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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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#ifndef _ASM_TILE_UACCESS_H
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#define _ASM_TILE_UACCESS_H
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* User space memory access functions
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#include <linux/sched.h>
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#include <asm-generic/uaccess-unaligned.h>
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#include <asm/processor.h>
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#define VERIFY_WRITE 1
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* The fs value determines whether argument validity checking should be
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* performed or not. If get_fs() == USER_DS, checking is performed, with
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* get_fs() == KERNEL_DS, checking is bypassed.
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* For historical reasons, these macros are grossly misnamed.
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#define MAKE_MM_SEG(a) ((mm_segment_t) { (a) })
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#define KERNEL_DS MAKE_MM_SEG(-1UL)
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#define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
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#define get_ds() (KERNEL_DS)
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#define get_fs() (current_thread_info()->addr_limit)
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#define set_fs(x) (current_thread_info()->addr_limit = (x))
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#define segment_eq(a, b) ((a).seg == (b).seg)
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* We could allow mapping all 16 MB at 0xfc000000, but we set up a
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* special hack in arch_setup_additional_pages() to auto-create a mapping
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* for the first 16 KB, and it would seem strange to have different
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* user-accessible semantics for memory at 0xfc000000 and above 0xfc004000.
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static inline int is_arch_mappable_range(unsigned long addr,
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return (addr >= MEM_USER_INTRPT &&
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addr < (MEM_USER_INTRPT + INTRPT_SIZE) &&
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size <= (MEM_USER_INTRPT + INTRPT_SIZE) - addr);
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#define is_arch_mappable_range is_arch_mappable_range
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#define is_arch_mappable_range(addr, size) 0
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* Test whether a block of memory is a valid user space address.
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* Returns 0 if the range is valid, nonzero otherwise.
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int __range_ok(unsigned long addr, unsigned long size);
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* access_ok: - Checks if a user space pointer is valid
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* @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
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* %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
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* to write to a block, it is always safe to read from it.
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* @addr: User space pointer to start of block to check
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* @size: Size of block to check
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* Context: User context only. This function may sleep.
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* Checks if a pointer to a block of memory in user space is valid.
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* Returns true (nonzero) if the memory block may be valid, false (zero)
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* if it is definitely invalid.
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* Note that, depending on architecture, this function probably just
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* checks that the pointer is in the user space range - after calling
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* this function, memory access functions may still return -EFAULT.
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#define access_ok(type, addr, size) ({ \
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__chk_user_ptr(addr); \
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likely(__range_ok((unsigned long)(addr), (size)) == 0); \
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* The exception table consists of pairs of addresses: the first is the
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* address of an instruction that is allowed to fault, and the second is
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* the address at which the program should continue. No registers are
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* modified, so it is entirely up to the continuation code to figure out
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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struct exception_table_entry {
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unsigned long insn, fixup;
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extern int fixup_exception(struct pt_regs *regs);
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* We return the __get_user_N function results in a structure,
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* thus in r0 and r1. If "err" is zero, "val" is the result
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* of the read; otherwise, "err" is -EFAULT.
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* We rarely need 8-byte values on a 32-bit architecture, but
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* we size the structure to accommodate. In practice, for the
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* the smaller reads, we can zero the high word for free, and
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* the caller will ignore it by virtue of casting anyway.
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unsigned long long val;
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* FIXME: we should express these as inline extended assembler, since
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* they're fundamentally just a variable dereference and some
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* supporting exception_table gunk. Note that (a la i386) we can
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* extend the copy_to_user and copy_from_user routines to call into
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* such extended assembler routines, though we will have to use a
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* different return code in that case (1, 2, or 4, rather than -EFAULT).
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extern struct __get_user __get_user_1(const void __user *);
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extern struct __get_user __get_user_2(const void __user *);
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extern struct __get_user __get_user_4(const void __user *);
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extern struct __get_user __get_user_8(const void __user *);
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extern int __put_user_1(long, void __user *);
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extern int __put_user_2(long, void __user *);
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extern int __put_user_4(long, void __user *);
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extern int __put_user_8(long long, void __user *);
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/* Unimplemented routines to cause linker failures */
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extern struct __get_user __get_user_bad(void);
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extern int __put_user_bad(void);
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* Careful: we have to cast the result to the type of the pointer
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* __get_user: - Get a simple variable from user space, with less checking.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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* Context: User context only. This function may sleep.
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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* Caller must check the pointer with access_ok() before calling this
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#define __get_user(x, ptr) \
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({ struct __get_user __ret; \
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__typeof__(*(ptr)) const __user *__gu_addr = (ptr); \
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__chk_user_ptr(__gu_addr); \
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switch (sizeof(*(__gu_addr))) { \
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__ret = __get_user_1(__gu_addr); \
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__ret = __get_user_2(__gu_addr); \
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__ret = __get_user_4(__gu_addr); \
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__ret = __get_user_8(__gu_addr); \
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__ret = __get_user_bad(); \
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(x) = (__typeof__(*__gu_addr)) (__typeof__(*__gu_addr - *__gu_addr)) \
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* __put_user: - Write a simple value into user space, with less checking.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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* Context: User context only. This function may sleep.
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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* Caller must check the pointer with access_ok() before calling this
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* Returns zero on success, or -EFAULT on error.
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* Implementation note: The "case 8" logic of casting to the type of
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* the result of subtracting the value from itself is basically a way
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* of keeping all integer types the same, but casting any pointers to
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* ptrdiff_t, i.e. also an integer type. This way there are no
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* questionable casts seen by the compiler on an ILP32 platform.
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#define __put_user(x, ptr) \
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__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
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typeof(*__pu_addr) __pu_val = (x); \
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__chk_user_ptr(__pu_addr); \
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switch (sizeof(__pu_val)) { \
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__pu_err = __put_user_1((long)__pu_val, __pu_addr); \
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__pu_err = __put_user_2((long)__pu_val, __pu_addr); \
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__pu_err = __put_user_4((long)__pu_val, __pu_addr); \
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__put_user_8((__typeof__(__pu_val - __pu_val))__pu_val,\
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__pu_err = __put_user_bad(); \
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* The versions of get_user and put_user without initial underscores
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* check the address of their arguments to make sure they are not
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#define put_user(x, ptr) \
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__typeof__(*(ptr)) __user *__Pu_addr = (ptr); \
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access_ok(VERIFY_WRITE, (__Pu_addr), sizeof(*(__Pu_addr))) ? \
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__put_user((x), (__Pu_addr)) : \
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#define get_user(x, ptr) \
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__typeof__(*(ptr)) const __user *__Gu_addr = (ptr); \
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access_ok(VERIFY_READ, (__Gu_addr), sizeof(*(__Gu_addr))) ? \
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__get_user((x), (__Gu_addr)) : \
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((x) = 0, -EFAULT); \
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* __copy_to_user() - copy data into user space, with less checking.
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* @to: Destination address, in user space.
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* @from: Source address, in kernel space.
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* @n: Number of bytes to copy.
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* Context: User context only. This function may sleep.
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* Copy data from kernel space to user space. Caller must check
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* the specified block with access_ok() before calling this function.
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* Returns number of bytes that could not be copied.
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* On success, this will be zero.
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* An alternate version - __copy_to_user_inatomic() - is designed
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* to be called from atomic context, typically bracketed by calls
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* to pagefault_disable() and pagefault_enable().
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extern unsigned long __must_check __copy_to_user_inatomic(
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void __user *to, const void *from, unsigned long n);
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static inline unsigned long __must_check
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__copy_to_user(void __user *to, const void *from, unsigned long n)
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return __copy_to_user_inatomic(to, from, n);
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static inline unsigned long __must_check
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copy_to_user(void __user *to, const void *from, unsigned long n)
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if (access_ok(VERIFY_WRITE, to, n))
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n = __copy_to_user(to, from, n);
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* __copy_from_user() - copy data from user space, with less checking.
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* @to: Destination address, in kernel space.
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* @from: Source address, in user space.
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* @n: Number of bytes to copy.
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* Context: User context only. This function may sleep.
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* Copy data from user space to kernel space. Caller must check
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* the specified block with access_ok() before calling this function.
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* Returns number of bytes that could not be copied.
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* On success, this will be zero.
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* If some data could not be copied, this function will pad the copied
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* data to the requested size using zero bytes.
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* An alternate version - __copy_from_user_inatomic() - is designed
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* to be called from atomic context, typically bracketed by calls
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* to pagefault_disable() and pagefault_enable(). This version
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* does *NOT* pad with zeros.
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extern unsigned long __must_check __copy_from_user_inatomic(
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void *to, const void __user *from, unsigned long n);
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extern unsigned long __must_check __copy_from_user_zeroing(
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void *to, const void __user *from, unsigned long n);
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static inline unsigned long __must_check
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__copy_from_user(void *to, const void __user *from, unsigned long n)
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return __copy_from_user_zeroing(to, from, n);
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static inline unsigned long __must_check
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_copy_from_user(void *to, const void __user *from, unsigned long n)
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if (access_ok(VERIFY_READ, from, n))
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n = __copy_from_user(to, from, n);
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#ifdef CONFIG_DEBUG_COPY_FROM_USER
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extern void copy_from_user_overflow(void)
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__compiletime_warning("copy_from_user() size is not provably correct");
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static inline unsigned long __must_check copy_from_user(void *to,
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const void __user *from,
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int sz = __compiletime_object_size(to);
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if (likely(sz == -1 || sz >= n))
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n = _copy_from_user(to, from, n);
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copy_from_user_overflow();
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#define copy_from_user _copy_from_user
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* __copy_in_user() - copy data within user space, with less checking.
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* @to: Destination address, in user space.
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* @from: Source address, in kernel space.
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* @n: Number of bytes to copy.
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* Context: User context only. This function may sleep.
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* Copy data from user space to user space. Caller must check
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* the specified blocks with access_ok() before calling this function.
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* Returns number of bytes that could not be copied.
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* On success, this will be zero.
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extern unsigned long __copy_in_user_inatomic(
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void __user *to, const void __user *from, unsigned long n);
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static inline unsigned long __must_check
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__copy_in_user(void __user *to, const void __user *from, unsigned long n)
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return __copy_in_user_inatomic(to, from, n);
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static inline unsigned long __must_check
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copy_in_user(void __user *to, const void __user *from, unsigned long n)
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if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n))
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n = __copy_in_user(to, from, n);
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* strlen_user: - Get the size of a string in user space.
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* @str: The string to measure.
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* Context: User context only. This function may sleep.
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* Get the size of a NUL-terminated string in user space.
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* Returns the size of the string INCLUDING the terminating NUL.
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* On exception, returns 0.
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* If there is a limit on the length of a valid string, you may wish to
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* consider using strnlen_user() instead.
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extern long strnlen_user_asm(const char __user *str, long n);
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static inline long __must_check strnlen_user(const char __user *str, long n)
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return strnlen_user_asm(str, n);
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#define strlen_user(str) strnlen_user(str, LONG_MAX)
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* strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
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* @dst: Destination address, in kernel space. This buffer must be at
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* least @count bytes long.
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* @src: Source address, in user space.
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* @count: Maximum number of bytes to copy, including the trailing NUL.
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* Copies a NUL-terminated string from userspace to kernel space.
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* Caller must check the specified block with access_ok() before calling
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* On success, returns the length of the string (not including the trailing
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* If access to userspace fails, returns -EFAULT (some data may have been
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* If @count is smaller than the length of the string, copies @count bytes
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* and returns @count.
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extern long strncpy_from_user_asm(char *dst, const char __user *src, long);
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static inline long __must_check __strncpy_from_user(
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char *dst, const char __user *src, long count)
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return strncpy_from_user_asm(dst, src, count);
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static inline long __must_check strncpy_from_user(
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char *dst, const char __user *src, long count)
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if (access_ok(VERIFY_READ, src, 1))
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return __strncpy_from_user(dst, src, count);
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* clear_user: - Zero a block of memory in user space.
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* @mem: Destination address, in user space.
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* @len: Number of bytes to zero.
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* Zero a block of memory in user space.
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* Returns number of bytes that could not be cleared.
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* On success, this will be zero.
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extern unsigned long clear_user_asm(void __user *mem, unsigned long len);
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static inline unsigned long __must_check __clear_user(
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void __user *mem, unsigned long len)
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return clear_user_asm(mem, len);
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static inline unsigned long __must_check clear_user(
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void __user *mem, unsigned long len)
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if (access_ok(VERIFY_WRITE, mem, len))
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return __clear_user(mem, len);
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* flush_user: - Flush a block of memory in user space from cache.
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* @mem: Destination address, in user space.
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* @len: Number of bytes to flush.
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* Returns number of bytes that could not be flushed.
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* On success, this will be zero.
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extern unsigned long flush_user_asm(void __user *mem, unsigned long len);
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static inline unsigned long __must_check __flush_user(
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void __user *mem, unsigned long len)
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retval = flush_user_asm(mem, len);
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static inline unsigned long __must_check flush_user(
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void __user *mem, unsigned long len)
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if (access_ok(VERIFY_WRITE, mem, len))
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return __flush_user(mem, len);
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* inv_user: - Invalidate a block of memory in user space from cache.
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* @mem: Destination address, in user space.
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* @len: Number of bytes to invalidate.
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* Returns number of bytes that could not be invalidated.
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* On success, this will be zero.
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* Note that on Tile64, the "inv" operation is in fact a
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* "flush and invalidate", so cache write-backs will occur prior
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* to the cache being marked invalid.
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extern unsigned long inv_user_asm(void __user *mem, unsigned long len);
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static inline unsigned long __must_check __inv_user(
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void __user *mem, unsigned long len)
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retval = inv_user_asm(mem, len);
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static inline unsigned long __must_check inv_user(
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void __user *mem, unsigned long len)
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if (access_ok(VERIFY_WRITE, mem, len))
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return __inv_user(mem, len);
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* finv_user: - Flush-inval a block of memory in user space from cache.
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* @mem: Destination address, in user space.
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* @len: Number of bytes to invalidate.
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* Returns number of bytes that could not be flush-invalidated.
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* On success, this will be zero.
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extern unsigned long finv_user_asm(void __user *mem, unsigned long len);
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static inline unsigned long __must_check __finv_user(
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void __user *mem, unsigned long len)
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retval = finv_user_asm(mem, len);
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static inline unsigned long __must_check finv_user(
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void __user *mem, unsigned long len)
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if (access_ok(VERIFY_WRITE, mem, len))
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return __finv_user(mem, len);
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#endif /* _ASM_TILE_UACCESS_H */