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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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143 lines
3.0 KiB
C
143 lines
3.0 KiB
C
/* MN10300 Userspace accessor functions
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*
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* Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/uaccess.h>
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/*
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* Copy a null terminated string from userspace.
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*/
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#define __do_strncpy_from_user(dst, src, count, res) \
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do { \
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int w; \
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asm volatile( \
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" mov %1,%0\n" \
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" cmp 0,%1\n" \
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" beq 2f\n" \
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"0:\n" \
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" movbu (%5),%2\n" \
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"1:\n" \
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" movbu %2,(%6)\n" \
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" inc %5\n" \
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" inc %6\n" \
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" cmp 0,%2\n" \
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" beq 2f\n" \
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" add -1,%1\n" \
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" bne 0b\n" \
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"2:\n" \
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" sub %1,%0\n" \
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"3:\n" \
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" .section .fixup,\"ax\"\n" \
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"4:\n" \
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" mov %3,%0\n" \
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" jmp 3b\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .balign 4\n" \
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" .long 0b,4b\n" \
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" .long 1b,4b\n" \
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" .previous" \
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:"=&r"(res), "=r"(count), "=&r"(w) \
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:"i"(-EFAULT), "1"(count), "a"(src), "a"(dst) \
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: "memory", "cc"); \
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} while (0)
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long
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strncpy_from_user(char *dst, const char *src, long count)
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{
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long res = -EFAULT;
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if (access_ok(VERIFY_READ, src, 1))
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__do_strncpy_from_user(dst, src, count, res);
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return res;
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}
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/*
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* Clear a userspace memory
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*/
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#define __do_clear_user(addr, size) \
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do { \
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int w; \
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asm volatile( \
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" cmp 0,%0\n" \
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" beq 1f\n" \
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" clr %1\n" \
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"0: movbu %1,(%3,%2)\n" \
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" inc %3\n" \
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" cmp %0,%3\n" \
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" bne 0b\n" \
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"1:\n" \
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" sub %3,%0\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: jmp 2b\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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" .balign 4\n" \
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" .long 0b,3b\n" \
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".previous\n" \
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: "+r"(size), "=&r"(w) \
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: "a"(addr), "d"(0) \
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: "memory", "cc"); \
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} while (0)
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unsigned long
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__clear_user(void *to, unsigned long n)
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{
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__do_clear_user(to, n);
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return n;
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}
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unsigned long
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clear_user(void *to, unsigned long n)
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{
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if (access_ok(VERIFY_WRITE, to, n))
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__do_clear_user(to, n);
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return n;
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}
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/*
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* Return the size of a string (including the ending 0)
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*
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* Return 0 on exception, a value greater than N if too long
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*/
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long strnlen_user(const char *s, long n)
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{
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unsigned long res, w;
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if (!__addr_ok(s))
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return 0;
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if (n < 0 || n + (u_long) s > current_thread_info()->addr_limit.seg)
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n = current_thread_info()->addr_limit.seg - (u_long)s;
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asm volatile(
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"0: cmp %4,%0\n"
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" beq 2f\n"
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"1: movbu (%0,%3),%1\n"
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" inc %0\n"
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" cmp 0,%1\n"
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" beq 3f\n"
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" bra 0b\n"
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"2: clr %0\n"
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"3:\n"
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".section .fixup,\"ax\"\n"
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"4: jmp 2b\n"
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".previous\n"
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".section __ex_table,\"a\"\n"
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" .balign 4\n"
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" .long 1b,4b\n"
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".previous\n"
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:"=d"(res), "=&r"(w)
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:"0"(0), "a"(s), "r"(n)
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: "memory", "cc");
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return res;
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}
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