From: John Hodge <tpg@prelude.mutabah.net>
Date: Fri, 23 Apr 2010 13:24:35 +0000 (+0800)
Subject: Fixes to error handling and User text mappings
X-Git-Tag: rel0.06~222
X-Git-Url: https://git.ucc.asn.au/?a=commitdiff_plain;h=7a6a1cbc62289d64d604fb2cb204d21659c4905e;p=tpg%2Facess2.git

Fixes to error handling and User text mappings
---

diff --git a/Kernel/Makefile.BuildNum b/Kernel/Makefile.BuildNum
index ce0a54c7..6b06f1ca 100644
--- a/Kernel/Makefile.BuildNum
+++ b/Kernel/Makefile.BuildNum
@@ -1 +1 @@
-BUILD_NUM = 2027
+BUILD_NUM = 2035
diff --git a/Kernel/arch/x86/link.ld b/Kernel/arch/x86/link.ld
index 2fe17641..75b712fb 100644
--- a/Kernel/arch/x86/link.ld
+++ b/Kernel/arch/x86/link.ld
@@ -24,6 +24,7 @@ SECTIONS {
 		_UsertextBase = .;
 		*(.usertext)
 	}
+	_UsertextEnd = .;
 	
 	.rodata ALIGN(0x1000): AT(ADDR(.rodata) - 0xC0000000) {
 		*(.initpd)
diff --git a/Kernel/arch/x86/mm_virt.c b/Kernel/arch/x86/mm_virt.c
index f2be750f..f3cd7bb7 100644
--- a/Kernel/arch/x86/mm_virt.c
+++ b/Kernel/arch/x86/mm_virt.c
@@ -66,6 +66,7 @@ typedef Uint32	tTabEnt;
 #endif
 
 // === IMPORTS ===
+extern void	_UsertextEnd, _UsertextBase;
 extern Uint32	gaInitPageDir[1024];
 extern Uint32	gaInitPageTable[1024];
 extern void	Threads_SegFault(tVAddr Addr);
@@ -153,6 +154,12 @@ void MM_InstallVirtual()
 		memset( &gaPageTable[i*1024], 0, 0x1000 );
 	}
 	#endif
+	
+	// Unset kernel on the User Text pages
+	for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
+		Log("MM_SetFlags( 0x%08x, 0, MM_PFLAG_KERNEL)", (tVAddr)&_UsertextBase + i*4096);
+		MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
+	}
 }
 
 /**
@@ -781,15 +788,25 @@ void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 	// Read-Only
 	if( Mask & MM_PFLAG_RO )
 	{
-		if( Flags & MM_PFLAG_RO )	*ent &= ~PF_WRITE;
-		else 	*ent |= PF_WRITE;
+		if( Flags & MM_PFLAG_RO ) {
+			*ent &= ~PF_WRITE;
+		}
+		else {
+			gaPageDir[VAddr >> 22] |= PF_WRITE;
+			*ent |= PF_WRITE;
+		}
 	}
 	
 	// Kernel
 	if( Mask & MM_PFLAG_KERNEL )
 	{
-		if( Flags & MM_PFLAG_KERNEL )	*ent &= ~PF_USER;
-		else	*ent |= PF_USER;
+		if( Flags & MM_PFLAG_KERNEL ) {
+			*ent &= ~PF_USER;
+		}
+		else {
+			gaPageDir[VAddr >> 22] |= PF_USER;
+			*ent |= PF_USER;
+		}
 	}
 	
 	// Copy-On-Write
@@ -804,6 +821,9 @@ void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 			*ent |= PF_WRITE;
 		}
 	}
+	
+	//Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
+	//	*ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 }
 
 /**
diff --git a/Kernel/arch/x86/proc.asm b/Kernel/arch/x86/proc.asm
new file mode 100644
index 00000000..9d752bf1
--- /dev/null
+++ b/Kernel/arch/x86/proc.asm
@@ -0,0 +1,126 @@
+; AcessOS Microkernel Version
+; Start.asm
+
+[bits 32]
+
+KERNEL_BASE	equ 0xC0000000
+
+KSTACK_USERSTATE_SIZE	equ	(4+8+1+5)*4	; SRegs, GPRegs, CPU, IRET
+
+[section .text]
+; --------------
+; Task Scheduler
+; --------------
+[extern Proc_Scheduler]
+[global SchedulerBase]
+SchedulerBase:
+	pusha
+	push ds
+	push es
+	push fs
+	push gs
+	
+	mov ax, 0x10
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+	
+	mov eax, [esp+12*4]	; CPU Number
+	push eax	; Pus as argument
+	
+	call Proc_Scheduler
+	
+	add esp, 4	; Remove Argument
+	
+	pop gs
+	pop fs
+	pop es
+	pop ds
+
+	mov dx, 0x20
+	mov al, 0x20
+	out dx, al		; ACK IRQ
+	popa
+	add esp, 4	; CPU ID
+	; No Error code / int num
+	iret
+
+[extern Proc_Clone]
+[extern Threads_Exit]
+[global SpawnTask]
+SpawnTask:
+	; Call Proc_Clone with Flags=0
+	xor eax, eax
+	push eax
+	push eax
+	call Proc_Clone
+	add esp, 8	; Remove arguments from stack
+	
+	test eax, eax
+	jnz .parent
+	
+	; In child, so now set up stack frame
+	mov ebx, [esp+4]	; Child Function
+	mov edx, [esp+8]	; Argument
+	; Child
+	push edx	; Argument
+	call ebx	; Function
+	call Threads_Exit	; Kill Thread
+	
+.parent:
+	ret
+
+;
+; Calls a user fault handler
+;
+[global Proc_AlterUserReturnAddr]
+[extern Proc_GetCurThread]
+Proc_AlterUserReturnAddr:
+	; EBP is the handler to use
+	
+	call Proc_GetCurThread
+	xchg bx, bx
+	
+	; EAX is the current thread
+	mov ebx, eax
+	mov eax, [ebx+40]	; Get Kernel Stack
+	sub eax, KSTACK_USERSTATE_SIZE	
+	
+	;
+	; NOTE: This can cause corruption if the signal happens while the user
+	;       has called a kernel operation.
+	; Good thing this can only be called on a user fault.
+	;
+	
+	; Get and alter User SP
+	mov ecx, [eax+KSTACK_USERSTATE_SIZE-12]
+	mov edx, [ebx+60]	; Get Signal Number
+	mov [ecx-4], edx
+	mov [ecx-8], DWORD User_Syscall_RetAndExit
+	sub ecx, 8
+	
+	; Restore Segment Registers
+	mov ax, 0x23
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+	
+	push 0x23	; SS
+	push ecx	; ESP
+	push 0x22	; EFLAGS
+	push 0x1B	; CS
+	push ebp	; EIP
+	
+	iret
+
+
+[section .usertext]
+User_Syscall_RetAndExit:
+	push eax
+	call User_Syscall_Exit
+User_Syscall_Exit:
+	xor eax, eax
+	mov ebx, [esp+4]
+	int 0xAC