#ifndef _ASM_M32R_UACCESS_H
#define _ASM_M32R_UACCESS_H

/*
 *  linux/include/asm-m32r/uaccess.h
 *
 *  M32R version.
 *    Copyright (C) 2004, 2006  Hirokazu Takata <takata at linux-m32r.org>
 */

/*
 * User space memory access functions
 */
#include <linux/errno.h>
#include <linux/thread_info.h>
#include <asm/page.h>
#include <asm/setup.h>

#define VERIFY_READ 0
#define VERIFY_WRITE 1

/*
 * The fs value determines whether argument validity checking should be
 * performed or not.  If get_fs() == USER_DS, checking is performed, with
 * get_fs() == KERNEL_DS, checking is bypassed.
 *
 * For historical reasons, these macros are grossly misnamed.
 */

#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })

#ifdef CONFIG_MMU

#define KERNEL_DS	MAKE_MM_SEG(0xFFFFFFFF)
#define USER_DS		MAKE_MM_SEG(PAGE_OFFSET)
#define get_ds()	(KERNEL_DS)
#define get_fs()	(current_thread_info()->addr_limit)
#define set_fs(x)	(current_thread_info()->addr_limit = (x))

#else /* not CONFIG_MMU */

#define KERNEL_DS	MAKE_MM_SEG(0xFFFFFFFF)
#define USER_DS		MAKE_MM_SEG(0xFFFFFFFF)
#define get_ds()	(KERNEL_DS)

static inline mm_segment_t get_fs(void)
{
	return USER_DS;
}

static inline void set_fs(mm_segment_t s)
{
}

#endif /* not CONFIG_MMU */

#define segment_eq(a,b)	((a).seg == (b).seg)

#define __addr_ok(addr) \
	((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))

/*
 * Test whether a block of memory is a valid user space address.
 * Returns 0 if the range is valid, nonzero otherwise.
 *
 * This is equivalent to the following test:
 * (u33)addr + (u33)size >= (u33)current->addr_limit.seg
 *
 * This needs 33-bit arithmetic. We have a carry...
 */
#define __range_ok(addr,size) ({					\
	unsigned long flag, roksum; 					\
	__chk_user_ptr(addr);						\
	asm ( 								\
		"	cmpu	%1, %1    ; clear cbit\n"		\
		"	addx	%1, %3    ; set cbit if overflow\n"	\
		"	subx	%0, %0\n"				\
		"	cmpu	%4, %1\n"				\
		"	subx	%0, %5\n"				\
		: "=&r" (flag), "=r" (roksum)				\
		: "1" (addr), "r" ((int)(size)), 			\
		  "r" (current_thread_info()->addr_limit.seg), "r" (0)	\
		: "cbit" );						\
	flag; })

/**
 * access_ok: - Checks if a user space pointer is valid
 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
 *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
 *        to write to a block, it is always safe to read from it.
 * @addr: User space pointer to start of block to check
 * @size: Size of block to check
 *
 * Context: User context only.  This function may sleep.
 *
 * Checks if a pointer to a block of memory in user space is valid.
 *
 * Returns true (nonzero) if the memory block may be valid, false (zero)
 * if it is definitely invalid.
 *
 * Note that, depending on architecture, this function probably just
 * checks that the pointer is in the user space range - after calling
 * this function, memory access functions may still return -EFAULT.
 */
#ifdef CONFIG_MMU
#define access_ok(type,addr,size) (likely(__range_ok(addr,size) == 0))
#else
static inline int access_ok(int type, const void *addr, unsigned long size)
{
	unsigned long val = (unsigned long)addr;

	return ((val >= memory_start) && ((val + size) < memory_end));
}
#endif /* CONFIG_MMU */

/*
 * The exception table consists of pairs of addresses: the first is the
 * address of an instruction that is allowed to fault, and the second is
 * the address at which the program should continue.  No registers are
 * modified, so it is entirely up to the continuation code to figure out
 * what to do.
 *
 * All the routines below use bits of fixup code that are out of line
 * with the main instruction path.  This means when everything is well,
 * we don't even have to jump over them.  Further, they do not intrude
 * on our cache or tlb entries.
 */

struct exception_table_entry
{
	unsigned long insn, fixup;
};

extern int fixup_exception(struct pt_regs *regs);

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 *
 * This gets kind of ugly. We want to return _two_ values in "get_user()"
 * and yet we don't want to do any pointers, because that is too much