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eb47e0293b
* copy_from_user() on access_ok() failure ought to zero the destination * none of those primitives should skip the access_ok() check in case of small constant size. Cc: stable@vger.kernel.org Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
422 lines
11 KiB
C
422 lines
11 KiB
C
/*
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* Authors: Bjorn Wesen (bjornw@axis.com)
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* Hans-Peter Nilsson (hp@axis.com)
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*/
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/* Asm:s have been tweaked (within the domain of correctness) to give
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satisfactory results for "gcc version 2.96 20000427 (experimental)".
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Check regularly...
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Register $r9 is chosen for temporaries, being a call-clobbered register
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first in line to be used (notably for local blocks), not colliding with
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parameter registers. */
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#ifndef _CRIS_UACCESS_H
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#define _CRIS_UACCESS_H
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#ifndef __ASSEMBLY__
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <asm/processor.h>
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#include <asm/page.h>
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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/*
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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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*
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* For historical reasons, these macros are grossly misnamed.
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*/
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#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
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/* addr_limit is the maximum accessible address for the task. we misuse
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* the KERNEL_DS and USER_DS values to both assign and compare the
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* addr_limit values through the equally misnamed get/set_fs macros.
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* (see above)
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*/
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#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
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#define USER_DS MAKE_MM_SEG(TASK_SIZE)
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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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#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
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#define __user_ok(addr, size) \
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(((size) <= TASK_SIZE) && ((addr) <= TASK_SIZE-(size)))
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#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
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#define access_ok(type, addr, size) __access_ok((unsigned long)(addr), (size))
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#include <arch/uaccess.h>
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/*
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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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* what to do.
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*
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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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*/
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struct exception_table_entry {
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unsigned long insn, fixup;
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};
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/*
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* These are the main single-value transfer routines. They automatically
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* use the right size if we just have the right pointer type.
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*
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* This gets kind of ugly. We want to return _two_ values in "get_user()"
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* and yet we don't want to do any pointers, because that is too much
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* of a performance impact. Thus we have a few rather ugly macros here,
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* and hide all the ugliness from the user.
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*
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* The "__xxx" versions of the user access functions are versions that
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* do not verify the address space, that must have been done previously
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* with a separate "access_ok()" call (this is used when we do multiple
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* accesses to the same area of user memory).
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*
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* As we use the same address space for kernel and user data on
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* CRIS, we can just do these as direct assignments. (Of course, the
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* exception handling means that it's no longer "just"...)
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*/
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#define get_user(x, ptr) \
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__get_user_check((x), (ptr), sizeof(*(ptr)))
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#define put_user(x, ptr) \
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__put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
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#define __get_user(x, ptr) \
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__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
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#define __put_user(x, ptr) \
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__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
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extern long __put_user_bad(void);
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#define __put_user_size(x, ptr, size, retval) \
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do { \
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retval = 0; \
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switch (size) { \
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case 1: \
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__put_user_asm(x, ptr, retval, "move.b"); \
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break; \
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case 2: \
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__put_user_asm(x, ptr, retval, "move.w"); \
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break; \
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case 4: \
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__put_user_asm(x, ptr, retval, "move.d"); \
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break; \
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case 8: \
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__put_user_asm_64(x, ptr, retval); \
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break; \
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default: \
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__put_user_bad(); \
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} \
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} while (0)
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#define __get_user_size(x, ptr, size, retval) \
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do { \
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retval = 0; \
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switch (size) { \
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case 1: \
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__get_user_asm(x, ptr, retval, "move.b"); \
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break; \
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case 2: \
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__get_user_asm(x, ptr, retval, "move.w"); \
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break; \
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case 4: \
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__get_user_asm(x, ptr, retval, "move.d"); \
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break; \
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case 8: \
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__get_user_asm_64(x, ptr, retval); \
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break; \
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default: \
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(x) = __get_user_bad(); \
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} \
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} while (0)
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#define __put_user_nocheck(x, ptr, size) \
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({ \
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long __pu_err; \
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__put_user_size((x), (ptr), (size), __pu_err); \
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__pu_err; \
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})
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#define __put_user_check(x, ptr, size) \
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({ \
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long __pu_err = -EFAULT; \
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__typeof__(*(ptr)) *__pu_addr = (ptr); \
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if (access_ok(VERIFY_WRITE, __pu_addr, size)) \
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__put_user_size((x), __pu_addr, (size), __pu_err); \
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__pu_err; \
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})
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struct __large_struct { unsigned long buf[100]; };
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#define __m(x) (*(struct __large_struct *)(x))
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#define __get_user_nocheck(x, ptr, size) \
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({ \
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long __gu_err, __gu_val; \
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__get_user_size(__gu_val, (ptr), (size), __gu_err); \
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(x) = (__force __typeof__(*(ptr)))__gu_val; \
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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, __gu_val = 0; \
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const __typeof__(*(ptr)) *__gu_addr = (ptr); \
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if (access_ok(VERIFY_READ, __gu_addr, size)) \
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__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
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(x) = (__force __typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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extern long __get_user_bad(void);
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/* More complex functions. Most are inline, but some call functions that
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live in lib/usercopy.c */
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extern unsigned long __copy_user(void __user *to, const void *from, unsigned long n);
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extern unsigned long __copy_user_zeroing(void *to, const void __user *from, unsigned long n);
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extern unsigned long __do_clear_user(void __user *to, unsigned long n);
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static inline long
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__strncpy_from_user(char *dst, const char __user *src, long count)
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{
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return __do_strncpy_from_user(dst, src, count);
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}
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static inline long
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strncpy_from_user(char *dst, const char __user *src, long count)
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{
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long res = -EFAULT;
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if (access_ok(VERIFY_READ, src, 1))
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res = __do_strncpy_from_user(dst, src, count);
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return res;
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}
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/* Note that these expand awfully if made into switch constructs, so
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don't do that. */
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static inline unsigned long
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__constant_copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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unsigned long ret = 0;
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if (n == 0)
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;
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else if (n == 1)
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__asm_copy_from_user_1(to, from, ret);
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else if (n == 2)
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__asm_copy_from_user_2(to, from, ret);
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else if (n == 3)
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__asm_copy_from_user_3(to, from, ret);
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else if (n == 4)
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__asm_copy_from_user_4(to, from, ret);
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else if (n == 5)
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__asm_copy_from_user_5(to, from, ret);
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else if (n == 6)
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__asm_copy_from_user_6(to, from, ret);
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else if (n == 7)
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__asm_copy_from_user_7(to, from, ret);
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else if (n == 8)
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__asm_copy_from_user_8(to, from, ret);
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else if (n == 9)
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__asm_copy_from_user_9(to, from, ret);
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else if (n == 10)
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__asm_copy_from_user_10(to, from, ret);
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else if (n == 11)
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__asm_copy_from_user_11(to, from, ret);
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else if (n == 12)
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__asm_copy_from_user_12(to, from, ret);
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else if (n == 13)
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__asm_copy_from_user_13(to, from, ret);
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else if (n == 14)
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__asm_copy_from_user_14(to, from, ret);
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else if (n == 15)
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__asm_copy_from_user_15(to, from, ret);
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else if (n == 16)
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__asm_copy_from_user_16(to, from, ret);
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else if (n == 20)
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__asm_copy_from_user_20(to, from, ret);
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else if (n == 24)
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__asm_copy_from_user_24(to, from, ret);
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else
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ret = __copy_user_zeroing(to, from, n);
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return ret;
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}
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/* Ditto, don't make a switch out of this. */
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static inline unsigned long
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__constant_copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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unsigned long ret = 0;
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if (n == 0)
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;
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else if (n == 1)
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__asm_copy_to_user_1(to, from, ret);
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else if (n == 2)
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__asm_copy_to_user_2(to, from, ret);
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else if (n == 3)
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__asm_copy_to_user_3(to, from, ret);
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else if (n == 4)
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__asm_copy_to_user_4(to, from, ret);
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else if (n == 5)
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__asm_copy_to_user_5(to, from, ret);
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else if (n == 6)
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__asm_copy_to_user_6(to, from, ret);
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else if (n == 7)
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__asm_copy_to_user_7(to, from, ret);
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else if (n == 8)
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__asm_copy_to_user_8(to, from, ret);
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else if (n == 9)
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__asm_copy_to_user_9(to, from, ret);
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else if (n == 10)
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__asm_copy_to_user_10(to, from, ret);
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else if (n == 11)
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__asm_copy_to_user_11(to, from, ret);
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else if (n == 12)
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__asm_copy_to_user_12(to, from, ret);
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else if (n == 13)
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__asm_copy_to_user_13(to, from, ret);
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else if (n == 14)
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__asm_copy_to_user_14(to, from, ret);
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else if (n == 15)
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__asm_copy_to_user_15(to, from, ret);
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else if (n == 16)
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__asm_copy_to_user_16(to, from, ret);
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else if (n == 20)
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__asm_copy_to_user_20(to, from, ret);
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else if (n == 24)
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__asm_copy_to_user_24(to, from, ret);
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else
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ret = __copy_user(to, from, n);
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return ret;
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}
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/* No switch, please. */
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static inline unsigned long
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__constant_clear_user(void __user *to, unsigned long n)
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{
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unsigned long ret = 0;
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if (n == 0)
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;
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else if (n == 1)
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__asm_clear_1(to, ret);
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else if (n == 2)
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__asm_clear_2(to, ret);
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else if (n == 3)
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__asm_clear_3(to, ret);
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else if (n == 4)
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__asm_clear_4(to, ret);
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else if (n == 8)
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__asm_clear_8(to, ret);
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else if (n == 12)
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__asm_clear_12(to, ret);
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else if (n == 16)
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__asm_clear_16(to, ret);
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else if (n == 20)
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__asm_clear_20(to, ret);
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else if (n == 24)
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__asm_clear_24(to, ret);
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else
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ret = __do_clear_user(to, n);
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return ret;
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}
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static inline size_t clear_user(void __user *to, size_t n)
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{
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if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
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return n;
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if (__builtin_constant_p(n))
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return __constant_clear_user(to, n);
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else
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return __do_clear_user(to, n);
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}
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static inline size_t copy_from_user(void *to, const void __user *from, size_t n)
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{
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if (unlikely(!access_ok(VERIFY_READ, from, n))) {
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memset(to, 0, n);
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return n;
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}
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if (__builtin_constant_p(n))
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return __constant_copy_from_user(to, from, n);
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else
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return __copy_user_zeroing(to, from, n);
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}
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static inline size_t copy_to_user(void __user *to, const void *from, size_t n)
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{
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if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
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return n;
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if (__builtin_constant_p(n))
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return __constant_copy_to_user(to, from, n);
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else
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return __copy_user(to, from, n);
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}
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/* We let the __ versions of copy_from/to_user inline, because they're often
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* used in fast paths and have only a small space overhead.
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*/
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static inline unsigned long
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__generic_copy_from_user_nocheck(void *to, const void __user *from,
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unsigned long n)
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{
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return __copy_user_zeroing(to, from, n);
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}
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static inline unsigned long
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__generic_copy_to_user_nocheck(void __user *to, const void *from,
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unsigned long n)
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{
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return __copy_user(to, from, n);
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}
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static inline unsigned long
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__generic_clear_user_nocheck(void __user *to, unsigned long n)
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{
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return __do_clear_user(to, n);
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}
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/* without checking */
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#define __copy_to_user(to, from, n) \
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__generic_copy_to_user_nocheck((to), (from), (n))
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#define __copy_from_user(to, from, n) \
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__generic_copy_from_user_nocheck((to), (from), (n))
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#define __copy_to_user_inatomic __copy_to_user
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#define __copy_from_user_inatomic __copy_from_user
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#define __clear_user(to, n) __generic_clear_user_nocheck((to), (n))
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#define strlen_user(str) strnlen_user((str), 0x7ffffffe)
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#endif /* __ASSEMBLY__ */
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#endif /* _CRIS_UACCESS_H */
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