/*
 *  arch/arm/include/asm/uaccess.h
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#ifndef _ASMARM_UACCESS_H
#define _ASMARM_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/string.h>
#include <linux/thread_info.h>
#include <asm/errno.h>
#include <asm/memory.h>
#include <asm/domain.h>
#include <asm/unified.h>
#include <asm/compiler.h>

#define VERIFY_READ 0
#define VERIFY_WRITE 1

/*
 * 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 two are intentionally not defined anywhere - if the kernel
 * code generates any references to them, that's a bug.
 */
extern int __get_user_bad(void);
extern int __put_user_bad(void);

/*
 * Note that this is actually 0x1,0000,0000
 */
#define KERNEL_DS	0x00000000
#define get_ds()	(KERNEL_DS)

#ifdef CONFIG_MMU

#define USER_DS		TASK_SIZE
#define get_fs()	(current_thread_info()->addr_limit)

static inline void set_fs(mm_segment_t fs)
{
	current_thread_info()->addr_limit = fs;
	modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
}

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

#define __addr_ok(addr) ({ \
	unsigned long flag; \
	__asm__("cmp %2, %0; movlo %0, #0" \
		: "=&r" (flag) \
		: "0" (current_thread_info()->addr_limit), "r" (addr) \
		: "cc"); \
	(flag == 0); })

/* We use 33-bit arithmetic here... */
#define __range_ok(addr,size) ({ \
	unsigned long flag, roksum; \
	__chk_user_ptr(addr);	\
	__asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
		: "=&r" (flag), "=&r" (roksum) \
		: "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
		: "cc"); \
	flag; })

/*
 * Single-value transfer routines.  They automatically use the right
 * size if we just have the right pointer type.  Note that the functions
 * which read from user space (*get_*) need to take care not to leak
 * kernel data even if the calling code is buggy and fails to check
 * the return value.  This means zeroing out the destination variable
 * or buffer on error.  Normally this is done out of line by the
 * fixup code, but there are a few places where it intrudes on the
 * main code path.  When we only write to user space, there is no
 * problem.
 */
extern int __get_user_1(void *);
extern int __get_user_2(void *);
extern int __get_user_4(void *);

#define __GUP_CLOBBER_1	"lr", "cc"
#ifdef CONFIG_CPU_USE_DOMAINS
#define __GUP_CLOBBER_2	"ip", "lr", "cc"
#else
#define __GUP_CLOBBER_2 "lr", "cc"
#endif
#define __GUP_CLOBBER_4	"lr", "cc"

#define __get_user_x(__r2,__p,__e,__l,__s)				\
	   __asm__ __volatile__ (					\
		__asmeq("%0", "r0") __asmeq("%1", "r2")			\
		__asmeq("%3", "r1")					\