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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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554bfeceb8
pa_memcpy() is the major memcpy implementation in the parisc kernel which is used to do any kind of userspace/kernel memory copies. Al Viro noticed various bugs in the implementation of pa_mempcy(), most notably that in case of faults it may report back to have copied more bytes than it actually did. Fixing those bugs is quite hard in the C-implementation, because the compiler is messing around with the registers and we are not guaranteed that specific variables are always in the same processor registers. This makes proper fault handling complicated. This patch implements pa_memcpy() in assembler. That way we have correct fault handling and adding a 64-bit copy routine was quite easy. Runtime tested with 32- and 64bit kernels. Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Cc: <stable@vger.kernel.org> # v4.9+ Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de>
87 lines
2.5 KiB
C
87 lines
2.5 KiB
C
/*
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* Optimized memory copy routines.
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*
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* Copyright (C) 2004 Randolph Chung <tausq@debian.org>
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* Copyright (C) 2013-2017 Helge Deller <deller@gmx.de>
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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 as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* Portions derived from the GNU C Library
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* Copyright (C) 1991, 1997, 2003 Free Software Foundation, Inc.
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*
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*/
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#include <linux/module.h>
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#include <linux/compiler.h>
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#include <linux/uaccess.h>
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DECLARE_PER_CPU(struct exception_data, exception_data);
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#define get_user_space() (segment_eq(get_fs(), KERNEL_DS) ? 0 : mfsp(3))
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#define get_kernel_space() (0)
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/* Returns 0 for success, otherwise, returns number of bytes not transferred. */
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extern unsigned long pa_memcpy(void *dst, const void *src,
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unsigned long len);
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unsigned long __copy_to_user(void __user *dst, const void *src,
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unsigned long len)
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{
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mtsp(get_kernel_space(), 1);
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mtsp(get_user_space(), 2);
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return pa_memcpy((void __force *)dst, src, len);
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}
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EXPORT_SYMBOL(__copy_to_user);
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unsigned long __copy_from_user(void *dst, const void __user *src,
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unsigned long len)
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{
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mtsp(get_user_space(), 1);
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mtsp(get_kernel_space(), 2);
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return pa_memcpy(dst, (void __force *)src, len);
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}
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EXPORT_SYMBOL(__copy_from_user);
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unsigned long copy_in_user(void __user *dst, const void __user *src, unsigned long len)
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{
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mtsp(get_user_space(), 1);
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mtsp(get_user_space(), 2);
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return pa_memcpy((void __force *)dst, (void __force *)src, len);
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}
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void * memcpy(void * dst,const void *src, size_t count)
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{
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mtsp(get_kernel_space(), 1);
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mtsp(get_kernel_space(), 2);
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pa_memcpy(dst, src, count);
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return dst;
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}
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EXPORT_SYMBOL(copy_in_user);
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EXPORT_SYMBOL(memcpy);
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long probe_kernel_read(void *dst, const void *src, size_t size)
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{
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unsigned long addr = (unsigned long)src;
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if (addr < PAGE_SIZE)
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return -EFAULT;
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/* check for I/O space F_EXTEND(0xfff00000) access as well? */
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return __probe_kernel_read(dst, src, size);
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}
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