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uaccess.h

#ifndef _ARCH_POWERPC_UACCESS_H
#define _ARCH_POWERPC_UACCESS_H

#ifdef __KERNEL__
#ifndef __ASSEMBLY__

#include <linux/sched.h>
#include <linux/errno.h>
#include <asm/asm-compat.h>
#include <asm/processor.h>
#include <asm/page.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.
 *
 * The fs/ds values are now the highest legal address in the "segment".
 * This simplifies the checking in the routines below.
 */

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

#define KERNEL_DS MAKE_MM_SEG(~0UL)
#ifdef __powerpc64__
/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
#define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
#else
#define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
#endif

#define get_ds()  (KERNEL_DS)
#define get_fs()  (current->thread.fs)
#define set_fs(val)     (current->thread.fs = (val))

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

#ifdef __powerpc64__
/*
 * This check is sufficient because there is a large enough
 * gap between user addresses and the kernel addresses
 */
#define __access_ok(addr, size, segment)  \
      (((addr) <= (segment).seg) && ((size) <= (segment).seg))

#else

#define __access_ok(addr, size, segment)  \
      (((addr) <= (segment).seg) &&       \
       (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))

#endif

#define access_ok(type, addr, size)       \
      (__chk_user_ptr(addr),              \
       __access_ok((__force unsigned long)(addr), (size), get_fs()))

/*
 * 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;
      unsigned long fixup;
};

/*
 * 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
 * of a performance impact. Thus we have a few rather ugly macros here,
 * and hide all the ugliness from the user.
 *
 * The "__xxx" versions of the user access functions are versions that
 * do not verify the address space, that must have been done previously
 * with a separate "access_ok()" call (this is used when we do multiple
 * accesses to the same area of user memory).
 *
 * As we use the same address space for kernel and user data on the
 * PowerPC, we can just do these as direct assignments.  (Of course, the
 * exception handling means that it's no longer "just"...)
 *
 * The "user64" versions of the user access functions are versions that
 * allow access of 64-bit data. The "get_user" functions do not
 * properly handle 64-bit data because the value gets down cast to a long.
 * The "put_user" functions already handle 64-bit data properly but we add
 * "user64" versions for completeness
 */
#define get_user(x, ptr) \
      __get_user_check((x), (ptr), sizeof(*(ptr)))
#define put_user(x, ptr) \
      __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

#define __get_user(x, ptr) \
      __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
#define __put_user(x, ptr) \
      __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

#ifndef __powerpc64__
#define __get_user64(x, ptr) \
      __get_user64_nocheck((x), (ptr), sizeof(*(ptr)))
#define __put_user64(x, ptr) __put_user(x, ptr)
#endif

#define __get_user_inatomic(x, ptr) \
      __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
#define __put_user_inatomic(x, ptr) \
      __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

#define __get_user_unaligned __get_user
#define __put_user_unaligned __put_user

extern long __put_user_bad(void);

/*
 * We don't tell gcc that we are accessing memory, but this is OK
 * because we do not write to any memory gcc knows about, so there
 * are no aliasing issues.
 */
#define __put_user_asm(x, addr, err, op)              \
      __asm__ __volatile__(                           \
            "1:   " op " %1,0(%2)   # put_user\n"           \
            "2:\n"                                    \
            ".section .fixup,\"ax\"\n"                \
            "3:   li %0,%3\n"                   \
            "     b 2b\n"                             \
            ".previous\n"                             \
            ".section __ex_table,\"a\"\n"             \
                  PPC_LONG_ALIGN "\n"                 \
                  PPC_LONG "1b,3b\n"                  \
            ".previous"                         \
            : "=r" (err)                              \
            : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))

#ifdef __powerpc64__
#define __put_user_asm2(x, ptr, retval)                     \
        __put_user_asm(x, ptr, retval, "std")
#else /* __powerpc64__ */
#define __put_user_asm2(x, addr, err)                       \
      __asm__ __volatile__(                           \
            "1:   stw %1,0(%2)\n"                     \
            "2:   stw %1+1,4(%2)\n"             \
            "3:\n"                                    \
            ".section .fixup,\"ax\"\n"                \
            "4:   li %0,%3\n"                   \
            "     b 3b\n"                             \
            ".previous\n"                             \
            ".section __ex_table,\"a\"\n"             \
                  PPC_LONG_ALIGN "\n"                 \
                  PPC_LONG "1b,4b\n"                  \
                  PPC_LONG "2b,4b\n"                  \
            ".previous"                         \
            : "=r" (err)                              \
            : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
#endif /* __powerpc64__ */

#define __put_user_size(x, ptr, size, retval)               \
do {                                            \
      retval = 0;                               \
      switch (size) {                                 \
        case 1: __put_user_asm(x, ptr, retval, "stb"); break;     \
        case 2: __put_user_asm(x, ptr, retval, "sth"); break;     \
        case 4: __put_user_asm(x, ptr, retval, "stw"); break;     \
        case 8: __put_user_asm2(x, ptr, retval); break;     \
        default: __put_user_bad();                    \
      }                                         \
} while (0)

#define __put_user_nocheck(x, ptr, size)              \
({                                              \
      long __pu_err;                                  \
      __typeof__(*(ptr)) __user *__pu_addr = (ptr);         \
      if (!is_kernel_addr((unsigned long)__pu_addr))        \
            might_sleep();                            \
      __chk_user_ptr(ptr);                            \
      __put_user_size((x), __pu_addr, (size), __pu_err);    \
      __pu_err;                                 \
})

#define __put_user_check(x, ptr, size)                            \
({                                                    \
      long __pu_err = -EFAULT;                              \
      __typeof__(*(ptr)) __user *__pu_addr = (ptr);               \
      might_sleep();                                        \
      if (access_ok(VERIFY_WRITE, __pu_addr, size))               \
            __put_user_size((x), __pu_addr, (size), __pu_err);    \
      __pu_err;                                       \
})

#define __put_user_nosleep(x, ptr, size)              \
({                                              \
      long __pu_err;                                  \
      __typeof__(*(ptr)) __user *__pu_addr = (ptr);         \
      __chk_user_ptr(ptr);                            \
      __put_user_size((x), __pu_addr, (size), __pu_err);    \
      __pu_err;                                 \
})


extern long __get_user_bad(void);

#define __get_user_asm(x, addr, err, op)        \
      __asm__ __volatile__(                     \
            "1:   "op" %1,0(%2)     # get_user\n"     \
            "2:\n"                              \
            ".section .fixup,\"ax\"\n"          \
            "3:   li %0,%3\n"             \
            "     li %1,0\n"              \
            "     b 2b\n"                       \
            ".previous\n"                       \
            ".section __ex_table,\"a\"\n"       \
                  PPC_LONG_ALIGN "\n"           \
                  PPC_LONG "1b,3b\n"            \
            ".previous"                   \
            : "=r" (err), "=r" (x)              \
            : "b" (addr), "i" (-EFAULT), "0" (err))

#ifdef __powerpc64__
#define __get_user_asm2(x, addr, err)                 \
      __get_user_asm(x, addr, err, "ld")
#else /* __powerpc64__ */
#define __get_user_asm2(x, addr, err)                 \
      __asm__ __volatile__(                     \
            "1:   lwz %1,0(%2)\n"               \
            "2:   lwz %1+1,4(%2)\n"       \
            "3:\n"                              \
            ".section .fixup,\"ax\"\n"          \
            "4:   li %0,%3\n"             \
            "     li %1,0\n"              \
            "     li %1+1,0\n"                  \
            "     b 3b\n"                       \
            ".previous\n"                       \
            ".section __ex_table,\"a\"\n"       \
                  PPC_LONG_ALIGN "\n"           \
                  PPC_LONG "1b,4b\n"            \
                  PPC_LONG "2b,4b\n"            \
            ".previous"                   \
            : "=r" (err), "=&r" (x)             \
            : "b" (addr), "i" (-EFAULT), "0" (err))
#endif /* __powerpc64__ */

#define __get_user_size(x, ptr, size, retval)               \
do {                                            \
      retval = 0;                               \
      __chk_user_ptr(ptr);                            \
      if (size > sizeof(x))                           \
            (x) = __get_user_bad();                   \
      switch (size) {                                 \
      case 1: __get_user_asm(x, ptr, retval, "lbz"); break; \
      case 2: __get_user_asm(x, ptr, retval, "lhz"); break; \
      case 4: __get_user_asm(x, ptr, retval, "lwz"); break; \
      case 8: __get_user_asm2(x, ptr, retval);  break;      \
      default: (x) = __get_user_bad();                \
      }                                         \
} while (0)

#define __get_user_nocheck(x, ptr, size)              \
({                                              \
      long __gu_err;                                  \
      unsigned long __gu_val;                         \
      const __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
      __chk_user_ptr(ptr);                            \
      if (!is_kernel_addr((unsigned long)__gu_addr))        \
            might_sleep();                            \
      __get_user_size(__gu_val, __gu_addr, (size), __gu_err);     \
      (x) = (__typeof__(*(ptr)))__gu_val;             \
      __gu_err;                                 \
})

#ifndef __powerpc64__
#define __get_user64_nocheck(x, ptr, size)                  \
({                                              \
      long __gu_err;                                  \
      long long __gu_val;                             \
      const __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
      __chk_user_ptr(ptr);                            \
      if (!is_kernel_addr((unsigned long)__gu_addr))        \
            might_sleep();                            \
      __get_user_size(__gu_val, __gu_addr, (size), __gu_err);     \
      (x) = (__typeof__(*(ptr)))__gu_val;             \
      __gu_err;                                 \
})
#endif /* __powerpc64__ */

#define __get_user_check(x, ptr, size)                            \
({                                                    \
      long __gu_err = -EFAULT;                              \
      unsigned long  __gu_val = 0;                          \
      const __typeof__(*(ptr)) __user *__gu_addr = (ptr);         \
      might_sleep();                                        \
      if (access_ok(VERIFY_READ, __gu_addr, (size)))              \
            __get_user_size(__gu_val, __gu_addr, (size), __gu_err);     \
      (x) = (__typeof__(*(ptr)))__gu_val;                   \
      __gu_err;                                       \
})

#define __get_user_nosleep(x, ptr, size)              \
({                                              \
      long __gu_err;                                  \
      unsigned long __gu_val;                         \
      const __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
      __chk_user_ptr(ptr);                            \
      __get_user_size(__gu_val, __gu_addr, (size), __gu_err);     \
      (x) = (__typeof__(*(ptr)))__gu_val;             \
      __gu_err;                                 \
})


/* more complex routines */

extern unsigned long __copy_tofrom_user(void __user *to,
            const void __user *from, unsigned long size);

#ifndef __powerpc64__

static inline unsigned long copy_from_user(void *to,
            const void __user *from, unsigned long n)
{
      unsigned long over;

      if (access_ok(VERIFY_READ, from, n))
            return __copy_tofrom_user((__force void __user *)to, from, n);
      if ((unsigned long)from < TASK_SIZE) {
            over = (unsigned long)from + n - TASK_SIZE;
            return __copy_tofrom_user((__force void __user *)to, from,
                        n - over) + over;
      }
      return n;
}

static inline unsigned long copy_to_user(void __user *to,
            const void *from, unsigned long n)
{
      unsigned long over;

      if (access_ok(VERIFY_WRITE, to, n))
            return __copy_tofrom_user(to, (__force void __user *)from, n);
      if ((unsigned long)to < TASK_SIZE) {
            over = (unsigned long)to + n - TASK_SIZE;
            return __copy_tofrom_user(to, (__force void __user *)from,
                        n - over) + over;
      }
      return n;
}

#else /* __powerpc64__ */

#define __copy_in_user(to, from, size) \
      __copy_tofrom_user((to), (from), (size))

extern unsigned long copy_from_user(void *to, const void __user *from,
                            unsigned long n);
extern unsigned long copy_to_user(void __user *to, const void *from,
                          unsigned long n);
extern unsigned long copy_in_user(void __user *to, const void __user *from,
                          unsigned long n);

#endif /* __powerpc64__ */

static inline unsigned long __copy_from_user_inatomic(void *to,
            const void __user *from, unsigned long n)
{
      if (__builtin_constant_p(n) && (n <= 8)) {
            unsigned long ret = 1;

            switch (n) {
            case 1:
                  __get_user_size(*(u8 *)to, from, 1, ret);
                  break;
            case 2:
                  __get_user_size(*(u16 *)to, from, 2, ret);
                  break;
            case 4:
                  __get_user_size(*(u32 *)to, from, 4, ret);
                  break;
            case 8:
                  __get_user_size(*(u64 *)to, from, 8, ret);
                  break;
            }
            if (ret == 0)
                  return 0;
      }
      return __copy_tofrom_user((__force void __user *)to, from, n);
}

static inline unsigned long __copy_to_user_inatomic(void __user *to,
            const void *from, unsigned long n)
{
      if (__builtin_constant_p(n) && (n <= 8)) {
            unsigned long ret = 1;

            switch (n) {
            case 1:
                  __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
                  break;
            case 2:
                  __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
                  break;
            case 4:
                  __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
                  break;
            case 8:
                  __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
                  break;
            }
            if (ret == 0)
                  return 0;
      }
      return __copy_tofrom_user(to, (__force const void __user *)from, n);
}

static inline unsigned long __copy_from_user(void *to,
            const void __user *from, unsigned long size)
{
      might_sleep();
      return __copy_from_user_inatomic(to, from, size);
}

static inline unsigned long __copy_to_user(void __user *to,
            const void *from, unsigned long size)
{
      might_sleep();
      return __copy_to_user_inatomic(to, from, size);
}

extern unsigned long __clear_user(void __user *addr, unsigned long size);

static inline unsigned long clear_user(void __user *addr, unsigned long size)
{
      might_sleep();
      if (likely(access_ok(VERIFY_WRITE, addr, size)))
            return __clear_user(addr, size);
      if ((unsigned long)addr < TASK_SIZE) {
            unsigned long over = (unsigned long)addr + size - TASK_SIZE;
            return __clear_user(addr, size - over) + over;
      }
      return size;
}

extern int __strncpy_from_user(char *dst, const char __user *src, long count);

static inline long strncpy_from_user(char *dst, const char __user *src,
            long count)
{
      might_sleep();
      if (likely(access_ok(VERIFY_READ, src, 1)))
            return __strncpy_from_user(dst, src, count);
      return -EFAULT;
}

/*
 * Return the size of a string (including the ending 0)
 *
 * Return 0 for error
 */
extern int __strnlen_user(const char __user *str, long len, unsigned long top);

/*
 * Returns the length of the string at str (including the null byte),
 * or 0 if we hit a page we can't access,
 * or something > len if we didn't find a null byte.
 *
 * The `top' parameter to __strnlen_user is to make sure that
 * we can never overflow from the user area into kernel space.
 */
static inline int strnlen_user(const char __user *str, long len)
{
      unsigned long top = current->thread.fs.seg;

      if ((unsigned long)str > top)
            return 0;
      return __strnlen_user(str, len, top);
}

#define strlen_user(str)      strnlen_user((str), 0x7ffffffe)

#endif  /* __ASSEMBLY__ */
#endif /* __KERNEL__ */

#endif      /* _ARCH_POWERPC_UACCESS_H */

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