401 lines
11 KiB
C
401 lines
11 KiB
C
#ifdef __KERNEL__
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#ifndef _PPC_UACCESS_H
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#define _PPC_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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#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 KERNEL_DS ((mm_segment_t) { ~0UL })
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#define USER_DS ((mm_segment_t) { TASK_SIZE - 1 })
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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 __access_ok(addr,size) \
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((addr) <= current->thread.fs.seg \
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&& ((size) == 0 || (size) - 1 <= current->thread.fs.seg - (addr)))
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#define access_ok(type, addr, size) \
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(__chk_user_ptr(addr),__access_ok((unsigned long)(addr),(size)))
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/* this function will go away soon - use access_ok() instead */
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extern inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
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{
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return access_ok(type, addr, size) ? 0 : -EFAULT;
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}
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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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{
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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 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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* The "user64" versions of the user access functions are versions that
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* allow access of 64-bit data. The "get_user" functions do not
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* properly handle 64-bit data because the value gets down cast to a long.
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* The "put_user" functions already handle 64-bit data properly but we add
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* "user64" versions for completeness
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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 get_user64(x,ptr) \
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__get_user64_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 put_user64(x,ptr) put_user(x,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 __get_user64(x,ptr) \
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__get_user64_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 __put_user64(x,ptr) __put_user(x,ptr)
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extern long __put_user_bad(void);
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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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__chk_user_ptr(ptr); \
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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)) __user *__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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#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, "stb"); \
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break; \
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case 2: \
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__put_user_asm(x, ptr, retval, "sth"); \
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break; \
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case 4: \
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__put_user_asm(x, ptr, retval, "stw"); \
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break; \
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case 8: \
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__put_user_asm2(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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/*
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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)\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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" .align 2\n" \
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" .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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#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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" .align 2\n" \
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" .long 1b,4b\n" \
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" .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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#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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__chk_user_ptr(ptr); \
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__get_user_size(__gu_val, (ptr), (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_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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__chk_user_ptr(ptr); \
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__get_user_size64(__gu_val, (ptr), (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_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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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_user64_check(x, ptr, size) \
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({ \
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long __gu_err = -EFAULT; \
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long long __gu_val = 0; \
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const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
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if (access_ok(VERIFY_READ, __gu_addr, (size))) \
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__get_user_size64(__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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extern long __get_user_bad(void);
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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, "lbz"); \
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break; \
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case 2: \
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__get_user_asm(x, ptr, retval, "lhz"); \
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break; \
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case 4: \
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__get_user_asm(x, ptr, retval, "lwz"); \
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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 __get_user_size64(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, "lbz"); \
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break; \
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case 2: \
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__get_user_asm(x, ptr, retval, "lhz"); \
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break; \
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case 4: \
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__get_user_asm(x, ptr, retval, "lwz"); \
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break; \
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case 8: \
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__get_user_asm2(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 __get_user_asm(x, addr, err, op) \
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__asm__ __volatile__( \
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"1: "op" %1,0(%2)\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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" .align 2\n" \
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" .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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#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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" .align 2\n" \
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" .long 1b,4b\n" \
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" .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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/* more complex routines */
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extern int __copy_tofrom_user(void __user *to, const void __user *from,
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unsigned long size);
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extern inline unsigned long
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copy_from_user(void *to, 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, n - over) + over;
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}
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return n;
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}
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extern inline unsigned long
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copy_to_user(void __user *to, 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, 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_from_user(void *to, const void __user *from, unsigned long size)
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{
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return __copy_tofrom_user((__force void __user *)to, from, size);
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}
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static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long size)
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{
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return __copy_tofrom_user(to, (__force void __user *)from, size);
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}
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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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extern unsigned long __clear_user(void __user *addr, unsigned long size);
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extern inline unsigned long
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clear_user(void __user *addr, unsigned long size)
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{
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if (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 int __strncpy_from_user(char *dst, const char __user *src, long count);
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extern 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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if (access_ok(VERIFY_READ, src, 1))
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return __strncpy_from_user(dst, src, count);
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return -EFAULT;
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}
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/*
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* Return the size of a string (including the ending 0)
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*
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* Return 0 for error
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*/
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extern int __strnlen_user(const char __user *str, long len, unsigned long top);
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/*
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* Returns the length of the string at str (including the null byte),
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* or 0 if we hit a page we can't access,
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* or something > len if we didn't find a null byte.
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*
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* The `top' parameter to __strnlen_user is to make sure that
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* we can never overflow from the user area into kernel space.
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*/
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extern __inline__ int strnlen_user(const char __user *str, long len)
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{
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unsigned long top = current->thread.fs.seg;
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if ((unsigned long)str > top)
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return 0;
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return __strnlen_user(str, len, top);
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}
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#define strlen_user(str) strnlen_user((str), 0x7ffffffe)
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#endif /* __ASSEMBLY__ */
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#endif /* _PPC_UACCESS_H */
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#endif /* __KERNEL__ */
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