Re: [ros-kernel] Problems with the last changes (mdl.c..)

[David W. <we...@cw...>]

On Tue, May 21, 2002 at 09:58:22PM +0200, Hartmut Birr wrote:
> This means, at each position where KeAttacheProcess is called, there must 
> be disable all thread switching.
>
I don't think that is possible since a KeAttachProcess'ed thread can 
access user space, in fact this is its main use.
 
> The patch solves my problem. But there exist two other problems. The patch 
> does not check if the stack is in kernel or in user space and there exist a 
> problem if the stack is located over a 4MB boundary. I think the real 
> problem is, that the mapping for the stack is created within the wrong 
> proccess context. My second patch solve this problem, but it must disable a 
> warning for bad mappings.
> 
I don't think there are any circumstances where a thread's kernel stack
could be in user-space however the 4MB boundary problem needs solving. 
I've attached a new more complete patch:

Index: ntoskrnl/include/internal/ps.h
===================================================================
RCS file: /CVS/ReactOS/reactos/ntoskrnl/include/internal/ps.h,v
retrieving revision 1.33
diff -u -r1.33 ps.h
--- ntoskrnl/include/internal/ps.h	14 May 2002 21:19:17 -0000	1.33
+++ ntoskrnl/include/internal/ps.h	22 May 2002 22:35:22 -0000
@@ -32,6 +32,7 @@
  * Defines for accessing KPCR and KTHREAD structure members
  */
 #define KTHREAD_INITIAL_STACK     0x18
+#define KTHREAD_STACK_LIMIT       0x1C
 #define KTHREAD_TEB               0x20
 #define KTHREAD_KERNEL_STACK      0x28
 #define KTHREAD_PREVIOUS_MODE     0x137
Index: ntoskrnl/ke/i386/tskswitch.S
===================================================================
RCS file: /CVS/ReactOS/reactos/ntoskrnl/ke/i386/tskswitch.S,v
retrieving revision 1.9
diff -u -r1.9 tskswitch.S
--- ntoskrnl/ke/i386/tskswitch.S	15 Jan 2002 02:51:32 -0000	1.9
+++ ntoskrnl/ke/i386/tskswitch.S	22 May 2002 22:35:25 -0000
@@ -29,9 +29,10 @@
 #include <internal/i386/segment.h>
 #include <internal/ps.h>
 #include <ddk/i386/tss.h>
-			
+#include <internal/ntoskrnl.h>
+		
 /* FUNCTIONS ****************************************************************/
-
+	
 .globl _Ki386ContextSwitch
 _Ki386ContextSwitch:
 /* 
@@ -97,6 +98,7 @@
 	movl	%esp, KTHREAD_KERNEL_STACK(%ebx)	
 	movl	8(%ebp), %ebx
 	movl	KTHREAD_KERNEL_STACK(%ebx), %esp
+	movl	KTHREAD_STACK_LIMIT(%ebx), %edi
 
 	/*
 	 * Set the stack pointer in this processors TSS
@@ -110,8 +112,25 @@
 	 */
 	movl	ETHREAD_THREADS_PROCESS(%ebx), %ebx
 	movl	KPROCESS_DIRECTORY_TABLE_BASE(%ebx), %eax
-	movl	%eax, %cr3 
+	movl	%eax, %cr3
 
+	/*
+	 * Set up the PDE for the top of the new stack.
+	 */
+	movl	$0, %ebx
+.L2:	movl	%edi, %esi
+	shr	$22, %esi
+	movl	0xF03C0000(,%esi, 4), %eax
+	cmpl	$0, %eax
+	jne	.L1
+	movl	_MmGlobalKernelPageDirectory(,%esi, 4), %eax
+	movl	%eax, 0xF03C0000(,%esi, 4)
+.L1:
+	addl	$4096, %edi
+	incl	%ebx
+	cmp	$(MM_STACK_SIZE / 4096), %ebx
+	jl	.L2
+		
 	/*
 	 * FIXME: Restore floating point state
 	 */