mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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1771c6e1a5
Exchange between user and kernel memory is coded in assembly language. Which means that such accesses won't be spotted by KASAN as a compiler instruments only C code. Add explicit KASAN checks to user memory access API to ensure that userspace writes to (or reads from) a valid kernel memory. Note: Unlike others strncpy_from_user() is written mostly in C and KASAN sees memory accesses in it. However, it makes sense to add explicit check for all @count bytes that *potentially* could be written to the kernel. [aryabinin@virtuozzo.com: move kasan check under the condition] Link: http://lkml.kernel.org/r/1462869209-21096-1-git-send-email-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/1462538722-1574-4-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
282 lines
7.1 KiB
C
282 lines
7.1 KiB
C
#ifndef _ASM_X86_UACCESS_64_H
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#define _ASM_X86_UACCESS_64_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/errno.h>
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#include <linux/lockdep.h>
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#include <linux/kasan-checks.h>
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#include <asm/alternative.h>
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#include <asm/cpufeatures.h>
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#include <asm/page.h>
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/*
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* Copy To/From Userspace
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*/
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/* Handles exceptions in both to and from, but doesn't do access_ok */
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__must_check unsigned long
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copy_user_enhanced_fast_string(void *to, const void *from, unsigned len);
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__must_check unsigned long
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copy_user_generic_string(void *to, const void *from, unsigned len);
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__must_check unsigned long
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copy_user_generic_unrolled(void *to, const void *from, unsigned len);
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static __always_inline __must_check unsigned long
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copy_user_generic(void *to, const void *from, unsigned len)
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{
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unsigned ret;
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/*
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* If CPU has ERMS feature, use copy_user_enhanced_fast_string.
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* Otherwise, if CPU has rep_good feature, use copy_user_generic_string.
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* Otherwise, use copy_user_generic_unrolled.
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*/
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alternative_call_2(copy_user_generic_unrolled,
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copy_user_generic_string,
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X86_FEATURE_REP_GOOD,
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copy_user_enhanced_fast_string,
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X86_FEATURE_ERMS,
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ASM_OUTPUT2("=a" (ret), "=D" (to), "=S" (from),
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"=d" (len)),
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"1" (to), "2" (from), "3" (len)
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: "memory", "rcx", "r8", "r9", "r10", "r11");
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return ret;
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}
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__must_check unsigned long
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copy_in_user(void __user *to, const void __user *from, unsigned len);
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static __always_inline __must_check
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int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size)
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{
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int ret = 0;
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if (!__builtin_constant_p(size))
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return copy_user_generic(dst, (__force void *)src, size);
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switch (size) {
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case 1:
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__uaccess_begin();
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__get_user_asm(*(u8 *)dst, (u8 __user *)src,
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ret, "b", "b", "=q", 1);
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__uaccess_end();
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return ret;
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case 2:
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__uaccess_begin();
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__get_user_asm(*(u16 *)dst, (u16 __user *)src,
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ret, "w", "w", "=r", 2);
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__uaccess_end();
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return ret;
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case 4:
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__uaccess_begin();
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__get_user_asm(*(u32 *)dst, (u32 __user *)src,
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ret, "l", "k", "=r", 4);
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__uaccess_end();
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return ret;
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case 8:
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__uaccess_begin();
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__get_user_asm(*(u64 *)dst, (u64 __user *)src,
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ret, "q", "", "=r", 8);
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__uaccess_end();
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return ret;
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case 10:
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__uaccess_begin();
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__get_user_asm(*(u64 *)dst, (u64 __user *)src,
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ret, "q", "", "=r", 10);
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if (likely(!ret))
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__get_user_asm(*(u16 *)(8 + (char *)dst),
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(u16 __user *)(8 + (char __user *)src),
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ret, "w", "w", "=r", 2);
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__uaccess_end();
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return ret;
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case 16:
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__uaccess_begin();
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__get_user_asm(*(u64 *)dst, (u64 __user *)src,
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ret, "q", "", "=r", 16);
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if (likely(!ret))
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__get_user_asm(*(u64 *)(8 + (char *)dst),
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(u64 __user *)(8 + (char __user *)src),
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ret, "q", "", "=r", 8);
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__uaccess_end();
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return ret;
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default:
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return copy_user_generic(dst, (__force void *)src, size);
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}
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}
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static __always_inline __must_check
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int __copy_from_user(void *dst, const void __user *src, unsigned size)
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{
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might_fault();
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kasan_check_write(dst, size);
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return __copy_from_user_nocheck(dst, src, size);
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}
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static __always_inline __must_check
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int __copy_to_user_nocheck(void __user *dst, const void *src, unsigned size)
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{
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int ret = 0;
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if (!__builtin_constant_p(size))
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return copy_user_generic((__force void *)dst, src, size);
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switch (size) {
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case 1:
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__uaccess_begin();
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__put_user_asm(*(u8 *)src, (u8 __user *)dst,
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ret, "b", "b", "iq", 1);
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__uaccess_end();
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return ret;
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case 2:
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__uaccess_begin();
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__put_user_asm(*(u16 *)src, (u16 __user *)dst,
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ret, "w", "w", "ir", 2);
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__uaccess_end();
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return ret;
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case 4:
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__uaccess_begin();
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__put_user_asm(*(u32 *)src, (u32 __user *)dst,
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ret, "l", "k", "ir", 4);
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__uaccess_end();
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return ret;
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case 8:
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__uaccess_begin();
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__put_user_asm(*(u64 *)src, (u64 __user *)dst,
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ret, "q", "", "er", 8);
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__uaccess_end();
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return ret;
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case 10:
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__uaccess_begin();
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__put_user_asm(*(u64 *)src, (u64 __user *)dst,
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ret, "q", "", "er", 10);
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if (likely(!ret)) {
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asm("":::"memory");
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__put_user_asm(4[(u16 *)src], 4 + (u16 __user *)dst,
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ret, "w", "w", "ir", 2);
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}
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__uaccess_end();
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return ret;
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case 16:
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__uaccess_begin();
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__put_user_asm(*(u64 *)src, (u64 __user *)dst,
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ret, "q", "", "er", 16);
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if (likely(!ret)) {
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asm("":::"memory");
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__put_user_asm(1[(u64 *)src], 1 + (u64 __user *)dst,
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ret, "q", "", "er", 8);
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}
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__uaccess_end();
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return ret;
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default:
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return copy_user_generic((__force void *)dst, src, size);
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}
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}
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static __always_inline __must_check
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int __copy_to_user(void __user *dst, const void *src, unsigned size)
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{
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might_fault();
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kasan_check_read(src, size);
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return __copy_to_user_nocheck(dst, src, size);
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}
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static __always_inline __must_check
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int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
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{
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int ret = 0;
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might_fault();
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if (!__builtin_constant_p(size))
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return copy_user_generic((__force void *)dst,
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(__force void *)src, size);
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switch (size) {
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case 1: {
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u8 tmp;
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__uaccess_begin();
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__get_user_asm(tmp, (u8 __user *)src,
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ret, "b", "b", "=q", 1);
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if (likely(!ret))
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__put_user_asm(tmp, (u8 __user *)dst,
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ret, "b", "b", "iq", 1);
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__uaccess_end();
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return ret;
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}
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case 2: {
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u16 tmp;
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__uaccess_begin();
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__get_user_asm(tmp, (u16 __user *)src,
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ret, "w", "w", "=r", 2);
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if (likely(!ret))
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__put_user_asm(tmp, (u16 __user *)dst,
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ret, "w", "w", "ir", 2);
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__uaccess_end();
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return ret;
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}
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case 4: {
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u32 tmp;
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__uaccess_begin();
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__get_user_asm(tmp, (u32 __user *)src,
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ret, "l", "k", "=r", 4);
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if (likely(!ret))
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__put_user_asm(tmp, (u32 __user *)dst,
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ret, "l", "k", "ir", 4);
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__uaccess_end();
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return ret;
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}
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case 8: {
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u64 tmp;
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__uaccess_begin();
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__get_user_asm(tmp, (u64 __user *)src,
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ret, "q", "", "=r", 8);
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if (likely(!ret))
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__put_user_asm(tmp, (u64 __user *)dst,
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ret, "q", "", "er", 8);
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__uaccess_end();
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return ret;
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}
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default:
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return copy_user_generic((__force void *)dst,
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(__force void *)src, size);
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}
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}
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static __must_check __always_inline int
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__copy_from_user_inatomic(void *dst, const void __user *src, unsigned size)
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{
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kasan_check_write(dst, size);
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return __copy_from_user_nocheck(dst, src, size);
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}
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static __must_check __always_inline int
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__copy_to_user_inatomic(void __user *dst, const void *src, unsigned size)
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{
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kasan_check_read(src, size);
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return __copy_to_user_nocheck(dst, src, size);
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}
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extern long __copy_user_nocache(void *dst, const void __user *src,
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unsigned size, int zerorest);
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static inline int
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__copy_from_user_nocache(void *dst, const void __user *src, unsigned size)
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{
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might_fault();
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kasan_check_write(dst, size);
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return __copy_user_nocache(dst, src, size, 1);
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}
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static inline int
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__copy_from_user_inatomic_nocache(void *dst, const void __user *src,
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unsigned size)
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{
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kasan_check_write(dst, size);
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return __copy_user_nocache(dst, src, size, 0);
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}
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unsigned long
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copy_user_handle_tail(char *to, char *from, unsigned len);
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#endif /* _ASM_X86_UACCESS_64_H */
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