96d4f267e4
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
110 lines
3.5 KiB
C
110 lines
3.5 KiB
C
/*
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* User memory access support for Hexagon
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*
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* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
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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 and
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* only version 2 as published by the Free Software Foundation.
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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., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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#ifndef _ASM_UACCESS_H
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#define _ASM_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/mm.h>
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#include <asm/segment.h>
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#include <asm/sections.h>
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/*
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* access_ok: - Checks if a user space pointer is valid
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* @addr: User space pointer to start of block to check
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* @size: Size of block to check
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* Checks if a pointer to a block of memory in user space is valid.
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*
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* Returns true (nonzero) if the memory block *may* be valid, false (zero)
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* if it is definitely invalid.
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*
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* User address space in Hexagon, like x86, goes to 0xbfffffff, so the
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* simple MSB-based tests used by MIPS won't work. Some further
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* optimization is probably possible here, but for now, keep it
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* reasonably simple and not *too* slow. After all, we've got the
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* MMU for backup.
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*/
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#define __access_ok(addr, size) \
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((get_fs().seg == KERNEL_DS.seg) || \
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(((unsigned long)addr < get_fs().seg) && \
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(unsigned long)size < (get_fs().seg - (unsigned long)addr)))
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/*
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* When a kernel-mode page fault is taken, the faulting instruction
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* address is checked against a table of exception_table_entries.
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* Each entry is a tuple of the address of an instruction that may
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* be authorized to fault, and the address at which execution should
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* be resumed instead of the faulting instruction, so as to effect
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* a workaround.
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*/
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/* Assembly somewhat optimized copy routines */
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unsigned long raw_copy_from_user(void *to, const void __user *from,
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unsigned long n);
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unsigned long raw_copy_to_user(void __user *to, const void *from,
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unsigned long n);
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#define INLINE_COPY_FROM_USER
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#define INLINE_COPY_TO_USER
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__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count);
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#define __clear_user(a, s) __clear_user_hexagon((a), (s))
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#define __strncpy_from_user(dst, src, n) hexagon_strncpy_from_user(dst, src, n)
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/* get around the ifndef in asm-generic/uaccess.h */
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#define __strnlen_user __strnlen_user
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extern long __strnlen_user(const char __user *src, long n);
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static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
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long n);
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#include <asm-generic/uaccess.h>
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/* Todo: an actual accelerated version of this. */
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static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
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long n)
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{
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long res = __strnlen_user(src, n);
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if (unlikely(!res))
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return -EFAULT;
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if (res > n) {
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long left = raw_copy_from_user(dst, src, n);
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if (unlikely(left))
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memset(dst + (n - left), 0, left);
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return n;
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} else {
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long left = raw_copy_from_user(dst, src, res);
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if (unlikely(left))
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memset(dst + (res - left), 0, left);
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return res-1;
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}
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}
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#endif
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