uaccess.h

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#ifndef _ASM_IA64_UACCESS_H
#define _ASM_IA64_UACCESS_H

/*
 * This file defines various macros to transfer memory areas across
 * the user/kernel boundary.  This needs to be done carefully because
 * this code is executed in kernel mode and uses user-specified
 * addresses.  Thus, we need to be careful not to let the user to
 * trick us into accessing kernel memory that would normally be
 * inaccessible.  This code is also fairly performance sensitive,
 * so we want to spend as little time doing safety checks as
 * possible.
 *
 * To make matters a bit more interesting, these macros sometimes also
 * called from within the kernel itself, in which case the address
 * validity check must be skipped.  The get_fs() macro tells us what
 * to do: if get_fs()==USER_DS, checking is performed, if
 * get_fs()==KERNEL_DS, checking is bypassed.
 *
 * Note that even if the memory area specified by the user is in a
 * valid address range, it is still possible that we'll get a page
 * fault while accessing it.  This is handled by filling out an
 * exception handler fixup entry for each instruction that has the
 * potential to fault.  When such a fault occurs, the page fault
 * handler checks to see whether the faulting instruction has a fixup
 * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and
 * then resumes execution at the continuation point.
 *
 * Based on <asm-alpha/uaccess.h>.
 *
 * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co
 *  David Mosberger-Tang <[email protected]>
 */

#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/page-flags.h>
#include <linux/mm.h>

#include <asm/intrinsics.h>
#include <asm/pgtable.h>
#include <asm/io.h>

/*
 * For historical reasons, the following macros are grossly misnamed:
 */
#define KERNEL_DS   ((mm_segment_t) { ~0UL })       /* cf. access_ok() */
#define USER_DS     ((mm_segment_t) { TASK_SIZE-1 })    /* cf. access_ok() */

#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)

/*
 * When accessing user memory, we need to make sure the entire area really is in
 * user-level space.  In order to do this efficiently, we make sure that the page at
 * address TASK_SIZE is never valid.  We also need to make sure that the address doesn't
 * point inside the virtually mapped linear page table.
 */
#define __access_ok(addr, size, segment)                        \
({                                          \
    __chk_user_ptr(addr);                               \
    (likely((unsigned long) (addr) <= (segment).seg)                \
     && ((segment).seg == KERNEL_DS.seg                     \
         || likely(REGION_OFFSET((unsigned long) (addr)) < RGN_MAP_LIMIT)));    \
})
#define access_ok(type, addr, size) __access_ok((addr), (size), get_fs())

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 *
 * Careful to not
 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
 * (b) require any knowledge of processes at this stage
 */
#define put_user(x, ptr)    __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)), get_fs())
#define get_user(x, ptr)    __get_user_check((x), (ptr), sizeof(*(ptr)), get_fs())

/*
 * The "__xxx" versions do not do address space checking, useful when
 * doing multiple accesses to the same area (the programmer has to do the
 * checks by hand with "access_ok()")
 */
#define __put_user(x, ptr)  __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
#define __get_user(x, ptr)  __get_user_nocheck((x), (ptr), sizeof(*(ptr)))

extern long __put_user_unaligned_unknown (void);

#define __put_user_unaligned(x, ptr)                                \
({                                              \
    long __ret;                                     \
    switch (sizeof(*(ptr))) {                               \
        case 1: __ret = __put_user((x), (ptr)); break;                  \
        case 2: __ret = (__put_user((x), (u8 __user *)(ptr)))               \
            | (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;      \
        case 4: __ret = (__put_user((x), (u16 __user *)(ptr)))              \
            | (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;        \
        case 8: __ret = (__put_user((x), (u32 __user *)(ptr)))              \
            | (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;        \
        default: __ret = __put_user_unaligned_unknown();                \
    }                                           \
    __ret;                                          \
})

extern long __get_user_unaligned_unknown (void);

#define __get_user_unaligned(x, ptr)                                \
({                                              \
    long __ret;                                     \
    switch (sizeof(*(ptr))) {                               \
        case 1: __ret = __get_user((x), (ptr)); break;                  \
        case 2: __ret = (__get_user((x), (u8 __user *)(ptr)))               \
            | (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break;      \
        case 4: __ret = (__get_user((x), (u16 __user *)(ptr)))              \
            | (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break;        \
        case 8: __ret = (__get_user((x), (u32 __user *)(ptr)))              \
            | (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break;        \
        default: __ret = __get_user_unaligned_unknown();                \
    }                                           \
    __ret;                                          \
})

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

/* We need to declare the __ex_table section before we can use it in .xdata.  */
asm (".section \"__ex_table\", \"a\"\n\t.previous");

# define __get_user_size(val, addr, n, err)                         \
do {                                                \
    register long __gu_r8 asm ("r8") = 0;                           \
    register long __gu_r9 asm ("r9");                           \
    asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \
         "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n"                     \
         "[1:]"                                     \
         : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8));            \
    (err) = __gu_r8;                                    \
    (val) = __gu_r9;                                    \
} while (0)

/*
 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it.  This
 * is because they do not write to any memory gcc knows about, so there are no aliasing
 * issues.
 */
# define __put_user_size(val, addr, n, err)                         \
do {                                                \
    register long __pu_r8 asm ("r8") = 0;                           \
    asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \
              "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n"                  \
              "[1:]"                                    \
              : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8));       \
    (err) = __pu_r8;                                    \
} while (0)

#else /* !ASM_SUPPORTED */
# define RELOC_TYPE 2   /* ip-rel */
# define __get_user_size(val, addr, n, err)             \
do {                                    \
    __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE);   \
    (err) = ia64_getreg(_IA64_REG_R8);              \
    (val) = ia64_getreg(_IA64_REG_R9);              \
} while (0)
# define __put_user_size(val, addr, n, err)                         \
do {                                                \
    __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, (unsigned long) (val));    \
    (err) = ia64_getreg(_IA64_REG_R8);                          \
} while (0)
#endif /* !ASM_SUPPORTED */

extern void __get_user_unknown (void);

/*
 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 * could clobber r8 and r9 (among others).  Thus, be careful not to evaluate it while
 * using r8/r9.
 */
#define __do_get_user(check, x, ptr, size, segment)                 \
({                                          \
    const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);              \
    __typeof__ (size) __gu_size = (size);                       \
    long __gu_err = -EFAULT;                            \
    unsigned long __gu_val = 0;                         \
    if (!check || __access_ok(__gu_ptr, size, segment))             \
        switch (__gu_size) {                            \
              case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break;  \
              case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break;  \
              case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break;  \
              case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break;  \
              default: __get_user_unknown(); break;             \
        }                                   \
    (x) = (__typeof__(*(__gu_ptr))) __gu_val;                   \
    __gu_err;                                   \
})

#define __get_user_nocheck(x, ptr, size)    __do_get_user(0, x, ptr, size, KERNEL_DS)
#define __get_user_check(x, ptr, size, segment) __do_get_user(1, x, ptr, size, segment)

extern void __put_user_unknown (void);

/*
 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which
 * could clobber r8 (among others).  Thus, be careful not to evaluate them while using r8.
 */
#define __do_put_user(check, x, ptr, size, segment)                 \
({                                          \
    __typeof__ (x) __pu_x = (x);                            \
    __typeof__ (*(ptr)) __user *__pu_ptr = (ptr);                   \
    __typeof__ (size) __pu_size = (size);                       \
    long __pu_err = -EFAULT;                            \
                                            \
    if (!check || __access_ok(__pu_ptr, __pu_size, segment))            \
        switch (__pu_size) {                            \
              case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break;    \
              case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break;    \
              case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break;    \
              case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break;    \
              default: __put_user_unknown(); break;             \
        }                                   \
    __pu_err;                                   \
})

#define __put_user_nocheck(x, ptr, size)    __do_put_user(0, x, ptr, size, KERNEL_DS)
#define __put_user_check(x, ptr, size, segment) __do_put_user(1, x, ptr, size, segment)

/*
 * Complex access routines
 */
extern unsigned long __must_check __copy_user (void __user *to, const void __user *from,
                           unsigned long count);

static inline unsigned long
__copy_to_user (void __user *to, const void *from, unsigned long count)
{
    return __copy_user(to, (__force void __user *) from, count);
}

static inline unsigned long
__copy_from_user (void *to, const void __user *from, unsigned long count)
{
    return __copy_user((__force void __user *) to, from, count);
}

#define __copy_to_user_inatomic     __copy_to_user
#define __copy_from_user_inatomic   __copy_from_user
#define copy_to_user(to, from, n)                           \
({                                          \
    void __user *__cu_to = (to);                            \
    const void *__cu_from = (from);                         \
    long __cu_len = (n);                                \
                                            \
    if (__access_ok(__cu_to, __cu_len, get_fs()))                   \
        __cu_len = __copy_user(__cu_to, (__force void __user *) __cu_from, __cu_len);   \
    __cu_len;                                   \
})

#define copy_from_user(to, from, n)                         \
({                                          \
    void *__cu_to = (to);                               \
    const void __user *__cu_from = (from);                      \
    long __cu_len = (n);                                \
                                            \
    __chk_user_ptr(__cu_from);                          \
    if (__access_ok(__cu_from, __cu_len, get_fs()))                 \
        __cu_len = __copy_user((__force void __user *) __cu_to, __cu_from, __cu_len);   \
    __cu_len;                                   \
})

#define __copy_in_user(to, from, size)  __copy_user((to), (from), (size))

static inline unsigned long
copy_in_user (void __user *to, const void __user *from, unsigned long n)
{
    if (likely(access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)))
        n = __copy_user(to, from, n);
    return n;
}

extern unsigned long __do_clear_user (void __user *, unsigned long);

#define __clear_user(to, n)     __do_clear_user(to, n)

#define clear_user(to, n)                   \
({                              \
    unsigned long __cu_len = (n);               \
    if (__access_ok(to, __cu_len, get_fs()))        \
        __cu_len = __do_clear_user(to, __cu_len);   \
    __cu_len;                       \
})


/*
 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else
 * strlen.
 */
extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len);

#define strncpy_from_user(to, from, n)                  \
({                                  \
    const char __user * __sfu_from = (from);            \
    long __sfu_ret = -EFAULT;                   \
    if (__access_ok(__sfu_from, 0, get_fs()))           \
        __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \
    __sfu_ret;                          \
})

/* Returns: 0 if bad, string length+1 (memory size) of string if ok */
extern unsigned long __strlen_user (const char __user *);

#define strlen_user(str)                \
({                          \
    const char __user *__su_str = (str);        \
    unsigned long __su_ret = 0;         \
    if (__access_ok(__su_str, 0, get_fs()))     \
        __su_ret = __strlen_user(__su_str); \
    __su_ret;                   \
})

/*
 * Returns: 0 if exception before NUL or reaching the supplied limit
 * (N), a value greater than N if the limit would be exceeded, else
 * strlen.
 */
extern unsigned long __strnlen_user (const char __user *, long);

#define strnlen_user(str, len)                  \
({                              \
    const char __user *__su_str = (str);            \
    unsigned long __su_ret = 0;             \
    if (__access_ok(__su_str, 0, get_fs()))         \
        __su_ret = __strnlen_user(__su_str, len);   \
    __su_ret;                       \
})

/* Generic code can't deal with the location-relative format that we use for compactness.  */
#define ARCH_HAS_SORT_EXTABLE
#define ARCH_HAS_SEARCH_EXTABLE

struct exception_table_entry {
    int addr;   /* location-relative address of insn this fixup is for */
    int cont;   /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
};

extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
extern const struct exception_table_entry *search_exception_tables (unsigned long addr);

static inline int
ia64_done_with_exception (struct pt_regs *regs)
{
    const struct exception_table_entry *e;
    e = search_exception_tables(regs->cr_iip + ia64_psr(regs)->ri);
    if (e) {
        ia64_handle_exception(regs, e);
        return 1;
    }
    return 0;
}

#define ARCH_HAS_TRANSLATE_MEM_PTR  1
static __inline__ char *
xlate_dev_mem_ptr (unsigned long p)
{
    struct page *page;
    char * ptr;

    page = pfn_to_page(p >> PAGE_SHIFT);
    if (PageUncached(page))
        ptr = (char *)p + __IA64_UNCACHED_OFFSET;
    else
        ptr = __va(p);

    return ptr;
}

/*
 * Convert a virtual cached kernel memory pointer to an uncached pointer
 */
static __inline__ char *
xlate_dev_kmem_ptr (char * p)
{
    struct page *page;
    char * ptr;

    page = virt_to_page((unsigned long)p);
    if (PageUncached(page))
        ptr = (char *)__pa(p) + __IA64_UNCACHED_OFFSET;
    else
        ptr = p;

    return ptr;
}

#endif /* _ASM_IA64_UACCESS_H */