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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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61 lines
1.2 KiB
ArmAsm
61 lines
1.2 KiB
ArmAsm
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/*
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* Copy to/from userspace with optional address space checking.
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*
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* Copyright 2004-2006 Atmel Corporation
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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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#include <linux/errno.h>
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#include <asm/page.h>
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#include <asm/thread_info.h>
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#include <asm/asm.h>
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/*
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* long strncpy_from_user(char *dst, const char *src, long count)
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*
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* On success, returns the length of the string, not including
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* the terminating NUL.
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*
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* If the string is longer than count, returns count
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*
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* If userspace access fails, returns -EFAULT
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*/
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.text
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.align 1
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.global strncpy_from_user
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.type strncpy_from_user, "function"
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strncpy_from_user:
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mov r9, -EFAULT
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branch_if_kernel r8, __strncpy_from_user
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ret_if_privileged r8, r11, r10, r9
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.global __strncpy_from_user
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.type __strncpy_from_user, "function"
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__strncpy_from_user:
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cp.w r10, 0
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reteq 0
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mov r9, r10
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1: ld.ub r8, r11++
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st.b r12++, r8
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cp.w r8, 0
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breq 2f
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sub r9, 1
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brne 1b
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2: sub r10, r9
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retal r10
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.section .fixup, "ax"
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.align 1
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3: mov r12, -EFAULT
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retal r12
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.section __ex_table, "a"
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.align 2
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.long 1b, 3b
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