1af1717dbf
The only reason uaccess routines might sleep is if they fault. Make this explicit. Arnd Bergmann suggested that the following code if (!is_kernel_addr((unsigned long)__pu_addr)) might_fault(); can be further simplified by adding a version of might_fault that includes the kernel addr check. Will be considered as a further optimization in future. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1369577426-26721-7-git-send-email-mst@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
454 lines
13 KiB
C
454 lines
13 KiB
C
#ifndef _ARCH_POWERPC_UACCESS_H
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#define _ARCH_POWERPC_UACCESS_H
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#ifdef __KERNEL__
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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/asm-compat.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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* The fs/ds values are now the highest legal address in the "segment".
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* This simplifies the checking in the routines below.
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*/
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#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
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#define KERNEL_DS MAKE_MM_SEG(~0UL)
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#ifdef __powerpc64__
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/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
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#define USER_DS MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
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#else
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#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
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#endif
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#define get_ds() (KERNEL_DS)
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#define get_fs() (current->thread.fs)
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#define set_fs(val) (current->thread.fs = (val))
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#define segment_eq(a, b) ((a).seg == (b).seg)
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#define user_addr_max() (get_fs().seg)
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#ifdef __powerpc64__
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/*
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* This check is sufficient because there is a large enough
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* gap between user addresses and the kernel addresses
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*/
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#define __access_ok(addr, size, segment) \
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(((addr) <= (segment).seg) && ((size) <= (segment).seg))
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#else
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#define __access_ok(addr, size, segment) \
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(((addr) <= (segment).seg) && \
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(((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
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#endif
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#define access_ok(type, addr, size) \
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(__chk_user_ptr(addr), \
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__access_ok((__force unsigned long)(addr), (size), get_fs()))
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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;
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unsigned long 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 the
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* PowerPC, 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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*/
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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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#define __get_user_inatomic(x, ptr) \
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__get_user_nosleep((x), (ptr), sizeof(*(ptr)))
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#define __put_user_inatomic(x, ptr) \
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__put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
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#define __get_user_unaligned __get_user
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#define __put_user_unaligned __put_user
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extern long __put_user_bad(void);
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/*
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* We don't tell gcc that we are accessing memory, but this is OK
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* because we do not write to any memory gcc knows about, so there
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* are no aliasing issues.
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*/
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#define __put_user_asm(x, addr, err, op) \
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__asm__ __volatile__( \
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"1: " op " %1,0(%2) # put_user\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: li %0,%3\n" \
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" b 2b\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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PPC_LONG_ALIGN "\n" \
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PPC_LONG "1b,3b\n" \
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".previous" \
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: "=r" (err) \
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: "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
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#ifdef __powerpc64__
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#define __put_user_asm2(x, ptr, retval) \
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__put_user_asm(x, ptr, retval, "std")
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#else /* __powerpc64__ */
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#define __put_user_asm2(x, addr, err) \
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__asm__ __volatile__( \
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"1: stw %1,0(%2)\n" \
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"2: stw %1+1,4(%2)\n" \
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"3:\n" \
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".section .fixup,\"ax\"\n" \
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"4: li %0,%3\n" \
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" b 3b\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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PPC_LONG_ALIGN "\n" \
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PPC_LONG "1b,4b\n" \
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PPC_LONG "2b,4b\n" \
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".previous" \
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: "=r" (err) \
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: "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
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#endif /* __powerpc64__ */
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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: __put_user_asm(x, ptr, retval, "stb"); break; \
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case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
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case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
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case 8: __put_user_asm2(x, ptr, retval); break; \
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default: __put_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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__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
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if (!is_kernel_addr((unsigned long)__pu_addr)) \
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might_fault(); \
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__chk_user_ptr(ptr); \
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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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#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)) __user *__pu_addr = (ptr); \
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might_fault(); \
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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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#define __put_user_nosleep(x, ptr, size) \
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({ \
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long __pu_err; \
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__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
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__chk_user_ptr(ptr); \
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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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extern long __get_user_bad(void);
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#define __get_user_asm(x, addr, err, op) \
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__asm__ __volatile__( \
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"1: "op" %1,0(%2) # get_user\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: li %0,%3\n" \
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" li %1,0\n" \
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" b 2b\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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PPC_LONG_ALIGN "\n" \
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PPC_LONG "1b,3b\n" \
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".previous" \
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: "=r" (err), "=r" (x) \
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: "b" (addr), "i" (-EFAULT), "0" (err))
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#ifdef __powerpc64__
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#define __get_user_asm2(x, addr, err) \
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__get_user_asm(x, addr, err, "ld")
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#else /* __powerpc64__ */
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#define __get_user_asm2(x, addr, err) \
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__asm__ __volatile__( \
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"1: lwz %1,0(%2)\n" \
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"2: lwz %1+1,4(%2)\n" \
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"3:\n" \
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".section .fixup,\"ax\"\n" \
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"4: li %0,%3\n" \
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" li %1,0\n" \
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" li %1+1,0\n" \
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" b 3b\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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PPC_LONG_ALIGN "\n" \
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PPC_LONG "1b,4b\n" \
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PPC_LONG "2b,4b\n" \
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".previous" \
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: "=r" (err), "=&r" (x) \
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: "b" (addr), "i" (-EFAULT), "0" (err))
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#endif /* __powerpc64__ */
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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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__chk_user_ptr(ptr); \
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if (size > sizeof(x)) \
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(x) = __get_user_bad(); \
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switch (size) { \
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case 1: __get_user_asm(x, ptr, retval, "lbz"); break; \
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case 2: __get_user_asm(x, ptr, retval, "lhz"); break; \
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case 4: __get_user_asm(x, ptr, retval, "lwz"); break; \
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case 8: __get_user_asm2(x, ptr, retval); break; \
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default: (x) = __get_user_bad(); \
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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; \
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unsigned long __gu_val; \
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const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
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__chk_user_ptr(ptr); \
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if (!is_kernel_addr((unsigned long)__gu_addr)) \
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might_fault(); \
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__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
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(x) = (__typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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#ifndef __powerpc64__
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#define __get_user64_nocheck(x, ptr, size) \
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({ \
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long __gu_err; \
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long long __gu_val; \
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const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
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__chk_user_ptr(ptr); \
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if (!is_kernel_addr((unsigned long)__gu_addr)) \
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might_fault(); \
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__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
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(x) = (__typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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#endif /* __powerpc64__ */
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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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unsigned long __gu_val = 0; \
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const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
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might_fault(); \
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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) = (__typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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#define __get_user_nosleep(x, ptr, size) \
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({ \
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long __gu_err; \
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unsigned long __gu_val; \
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const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
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__chk_user_ptr(ptr); \
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__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
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(x) = (__typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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/* more complex routines */
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extern unsigned long __copy_tofrom_user(void __user *to,
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const void __user *from, unsigned long size);
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#ifndef __powerpc64__
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static inline unsigned long copy_from_user(void *to,
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const void __user *from, unsigned long n)
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{
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unsigned long over;
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if (access_ok(VERIFY_READ, from, n))
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return __copy_tofrom_user((__force void __user *)to, from, n);
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if ((unsigned long)from < TASK_SIZE) {
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over = (unsigned long)from + n - TASK_SIZE;
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return __copy_tofrom_user((__force void __user *)to, from,
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n - over) + over;
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}
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return n;
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}
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static inline unsigned long copy_to_user(void __user *to,
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const void *from, unsigned long n)
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{
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unsigned long over;
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if (access_ok(VERIFY_WRITE, to, n))
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return __copy_tofrom_user(to, (__force void __user *)from, n);
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if ((unsigned long)to < TASK_SIZE) {
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over = (unsigned long)to + n - TASK_SIZE;
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return __copy_tofrom_user(to, (__force void __user *)from,
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n - over) + over;
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}
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return n;
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}
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#else /* __powerpc64__ */
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#define __copy_in_user(to, from, size) \
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__copy_tofrom_user((to), (from), (size))
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extern unsigned long copy_from_user(void *to, const void __user *from,
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unsigned long n);
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extern unsigned long copy_to_user(void __user *to, const void *from,
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unsigned long n);
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extern unsigned long copy_in_user(void __user *to, const void __user *from,
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unsigned long n);
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#endif /* __powerpc64__ */
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static inline unsigned long __copy_from_user_inatomic(void *to,
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const void __user *from, unsigned long n)
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{
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if (__builtin_constant_p(n) && (n <= 8)) {
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unsigned long ret = 1;
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switch (n) {
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case 1:
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__get_user_size(*(u8 *)to, from, 1, ret);
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break;
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case 2:
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__get_user_size(*(u16 *)to, from, 2, ret);
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break;
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case 4:
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__get_user_size(*(u32 *)to, from, 4, ret);
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break;
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case 8:
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__get_user_size(*(u64 *)to, from, 8, ret);
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break;
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}
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if (ret == 0)
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return 0;
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}
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return __copy_tofrom_user((__force void __user *)to, from, n);
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}
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static inline unsigned long __copy_to_user_inatomic(void __user *to,
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const void *from, unsigned long n)
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{
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if (__builtin_constant_p(n) && (n <= 8)) {
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unsigned long ret = 1;
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switch (n) {
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case 1:
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__put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
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break;
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case 2:
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__put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
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break;
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case 4:
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__put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
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break;
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case 8:
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__put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
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break;
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}
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if (ret == 0)
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return 0;
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}
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return __copy_tofrom_user(to, (__force const void __user *)from, n);
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}
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static inline unsigned long __copy_from_user(void *to,
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const void __user *from, unsigned long size)
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{
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might_fault();
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return __copy_from_user_inatomic(to, from, size);
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}
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static inline unsigned long __copy_to_user(void __user *to,
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const void *from, unsigned long size)
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{
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might_fault();
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return __copy_to_user_inatomic(to, from, size);
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}
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extern unsigned long __clear_user(void __user *addr, unsigned long size);
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static inline unsigned long clear_user(void __user *addr, unsigned long size)
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{
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might_fault();
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if (likely(access_ok(VERIFY_WRITE, addr, size)))
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return __clear_user(addr, size);
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if ((unsigned long)addr < TASK_SIZE) {
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unsigned long over = (unsigned long)addr + size - TASK_SIZE;
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return __clear_user(addr, size - over) + over;
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}
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return size;
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}
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extern long strncpy_from_user(char *dst, const char __user *src, long count);
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extern __must_check long strlen_user(const char __user *str);
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extern __must_check long strnlen_user(const char __user *str, long n);
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#endif /* __ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _ARCH_POWERPC_UACCESS_H */
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