x86: commonize __range_not_ok.

[linux-2.6/libata-dev.git] / include / asm-x86 / uaccess_32.h

#ifndef __i386_UACCESS_H
#define __i386_UACCESS_H

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

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


#define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFFUL)
#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))

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

/*
 * movsl can be slow when source and dest are not both 8-byte aligned
 */
#ifdef CONFIG_X86_INTEL_USERCOPY
extern struct movsl_mask {
        int mask;
} ____cacheline_aligned_in_smp movsl_mask;
#endif

#define __addr_ok(addr)                                 \
        ((unsigned long __force)(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_not_ok(addr, size)                                      \
({                                                                      \
        unsigned long flag, roksum;                                     \
        __chk_user_ptr(addr);                                           \
        asm("add %3,%1 ; sbb %0,%0; cmp %1,%4; sbb $0,%0"               \
            :"=&r" (flag), "=r" (roksum)                                \
            :"1" (addr), "g" ((int)(size)),                             \
            "rm" (current_thread_info()->addr_limit.seg));              \
        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.
 */
#define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0))

/*
 * 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
 * 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).
 */

extern void __get_user_1(void);
extern void __get_user_2(void);
extern void __get_user_4(void);

#define __get_user_x(size, ret, x, ptr)       \
        asm volatile("call __get_user_" #size \
                     :"=a" (ret),"=d" (x)     \
                     :"0" (ptr))


/* Careful: we have to cast the result to the type of the pointer
 * for sign reasons */

/**
 * 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)                                                \
({                                                                      \
        int __ret_gu;                                                   \
        unsigned long __val_gu;                                         \
        __chk_user_ptr(ptr);                                            \
        switch (sizeof(*(ptr))) {                                       \
        case 1:                                                         \
                __get_user_x(1, __ret_gu, __val_gu, ptr);               \
                break;                                                  \
        case 2:                                                         \
                __get_user_x(2, __ret_gu, __val_gu, ptr);               \
                break;                                                  \
        case 4:                                                         \
                __get_user_x(4, __ret_gu, __val_gu, ptr);               \
                break;                                                  \
        default:                                                        \
                __get_user_x(X, __ret_gu, __val_gu, ptr);               \
                break;                                                  \
        }                                                               \
        (x) = (__typeof__(*(ptr)))__val_gu;                             \
        __ret_gu;                                                       \
})

extern void __put_user_bad(void);

/*
 * Strange magic calling convention: pointer in %ecx,
 * value in %eax(:%edx), return value in %eax, no clobbers.
 */
extern void __put_user_1(void);
extern void __put_user_2(void);
extern void __put_user_4(void);
extern void __put_user_8(void);

#define __put_user_x(size, x, ptr)                              \
        asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
                     :"0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")

#define __put_user_8(x, ptr)                                    \
        asm volatile("call __put_user_8" : "=a" (__ret_pu)      \
                     : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")


/**
 * 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.
 */
#ifdef CONFIG_X86_WP_WORKS_OK

#define put_user(x, ptr)                                        \
({                                                              \
        int __ret_pu;                                           \
        __typeof__(*(ptr)) __pu_val;                            \
        __chk_user_ptr(ptr);                                    \
        __pu_val = x;                                           \
        switch (sizeof(*(ptr))) {                               \
        case 1:                                                 \
                __put_user_x(1, __pu_val, ptr);                 \
                break;                                          \
        case 2:                                                 \
                __put_user_x(2, __pu_val, ptr);                 \
                break;                                          \
        case 4:                                                 \
                __put_user_x(4, __pu_val, ptr);                 \
                break;                                          \
        case 8:                                                 \
                __put_user_8(__pu_val, ptr);                    \
                break;                                          \
        default:                                                \
                __put_user_x(X, __pu_val, ptr);                 \
                break;                                          \
        }                                                       \
        __ret_pu;                                               \
})

#else
#define put_user(x, ptr)                                        \
({                                                              \
        int __ret_pu;                                           \
        __typeof__(*(ptr))__pus_tmp = x;                        \
        __ret_pu = 0;                                           \
        if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp,         \
                                       sizeof(*(ptr))) != 0))   \
                __ret_pu = -EFAULT;                             \
        __ret_pu;                                               \
})


#endif

/**
 * __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)))


/**
 * __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((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

#define __put_user_nocheck(x, ptr, size)                        \
({                                                              \
        long __pu_err;                                          \
        __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \
        __pu_err;                                               \
})


#define __put_user_u64(x, addr, err)                                    \
        asm volatile("1:        movl %%eax,0(%2)\n"                     \
                     "2:        movl %%edx,4(%2)\n"                     \
                     "3:\n"                                             \
                     ".section .fixup,\"ax\"\n"                         \
                     "4:        movl %3,%0\n"                           \
                     "  jmp 3b\n"                                       \
                     ".previous\n"                                      \
                     _ASM_EXTABLE(1b, 4b)                               \
                     _ASM_EXTABLE(2b, 4b)                               \
                     : "=r" (err)                                       \
                     : "A" (x), "r" (addr), "i" (-EFAULT), "0" (err))

#ifdef CONFIG_X86_WP_WORKS_OK

#define __put_user_size(x, ptr, size, retval, errret)                   \
do {                                                                    \
        retval = 0;                                                     \
        __chk_user_ptr(ptr);                                            \
        switch (size) {                                                 \
        case 1:                                                         \
                __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
                break;                                                  \
        case 2:                                                         \
                __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
                break;                                                  \
        case 4:                                                         \
                __put_user_asm(x, ptr, retval, "l", "",  "ir", errret); \
                break;                                                  \
        case 8:                                                         \
                __put_user_u64((__typeof__(*ptr))(x), ptr, retval);     \
                break;                                                  \
        default:                                                        \
                __put_user_bad();                                       \
        }                                                               \
} while (0)

#else

#define __put_user_size(x, ptr, size, retval, errret)                   \
do {                                                                    \
        __typeof__(*(ptr))__pus_tmp = x;                                \
        retval = 0;                                                     \
                                                                        \
        if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0))    \
                retval = errret;                                        \
} while (0)

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

/*
 * Tell gcc we read from memory instead of writing: this is because
 * we do not write to any memory gcc knows about, so there are no
 * aliasing issues.
 */
#define __put_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
        asm volatile("1:        mov"itype" %"rtype"1,%2\n"              \
                     "2:\n"                                             \
                     ".section .fixup,\"ax\"\n"                         \
                     "3:        movl %3,%0\n"                           \
                     "  jmp 2b\n"                                       \
                     ".previous\n"                                      \
                     _ASM_EXTABLE(1b, 3b)                               \
                     : "=r"(err)                                        \
                     : ltype (x), "m" (__m(addr)), "i" (errret), "0" (err))


#define __get_user_nocheck(x, ptr, size)                                \
({                                                                      \
        long __gu_err;                                                  \
        unsigned long __gu_val;                                         \
        __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT);    \
        (x) = (__typeof__(*(ptr)))__gu_val;                             \
        __gu_err;                                                       \
})

extern long __get_user_bad(void);

#define __get_user_size(x, ptr, size, retval, errret)                   \
do {                                                                    \
        retval = 0;                                                     \
        __chk_user_ptr(ptr);                                            \
        switch (size) {                                                 \
        case 1:                                                         \
                __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
                break;                                                  \
        case 2:                                                         \
                __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
                break;                                                  \
        case 4:                                                         \
                __get_user_asm(x, ptr, retval, "l", "", "=r", errret);  \
                break;                                                  \
        default:                                                        \
                (x) = __get_user_bad();                                 \
        }                                                               \
} while (0)

#define __get_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
        asm volatile("1:        mov"itype" %2,%"rtype"1\n"              \
                     "2:\n"                                             \
                     ".section .fixup,\"ax\"\n"                         \
                     "3:        movl %3,%0\n"                           \
                     "  xor"itype" %"rtype"1,%"rtype"1\n"               \
                     "  jmp 2b\n"                                       \
                     ".previous\n"                                      \
                     _ASM_EXTABLE(1b, 3b)                               \
                     : "=r" (err), ltype (x)                            \
                     : "m" (__m(addr)), "i" (errret), "0" (err))


unsigned long __must_check __copy_to_user_ll
                (void __user *to, const void *from, unsigned long n);
unsigned long __must_check __copy_from_user_ll
                (void *to, const void __user *from, unsigned long n);
unsigned long __must_check __copy_from_user_ll_nozero
                (void *to, const void __user *from, unsigned long n);
unsigned long __must_check __copy_from_user_ll_nocache
                (void *to, const void __user *from, unsigned long n);
unsigned long __must_check __copy_from_user_ll_nocache_nozero
                (void *to, const void __user *from, unsigned long n);

/**
 * __copy_to_user_inatomic: - 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.
 *
 * Copy data from kernel space to user space.  Caller must check
 * the specified block with access_ok() before calling this function.
 * The caller should also make sure he pins the user space address
 * so that the we don't result in page fault and sleep.
 *
 * Here we special-case 1, 2 and 4-byte copy_*_user invocations.  On a fault
 * we return the initial request size (1, 2 or 4), as copy_*_user should do.
 * If a store crosses a page boundary and gets a fault, the x86 will not write
 * anything, so this is accurate.
 */

static __always_inline unsigned long __must_check
__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
{
        if (__builtin_constant_p(n)) {
                unsigned long ret;

                switch (n) {
                case 1:
                        __put_user_size(*(u8 *)from, (u8 __user *)to,
                                        1, ret, 1);
                        return ret;
                case 2:
                        __put_user_size(*(u16 *)from, (u16 __user *)to,
                                        2, ret, 2);
                        return ret;
                case 4:
                        __put_user_size(*(u32 *)from, (u32 __user *)to,
                                        4, ret, 4);
                        return ret;
                }
        }
        return __copy_to_user_ll(to, from, n);
}

/**
 * __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.
 */
static __always_inline unsigned long __must_check
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
       might_sleep();
       return __copy_to_user_inatomic(to, from, n);
}

static __always_inline unsigned long
__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
{
        /* Avoid zeroing the tail if the copy fails..
         * If 'n' is constant and 1, 2, or 4, we do still zero on a failure,
         * but as the zeroing behaviour is only significant when n is not
         * constant, that shouldn't be a problem.
         */
        if (__builtin_constant_p(n)) {
                unsigned long ret;

                switch (n) {
                case 1:
                        __get_user_size(*(u8 *)to, from, 1, ret, 1);
                        return ret;
                case 2:
                        __get_user_size(*(u16 *)to, from, 2, ret, 2);
                        return ret;
                case 4:
                        __get_user_size(*(u32 *)to, from, 4, ret, 4);
                        return ret;
                }
        }
        return __copy_from_user_ll_nozero(to, from, n);
}

/**
 * __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.
 *
 * An alternate version - __copy_from_user_inatomic() - may be called from
 * atomic context and will fail rather than sleep.  In this case the
 * uncopied bytes will *NOT* be padded with zeros.  See fs/filemap.h
 * for explanation of why this is needed.
 */
static __always_inline unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
        might_sleep();
        if (__builtin_constant_p(n)) {
                unsigned long ret;

                switch (n) {
                case 1:
                        __get_user_size(*(u8 *)to, from, 1, ret, 1);
                        return ret;
                case 2:
                        __get_user_size(*(u16 *)to, from, 2, ret, 2);
                        return ret;
                case 4:
                        __get_user_size(*(u32 *)to, from, 4, ret, 4);
                        return ret;
                }
        }
        return __copy_from_user_ll(to, from, n);
}

#define ARCH_HAS_NOCACHE_UACCESS

static __always_inline unsigned long __copy_from_user_nocache(void *to,
                                const void __user *from, unsigned long n)
{
        might_sleep();
        if (__builtin_constant_p(n)) {
                unsigned long ret;

                switch (n) {
                case 1:
                        __get_user_size(*(u8 *)to, from, 1, ret, 1);
                        return ret;
                case 2:
                        __get_user_size(*(u16 *)to, from, 2, ret, 2);
                        return ret;
                case 4:
                        __get_user_size(*(u32 *)to, from, 4, ret, 4);
                        return ret;
                }
        }
        return __copy_from_user_ll_nocache(to, from, n);
}

static __always_inline unsigned long
__copy_from_user_inatomic_nocache(void *to, const void __user *from,
                                  unsigned long n)
{
       return __copy_from_user_ll_nocache_nozero(to, from, n);
}

unsigned long __must_check copy_to_user(void __user *to,
                                        const void *from, unsigned long n);
unsigned long __must_check copy_from_user(void *to,
                                          const void __user *from,
                                          unsigned long n);
long __must_check strncpy_from_user(char *dst, const char __user *src,
                                    long count);
long __must_check __strncpy_from_user(char *dst,
                                      const char __user *src, long count);

/**
 * 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.
 */
#define strlen_user(str) strnlen_user(str, LONG_MAX)

long strnlen_user(const char __user *str, long n);
unsigned long __must_check clear_user(void __user *mem, unsigned long len);
unsigned long __must_check __clear_user(void __user *mem, unsigned long len);

#endif /* __i386_UACCESS_H */