/*
 * Copyright 2002-2005, Axel Dörfler, axeld@pinc-software.de.
 * Distributed 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_KERNEL_H
#define _KERNEL_KERNEL_H


#include <config/types.h>

#include <arch_kernel.h>
#include <arch_config.h>


#ifndef KERNEL_LOAD_BASE
#       define KERNEL_LOAD_BASE         KERNEL_BASE
#endif

// macro to check whether an address is in the kernel address space (avoid
// always-true checks)
#if KERNEL_BASE == 0
#       define IS_KERNEL_ADDRESS(x)             ((addr_t)(x) <= KERNEL_TOP)
#elif KERNEL_TOP == __HAIKU_ADDR_MAX
#       define IS_KERNEL_ADDRESS(x)             ((addr_t)(x) >= KERNEL_BASE)
#else
#       define IS_KERNEL_ADDRESS(x) \
                ((addr_t)(x) >= KERNEL_BASE && (addr_t)(x) <= KERNEL_TOP)
#endif

#ifndef _BOOT_MODE

// Buffers passed in from user-space shouldn't point into the kernel.
#if USER_BASE == 0
#       define IS_USER_ADDRESS(x)               ((addr_t)(x) <= USER_TOP)
#elif USER_TOP == __HAIKU_ADDR_MAX
#       define IS_USER_ADDRESS(x)               ((addr_t)(x) >= USER_BASE)
#else
#       define IS_USER_ADDRESS(x) \
                ((addr_t)(x) >= USER_BASE && (addr_t)(x) <= USER_TOP)
#endif

#ifdef __cplusplus
// Validate that an address range is fully in userspace.
static inline bool
is_user_address_range(const void* addr, size_t size)
{
        addr_t address = (addr_t)addr;

        // Check for overflows on all addresses.
        if ((address + size) < address)
                return false;

        // Validate that both the start and end address are in userspace
        return IS_USER_ADDRESS(address) && IS_USER_ADDRESS(address + size - 1);
}
#endif

#endif // !_BOOT_MODE

#define DEBUG_KERNEL_STACKS
        // Note, debugging kernel stacks doesn't really work yet. Since the
        // interrupt will also try to use the stack on a page fault, all
        // you get is a double fault.
        // At least, you then know that the stack overflows in this case :)

/** Size of the kernel stack */
#ifdef B_HAIKU_64_BIT
        #define KERNEL_STACK_SIZE               (B_PAGE_SIZE * 4)       // 16 kB
#else
        #define KERNEL_STACK_SIZE               (B_PAGE_SIZE * 3)       // 12 kB
#endif

#ifdef DEBUG_KERNEL_STACKS
#       define KERNEL_STACK_GUARD_PAGES 1
#else
#       define KERNEL_STACK_GUARD_PAGES 0
#endif

/** Size of the environmental variables space for a process */
#define ENV_SIZE        (B_PAGE_SIZE * 8)


#define ROUNDDOWN(a, b) (((a) / (b)) * (b))
#define ROUNDUP(a, b)   ROUNDDOWN((a) + (b) - 1, b)
#define HOWMANY(a, b)   (((a) + ((b) - 1)) / (b))


#define CHECK_BIT(a, b) ((a) & (1 << (b)))
#define SET_BIT(a, b) ((a) | (1 << (b)))
#define CLEAR_BIT(a, b) ((a) & (~(1 << (b))))
#define GET_BIT(a, b) ((a & b) != 0)
#define TOGGLE_BIT(a, b) (a ^= b)


/* during kernel startup, interrupts are disabled (among other things) */
extern bool gKernelStartup;
extern bool gKernelShutdown;


#ifdef __cplusplus
extern "C" {
#endif

status_t system_shutdown(bool reboot);
status_t _user_shutdown(bool reboot);

#ifdef __cplusplus
}
#endif

#endif  /* _KERNEL_KERNEL_H */