forked from Minki/linux
426 lines
12 KiB
C
426 lines
12 KiB
C
#ifndef __SCORE_UACCESS_H
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#define __SCORE_UACCESS_H
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/thread_info.h>
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#include <asm/extable.h>
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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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 segment_eq(a, b) ((a).seg == (b).seg)
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/*
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* Is a address valid? This does a straighforward calculation rather
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* than tests.
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*
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* Address valid if:
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* - "addr" doesn't have any high-bits set
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* - AND "size" doesn't have any high-bits set
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* - AND "addr+size" doesn't have any high-bits set
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* - OR we are in kernel mode.
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*
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* __ua_size() is a trick to avoid runtime checking of positive constant
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* sizes; for those we already know at compile time that the size is ok.
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*/
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#define __ua_size(size) \
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((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
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/*
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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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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* Checks if a pointer to a block of memory in user space is valid.
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*
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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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*
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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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*/
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#define __access_ok(addr, size) \
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(((long)((get_fs().seg) & \
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((addr) | ((addr) + (size)) | \
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__ua_size(size)))) == 0)
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#define access_ok(type, addr, size) \
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likely(__access_ok((unsigned long)(addr), (size)))
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/*
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* put_user: - Write a simple value into user space.
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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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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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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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*
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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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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
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/*
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* get_user: - Get a simple variable from user space.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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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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*
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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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*
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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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*/
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#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
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/*
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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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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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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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*
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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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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
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/*
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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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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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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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*
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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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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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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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*/
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#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
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struct __large_struct { unsigned long buf[100]; };
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#define __m(x) (*(struct __large_struct __user *)(x))
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/*
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* Yuck. We need two variants, one for 64bit operation and one
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* for 32 bit mode and old iron.
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*/
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extern void __get_user_unknown(void);
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#define __get_user_common(val, size, ptr) \
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do { \
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switch (size) { \
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case 1: \
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__get_user_asm(val, "lb", ptr); \
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break; \
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case 2: \
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__get_user_asm(val, "lh", ptr); \
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break; \
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case 4: \
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__get_user_asm(val, "lw", ptr); \
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break; \
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case 8: \
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if (__copy_from_user((void *)&val, ptr, 8) == 0) \
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__gu_err = 0; \
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else \
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__gu_err = -EFAULT; \
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break; \
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default: \
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__get_user_unknown(); \
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break; \
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} \
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} while (0)
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#define __get_user_nocheck(x, ptr, size) \
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({ \
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long __gu_err = 0; \
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__get_user_common((x), size, ptr); \
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__gu_err; \
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})
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#define __get_user_check(x, ptr, size) \
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({ \
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long __gu_err = -EFAULT; \
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const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
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\
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if (likely(access_ok(VERIFY_READ, __gu_ptr, size))) \
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__get_user_common((x), size, __gu_ptr); \
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else \
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(x) = 0; \
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\
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__gu_err; \
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})
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#define __get_user_asm(val, insn, addr) \
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{ \
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long __gu_tmp; \
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\
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__asm__ __volatile__( \
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"1:" insn " %1, %3\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3:li %0, %4\n" \
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"li %1, 0\n" \
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"j 2b\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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".word 1b, 3b\n" \
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".previous\n" \
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: "=r" (__gu_err), "=r" (__gu_tmp) \
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: "0" (0), "o" (__m(addr)), "i" (-EFAULT)); \
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\
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(val) = (__typeof__(*(addr))) __gu_tmp; \
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}
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/*
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* Yuck. We need two variants, one for 64bit operation and one
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* for 32 bit mode and old iron.
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*/
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#define __put_user_nocheck(val, ptr, size) \
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({ \
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__typeof__(*(ptr)) __pu_val; \
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long __pu_err = 0; \
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\
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__pu_val = (val); \
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switch (size) { \
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case 1: \
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__put_user_asm("sb", ptr); \
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break; \
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case 2: \
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__put_user_asm("sh", ptr); \
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break; \
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case 4: \
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__put_user_asm("sw", ptr); \
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break; \
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case 8: \
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if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0) \
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__pu_err = 0; \
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else \
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__pu_err = -EFAULT; \
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break; \
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default: \
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__put_user_unknown(); \
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break; \
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} \
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__pu_err; \
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})
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#define __put_user_check(val, ptr, size) \
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({ \
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__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
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__typeof__(*(ptr)) __pu_val = (val); \
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long __pu_err = -EFAULT; \
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\
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if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) { \
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switch (size) { \
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case 1: \
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__put_user_asm("sb", __pu_addr); \
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break; \
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case 2: \
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__put_user_asm("sh", __pu_addr); \
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break; \
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case 4: \
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__put_user_asm("sw", __pu_addr); \
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break; \
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case 8: \
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if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\
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__pu_err = 0; \
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else \
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__pu_err = -EFAULT; \
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break; \
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default: \
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__put_user_unknown(); \
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break; \
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} \
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} \
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__pu_err; \
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})
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#define __put_user_asm(insn, ptr) \
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__asm__ __volatile__( \
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"1:" insn " %2, %3\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3:li %0, %4\n" \
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"j 2b\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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".word 1b, 3b\n" \
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".previous\n" \
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: "=r" (__pu_err) \
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: "0" (0), "r" (__pu_val), "o" (__m(ptr)), \
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"i" (-EFAULT));
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extern void __put_user_unknown(void);
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extern int __copy_tofrom_user(void *to, const void *from, unsigned long len);
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static inline unsigned long
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copy_from_user(void *to, const void *from, unsigned long len)
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{
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unsigned long res = len;
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if (likely(access_ok(VERIFY_READ, from, len)))
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res = __copy_tofrom_user(to, from, len);
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if (unlikely(res))
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memset(to + (len - res), 0, res);
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return res;
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}
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static inline unsigned long
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copy_to_user(void *to, const void *from, unsigned long len)
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{
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if (likely(access_ok(VERIFY_WRITE, to, len)))
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len = __copy_tofrom_user(to, from, len);
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return len;
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}
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static inline unsigned long
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__copy_from_user(void *to, const void *from, unsigned long len)
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{
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unsigned long left = __copy_tofrom_user(to, from, len);
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if (unlikely(left))
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memset(to + (len - left), 0, left);
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return left;
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}
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#define __copy_to_user(to, from, len) \
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__copy_tofrom_user((to), (from), (len))
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static inline unsigned long
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__copy_to_user_inatomic(void *to, const void *from, unsigned long len)
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{
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return __copy_to_user(to, from, len);
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}
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static inline unsigned long
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__copy_from_user_inatomic(void *to, const void *from, unsigned long len)
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{
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return __copy_tofrom_user(to, from, len);
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}
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#define __copy_in_user(to, from, len) __copy_tofrom_user(to, from, len)
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static inline unsigned long
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copy_in_user(void *to, const void *from, unsigned long len)
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{
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if (access_ok(VERIFY_READ, from, len) &&
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access_ok(VERFITY_WRITE, to, len))
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return __copy_tofrom_user(to, from, len);
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}
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/*
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* __clear_user: - Zero a block of memory in user space, with less checking.
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* @to: Destination address, in user space.
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* @n: Number of bytes to zero.
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*
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* Zero a block of memory in user space. Caller must check
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* the specified block with access_ok() before calling this function.
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*
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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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*/
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extern unsigned long __clear_user(void __user *src, unsigned long size);
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static inline unsigned long clear_user(char *src, unsigned long size)
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{
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if (access_ok(VERIFY_WRITE, src, size))
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return __clear_user(src, size);
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return -EFAULT;
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}
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/*
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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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*
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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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* this function.
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*
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* On success, returns the length of the string (not including the trailing
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* NUL).
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*
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* If access to userspace fails, returns -EFAULT (some data may have been
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* copied).
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*
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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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*/
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extern int __strncpy_from_user(char *dst, const char *src, long len);
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static inline int strncpy_from_user(char *dst, const char *src, long len)
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{
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if (access_ok(VERIFY_READ, src, 1))
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return __strncpy_from_user(dst, src, len);
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return -EFAULT;
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}
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extern int __strlen_user(const char *src);
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static inline long strlen_user(const char __user *src)
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{
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return __strlen_user(src);
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}
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extern int __strnlen_user(const char *str, long len);
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static inline long strnlen_user(const char __user *str, long len)
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{
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if (!access_ok(VERIFY_READ, str, 0))
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return 0;
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else
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return __strnlen_user(str, len);
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}
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#endif /* __SCORE_UACCESS_H */
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