641 lines
19 KiB
C
641 lines
19 KiB
C
#ifndef __i386_UACCESS_H
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#define __i386_UACCESS_H
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/*
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* User space memory access functions
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*/
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#include <linux/errno.h>
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#include <linux/thread_info.h>
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#include <linux/prefetch.h>
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#include <linux/string.h>
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#include <asm/asm.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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#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFUL)
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#define USER_DS MAKE_MM_SEG(PAGE_OFFSET)
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#define get_ds() (KERNEL_DS)
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#define get_fs() (current_thread_info()->addr_limit)
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#define set_fs(x) (current_thread_info()->addr_limit = (x))
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#define segment_eq(a, b) ((a).seg == (b).seg)
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/*
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* movsl can be slow when source and dest are not both 8-byte aligned
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*/
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#ifdef CONFIG_X86_INTEL_USERCOPY
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extern struct movsl_mask {
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int mask;
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} ____cacheline_aligned_in_smp movsl_mask;
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#endif
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#define __addr_ok(addr) \
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((unsigned long __force)(addr) < \
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(current_thread_info()->addr_limit.seg))
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/*
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* Test whether a block of memory is a valid user space address.
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* Returns 0 if the range is valid, nonzero otherwise.
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*
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* This is equivalent to the following test:
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* (u33)addr + (u33)size >= (u33)current->addr_limit.seg
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*
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* This needs 33-bit arithmetic. We have a carry...
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*/
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#define __range_ok(addr, size) \
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({ \
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unsigned long flag, roksum; \
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__chk_user_ptr(addr); \
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asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \
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:"=&r" (flag), "=r" (roksum) \
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:"1" (addr), "g" ((int)(size)), \
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"rm" (current_thread_info()->addr_limit.seg)); \
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flag; \
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})
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/**
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* access_ok: - Checks if a user space pointer is valid
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* @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
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* %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
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* to write to a block, it is always safe to read from it.
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* @addr: User space pointer to start of block to check
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* @size: Size of block to check
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*
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* Context: User context only. This function may sleep.
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*
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* Checks if a pointer to a block of memory in user space is valid.
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*
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* Returns true (nonzero) if the memory block may be valid, false (zero)
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* if it is definitely invalid.
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*
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* Note that, depending on architecture, this function probably just
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* checks that the pointer is in the user space range - after calling
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* this function, memory access functions may still return -EFAULT.
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*/
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#define access_ok(type, addr, size) (likely(__range_ok(addr, size) == 0))
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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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extern int fixup_exception(struct pt_regs *regs);
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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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extern void __get_user_1(void);
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extern void __get_user_2(void);
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extern void __get_user_4(void);
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#define __get_user_x(size, ret, x, ptr) \
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asm volatile("call __get_user_" #size \
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:"=a" (ret),"=d" (x) \
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:"0" (ptr))
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/* Careful: we have to cast the result to the type of the pointer
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* for sign reasons */
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/**
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* get_user: - Get a simple variable from user space.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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*/
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#define get_user(x, ptr) \
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({ \
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int __ret_gu; \
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unsigned long __val_gu; \
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__chk_user_ptr(ptr); \
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switch (sizeof(*(ptr))) { \
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case 1: \
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__get_user_x(1, __ret_gu, __val_gu, ptr); \
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break; \
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case 2: \
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__get_user_x(2, __ret_gu, __val_gu, ptr); \
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break; \
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case 4: \
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__get_user_x(4, __ret_gu, __val_gu, ptr); \
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break; \
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default: \
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__get_user_x(X, __ret_gu, __val_gu, ptr); \
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break; \
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} \
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(x) = (__typeof__(*(ptr)))__val_gu; \
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__ret_gu; \
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})
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extern void __put_user_bad(void);
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/*
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* Strange magic calling convention: pointer in %ecx,
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* value in %eax(:%edx), return value in %eax, no clobbers.
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*/
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extern void __put_user_1(void);
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extern void __put_user_2(void);
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extern void __put_user_4(void);
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extern void __put_user_8(void);
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#define __put_user_1(x, ptr) \
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asm volatile("call __put_user_1" : "=a" (__ret_pu) \
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: "0" ((typeof(*(ptr)))(x)), "c" (ptr))
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#define __put_user_2(x, ptr) \
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asm volatile("call __put_user_2" : "=a" (__ret_pu) \
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: "0" ((typeof(*(ptr)))(x)), "c" (ptr))
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#define __put_user_4(x, ptr) \
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asm volatile("call __put_user_4" : "=a" (__ret_pu) \
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: "0" ((typeof(*(ptr)))(x)), "c" (ptr))
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#define __put_user_8(x, ptr) \
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asm volatile("call __put_user_8" : "=a" (__ret_pu) \
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: "A" ((typeof(*(ptr)))(x)), "c" (ptr))
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#define __put_user_X(x, ptr) \
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asm volatile("call __put_user_X" : "=a" (__ret_pu) \
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: "c" (ptr))
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/**
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* put_user: - Write a simple value into user space.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#ifdef CONFIG_X86_WP_WORKS_OK
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#define put_user(x, ptr) \
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({ \
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int __ret_pu; \
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__typeof__(*(ptr)) __pu_val; \
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__chk_user_ptr(ptr); \
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__pu_val = x; \
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switch (sizeof(*(ptr))) { \
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case 1: \
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__put_user_1(__pu_val, ptr); \
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break; \
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case 2: \
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__put_user_2(__pu_val, ptr); \
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break; \
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case 4: \
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__put_user_4(__pu_val, ptr); \
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break; \
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case 8: \
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__put_user_8(__pu_val, ptr); \
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break; \
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default: \
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__put_user_X(__pu_val, ptr); \
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break; \
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} \
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__ret_pu; \
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})
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#else
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#define put_user(x, ptr) \
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({ \
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int __ret_pu; \
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__typeof__(*(ptr))__pus_tmp = x; \
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__ret_pu = 0; \
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if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \
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sizeof(*(ptr))) != 0)) \
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__ret_pu = -EFAULT; \
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__ret_pu; \
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})
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#endif
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/**
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* __get_user: - Get a simple variable from user space, with less checking.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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*/
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#define __get_user(x, ptr) \
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__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
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/**
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* __put_user: - Write a simple value into user space, with less checking.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#define __put_user(x, ptr) \
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__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
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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, -EFAULT); \
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__pu_err; \
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})
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#define __put_user_u64(x, addr, err) \
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asm volatile("1: movl %%eax,0(%2)\n" \
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"2: movl %%edx,4(%2)\n" \
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"3:\n" \
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".section .fixup,\"ax\"\n" \
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"4: movl %3,%0\n" \
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" jmp 3b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 4b) \
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_ASM_EXTABLE(2b, 4b) \
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: "=r" (err) \
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: "A" (x), "r" (addr), "i" (-EFAULT), "0" (err))
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#ifdef CONFIG_X86_WP_WORKS_OK
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#define __put_user_size(x, ptr, size, retval, errret) \
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do { \
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retval = 0; \
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__chk_user_ptr(ptr); \
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switch (size) { \
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case 1: \
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__put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
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break; \
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case 2: \
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__put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
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break; \
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case 4: \
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__put_user_asm(x, ptr, retval, "l", "", "ir", errret); \
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break; \
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case 8: \
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__put_user_u64((__typeof__(*ptr))(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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#else
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#define __put_user_size(x, ptr, size, retval, errret) \
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do { \
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__typeof__(*(ptr))__pus_tmp = x; \
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retval = 0; \
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\
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if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \
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retval = errret; \
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} while (0)
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#endif
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struct __large_struct { unsigned long buf[100]; };
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#define __m(x) (*(struct __large_struct __user *)(x))
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/*
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* Tell gcc we read from memory instead of writing: this is because
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* we do not write to any memory gcc knows about, so there are no
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* aliasing issues.
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*/
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#define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
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asm volatile("1: mov"itype" %"rtype"1,%2\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: movl %3,%0\n" \
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" jmp 2b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 3b) \
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: "=r"(err) \
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: ltype (x), "m" (__m(addr)), "i" (errret), "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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__get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
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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, errret) \
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do { \
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retval = 0; \
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__chk_user_ptr(ptr); \
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switch (size) { \
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case 1: \
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__get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
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break; \
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case 2: \
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__get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
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break; \
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case 4: \
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__get_user_asm(x, ptr, retval, "l", "", "=r", errret); \
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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, itype, rtype, ltype, errret) \
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asm volatile("1: mov"itype" %2,%"rtype"1\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: movl %3,%0\n" \
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" xor"itype" %"rtype"1,%"rtype"1\n" \
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" jmp 2b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 3b) \
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: "=r" (err), ltype (x) \
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: "m" (__m(addr)), "i" (errret), "0" (err))
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unsigned long __must_check __copy_to_user_ll
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(void __user *to, const void *from, unsigned long n);
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unsigned long __must_check __copy_from_user_ll
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(void *to, const void __user *from, unsigned long n);
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unsigned long __must_check __copy_from_user_ll_nozero
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(void *to, const void __user *from, unsigned long n);
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unsigned long __must_check __copy_from_user_ll_nocache
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(void *to, const void __user *from, unsigned long n);
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unsigned long __must_check __copy_from_user_ll_nocache_nozero
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(void *to, const void __user *from, unsigned long n);
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/**
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* __copy_to_user_inatomic: - Copy a block of data into user space, with less checking.
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* @to: Destination address, in user space.
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* @from: Source address, in kernel space.
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* @n: Number of bytes to copy.
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*
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* Context: User context only.
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*
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* Copy data from kernel space to user space. Caller must check
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* the specified block with access_ok() before calling this function.
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* The caller should also make sure he pins the user space address
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* so that the we don't result in page fault and sleep.
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*
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* Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault
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* we return the initial request size (1, 2 or 4), as copy_*_user should do.
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* If a store crosses a page boundary and gets a fault, the x86 will not write
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* anything, so this is accurate.
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*/
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static __always_inline unsigned long __must_check
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__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
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{
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if (__builtin_constant_p(n)) {
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unsigned long ret;
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switch (n) {
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case 1:
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__put_user_size(*(u8 *)from, (u8 __user *)to,
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1, ret, 1);
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return ret;
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case 2:
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__put_user_size(*(u16 *)from, (u16 __user *)to,
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2, ret, 2);
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return ret;
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case 4:
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__put_user_size(*(u32 *)from, (u32 __user *)to,
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4, ret, 4);
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return ret;
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}
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}
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|
return __copy_to_user_ll(to, from, n);
|
|
}
|
|
|
|
/**
|
|
* __copy_to_user: - Copy a block of data into user space, with less checking.
|
|
* @to: Destination address, in user space.
|
|
* @from: Source address, in kernel space.
|
|
* @n: Number of bytes to copy.
|
|
*
|
|
* Context: User context only. This function may sleep.
|
|
*
|
|
* Copy data from kernel space to user space. Caller must check
|
|
* the specified block with access_ok() before calling this function.
|
|
*
|
|
* Returns number of bytes that could not be copied.
|
|
* On success, this will be zero.
|
|
*/
|
|
static __always_inline unsigned long __must_check
|
|
__copy_to_user(void __user *to, const void *from, unsigned long n)
|
|
{
|
|
might_sleep();
|
|
return __copy_to_user_inatomic(to, from, n);
|
|
}
|
|
|
|
static __always_inline unsigned long
|
|
__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
|
|
{
|
|
/* Avoid zeroing the tail if the copy fails..
|
|
* If 'n' is constant and 1, 2, or 4, we do still zero on a failure,
|
|
* but as the zeroing behaviour is only significant when n is not
|
|
* constant, that shouldn't be a problem.
|
|
*/
|
|
if (__builtin_constant_p(n)) {
|
|
unsigned long ret;
|
|
|
|
switch (n) {
|
|
case 1:
|
|
__get_user_size(*(u8 *)to, from, 1, ret, 1);
|
|
return ret;
|
|
case 2:
|
|
__get_user_size(*(u16 *)to, from, 2, ret, 2);
|
|
return ret;
|
|
case 4:
|
|
__get_user_size(*(u32 *)to, from, 4, ret, 4);
|
|
return ret;
|
|
}
|
|
}
|
|
return __copy_from_user_ll_nozero(to, from, n);
|
|
}
|
|
|
|
/**
|
|
* __copy_from_user: - Copy a block of data from user space, with less checking.
|
|
* @to: Destination address, in kernel space.
|
|
* @from: Source address, in user space.
|
|
* @n: Number of bytes to copy.
|
|
*
|
|
* Context: User context only. This function may sleep.
|
|
*
|
|
* Copy data from user space to kernel space. Caller must check
|
|
* the specified block with access_ok() before calling this function.
|
|
*
|
|
* Returns number of bytes that could not be copied.
|
|
* On success, this will be zero.
|
|
*
|
|
* If some data could not be copied, this function will pad the copied
|
|
* data to the requested size using zero bytes.
|
|
*
|
|
* An alternate version - __copy_from_user_inatomic() - may be called from
|
|
* atomic context and will fail rather than sleep. In this case the
|
|
* uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h
|
|
* for explanation of why this is needed.
|
|
*/
|
|
static __always_inline unsigned long
|
|
__copy_from_user(void *to, const void __user *from, unsigned long n)
|
|
{
|
|
might_sleep();
|
|
if (__builtin_constant_p(n)) {
|
|
unsigned long ret;
|
|
|
|
switch (n) {
|
|
case 1:
|
|
__get_user_size(*(u8 *)to, from, 1, ret, 1);
|
|
return ret;
|
|
case 2:
|
|
__get_user_size(*(u16 *)to, from, 2, ret, 2);
|
|
return ret;
|
|
case 4:
|
|
__get_user_size(*(u32 *)to, from, 4, ret, 4);
|
|
return ret;
|
|
}
|
|
}
|
|
return __copy_from_user_ll(to, from, n);
|
|
}
|
|
|
|
#define ARCH_HAS_NOCACHE_UACCESS
|
|
|
|
static __always_inline unsigned long __copy_from_user_nocache(void *to,
|
|
const void __user *from, unsigned long n)
|
|
{
|
|
might_sleep();
|
|
if (__builtin_constant_p(n)) {
|
|
unsigned long ret;
|
|
|
|
switch (n) {
|
|
case 1:
|
|
__get_user_size(*(u8 *)to, from, 1, ret, 1);
|
|
return ret;
|
|
case 2:
|
|
__get_user_size(*(u16 *)to, from, 2, ret, 2);
|
|
return ret;
|
|
case 4:
|
|
__get_user_size(*(u32 *)to, from, 4, ret, 4);
|
|
return ret;
|
|
}
|
|
}
|
|
return __copy_from_user_ll_nocache(to, from, n);
|
|
}
|
|
|
|
static __always_inline unsigned long
|
|
__copy_from_user_inatomic_nocache(void *to, const void __user *from,
|
|
unsigned long n)
|
|
{
|
|
return __copy_from_user_ll_nocache_nozero(to, from, n);
|
|
}
|
|
|
|
unsigned long __must_check copy_to_user(void __user *to,
|
|
const void *from, unsigned long n);
|
|
unsigned long __must_check copy_from_user(void *to,
|
|
const void __user *from,
|
|
unsigned long n);
|
|
long __must_check strncpy_from_user(char *dst, const char __user *src,
|
|
long count);
|
|
long __must_check __strncpy_from_user(char *dst,
|
|
const char __user *src, long count);
|
|
|
|
/**
|
|
* strlen_user: - Get the size of a string in user space.
|
|
* @str: The string to measure.
|
|
*
|
|
* Context: User context only. This function may sleep.
|
|
*
|
|
* Get the size of a NUL-terminated string in user space.
|
|
*
|
|
* Returns the size of the string INCLUDING the terminating NUL.
|
|
* On exception, returns 0.
|
|
*
|
|
* If there is a limit on the length of a valid string, you may wish to
|
|
* consider using strnlen_user() instead.
|
|
*/
|
|
#define strlen_user(str) strnlen_user(str, LONG_MAX)
|
|
|
|
long strnlen_user(const char __user *str, long n);
|
|
unsigned long __must_check clear_user(void __user *mem, unsigned long len);
|
|
unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
|
|
|
|
#endif /* __i386_UACCESS_H */
|