Merge tag 'gpio-v3.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw...

[linux-2.6.git] / arch / x86 / include / asm / uaccess.h

#ifndef _ASM_X86_UACCESS_H
#define _ASM_X86_UACCESS_H
/*
 * User space memory access functions
 */
#include <linux/errno.h>
#include <linux/compiler.h>
#include <linux/thread_info.h>
#include <linux/string.h>
#include <asm/asm.h>
#include <asm/page.h>
#include <asm/smap.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(-1UL)
#define USER_DS         MAKE_MM_SEG(TASK_SIZE_MAX)

#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)

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

/*
 * 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 (u65 for x86_64)
 *
 * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry...
 */

#define __range_not_ok(addr, size, limit)                               \
({                                                                      \
        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" ((long)(size)),                           \
              "rm" (limit));                                            \
        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, user_addr_max()) == 0))

/*
 * The exception table consists of pairs of addresses relative to the
 * exception table enty itself: 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 {
        int insn, fixup;
};
/* This is not the generic standard exception_table_entry format */
#define ARCH_HAS_SORT_EXTABLE
#define ARCH_HAS_SEARCH_EXTABLE

extern int fixup_exception(struct pt_regs *regs);
extern int early_fixup_exception(unsigned long *ip);

/*
 * 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 int __get_user_1(void);
extern int __get_user_2(void);
extern int __get_user_4(void);
extern int __get_user_8(void);
extern int __get_user_bad(void);

/*
 * This is a type: either unsigned long, if the argument fits into
 * that type, or otherwise unsigned long long.
 */
#define __inttype(x) \
__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))

/**
 * 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.
 */
/*
 * Careful: we have to cast the result to the type of the pointer
 * for sign reasons.
 *
 * The use of _ASM_DX as the register specifier is a bit of a
 * simplification, as gcc only cares about it as the starting point
 * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits
 * (%ecx being the next register in gcc's x86 register sequence), and
 * %rdx on 64 bits.
 *
 * Clang/LLVM cares about the size of the register, but still wants
 * the base register for something that ends up being a pair.
 */
#define get_user(x, ptr)                                                \
({                                                                      \
        int __ret_gu;                                                   \
        register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX);            \
        __chk_user_ptr(ptr);                                            \
        might_fault();                                                  \
        asm volatile("call __get_user_%P3"                              \
                     : "=a" (__ret_gu), "=r" (__val_gu)                 \
                     : "0" (ptr), "i" (sizeof(*(ptr))));                \
        (x) = (__typeof__(*(ptr))) __val_gu;                            \
        __ret_gu;                                                       \
})

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



#ifdef CONFIG_X86_32
#define __put_user_asm_u64(x, addr, err, errret)                        \
        asm volatile(ASM_STAC "\n"                                      \
                     "1:        movl %%eax,0(%2)\n"                     \
                     "2:        movl %%edx,4(%2)\n"                     \
                     "3: " ASM_CLAC "\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" (errret), "0" (err))

#define __put_user_asm_ex_u64(x, addr)                                  \
        asm volatile(ASM_STAC "\n"                                      \
                     "1:        movl %%eax,0(%1)\n"                     \
                     "2:        movl %%edx,4(%1)\n"                     \
                     "3: " ASM_CLAC "\n"                                \
                     _ASM_EXTABLE_EX(1b, 2b)                            \
                     _ASM_EXTABLE_EX(2b, 3b)                            \
                     : : "A" (x), "r" (addr))

#define __put_user_x8(x, ptr, __ret_pu)                         \
        asm volatile("call __put_user_8" : "=a" (__ret_pu)      \
                     : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
#else
#define __put_user_asm_u64(x, ptr, retval, errret) \
        __put_user_asm(x, ptr, retval, "q", "", "er", errret)
#define __put_user_asm_ex_u64(x, addr)  \
        __put_user_asm_ex(x, addr, "q", "", "er")
#define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
#endif

extern void __put_user_bad(void);

/*
 * Strange magic calling convention: pointer in %ecx,
 * value in %eax(:%edx), return value in %eax. clobbers %rbx
 */
extern void __put_user_1(void);
extern void __put_user_2(void);
extern void __put_user_4(void);
extern void __put_user_8(void);

/**
 * 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)                                        \
({                                                              \
        int __ret_pu;                                           \
        __typeof__(*(ptr)) __pu_val;                            \
        __chk_user_ptr(ptr);                                    \
        might_fault();                                          \
        __pu_val = x;                                           \
        switch (sizeof(*(ptr))) {                               \
        case 1:                                                 \
                __put_user_x(1, __pu_val, ptr, __ret_pu);       \
                break;                                          \
        case 2:                                                 \
                __put_user_x(2, __pu_val, ptr, __ret_pu);       \
                break;                                          \
        case 4:                                                 \
                __put_user_x(4, __pu_val, ptr, __ret_pu);       \
                break;                                          \
        case 8:                                                 \
                __put_user_x8(__pu_val, ptr, __ret_pu);         \
                break;                                          \
        default:                                                \
                __put_user_x(X, __pu_val, ptr, __ret_pu);       \
                break;                                          \
        }                                                       \
        __ret_pu;                                               \
})

#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", "k", "ir", errret); \
                break;                                                  \
        case 8:                                                         \
                __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval,  \
                                   errret);                             \
                break;                                                  \
        default:                                                        \
                __put_user_bad();                                       \
        }                                                               \
} while (0)

#define __put_user_size_ex(x, ptr, size)                                \
do {                                                                    \
        __chk_user_ptr(ptr);                                            \
        switch (size) {                                                 \
        case 1:                                                         \
                __put_user_asm_ex(x, ptr, "b", "b", "iq");              \
                break;                                                  \
        case 2:                                                         \
                __put_user_asm_ex(x, ptr, "w", "w", "ir");              \
                break;                                                  \
        case 4:                                                         \
                __put_user_asm_ex(x, ptr, "l", "k", "ir");              \
                break;                                                  \
        case 8:                                                         \
                __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr);      \
                break;                                                  \
        default:                                                        \
                __put_user_bad();                                       \
        }                                                               \
} while (0)

#ifdef CONFIG_X86_32
#define __get_user_asm_u64(x, ptr, retval, errret)      (x) = __get_user_bad()
#define __get_user_asm_ex_u64(x, ptr)                   (x) = __get_user_bad()
#else
#define __get_user_asm_u64(x, ptr, retval, errret) \
         __get_user_asm(x, ptr, retval, "q", "", "=r", errret)
#define __get_user_asm_ex_u64(x, ptr) \
         __get_user_asm_ex(x, ptr, "q", "", "=r")
#endif

#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", "k", "=r", errret); \
                break;                                                  \
        case 8:                                                         \
                __get_user_asm_u64(x, ptr, retval, errret);             \
                break;                                                  \
        default:                                                        \
                (x) = __get_user_bad();                                 \
        }                                                               \
} while (0)

#define __get_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
        asm volatile(ASM_STAC "\n"                                      \
                     "1:        mov"itype" %2,%"rtype"1\n"              \
                     "2: " ASM_CLAC "\n"                                \
                     ".section .fixup,\"ax\"\n"                         \
                     "3:        mov %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))

#define __get_user_size_ex(x, ptr, size)                                \
do {                                                                    \
        __chk_user_ptr(ptr);                                            \
        switch (size) {                                                 \
        case 1:                                                         \
                __get_user_asm_ex(x, ptr, "b", "b", "=q");              \
                break;                                                  \
        case 2:                                                         \
                __get_user_asm_ex(x, ptr, "w", "w", "=r");              \
                break;                                                  \
        case 4:                                                         \
                __get_user_asm_ex(x, ptr, "l", "k", "=r");              \
                break;                                                  \
        case 8:                                                         \
                __get_user_asm_ex_u64(x, ptr);                          \
                break;                                                  \
        default:                                                        \
                (x) = __get_user_bad();                                 \
        }                                                               \
} while (0)

#define __get_user_asm_ex(x, addr, itype, rtype, ltype)                 \
        asm volatile("1:        mov"itype" %1,%"rtype"0\n"              \
                     "2:\n"                                             \
                     _ASM_EXTABLE_EX(1b, 2b)                            \
                     : ltype(x) : "m" (__m(addr)))

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

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

/* FIXME: this hack is definitely wrong -AK */
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(ASM_STAC "\n"                                      \
                     "1:        mov"itype" %"rtype"1,%2\n"              \
                     "2: " ASM_CLAC "\n"                                \
                     ".section .fixup,\"ax\"\n"                         \
                     "3:        mov %3,%0\n"                            \
                     "  jmp 2b\n"                                       \
                     ".previous\n"                                      \
                     _ASM_EXTABLE(1b, 3b)                               \
                     : "=r"(err)                                        \
                     : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))

#define __put_user_asm_ex(x, addr, itype, rtype, ltype)                 \
        asm volatile("1:        mov"itype" %"rtype"0,%1\n"              \
                     "2:\n"                                             \
                     _ASM_EXTABLE_EX(1b, 2b)                            \
                     : : ltype(x), "m" (__m(addr)))

/*
 * uaccess_try and catch
 */
#define uaccess_try     do {                                            \
        current_thread_info()->uaccess_err = 0;                         \
        stac();                                                         \
        barrier();

#define uaccess_catch(err)                                              \
        clac();                                                         \
        (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0);    \
} while (0)

/**
 * __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 __get_user_unaligned __get_user
#define __put_user_unaligned __put_user

/*
 * {get|put}_user_try and catch
 *
 * get_user_try {
 *      get_user_ex(...);
 * } get_user_catch(err)
 */
#define get_user_try            uaccess_try
#define get_user_catch(err)     uaccess_catch(err)

#define get_user_ex(x, ptr)     do {                                    \
        unsigned long __gue_val;                                        \
        __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr))));       \
        (x) = (__force __typeof__(*(ptr)))__gue_val;                    \
} while (0)

#define put_user_try            uaccess_try
#define put_user_catch(err)     uaccess_catch(err)

#define put_user_ex(x, ptr)                                             \
        __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))

extern unsigned long
copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
extern __must_check long
strncpy_from_user(char *dst, const char __user *src, long count);

extern __must_check long strlen_user(const char __user *str);
extern __must_check 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);

/*
 * 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 ARCH_HAS_NOCACHE_UACCESS 1

#ifdef CONFIG_X86_32
# include <asm/uaccess_32.h>
#else
# include <asm/uaccess_64.h>
#endif

unsigned long __must_check _copy_from_user(void *to, const void __user *from,
                                           unsigned n);
unsigned long __must_check _copy_to_user(void __user *to, const void *from,
                                         unsigned n);

#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
# define copy_user_diag __compiletime_error
#else
# define copy_user_diag __compiletime_warning
#endif

extern void copy_user_diag("copy_from_user() buffer size is too small")
copy_from_user_overflow(void);
extern void copy_user_diag("copy_to_user() buffer size is too small")
copy_to_user_overflow(void) __asm__("copy_from_user_overflow");

#undef copy_user_diag

#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS

extern void
__compiletime_warning("copy_from_user() buffer size is not provably correct")
__copy_from_user_overflow(void) __asm__("copy_from_user_overflow");
#define __copy_from_user_overflow(size, count) __copy_from_user_overflow()

extern void
__compiletime_warning("copy_to_user() buffer size is not provably correct")
__copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
#define __copy_to_user_overflow(size, count) __copy_to_user_overflow()

#else

static inline void
__copy_from_user_overflow(int size, unsigned long count)
{
        WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
}

#define __copy_to_user_overflow __copy_from_user_overflow

#endif

static inline unsigned long __must_check
copy_from_user(void *to, const void __user *from, unsigned long n)
{
        int sz = __compiletime_object_size(to);

        might_fault();

        /*
         * While we would like to have the compiler do the checking for us
         * even in the non-constant size case, any false positives there are
         * a problem (especially when DEBUG_STRICT_USER_COPY_CHECKS, but even
         * without - the [hopefully] dangerous looking nature of the warning
         * would make people go look at the respecitive call sites over and
         * over again just to find that there's no problem).
         *
         * And there are cases where it's just not realistic for the compiler
         * to prove the count to be in range. For example when multiple call
         * sites of a helper function - perhaps in different source files -
         * all doing proper range checking, yet the helper function not doing
         * so again.
         *
         * Therefore limit the compile time checking to the constant size
         * case, and do only runtime checking for non-constant sizes.
         */

        if (likely(sz < 0 || sz >= n))
                n = _copy_from_user(to, from, n);
        else if(__builtin_constant_p(n))
                copy_from_user_overflow();
        else
                __copy_from_user_overflow(sz, n);

        return n;
}

static inline unsigned long __must_check
copy_to_user(void __user *to, const void *from, unsigned long n)
{
        int sz = __compiletime_object_size(from);

        might_fault();

        /* See the comment in copy_from_user() above. */
        if (likely(sz < 0 || sz >= n))
                n = _copy_to_user(to, from, n);
        else if(__builtin_constant_p(n))
                copy_to_user_overflow();
        else
                __copy_to_user_overflow(sz, n);

        return n;
}

#undef __copy_from_user_overflow
#undef __copy_to_user_overflow

#endif /* _ASM_X86_UACCESS_H */