Commit 2350ebe2 authored by Russell King's avatar Russell King
Browse files

ARM: uaccess: add further explanation of __range_ok() 



Detail the success return condition, and that we rely on KERNEL_DS
being zero for this to operate correctly.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent 6da5238f

arch/arm/include/asm/uaccess.h

+5 −1
Original line number Diff line number Diff line
@@ -78,7 +78,11 @@ static inline void set_fs(mm_segment_t fs) 


#define segment_eq(a, b)	((a) == (b))



/* We use 33-bit arithmetic here... */

/*

 * We use 33-bit arithmetic here.  Success returns zero, failure returns

 * addr_limit.  We take advantage that addr_limit will be zero for KERNEL_DS,

 * so this will always return success in that case.

 */

#define __range_ok(addr, size) ({ \

	unsigned long flag, roksum; \

	__chk_user_ptr(addr);	\

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