haiku/headers/private/kernel/arch/x86/arch_kernel.h
Axel Dörfler 7cbf8fdd5a First part of the vm86 work by Jan Klötzke:
* Allow userland teams to create areas below 1 MB when requested specifically.
* Note, this is a temporary solution - see the comments in the code.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25358 a95241bf-73f2-0310-859d-f6bbb57e9c96
2008-05-07 21:21:43 +00:00

39 lines
1.4 KiB
C

/*
* Copyright 2004-2008, Haiku Inc. All rights reserved.
* Distributes under the terms of the MIT license.
*
* Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
* Distributed under the terms of the NewOS License.
*/
#ifndef _KERNEL_ARCH_x86_KERNEL_H
#define _KERNEL_ARCH_x86_KERNEL_H
#ifndef _ASSEMBLER
# include <arch/cpu.h>
#endif
// memory layout
#define KERNEL_BASE 0x80000000
#define KERNEL_SIZE 0x80000000
#define KERNEL_TOP (KERNEL_BASE + (KERNEL_SIZE - 1))
/* User space layout is a little special:
* The user space does not completely cover the space not covered by the
* kernel. There is a gap of 64kb between the user and kernel space. The 64kb
* region assures a user space thread cannot pass a buffer into the kernel as
* part of a syscall that would cross into kernel space.
* Furthermore no areas are placed in the lower 1Mb unless the application
* explicitly requests it to find null pointer references.
* TODO: introduce the 1Mb lower barrier again - it's only used for vm86 mode,
* and this should be moved into the kernel (and address space) completely.
*/
#define USER_BASE 0x00
#define USER_BASE_ANY 0x100000
#define USER_SIZE (KERNEL_BASE - 0x10000)
#define USER_TOP (USER_BASE + USER_SIZE)
#define USER_STACK_REGION 0x70000000
#define USER_STACK_REGION_SIZE (USER_TOP - USER_STACK_REGION)
#endif /* _KERNEL_ARCH_x86_KERNEL_H */