d2e76a31c6
commit ff8a8f59c99f6a7c656387addc4d9f2247d75077 upstream. In the event that random_get_entropy() can't access a cycle counter or similar, falling back to returning 0 is really not the best we can do. Instead, at least calling random_get_entropy_fallback() would be preferable, because that always needs to return _something_, even falling back to jiffies eventually. It's not as though random_get_entropy_fallback() is super high precision or guaranteed to be entropic, but basically anything that's not zero all the time is better than returning zero all the time. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
20 lines
577 B
C
20 lines
577 B
C
/*
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* arch/arm/include/asm/timex.h
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*
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* Copyright (C) 1997,1998 Russell King
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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 as
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* published by the Free Software Foundation.
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*
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* Architecture Specific TIME specifications
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*/
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#ifndef _ASMARM_TIMEX_H
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#define _ASMARM_TIMEX_H
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typedef unsigned long cycles_t;
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#define get_cycles() ({ cycles_t c; read_current_timer(&c) ? 0 : c; })
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#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback())
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#endif
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