From 12700c17fc286149324f92d6d380bc48e43f253d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 15 Feb 2022 17:55:04 +0100 Subject: uaccess: generalize access_ok() 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 Acked-by: Mark Rutland [arm64, asm-generic] Acked-by: Geert Uytterhoeven Acked-by: Stafford Horne Acked-by: Dinh Nguyen Signed-off-by: Arnd Bergmann --- include/asm-generic/uaccess.h | 21 +-------------------- 1 file changed, 1 insertion(+), 20 deletions(-) (limited to 'include/asm-generic/uaccess.h') diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index 0870fa11a7c5..ebc685dc8d74 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -114,28 +114,9 @@ static inline void set_fs(mm_segment_t fs) } #endif -#ifndef uaccess_kernel -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) -#endif - -#ifndef user_addr_max -#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) -#endif - #endif /* CONFIG_SET_FS */ -#define access_ok(addr, size) __access_ok((unsigned long)(addr),(size)) - -/* - * The architecture should really override this if possible, at least - * doing a check on the get_fs() - */ -#ifndef __access_ok -static inline int __access_ok(unsigned long addr, unsigned long size) -{ - return 1; -} -#endif +#include /* * These are the main single-value transfer routines. They automatically -- cgit v1.2.3