/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_UACCESS_H
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#define _ASM_X86_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/compiler.h>
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#include <linux/kasan-checks.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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#include <asm/smap.h>
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#include <asm/extable.h>
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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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static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit)
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{
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/*
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* If we have used "sizeof()" for the size,
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* we know it won't overflow the limit (but
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* it might overflow the 'addr', so it's
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* important to subtract the size from the
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* limit, not add it to the address).
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*/
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if (__builtin_constant_p(size))
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return unlikely(addr > limit - size);
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/* Arbitrary sizes? Be careful about overflow */
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addr += size;
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if (unlikely(addr < size))
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return true;
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return unlikely(addr > limit);
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}
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#define __range_not_ok(addr, size, limit) \
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({ \
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__chk_user_ptr(addr); \
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__chk_range_not_ok((unsigned long __force)(addr), size, limit); \
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})
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#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
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static inline bool pagefault_disabled(void);
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# define WARN_ON_IN_IRQ() \
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WARN_ON_ONCE(!in_task() && !pagefault_disabled())
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#else
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# define WARN_ON_IN_IRQ()
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#endif
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/**
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* access_ok - Checks if a user space pointer is valid
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* @addr: User space pointer to start of block to check
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* @size: Size of block to check
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* Checks if a pointer to a block of memory in user space is valid.
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*
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* 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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* Return: 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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#define access_ok(addr, size) \
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({ \
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WARN_ON_IN_IRQ(); \
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likely(!__range_not_ok(addr, size, TASK_SIZE_MAX)); \
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})
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extern int __get_user_1(void);
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extern int __get_user_2(void);
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extern int __get_user_4(void);
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extern int __get_user_8(void);
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extern int __get_user_nocheck_1(void);
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extern int __get_user_nocheck_2(void);
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extern int __get_user_nocheck_4(void);
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extern int __get_user_nocheck_8(void);
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extern int __get_user_bad(void);
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#define __uaccess_begin() stac()
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#define __uaccess_end() clac()
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#define __uaccess_begin_nospec() \
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({ \
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stac(); \
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barrier_nospec(); \
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})
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/*
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* This is the smallest unsigned integer type that can fit a value
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* (up to 'long long')
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*/
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#define __inttype(x) __typeof__( \
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__typefits(x,char, \
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__typefits(x,short, \
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__typefits(x,int, \
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__typefits(x,long,0ULL)))))
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#define __typefits(x,type,not) \
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__builtin_choose_expr(sizeof(x)<=sizeof(type),(unsigned type)0,not)
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/*
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* This is used for both get_user() and __get_user() to expand to
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* the proper special function call that has odd calling conventions
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* due to returning both a value and an error, and that depends on
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* the size of the pointer passed in.
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*
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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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* The use of _ASM_DX as the register specifier is a bit of a
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* simplification, as gcc only cares about it as the starting point
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* and not size: for a 64-bit value it will use %ecx:%edx on 32 bits
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* (%ecx being the next register in gcc's x86 register sequence), and
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* %rdx on 64 bits.
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*
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* Clang/LLVM cares about the size of the register, but still wants
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* the base register for something that ends up being a pair.
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*/
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#define do_get_user_call(fn,x,ptr) \
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({ \
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int __ret_gu; \
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register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \
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__chk_user_ptr(ptr); \
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asm volatile("call __" #fn "_%P4" \
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: "=a" (__ret_gu), "=r" (__val_gu), \
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ASM_CALL_CONSTRAINT \
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: "0" (ptr), "i" (sizeof(*(ptr)))); \
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(x) = (__force __typeof__(*(ptr))) __val_gu; \
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__builtin_expect(__ret_gu, 0); \
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})
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/**
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* get_user - Get a simple variable from user space.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Return: 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) ({ might_fault(); do_get_user_call(get_user,x,ptr); })
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/**
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* __get_user - Get a simple variable from user space, with less checking.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Return: 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) do_get_user_call(get_user_nocheck,x,ptr)
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#ifdef CONFIG_X86_32
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#define __put_user_goto_u64(x, addr, label) \
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asm_volatile_goto("\n" \
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"1: movl %%eax,0(%1)\n" \
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"2: movl %%edx,4(%1)\n" \
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_ASM_EXTABLE_UA(1b, %l2) \
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_ASM_EXTABLE_UA(2b, %l2) \
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: : "A" (x), "r" (addr) \
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: : label)
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#else
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#define __put_user_goto_u64(x, ptr, label) \
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__put_user_goto(x, ptr, "q", "er", label)
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#endif
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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 %ecx. clobbers %rbx
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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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extern void __put_user_nocheck_1(void);
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extern void __put_user_nocheck_2(void);
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extern void __put_user_nocheck_4(void);
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extern void __put_user_nocheck_8(void);
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/*
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* ptr must be evaluated and assigned to the temporary __ptr_pu before
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* the assignment of x to __val_pu, to avoid any function calls
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* involved in the ptr expression (possibly implicitly generated due
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* to KASAN) from clobbering %ax.
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*/
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#define do_put_user_call(fn,x,ptr) \
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({ \
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int __ret_pu; \
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void __user *__ptr_pu; \
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register __typeof__(*(ptr)) __val_pu asm("%"_ASM_AX); \
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__chk_user_ptr(ptr); \
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__ptr_pu = (ptr); \
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__val_pu = (x); \
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asm volatile("call __" #fn "_%P[size]" \
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: "=c" (__ret_pu), \
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ASM_CALL_CONSTRAINT \
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: "0" (__ptr_pu), \
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"r" (__val_pu), \
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[size] "i" (sizeof(*(ptr))) \
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:"ebx"); \
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__builtin_expect(__ret_pu, 0); \
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})
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/**
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* put_user - Write a simple value into user space.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Return: zero on success, or -EFAULT on error.
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*/
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#define put_user(x, ptr) ({ might_fault(); do_put_user_call(put_user,x,ptr); })
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/**
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* __put_user - Write a simple value into user space, with less checking.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Return: zero on success, or -EFAULT on error.
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*/
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#define __put_user(x, ptr) do_put_user_call(put_user_nocheck,x,ptr)
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#define __put_user_size(x, ptr, size, label) \
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do { \
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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_goto(x, ptr, "b", "iq", label); \
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break; \
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case 2: \
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__put_user_goto(x, ptr, "w", "ir", label); \
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break; \
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case 4: \
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__put_user_goto(x, ptr, "l", "ir", label); \
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break; \
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case 8: \
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__put_user_goto_u64(x, ptr, label); \
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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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#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
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#ifdef CONFIG_X86_32
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#define __get_user_asm_u64(x, ptr, label) do { \
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unsigned int __gu_low, __gu_high; \
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const unsigned int __user *__gu_ptr; \
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__gu_ptr = (const void __user *)(ptr); \
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__get_user_asm(__gu_low, __gu_ptr, "l", "=r", label); \
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__get_user_asm(__gu_high, __gu_ptr+1, "l", "=r", label); \
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(x) = ((unsigned long long)__gu_high << 32) | __gu_low; \
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} while (0)
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#else
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#define __get_user_asm_u64(x, ptr, label) \
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__get_user_asm(x, ptr, "q", "=r", label)
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#endif
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#define __get_user_size(x, ptr, size, label) \
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do { \
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__chk_user_ptr(ptr); \
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switch (size) { \
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case 1: { \
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unsigned char x_u8__; \
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__get_user_asm(x_u8__, ptr, "b", "=q", label); \
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(x) = x_u8__; \
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break; \
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} \
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case 2: \
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__get_user_asm(x, ptr, "w", "=r", label); \
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break; \
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case 4: \
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__get_user_asm(x, ptr, "l", "=r", label); \
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break; \
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case 8: \
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__get_user_asm_u64(x, ptr, label); \
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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, itype, ltype, label) \
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asm_volatile_goto("\n" \
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"1: mov"itype" %[umem],%[output]\n" \
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_ASM_EXTABLE_UA(1b, %l2) \
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: [output] ltype(x) \
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: [umem] "m" (__m(addr)) \
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: : label)
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#else // !CONFIG_CC_HAS_ASM_GOTO_OUTPUT
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#ifdef CONFIG_X86_32
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#define __get_user_asm_u64(x, ptr, retval) \
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({ \
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__typeof__(ptr) __ptr = (ptr); \
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asm volatile("\n" \
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"1: movl %[lowbits],%%eax\n" \
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"2: movl %[highbits],%%edx\n" \
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"3:\n" \
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".section .fixup,\"ax\"\n" \
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"4: mov %[efault],%[errout]\n" \
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" xorl %%eax,%%eax\n" \
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" xorl %%edx,%%edx\n" \
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" jmp 3b\n" \
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".previous\n" \
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_ASM_EXTABLE_UA(1b, 4b) \
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_ASM_EXTABLE_UA(2b, 4b) \
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: [errout] "=r" (retval), \
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[output] "=&A"(x) \
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: [lowbits] "m" (__m(__ptr)), \
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[highbits] "m" __m(((u32 __user *)(__ptr)) + 1), \
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[efault] "i" (-EFAULT), "0" (retval)); \
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})
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#else
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#define __get_user_asm_u64(x, ptr, retval) \
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__get_user_asm(x, ptr, retval, "q", "=r")
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#endif
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#define __get_user_size(x, ptr, size, retval) \
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do { \
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unsigned char x_u8__; \
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\
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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_u8__, ptr, retval, "b", "=q"); \
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(x) = x_u8__; \
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break; \
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case 2: \
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__get_user_asm(x, ptr, retval, "w", "=r"); \
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break; \
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case 4: \
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__get_user_asm(x, ptr, retval, "l", "=r"); \
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break; \
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case 8: \
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__get_user_asm_u64(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, itype, ltype) \
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asm volatile("\n" \
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"1: mov"itype" %[umem],%[output]\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: mov %[efault],%[errout]\n" \
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" xorl %k[output],%k[output]\n" \
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" jmp 2b\n" \
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".previous\n" \
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_ASM_EXTABLE_UA(1b, 3b) \
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: [errout] "=r" (err), \
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[output] ltype(x) \
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: [umem] "m" (__m(addr)), \
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[efault] "i" (-EFAULT), "0" (err))
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#endif // CONFIG_CC_ASM_GOTO_OUTPUT
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/* FIXME: this hack is definitely wrong -AK */
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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_goto(x, addr, itype, ltype, label) \
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asm_volatile_goto("\n" \
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"1: mov"itype" %0,%1\n" \
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_ASM_EXTABLE_UA(1b, %l2) \
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: : ltype(x), "m" (__m(addr)) \
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: : label)
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|
extern unsigned long
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copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
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extern __must_check long
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strncpy_from_user(char *dst, const char __user *src, long count);
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extern __must_check long strnlen_user(const char __user *str, long n);
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|
unsigned long __must_check clear_user(void __user *mem, unsigned long len);
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unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
|
|
#ifdef CONFIG_ARCH_HAS_COPY_MC
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unsigned long __must_check
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copy_mc_to_kernel(void *to, const void *from, unsigned len);
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#define copy_mc_to_kernel copy_mc_to_kernel
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|
unsigned long __must_check
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copy_mc_to_user(void *to, const void *from, unsigned len);
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#endif
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|
/*
|
* movsl can be slow when source and dest are not both 8-byte aligned
|
*/
|
#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;
|
#endif
|
|
#define ARCH_HAS_NOCACHE_UACCESS 1
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|
#ifdef CONFIG_X86_32
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# include <asm/uaccess_32.h>
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#else
|
# include <asm/uaccess_64.h>
|
#endif
|
|
/*
|
* The "unsafe" user accesses aren't really "unsafe", but the naming
|
* is a big fat warning: you have to not only do the access_ok()
|
* checking before using them, but you have to surround them with the
|
* user_access_begin/end() pair.
|
*/
|
static __must_check __always_inline bool user_access_begin(const void __user *ptr, size_t len)
|
{
|
if (unlikely(!access_ok(ptr,len)))
|
return 0;
|
__uaccess_begin_nospec();
|
return 1;
|
}
|
#define user_access_begin(a,b) user_access_begin(a,b)
|
#define user_access_end() __uaccess_end()
|
|
#define user_access_save() smap_save()
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#define user_access_restore(x) smap_restore(x)
|
|
#define unsafe_put_user(x, ptr, label) \
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__put_user_size((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)), label)
|
|
#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
|
#define unsafe_get_user(x, ptr, err_label) \
|
do { \
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__inttype(*(ptr)) __gu_val; \
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__get_user_size(__gu_val, (ptr), sizeof(*(ptr)), err_label); \
|
(x) = (__force __typeof__(*(ptr)))__gu_val; \
|
} while (0)
|
#else // !CONFIG_CC_HAS_ASM_GOTO_OUTPUT
|
#define unsafe_get_user(x, ptr, err_label) \
|
do { \
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int __gu_err; \
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__inttype(*(ptr)) __gu_val; \
|
__get_user_size(__gu_val, (ptr), sizeof(*(ptr)), __gu_err); \
|
(x) = (__force __typeof__(*(ptr)))__gu_val; \
|
if (unlikely(__gu_err)) goto err_label; \
|
} while (0)
|
#endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT
|
|
/*
|
* We want the unsafe accessors to always be inlined and use
|
* the error labels - thus the macro games.
|
*/
|
#define unsafe_copy_loop(dst, src, len, type, label) \
|
while (len >= sizeof(type)) { \
|
unsafe_put_user(*(type *)(src),(type __user *)(dst),label); \
|
dst += sizeof(type); \
|
src += sizeof(type); \
|
len -= sizeof(type); \
|
}
|
|
#define unsafe_copy_to_user(_dst,_src,_len,label) \
|
do { \
|
char __user *__ucu_dst = (_dst); \
|
const char *__ucu_src = (_src); \
|
size_t __ucu_len = (_len); \
|
unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u64, label); \
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unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u32, label); \
|
unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u16, label); \
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unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \
|
} while (0)
|
|
#define HAVE_GET_KERNEL_NOFAULT
|
|
#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
|
#define __get_kernel_nofault(dst, src, type, err_label) \
|
__get_user_size(*((type *)(dst)), (__force type __user *)(src), \
|
sizeof(type), err_label)
|
#else // !CONFIG_CC_HAS_ASM_GOTO_OUTPUT
|
#define __get_kernel_nofault(dst, src, type, err_label) \
|
do { \
|
int __kr_err; \
|
\
|
__get_user_size(*((type *)(dst)), (__force type __user *)(src), \
|
sizeof(type), __kr_err); \
|
if (unlikely(__kr_err)) \
|
goto err_label; \
|
} while (0)
|
#endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT
|
|
#define __put_kernel_nofault(dst, src, type, err_label) \
|
__put_user_size(*((type *)(src)), (__force type __user *)(dst), \
|
sizeof(type), err_label)
|
|
#endif /* _ASM_X86_UACCESS_H */
|
