12700c17fc
There are many different ways that access_ok() is defined across architectures, but in the end, they all just compare against the user_addr_max() value or they accept anything. Provide one definition that works for most architectures, checking against TASK_SIZE_MAX for user processes or skipping the check inside of uaccess_kernel() sections. For architectures without CONFIG_SET_FS(), this should be the fastest check, as it comes down to a single comparison of a pointer against a compile-time constant, while the architecture specific versions tend to do something more complex for historic reasons or get something wrong. Type checking for __user annotations is handled inconsistently across architectures, but this is easily simplified as well by using an inline function that takes a 'const void __user *' argument. A handful of callers need an extra __user annotation for this. Some architectures had trick to use 33-bit or 65-bit arithmetic on the addresses to calculate the overflow, however this simpler version uses fewer registers, which means it can produce better object code in the end despite needing a second (statically predicted) branch. Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64, asm-generic] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Stafford Horne <shorne@gmail.com> Acked-by: Dinh Nguyen <dinguyen@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
39 lines
1.1 KiB
C
39 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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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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#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 <asm/sections.h>
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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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#include <asm-generic/uaccess.h>
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#endif
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