm {
+	IMPORT	SYS_PROGRESS1,old_stk,new_rip;
+
+	MOV	U64 [&old_stk],RSP
+
+	LEA	RAX,[R3_CALLBACK]
+	MOV	U64 [&new_rip],RAX
+	
+	MOV	AX,GDT_ZERO_DS_RING3_SEL+3
+	MOV	DS,AX
+	MOV	ES,AX
+
+	PUSH	U32 GDT_ZERO_DS_RING3_SEL+3	//STKSEG
+	PUSH	U64 [&old_stk]
+	PUSH	U32 0		//FLAGS--interrupts off
+	PUSH	U32 GDT_CS64_RING3_SEL+3
+	LEA	RAX,[R3_START]
+	PUSH	RAX
+	IRET
+
+R3_START:
+	INC	U64 [SYS_PROGRESS1]
+	CLI	//This causes general protection fault #13
+
+R3_CALLBACK:
+	MOV	AX,GDT_ZERO_DS_SEL
+	MOV	DS,AX
+	MOV	ES,AX
+  }
+
+  TSSBusy(Gs->tss->tr,OFF);
+  SetRAX(Gs->tss->tr);
+asm {	LTR	AX}
+
+  IntEntrySet(0x0D,old_pf,IDTET_IRQ,0);
+  Sti;
+  "Progress1 After :%X\n",progress1;
+}
+
+
+Ring3Demo;