headers/private/kernel/arch/sh4/kernel.h

   1 /*
   2 ** Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
   3 ** Distributed under the terms of the NewOS License.
   4 */
   5 #ifndef _NEWOS_KERNEL_ARCH_SH4_KERNEL_H
   6 #define _NEWOS_KERNEL_ARCH_SH4_KERNEL_H
   7
   8 #include <arch/sh4/sh4.h>
   9
  10 // memory layout
  11 #define KERNEL_BASE P3_AREA
  12 #define KERNEL_SIZE P3_AREA_LEN
  13 #define KERNEL_TOP  (KERNEL_BASE + (KERNEL_SIZE - 1))
  14
  15 /*
  16 ** User space layout is a little special:
  17 ** The user space does not completely cover the space not covered by the kernel.
  18 ** This is accomplished by starting user space at 1Mb and running to 64kb short of kernel space.
  19 ** The lower 1Mb reserved spot makes it easy to find null pointer references and guarantees a
  20 ** region wont be placed there. The 64kb region assures a user space thread cannot pass
  21 ** a buffer into the kernel as part of a syscall that would cross into kernel space.
  22 */
  23 #define USER_BASE   (U0_AREA + 0x100000)
  24 #define USER_SIZE   (U0_AREA_LEN - (0x10000 + 0x100000))
  25 #define USER_TOP    (USER_BASE + USER_SIZE)
  26
  27 #define USER_STACK_REGION (USER_BASE + USER_SIZE - USER_STACK_REGION_SIZE)
  28 #define USER_STACK_REGION_SIZE 0x10000000
  29
  30 #endif