592 lines
16 KiB
C
592 lines
16 KiB
C
/*
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* arch/arm/include/asm/uaccess.h
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef _ASMARM_UACCESS_H
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#define _ASMARM_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/string.h>
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#include <asm/memory.h>
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#include <asm/domain.h>
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#include <asm/unified.h>
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#include <asm/compiler.h>
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#include <asm/extable.h>
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/*
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* These two functions allow hooking accesses to userspace to increase
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* system integrity by ensuring that the kernel can not inadvertantly
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* perform such accesses (eg, via list poison values) which could then
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* be exploited for priviledge escalation.
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*/
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static inline unsigned int uaccess_save_and_enable(void)
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{
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#ifdef CONFIG_CPU_SW_DOMAIN_PAN
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unsigned int old_domain = get_domain();
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/* Set the current domain access to permit user accesses */
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set_domain((old_domain & ~domain_mask(DOMAIN_USER)) |
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domain_val(DOMAIN_USER, DOMAIN_CLIENT));
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return old_domain;
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#else
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return 0;
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#endif
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}
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static inline void uaccess_restore(unsigned int flags)
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{
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#ifdef CONFIG_CPU_SW_DOMAIN_PAN
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/* Restore the user access mask */
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set_domain(flags);
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#endif
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}
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/*
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* These two are intentionally not defined anywhere - if the kernel
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* code generates any references to them, that's a bug.
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*/
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extern int __get_user_bad(void);
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extern int __put_user_bad(void);
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/*
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* Note that this is actually 0x1,0000,0000
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*/
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#define KERNEL_DS 0x00000000
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#define get_ds() (KERNEL_DS)
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#ifdef CONFIG_MMU
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#define USER_DS TASK_SIZE
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#define get_fs() (current_thread_info()->addr_limit)
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static inline void set_fs(mm_segment_t fs)
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{
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current_thread_info()->addr_limit = fs;
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/*
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* Prevent a mispredicted conditional call to set_fs from forwarding
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* the wrong address limit to access_ok under speculation.
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*/
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dsb(nsh);
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isb();
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modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
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}
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#define segment_eq(a, b) ((a) == (b))
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/* We use 33-bit arithmetic here... */
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#define __range_ok(addr, size) ({ \
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unsigned long flag, roksum; \
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__chk_user_ptr(addr); \
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__asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
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: "=&r" (flag), "=&r" (roksum) \
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: "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
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: "cc"); \
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flag; })
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/*
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* This is a type: either unsigned long, if the argument fits into
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* that type, or otherwise unsigned long long.
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*/
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#define __inttype(x) \
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__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
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/*
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* Sanitise a uaccess pointer such that it becomes NULL if addr+size
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* is above the current addr_limit.
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*/
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#define uaccess_mask_range_ptr(ptr, size) \
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((__typeof__(ptr))__uaccess_mask_range_ptr(ptr, size))
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static inline void __user *__uaccess_mask_range_ptr(const void __user *ptr,
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size_t size)
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{
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void __user *safe_ptr = (void __user *)ptr;
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unsigned long tmp;
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asm volatile(
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" sub %1, %3, #1\n"
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" subs %1, %1, %0\n"
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" addhs %1, %1, #1\n"
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" subhss %1, %1, %2\n"
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" movlo %0, #0\n"
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: "+r" (safe_ptr), "=&r" (tmp)
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: "r" (size), "r" (current_thread_info()->addr_limit)
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: "cc");
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csdb();
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return safe_ptr;
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}
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/*
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* Single-value transfer routines. They automatically use the right
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* size if we just have the right pointer type. Note that the functions
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* which read from user space (*get_*) need to take care not to leak
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* kernel data even if the calling code is buggy and fails to check
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* the return value. This means zeroing out the destination variable
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* or buffer on error. Normally this is done out of line by the
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* fixup code, but there are a few places where it intrudes on the
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* main code path. When we only write to user space, there is no
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* problem.
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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_32t_8(void *);
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extern int __get_user_8(void *);
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extern int __get_user_64t_1(void *);
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extern int __get_user_64t_2(void *);
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extern int __get_user_64t_4(void *);
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#define __GUP_CLOBBER_1 "lr", "cc"
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#ifdef CONFIG_CPU_USE_DOMAINS
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#define __GUP_CLOBBER_2 "ip", "lr", "cc"
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#else
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#define __GUP_CLOBBER_2 "lr", "cc"
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#endif
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#define __GUP_CLOBBER_4 "lr", "cc"
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#define __GUP_CLOBBER_32t_8 "lr", "cc"
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#define __GUP_CLOBBER_8 "lr", "cc"
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#define __get_user_x(__r2, __p, __e, __l, __s) \
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__asm__ __volatile__ ( \
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__asmeq("%0", "r0") __asmeq("%1", "r2") \
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__asmeq("%3", "r1") \
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"bl __get_user_" #__s \
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: "=&r" (__e), "=r" (__r2) \
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: "0" (__p), "r" (__l) \
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: __GUP_CLOBBER_##__s)
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/* narrowing a double-word get into a single 32bit word register: */
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#ifdef __ARMEB__
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#define __get_user_x_32t(__r2, __p, __e, __l, __s) \
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__get_user_x(__r2, __p, __e, __l, 32t_8)
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#else
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#define __get_user_x_32t __get_user_x
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#endif
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/*
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* storing result into proper least significant word of 64bit target var,
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* different only for big endian case where 64 bit __r2 lsw is r3:
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*/
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#ifdef __ARMEB__
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#define __get_user_x_64t(__r2, __p, __e, __l, __s) \
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__asm__ __volatile__ ( \
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__asmeq("%0", "r0") __asmeq("%1", "r2") \
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__asmeq("%3", "r1") \
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"bl __get_user_64t_" #__s \
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: "=&r" (__e), "=r" (__r2) \
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: "0" (__p), "r" (__l) \
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: __GUP_CLOBBER_##__s)
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#else
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#define __get_user_x_64t __get_user_x
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#endif
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#define __get_user_check(x, p) \
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({ \
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unsigned long __limit = current_thread_info()->addr_limit - 1; \
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register typeof(*(p)) __user *__p asm("r0") = (p); \
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register __inttype(x) __r2 asm("r2"); \
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register unsigned long __l asm("r1") = __limit; \
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register int __e asm("r0"); \
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unsigned int __ua_flags = uaccess_save_and_enable(); \
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switch (sizeof(*(__p))) { \
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case 1: \
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if (sizeof((x)) >= 8) \
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__get_user_x_64t(__r2, __p, __e, __l, 1); \
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else \
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__get_user_x(__r2, __p, __e, __l, 1); \
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break; \
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case 2: \
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if (sizeof((x)) >= 8) \
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__get_user_x_64t(__r2, __p, __e, __l, 2); \
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else \
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__get_user_x(__r2, __p, __e, __l, 2); \
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break; \
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case 4: \
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if (sizeof((x)) >= 8) \
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__get_user_x_64t(__r2, __p, __e, __l, 4); \
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else \
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__get_user_x(__r2, __p, __e, __l, 4); \
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break; \
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case 8: \
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if (sizeof((x)) < 8) \
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__get_user_x_32t(__r2, __p, __e, __l, 4); \
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else \
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__get_user_x(__r2, __p, __e, __l, 8); \
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break; \
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default: __e = __get_user_bad(); break; \
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} \
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uaccess_restore(__ua_flags); \
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x = (typeof(*(p))) __r2; \
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__e; \
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})
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#define get_user(x, p) \
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({ \
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might_fault(); \
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__get_user_check(x, p); \
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})
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extern int __put_user_1(void *, unsigned int);
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extern int __put_user_2(void *, unsigned int);
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extern int __put_user_4(void *, unsigned int);
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extern int __put_user_8(void *, unsigned long long);
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#define __put_user_check(__pu_val, __ptr, __err, __s) \
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({ \
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unsigned long __limit = current_thread_info()->addr_limit - 1; \
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register typeof(__pu_val) __r2 asm("r2") = __pu_val; \
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register const void __user *__p asm("r0") = __ptr; \
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register unsigned long __l asm("r1") = __limit; \
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register int __e asm("r0"); \
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__asm__ __volatile__ ( \
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__asmeq("%0", "r0") __asmeq("%2", "r2") \
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__asmeq("%3", "r1") \
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"bl __put_user_" #__s \
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: "=&r" (__e) \
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: "0" (__p), "r" (__r2), "r" (__l) \
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: "ip", "lr", "cc"); \
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__err = __e; \
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})
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#else /* CONFIG_MMU */
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/*
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* uClinux has only one addr space, so has simplified address limits.
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*/
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#define USER_DS KERNEL_DS
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#define segment_eq(a, b) (1)
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#define __addr_ok(addr) ((void)(addr), 1)
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#define __range_ok(addr, size) ((void)(addr), 0)
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#define get_fs() (KERNEL_DS)
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static inline void set_fs(mm_segment_t fs)
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{
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}
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#define get_user(x, p) __get_user(x, p)
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#define __put_user_check __put_user_nocheck
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#endif /* CONFIG_MMU */
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#define access_ok(type, addr, size) (__range_ok(addr, size) == 0)
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#define user_addr_max() \
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(uaccess_kernel() ? ~0UL : get_fs())
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#ifdef CONFIG_CPU_SPECTRE
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/*
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* When mitigating Spectre variant 1, it is not worth fixing the non-
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* verifying accessors, because we need to add verification of the
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* address space there. Force these to use the standard get_user()
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* version instead.
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*/
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#define __get_user(x, ptr) get_user(x, ptr)
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#else
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/*
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* The "__xxx" versions of the user access functions do not verify the
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* address space - it must have been done previously with a separate
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* "access_ok()" call.
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*
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* The "xxx_error" versions set the third argument to EFAULT if an
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* error occurs, and leave it unchanged on success. Note that these
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* versions are void (ie, don't return a value as such).
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*/
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#define __get_user(x, ptr) \
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({ \
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long __gu_err = 0; \
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__get_user_err((x), (ptr), __gu_err); \
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__gu_err; \
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})
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#define __get_user_err(x, ptr, err) \
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do { \
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unsigned long __gu_addr = (unsigned long)(ptr); \
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unsigned long __gu_val; \
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unsigned int __ua_flags; \
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__chk_user_ptr(ptr); \
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might_fault(); \
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__ua_flags = uaccess_save_and_enable(); \
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switch (sizeof(*(ptr))) { \
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case 1: __get_user_asm_byte(__gu_val, __gu_addr, err); break; \
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case 2: __get_user_asm_half(__gu_val, __gu_addr, err); break; \
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case 4: __get_user_asm_word(__gu_val, __gu_addr, err); break; \
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default: (__gu_val) = __get_user_bad(); \
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} \
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uaccess_restore(__ua_flags); \
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(x) = (__typeof__(*(ptr)))__gu_val; \
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} while (0)
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#define __get_user_asm(x, addr, err, instr) \
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__asm__ __volatile__( \
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"1: " TUSER(instr) " %1, [%2], #0\n" \
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"2:\n" \
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" .pushsection .text.fixup,\"ax\"\n" \
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" .align 2\n" \
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"3: mov %0, %3\n" \
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" mov %1, #0\n" \
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" b 2b\n" \
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" .popsection\n" \
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" .pushsection __ex_table,\"a\"\n" \
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" .align 3\n" \
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" .long 1b, 3b\n" \
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" .popsection" \
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: "+r" (err), "=&r" (x) \
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: "r" (addr), "i" (-EFAULT) \
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: "cc")
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#define __get_user_asm_byte(x, addr, err) \
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__get_user_asm(x, addr, err, ldrb)
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#if __LINUX_ARM_ARCH__ >= 6
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#define __get_user_asm_half(x, addr, err) \
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__get_user_asm(x, addr, err, ldrh)
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#else
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#ifndef __ARMEB__
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#define __get_user_asm_half(x, __gu_addr, err) \
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({ \
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unsigned long __b1, __b2; \
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__get_user_asm_byte(__b1, __gu_addr, err); \
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__get_user_asm_byte(__b2, __gu_addr + 1, err); \
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(x) = __b1 | (__b2 << 8); \
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})
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#else
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#define __get_user_asm_half(x, __gu_addr, err) \
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({ \
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unsigned long __b1, __b2; \
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__get_user_asm_byte(__b1, __gu_addr, err); \
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__get_user_asm_byte(__b2, __gu_addr + 1, err); \
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(x) = (__b1 << 8) | __b2; \
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})
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#endif
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#endif /* __LINUX_ARM_ARCH__ >= 6 */
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#define __get_user_asm_word(x, addr, err) \
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__get_user_asm(x, addr, err, ldr)
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#endif
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#define __put_user_switch(x, ptr, __err, __fn) \
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do { \
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const __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \
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__typeof__(*(ptr)) __pu_val = (x); \
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unsigned int __ua_flags; \
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might_fault(); \
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__ua_flags = uaccess_save_and_enable(); \
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switch (sizeof(*(ptr))) { \
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case 1: __fn(__pu_val, __pu_ptr, __err, 1); break; \
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case 2: __fn(__pu_val, __pu_ptr, __err, 2); break; \
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case 4: __fn(__pu_val, __pu_ptr, __err, 4); break; \
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case 8: __fn(__pu_val, __pu_ptr, __err, 8); break; \
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default: __err = __put_user_bad(); break; \
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} \
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uaccess_restore(__ua_flags); \
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} while (0)
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#define put_user(x, ptr) \
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({ \
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int __pu_err = 0; \
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__put_user_switch((x), (ptr), __pu_err, __put_user_check); \
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__pu_err; \
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})
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#ifdef CONFIG_CPU_SPECTRE
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/*
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* When mitigating Spectre variant 1.1, all accessors need to include
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* verification of the address space.
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*/
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#define __put_user(x, ptr) put_user(x, ptr)
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#else
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#define __put_user(x, ptr) \
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({ \
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long __pu_err = 0; \
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__put_user_switch((x), (ptr), __pu_err, __put_user_nocheck); \
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__pu_err; \
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})
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#define __put_user_nocheck(x, __pu_ptr, __err, __size) \
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do { \
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unsigned long __pu_addr = (unsigned long)__pu_ptr; \
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__put_user_nocheck_##__size(x, __pu_addr, __err); \
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} while (0)
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#define __put_user_nocheck_1 __put_user_asm_byte
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#define __put_user_nocheck_2 __put_user_asm_half
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#define __put_user_nocheck_4 __put_user_asm_word
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#define __put_user_nocheck_8 __put_user_asm_dword
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#define __put_user_asm(x, __pu_addr, err, instr) \
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__asm__ __volatile__( \
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"1: " TUSER(instr) " %1, [%2], #0\n" \
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"2:\n" \
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" .pushsection .text.fixup,\"ax\"\n" \
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" .align 2\n" \
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"3: mov %0, %3\n" \
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" b 2b\n" \
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" .popsection\n" \
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" .pushsection __ex_table,\"a\"\n" \
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" .align 3\n" \
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" .long 1b, 3b\n" \
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" .popsection" \
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: "+r" (err) \
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: "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
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: "cc")
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#define __put_user_asm_byte(x, __pu_addr, err) \
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__put_user_asm(x, __pu_addr, err, strb)
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#if __LINUX_ARM_ARCH__ >= 6
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#define __put_user_asm_half(x, __pu_addr, err) \
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__put_user_asm(x, __pu_addr, err, strh)
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#else
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#ifndef __ARMEB__
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#define __put_user_asm_half(x, __pu_addr, err) \
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({ \
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unsigned long __temp = (__force unsigned long)(x); \
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__put_user_asm_byte(__temp, __pu_addr, err); \
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__put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
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})
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#else
|
|
#define __put_user_asm_half(x, __pu_addr, err) \
|
|
({ \
|
|
unsigned long __temp = (__force unsigned long)(x); \
|
|
__put_user_asm_byte(__temp >> 8, __pu_addr, err); \
|
|
__put_user_asm_byte(__temp, __pu_addr + 1, err); \
|
|
})
|
|
#endif
|
|
|
|
#endif /* __LINUX_ARM_ARCH__ >= 6 */
|
|
|
|
#define __put_user_asm_word(x, __pu_addr, err) \
|
|
__put_user_asm(x, __pu_addr, err, str)
|
|
|
|
#ifndef __ARMEB__
|
|
#define __reg_oper0 "%R2"
|
|
#define __reg_oper1 "%Q2"
|
|
#else
|
|
#define __reg_oper0 "%Q2"
|
|
#define __reg_oper1 "%R2"
|
|
#endif
|
|
|
|
#define __put_user_asm_dword(x, __pu_addr, err) \
|
|
__asm__ __volatile__( \
|
|
ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \
|
|
ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \
|
|
THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \
|
|
THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \
|
|
"3:\n" \
|
|
" .pushsection .text.fixup,\"ax\"\n" \
|
|
" .align 2\n" \
|
|
"4: mov %0, %3\n" \
|
|
" b 3b\n" \
|
|
" .popsection\n" \
|
|
" .pushsection __ex_table,\"a\"\n" \
|
|
" .align 3\n" \
|
|
" .long 1b, 4b\n" \
|
|
" .long 2b, 4b\n" \
|
|
" .popsection" \
|
|
: "+r" (err), "+r" (__pu_addr) \
|
|
: "r" (x), "i" (-EFAULT) \
|
|
: "cc")
|
|
|
|
#endif /* !CONFIG_CPU_SPECTRE */
|
|
|
|
#ifdef CONFIG_MMU
|
|
extern unsigned long __must_check
|
|
arm_copy_from_user(void *to, const void __user *from, unsigned long n);
|
|
|
|
static inline unsigned long __must_check
|
|
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
|
|
{
|
|
unsigned int __ua_flags;
|
|
|
|
__ua_flags = uaccess_save_and_enable();
|
|
n = arm_copy_from_user(to, from, n);
|
|
uaccess_restore(__ua_flags);
|
|
return n;
|
|
}
|
|
|
|
extern unsigned long __must_check
|
|
arm_copy_to_user(void __user *to, const void *from, unsigned long n);
|
|
extern unsigned long __must_check
|
|
__copy_to_user_std(void __user *to, const void *from, unsigned long n);
|
|
|
|
static inline unsigned long __must_check
|
|
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
|
|
{
|
|
#ifndef CONFIG_UACCESS_WITH_MEMCPY
|
|
unsigned int __ua_flags;
|
|
__ua_flags = uaccess_save_and_enable();
|
|
n = arm_copy_to_user(to, from, n);
|
|
uaccess_restore(__ua_flags);
|
|
return n;
|
|
#else
|
|
return arm_copy_to_user(to, from, n);
|
|
#endif
|
|
}
|
|
|
|
extern unsigned long __must_check
|
|
arm_clear_user(void __user *addr, unsigned long n);
|
|
extern unsigned long __must_check
|
|
__clear_user_std(void __user *addr, unsigned long n);
|
|
|
|
static inline unsigned long __must_check
|
|
__clear_user(void __user *addr, unsigned long n)
|
|
{
|
|
unsigned int __ua_flags = uaccess_save_and_enable();
|
|
n = arm_clear_user(addr, n);
|
|
uaccess_restore(__ua_flags);
|
|
return n;
|
|
}
|
|
|
|
#else
|
|
static inline unsigned long
|
|
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
|
|
{
|
|
memcpy(to, (const void __force *)from, n);
|
|
return 0;
|
|
}
|
|
static inline unsigned long
|
|
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
|
|
{
|
|
memcpy((void __force *)to, from, n);
|
|
return 0;
|
|
}
|
|
#define __clear_user(addr, n) (memset((void __force *)addr, 0, n), 0)
|
|
#endif
|
|
#define INLINE_COPY_TO_USER
|
|
#define INLINE_COPY_FROM_USER
|
|
|
|
static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
|
|
{
|
|
if (access_ok(VERIFY_WRITE, to, n))
|
|
n = __clear_user(to, n);
|
|
return n;
|
|
}
|
|
|
|
/* These are from lib/ code, and use __get_user() and friends */
|
|
extern long strncpy_from_user(char *dest, const char __user *src, long count);
|
|
|
|
extern __must_check long strnlen_user(const char __user *str, long n);
|
|
|
|
#endif /* _ASMARM_UACCESS_H */
|