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uaccess.h

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 * Copyright (C) 2007  Maciej W. Rozycki
 */
#ifndef _ASM_UACCESS_H
#define _ASM_UACCESS_H

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/thread_info.h>

/*
 * 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.
 */
#ifdef CONFIG_32BIT

#define __UA_LIMIT      0x80000000UL

#define __UA_ADDR ".word"
#define __UA_LA         "la"
#define __UA_ADDU "addu"
#define __UA_t0         "$8"
#define __UA_t1         "$9"

#endif /* CONFIG_32BIT */

#ifdef CONFIG_64BIT

#define __UA_LIMIT      (- TASK_SIZE)

#define __UA_ADDR ".dword"
#define __UA_LA         "dla"
#define __UA_ADDU "daddu"
#define __UA_t0         "$12"
#define __UA_t1         "$13"

#endif /* CONFIG_64BIT */

/*
 * USER_DS is a bitmask that has the bits set that may not be set in a valid
 * userspace address.  Note that we limit 32-bit userspace to 0x7fff8000 but
 * the arithmetic we're doing only works if the limit is a power of two, so
 * we use 0x80000000 here on 32-bit kernels.  If a process passes an invalid
 * address in this range it's the process's problem, not ours :-)
 */

#define KERNEL_DS ((mm_segment_t) { 0UL })
#define USER_DS         ((mm_segment_t) { __UA_LIMIT })

#define VERIFY_READ    0
#define VERIFY_WRITE   1

#define get_ds()  (KERNEL_DS)
#define get_fs()  (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))

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


/*
 * Is a address valid? This does a straighforward calculation rather
 * than tests.
 *
 * Address valid if:
 *  - "addr" doesn't have any high-bits set
 *  - AND "size" doesn't have any high-bits set
 *  - AND "addr+size" doesn't have any high-bits set
 *  - OR we are in kernel mode.
 *
 * __ua_size() is a trick to avoid runtime checking of positive constant
 * sizes; for those we already know at compile time that the size is ok.
 */
#define __ua_size(size)                                     \
      ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))

/*
 * 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.
 */

#define __access_mask get_fs().seg

#define __access_ok(addr, size, mask)                             \
      (((signed long)((mask) & ((addr) | ((addr) + (size)) | __ua_size(size)))) == 0)

#define access_ok(type, addr, size)                         \
      likely(__access_ok((unsigned long)(addr), (size), __access_mask))

/*
 * put_user: - Write a simple value into user space.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define put_user(x,ptr) \
      __put_user_check((x), (ptr), sizeof(*(ptr)))

/*
 * get_user: - Get a simple variable from user space.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define get_user(x,ptr) \
      __get_user_check((x), (ptr), sizeof(*(ptr)))

/*
 * __put_user: - Write a simple value into user space, with less checking.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define __put_user(x,ptr) \
      __put_user_nocheck((x), (ptr), sizeof(*(ptr)))

/*
 * __get_user: - Get a simple variable from user space, with less checking.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define __get_user(x,ptr) \
      __get_user_nocheck((x), (ptr), sizeof(*(ptr)))

struct __large_struct { unsigned long buf[100]; };
#define __m(x) (*(struct __large_struct __user *)(x))

/*
 * Yuck.  We need two variants, one for 64bit operation and one
 * for 32 bit mode and old iron.
 */
#ifdef CONFIG_32BIT
#define __GET_USER_DW(val, ptr) __get_user_asm_ll32(val, ptr)
#endif
#ifdef CONFIG_64BIT
#define __GET_USER_DW(val, ptr) __get_user_asm(val, "ld", ptr)
#endif

extern void __get_user_unknown(void);

#define __get_user_common(val, size, ptr)                   \
do {                                                  \
      switch (size) {                                       \
      case 1: __get_user_asm(val, "lb", ptr); break;              \
      case 2: __get_user_asm(val, "lh", ptr); break;              \
      case 4: __get_user_asm(val, "lw", ptr); break;              \
      case 8: __GET_USER_DW(val, ptr); break;                     \
      default: __get_user_unknown(); break;                       \
      }                                               \
} while (0)

#define __get_user_nocheck(x, ptr, size)                    \
({                                                    \
      int __gu_err;                                         \
                                                      \
      __get_user_common((x), size, ptr);                    \
      __gu_err;                                       \
})

#define __get_user_check(x, ptr, size)                            \
({                                                    \
      int __gu_err = -EFAULT;                               \
      const __typeof__(*(ptr)) __user * __gu_ptr = (ptr);         \
                                                      \
      if (likely(access_ok(VERIFY_READ,  __gu_ptr, size)))        \
            __get_user_common((x), size, __gu_ptr);               \
                                                      \
      __gu_err;                                       \
})

#define __get_user_asm(val, insn, addr)                           \
{                                                     \
      long __gu_tmp;                                        \
                                                      \
      __asm__ __volatile__(                                 \
      "1:   " insn "    %1, %3                        \n"   \
      "2:                                       \n"   \
      "     .section .fixup,\"ax\"                    \n"   \
      "3:   li    %0, %4                              \n"   \
      "     j     2b                            \n"   \
      "     .previous                           \n"   \
      "     .section __ex_table,\"a\"                 \n"   \
      "     "__UA_ADDR "\t1b, 3b                      \n"   \
      "     .previous                           \n"   \
      : "=r" (__gu_err), "=r" (__gu_tmp)                    \
      : "0" (0), "o" (__m(addr)), "i" (-EFAULT));                 \
                                                      \
      (val) = (__typeof__(*(addr))) __gu_tmp;                     \
}

/*
 * Get a long long 64 using 32 bit registers.
 */
#define __get_user_asm_ll32(val, addr)                            \
{                                                     \
      union {                                               \
            unsigned long long      l;                      \
            __typeof__(*(addr))     t;                      \
      } __gu_tmp;                                     \
                                                      \
      __asm__ __volatile__(                                 \
      "1:   lw    %1, (%3)                      \n"   \
      "2:   lw    %D1, 4(%3)                    \n"   \
      "3:   .section    .fixup,\"ax\"                 \n"   \
      "4:   li    %0, %4                              \n"   \
      "     move  %1, $0                              \n"   \
      "     move  %D1, $0                             \n"   \
      "     j     3b                            \n"   \
      "     .previous                           \n"   \
      "     .section    __ex_table,\"a\"        \n"   \
      "     " __UA_ADDR "     1b, 4b                        \n"   \
      "     " __UA_ADDR "     2b, 4b                        \n"   \
      "     .previous                           \n"   \
      : "=r" (__gu_err), "=&r" (__gu_tmp.l)                       \
      : "0" (0), "r" (addr), "i" (-EFAULT));                      \
                                                      \
      (val) = __gu_tmp.t;                                   \
}

/*
 * Yuck.  We need two variants, one for 64bit operation and one
 * for 32 bit mode and old iron.
 */
#ifdef CONFIG_32BIT
#define __PUT_USER_DW(ptr) __put_user_asm_ll32(ptr)
#endif
#ifdef CONFIG_64BIT
#define __PUT_USER_DW(ptr) __put_user_asm("sd", ptr)
#endif

#define __put_user_nocheck(x, ptr, size)                    \
({                                                    \
      __typeof__(*(ptr)) __pu_val;                          \
      int __pu_err = 0;                               \
                                                      \
      __pu_val = (x);                                       \
      switch (size) {                                       \
      case 1: __put_user_asm("sb", ptr); break;             \
      case 2: __put_user_asm("sh", ptr); break;             \
      case 4: __put_user_asm("sw", ptr); break;             \
      case 8: __PUT_USER_DW(ptr); break;                    \
      default: __put_user_unknown(); break;                       \
      }                                               \
      __pu_err;                                       \
})

#define __put_user_check(x, ptr, size)                            \
({                                                    \
      __typeof__(*(ptr)) __user *__pu_addr = (ptr);               \
      __typeof__(*(ptr)) __pu_val = (x);                    \
      int __pu_err = -EFAULT;                               \
                                                      \
      if (likely(access_ok(VERIFY_WRITE,  __pu_addr, size))) {    \
            switch (size) {                                 \
            case 1: __put_user_asm("sb", __pu_addr); break;       \
            case 2: __put_user_asm("sh", __pu_addr); break;       \
            case 4: __put_user_asm("sw", __pu_addr); break;       \
            case 8: __PUT_USER_DW(__pu_addr); break;        \
            default: __put_user_unknown(); break;                 \
            }                                         \
      }                                               \
      __pu_err;                                       \
})

#define __put_user_asm(insn, ptr)                           \
{                                                     \
      __asm__ __volatile__(                                 \
      "1:   " insn "    %z2, %3           # __put_user_asm\n"     \
      "2:                                       \n"   \
      "     .section    .fixup,\"ax\"                 \n"   \
      "3:   li    %0, %4                              \n"   \
      "     j     2b                            \n"   \
      "     .previous                           \n"   \
      "     .section    __ex_table,\"a\"        \n"   \
      "     " __UA_ADDR "     1b, 3b                        \n"   \
      "     .previous                           \n"   \
      : "=r" (__pu_err)                               \
      : "0" (0), "Jr" (__pu_val), "o" (__m(ptr)),                 \
        "i" (-EFAULT));                               \
}

#define __put_user_asm_ll32(ptr)                            \
{                                                     \
      __asm__ __volatile__(                                 \
      "1:   sw    %2, (%3)    # __put_user_asm_ll32   \n"   \
      "2:   sw    %D2, 4(%3)                    \n"   \
      "3:                                       \n"   \
      "     .section    .fixup,\"ax\"                 \n"   \
      "4:   li    %0, %4                              \n"   \
      "     j     3b                            \n"   \
      "     .previous                           \n"   \
      "     .section    __ex_table,\"a\"        \n"   \
      "     " __UA_ADDR "     1b, 4b                        \n"   \
      "     " __UA_ADDR "     2b, 4b                        \n"   \
      "     .previous"                                \
      : "=r" (__pu_err)                               \
      : "0" (0), "r" (__pu_val), "r" (ptr),                       \
        "i" (-EFAULT));                               \
}

extern void __put_user_unknown(void);

/*
 * put_user_unaligned: - Write a simple value into user space.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define put_user_unaligned(x,ptr)   \
      __put_user_unaligned_check((x),(ptr),sizeof(*(ptr)))

/*
 * get_user_unaligned: - Get a simple variable from user space.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define get_user_unaligned(x,ptr) \
      __get_user_unaligned_check((x),(ptr),sizeof(*(ptr)))

/*
 * __put_user_unaligned: - Write a simple value into user space, with less checking.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define __put_user_unaligned(x,ptr) \
      __put_user_unaligned_nocheck((x),(ptr),sizeof(*(ptr)))

/*
 * __get_user_unaligned: - Get a simple variable from user space, with less checking.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define __get_user_unaligned(x,ptr) \
      __get_user__unalignednocheck((x),(ptr),sizeof(*(ptr)))

/*
 * Yuck.  We need two variants, one for 64bit operation and one
 * for 32 bit mode and old iron.
 */
#ifdef CONFIG_32BIT
#define __GET_USER_UNALIGNED_DW(val, ptr)                   \
      __get_user_unaligned_asm_ll32(val, ptr)
#endif
#ifdef CONFIG_64BIT
#define __GET_USER_UNALIGNED_DW(val, ptr)                   \
      __get_user_unaligned_asm(val, "uld", ptr)
#endif

extern void __get_user_unaligned_unknown(void);

#define __get_user_unaligned_common(val, size, ptr)               \
do {                                                  \
      switch (size) {                                       \
      case 1: __get_user_asm(val, "lb", ptr); break;              \
      case 2: __get_user_unaligned_asm(val, "ulh", ptr); break;   \
      case 4: __get_user_unaligned_asm(val, "ulw", ptr); break;   \
      case 8: __GET_USER_UNALIGNED_DW(val, ptr); break;           \
      default: __get_user_unaligned_unknown(); break;             \
      }                                               \
} while (0)

#define __get_user_unaligned_nocheck(x,ptr,size)                  \
({                                                    \
      int __gu_err;                                         \
                                                      \
      __get_user_unaligned_common((x), size, ptr);                \
      __gu_err;                                       \
})

#define __get_user_unaligned_check(x,ptr,size)                    \
({                                                    \
      int __gu_err = -EFAULT;                               \
      const __typeof__(*(ptr)) __user * __gu_ptr = (ptr);         \
                                                      \
      if (likely(access_ok(VERIFY_READ,  __gu_ptr, size)))        \
            __get_user_unaligned_common((x), size, __gu_ptr);     \
                                                      \
      __gu_err;                                       \
})

#define __get_user_unaligned_asm(val, insn, addr)                 \
{                                                     \
      long __gu_tmp;                                        \
                                                      \
      __asm__ __volatile__(                                 \
      "1:   " insn "    %1, %3                        \n"   \
      "2:                                       \n"   \
      "     .section .fixup,\"ax\"                    \n"   \
      "3:   li    %0, %4                              \n"   \
      "     j     2b                            \n"   \
      "     .previous                           \n"   \
      "     .section __ex_table,\"a\"                 \n"   \
      "     "__UA_ADDR "\t1b, 3b                      \n"   \
      "     "__UA_ADDR "\t1b + 4, 3b                  \n"   \
      "     .previous                           \n"   \
      : "=r" (__gu_err), "=r" (__gu_tmp)                    \
      : "0" (0), "o" (__m(addr)), "i" (-EFAULT));                 \
                                                      \
      (val) = (__typeof__(*(addr))) __gu_tmp;                     \
}

/*
 * Get a long long 64 using 32 bit registers.
 */
#define __get_user_unaligned_asm_ll32(val, addr)                  \
{                                                     \
        unsigned long long __gu_tmp;                              \
                                                      \
      __asm__ __volatile__(                                 \
      "1:   ulw   %1, (%3)                      \n"   \
      "2:   ulw   %D1, 4(%3)                    \n"   \
      "     move  %0, $0                              \n"   \
      "3:   .section    .fixup,\"ax\"                 \n"   \
      "4:   li    %0, %4                              \n"   \
      "     move  %1, $0                              \n"   \
      "     move  %D1, $0                             \n"   \
      "     j     3b                            \n"   \
      "     .previous                           \n"   \
      "     .section    __ex_table,\"a\"        \n"   \
      "     " __UA_ADDR "     1b, 4b                        \n"   \
      "     " __UA_ADDR "     1b + 4, 4b              \n"   \
      "     " __UA_ADDR "     2b, 4b                        \n"   \
      "     " __UA_ADDR "     2b + 4, 4b              \n"   \
      "     .previous                           \n"   \
      : "=r" (__gu_err), "=&r" (__gu_tmp)                   \
      : "0" (0), "r" (addr), "i" (-EFAULT));                      \
      (val) = (__typeof__(*(addr))) __gu_tmp;                     \
}

/*
 * Yuck.  We need two variants, one for 64bit operation and one
 * for 32 bit mode and old iron.
 */
#ifdef CONFIG_32BIT
#define __PUT_USER_UNALIGNED_DW(ptr) __put_user_unaligned_asm_ll32(ptr)
#endif
#ifdef CONFIG_64BIT
#define __PUT_USER_UNALIGNED_DW(ptr) __put_user_unaligned_asm("usd", ptr)
#endif

#define __put_user_unaligned_nocheck(x,ptr,size)                  \
({                                                    \
      __typeof__(*(ptr)) __pu_val;                          \
      int __pu_err = 0;                               \
                                                      \
      __pu_val = (x);                                       \
      switch (size) {                                       \
      case 1: __put_user_asm("sb", ptr); break;             \
      case 2: __put_user_unaligned_asm("ush", ptr); break;        \
      case 4: __put_user_unaligned_asm("usw", ptr); break;        \
      case 8: __PUT_USER_UNALIGNED_DW(ptr); break;                \
      default: __put_user_unaligned_unknown(); break;             \
      }                                               \
      __pu_err;                                       \
})

#define __put_user_unaligned_check(x,ptr,size)                    \
({                                                    \
      __typeof__(*(ptr)) __user *__pu_addr = (ptr);               \
      __typeof__(*(ptr)) __pu_val = (x);                    \
      int __pu_err = -EFAULT;                               \
                                                      \
      if (likely(access_ok(VERIFY_WRITE,  __pu_addr, size))) {    \
            switch (size) {                                 \
            case 1: __put_user_asm("sb", __pu_addr); break;       \
            case 2: __put_user_unaligned_asm("ush", __pu_addr); break; \
            case 4: __put_user_unaligned_asm("usw", __pu_addr); break; \
            case 8: __PUT_USER_UNALGINED_DW(__pu_addr); break;    \
            default: __put_user_unaligned_unknown(); break;       \
            }                                         \
      }                                               \
      __pu_err;                                       \
})

#define __put_user_unaligned_asm(insn, ptr)                       \
{                                                     \
      __asm__ __volatile__(                                 \
      "1:   " insn "    %z2, %3           # __put_user_unaligned_asm\n" \
      "2:                                       \n"   \
      "     .section    .fixup,\"ax\"                 \n"   \
      "3:   li    %0, %4                              \n"   \
      "     j     2b                            \n"   \
      "     .previous                           \n"   \
      "     .section    __ex_table,\"a\"        \n"   \
      "     " __UA_ADDR "     1b, 3b                        \n"   \
      "     .previous                           \n"   \
      : "=r" (__pu_err)                               \
      : "0" (0), "Jr" (__pu_val), "o" (__m(ptr)),                 \
        "i" (-EFAULT));                               \
}

#define __put_user_unaligned_asm_ll32(ptr)                        \
{                                                     \
      __asm__ __volatile__(                                 \
      "1:   sw    %2, (%3)    # __put_user_unaligned_asm_ll32     \n" \
      "2:   sw    %D2, 4(%3)                    \n"   \
      "3:                                       \n"   \
      "     .section    .fixup,\"ax\"                 \n"   \
      "4:   li    %0, %4                              \n"   \
      "     j     3b                            \n"   \
      "     .previous                           \n"   \
      "     .section    __ex_table,\"a\"        \n"   \
      "     " __UA_ADDR "     1b, 4b                        \n"   \
      "     " __UA_ADDR "     1b + 4, 4b              \n"   \
      "     " __UA_ADDR "     2b, 4b                        \n"   \
      "     " __UA_ADDR "     2b + 4, 4b              \n"   \
      "     .previous"                                \
      : "=r" (__pu_err)                               \
      : "0" (0), "r" (__pu_val), "r" (ptr),                       \
        "i" (-EFAULT));                               \
}

extern void __put_user_unaligned_unknown(void);

/*
 * We're generating jump to subroutines which will be outside the range of
 * jump instructions
 */
#ifdef MODULE
#define __MODULE_JAL(destination)                           \
      ".set\tnoat\n\t"                                \
      __UA_LA "\t$1, " #destination "\n\t"                        \
      "jalr\t$1\n\t"                                        \
      ".set\tat\n\t"
#else
#define __MODULE_JAL(destination)                           \
      "jal\t" #destination "\n\t"
#endif

#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
#define DADDI_SCRATCH "$0"
#else
#define DADDI_SCRATCH "$3"
#endif

extern size_t __copy_user(void *__to, const void *__from, size_t __n);

#define __invoke_copy_to_user(to, from, n)                        \
({                                                    \
      register void __user *__cu_to_r __asm__("$4");              \
      register const void *__cu_from_r __asm__("$5");             \
      register long __cu_len_r __asm__("$6");                     \
                                                      \
      __cu_to_r = (to);                               \
      __cu_from_r = (from);                                 \
      __cu_len_r = (n);                               \
      __asm__ __volatile__(                                 \
      __MODULE_JAL(__copy_user)                             \
      : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)   \
      :                                               \
      : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",           \
        DADDI_SCRATCH, "memory");                           \
      __cu_len_r;                                     \
})

/*
 * __copy_to_user: - Copy a block of data into user space, with less checking.
 * @to:   Destination address, in user space.
 * @from: Source address, in kernel space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from kernel space to user space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 */
#define __copy_to_user(to, from, n)                         \
({                                                    \
      void __user *__cu_to;                                 \
      const void *__cu_from;                                \
      long __cu_len;                                        \
                                                      \
      might_sleep();                                        \
      __cu_to = (to);                                       \
      __cu_from = (from);                                   \
      __cu_len = (n);                                       \
      __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len);   \
      __cu_len;                                       \
})

extern size_t __copy_user_inatomic(void *__to, const void *__from, size_t __n);

#define __copy_to_user_inatomic(to, from, n)                      \
({                                                    \
      void __user *__cu_to;                                 \
      const void *__cu_from;                                \
      long __cu_len;                                        \
                                                      \
      __cu_to = (to);                                       \
      __cu_from = (from);                                   \
      __cu_len = (n);                                       \
      __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len);   \
      __cu_len;                                       \
})

#define __copy_from_user_inatomic(to, from, n)                    \
({                                                    \
      void *__cu_to;                                        \
      const void __user *__cu_from;                         \
      long __cu_len;                                        \
                                                      \
      __cu_to = (to);                                       \
      __cu_from = (from);                                   \
      __cu_len = (n);                                       \
      __cu_len = __invoke_copy_from_user_inatomic(__cu_to, __cu_from,   \
                                                  __cu_len);            \
      __cu_len;                                       \
})

/*
 * copy_to_user: - Copy a block of data into user space.
 * @to:   Destination address, in user space.
 * @from: Source address, in kernel space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from kernel space to user space.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 */
#define copy_to_user(to, from, n)                           \
({                                                    \
      void __user *__cu_to;                                 \
      const void *__cu_from;                                \
      long __cu_len;                                        \
                                                      \
      might_sleep();                                        \
      __cu_to = (to);                                       \
      __cu_from = (from);                                   \
      __cu_len = (n);                                       \
      if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))             \
            __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,  \
                                             __cu_len);           \
      __cu_len;                                       \
})

#define __invoke_copy_from_user(to, from, n)                      \
({                                                    \
      register void *__cu_to_r __asm__("$4");                     \
      register const void __user *__cu_from_r __asm__("$5");            \
      register long __cu_len_r __asm__("$6");                     \
                                                      \
      __cu_to_r = (to);                               \
      __cu_from_r = (from);                                 \
      __cu_len_r = (n);                               \
      __asm__ __volatile__(                                 \
      ".set\tnoreorder\n\t"                                 \
      __MODULE_JAL(__copy_user)                             \
      ".set\tnoat\n\t"                                \
      __UA_ADDU "\t$1, %1, %2\n\t"                          \
      ".set\tat\n\t"                                        \
      ".set\treorder"                                       \
      : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)   \
      :                                               \
      : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",           \
        DADDI_SCRATCH, "memory");                           \
      __cu_len_r;                                     \
})

#define __invoke_copy_from_user_inatomic(to, from, n)             \
({                                                    \
      register void *__cu_to_r __asm__("$4");                     \
      register const void __user *__cu_from_r __asm__("$5");            \
      register long __cu_len_r __asm__("$6");                     \
                                                      \
      __cu_to_r = (to);                               \
      __cu_from_r = (from);                                 \
      __cu_len_r = (n);                               \
      __asm__ __volatile__(                                 \
      ".set\tnoreorder\n\t"                                 \
      __MODULE_JAL(__copy_user_inatomic)                    \
      ".set\tnoat\n\t"                                \
      __UA_ADDU "\t$1, %1, %2\n\t"                          \
      ".set\tat\n\t"                                        \
      ".set\treorder"                                       \
      : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)   \
      :                                               \
      : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",           \
        DADDI_SCRATCH, "memory");                           \
      __cu_len_r;                                     \
})

/*
 * __copy_from_user: - Copy a block of data from user space, with less checking.
 * @to:   Destination address, in kernel space.
 * @from: Source address, in user space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from user space to kernel space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 *
 * If some data could not be copied, this function will pad the copied
 * data to the requested size using zero bytes.
 */
#define __copy_from_user(to, from, n)                             \
({                                                    \
      void *__cu_to;                                        \
      const void __user *__cu_from;                         \
      long __cu_len;                                        \
                                                      \
      might_sleep();                                        \
      __cu_to = (to);                                       \
      __cu_from = (from);                                   \
      __cu_len = (n);                                       \
      __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,            \
                                         __cu_len);               \
      __cu_len;                                       \
})

/*
 * copy_from_user: - Copy a block of data from user space.
 * @to:   Destination address, in kernel space.
 * @from: Source address, in user space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from user space to kernel space.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 *
 * If some data could not be copied, this function will pad the copied
 * data to the requested size using zero bytes.
 */
#define copy_from_user(to, from, n)                         \
({                                                    \
      void *__cu_to;                                        \
      const void __user *__cu_from;                         \
      long __cu_len;                                        \
                                                      \
      might_sleep();                                        \
      __cu_to = (to);                                       \
      __cu_from = (from);                                   \
      __cu_len = (n);                                       \
      if (access_ok(VERIFY_READ, __cu_from, __cu_len))            \
            __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,      \
                                               __cu_len);         \
      __cu_len;                                       \
})

#define __copy_in_user(to, from, n) __copy_from_user(to, from, n)

#define copy_in_user(to, from, n)                           \
({                                                    \
      void __user *__cu_to;                                 \
      const void __user *__cu_from;                         \
      long __cu_len;                                        \
                                                      \
      might_sleep();                                        \
      __cu_to = (to);                                       \
      __cu_from = (from);                                   \
      __cu_len = (n);                                       \
      if (likely(access_ok(VERIFY_READ, __cu_from, __cu_len) &&   \
                 access_ok(VERIFY_WRITE, __cu_to, __cu_len)))           \
            __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,      \
                                               __cu_len);         \
      __cu_len;                                       \
})

/*
 * __clear_user: - Zero a block of memory in user space, with less checking.
 * @to:   Destination address, in user space.
 * @n:    Number of bytes to zero.
 *
 * Zero a block of memory in user space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be cleared.
 * On success, this will be zero.
 */
static inline __kernel_size_t
__clear_user(void __user *addr, __kernel_size_t size)
{
      __kernel_size_t res;

      might_sleep();
      __asm__ __volatile__(
            "move\t$4, %1\n\t"
            "move\t$5, $0\n\t"
            "move\t$6, %2\n\t"
            __MODULE_JAL(__bzero)
            "move\t%0, $6"
            : "=r" (res)
            : "r" (addr), "r" (size)
            : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");

      return res;
}

#define clear_user(addr,n)                                  \
({                                                    \
      void __user * __cl_addr = (addr);                     \
      unsigned long __cl_size = (n);                              \
      if (__cl_size && access_ok(VERIFY_WRITE,              \
            ((unsigned long)(__cl_addr)), __cl_size))       \
            __cl_size = __clear_user(__cl_addr, __cl_size);       \
      __cl_size;                                      \
})

/*
 * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 * @dst:   Destination address, in kernel space.  This buffer must be at
 *         least @count bytes long.
 * @src:   Source address, in user space.
 * @count: Maximum number of bytes to copy, including the trailing NUL.
 *
 * Copies a NUL-terminated string from userspace to kernel space.
 * Caller must check the specified block with access_ok() before calling
 * this function.
 *
 * On success, returns the length of the string (not including the trailing
 * NUL).
 *
 * If access to userspace fails, returns -EFAULT (some data may have been
 * copied).
 *
 * If @count is smaller than the length of the string, copies @count bytes
 * and returns @count.
 */
static inline long
__strncpy_from_user(char *__to, const char __user *__from, long __len)
{
      long res;

      might_sleep();
      __asm__ __volatile__(
            "move\t$4, %1\n\t"
            "move\t$5, %2\n\t"
            "move\t$6, %3\n\t"
            __MODULE_JAL(__strncpy_from_user_nocheck_asm)
            "move\t%0, $2"
            : "=r" (res)
            : "r" (__to), "r" (__from), "r" (__len)
            : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");

      return res;
}

/*
 * strncpy_from_user: - Copy a NUL terminated string from userspace.
 * @dst:   Destination address, in kernel space.  This buffer must be at
 *         least @count bytes long.
 * @src:   Source address, in user space.
 * @count: Maximum number of bytes to copy, including the trailing NUL.
 *
 * Copies a NUL-terminated string from userspace to kernel space.
 *
 * On success, returns the length of the string (not including the trailing
 * NUL).
 *
 * If access to userspace fails, returns -EFAULT (some data may have been
 * copied).
 *
 * If @count is smaller than the length of the string, copies @count bytes
 * and returns @count.
 */
static inline long
strncpy_from_user(char *__to, const char __user *__from, long __len)
{
      long res;

      might_sleep();
      __asm__ __volatile__(
            "move\t$4, %1\n\t"
            "move\t$5, %2\n\t"
            "move\t$6, %3\n\t"
            __MODULE_JAL(__strncpy_from_user_asm)
            "move\t%0, $2"
            : "=r" (res)
            : "r" (__to), "r" (__from), "r" (__len)
            : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");

      return res;
}

/* Returns: 0 if bad, string length+1 (memory size) of string if ok */
static inline long __strlen_user(const char __user *s)
{
      long res;

      might_sleep();
      __asm__ __volatile__(
            "move\t$4, %1\n\t"
            __MODULE_JAL(__strlen_user_nocheck_asm)
            "move\t%0, $2"
            : "=r" (res)
            : "r" (s)
            : "$2", "$4", __UA_t0, "$31");

      return res;
}

/*
 * strlen_user: - Get the size of a string in user space.
 * @str: The string to measure.
 *
 * Context: User context only.  This function may sleep.
 *
 * Get the size of a NUL-terminated string in user space.
 *
 * Returns the size of the string INCLUDING the terminating NUL.
 * On exception, returns 0.
 *
 * If there is a limit on the length of a valid string, you may wish to
 * consider using strnlen_user() instead.
 */
static inline long strlen_user(const char __user *s)
{
      long res;

      might_sleep();
      __asm__ __volatile__(
            "move\t$4, %1\n\t"
            __MODULE_JAL(__strlen_user_asm)
            "move\t%0, $2"
            : "=r" (res)
            : "r" (s)
            : "$2", "$4", __UA_t0, "$31");

      return res;
}

/* Returns: 0 if bad, string length+1 (memory size) of string if ok */
static inline long __strnlen_user(const char __user *s, long n)
{
      long res;

      might_sleep();
      __asm__ __volatile__(
            "move\t$4, %1\n\t"
            "move\t$5, %2\n\t"
            __MODULE_JAL(__strnlen_user_nocheck_asm)
            "move\t%0, $2"
            : "=r" (res)
            : "r" (s), "r" (n)
            : "$2", "$4", "$5", __UA_t0, "$31");

      return res;
}

/*
 * strlen_user: - Get the size of a string in user space.
 * @str: The string to measure.
 *
 * Context: User context only.  This function may sleep.
 *
 * Get the size of a NUL-terminated string in user space.
 *
 * Returns the size of the string INCLUDING the terminating NUL.
 * On exception, returns 0.
 *
 * If there is a limit on the length of a valid string, you may wish to
 * consider using strnlen_user() instead.
 */
static inline long strnlen_user(const char __user *s, long n)
{
      long res;

      might_sleep();
      __asm__ __volatile__(
            "move\t$4, %1\n\t"
            "move\t$5, %2\n\t"
            __MODULE_JAL(__strnlen_user_asm)
            "move\t%0, $2"
            : "=r" (res)
            : "r" (s), "r" (n)
            : "$2", "$4", "$5", __UA_t0, "$31");

      return res;
}

struct exception_table_entry
{
      unsigned long insn;
      unsigned long nextinsn;
};

extern int fixup_exception(struct pt_regs *regs);

#endif /* _ASM_UACCESS_H */

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