From 71cc2c05cc1c0f6f61c6698ce3838b342ff5f3ca Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Fri, 8 Apr 2022 18:03:13 +0200 Subject: [PATCH] nios2: use fallback for random_get_entropy() instead of zero commit c04e72700f2293013dab40208e809369378f224c 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 Cc: Arnd Bergmann Acked-by: Dinh Nguyen Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- arch/nios2/include/asm/timex.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/nios2/include/asm/timex.h b/arch/nios2/include/asm/timex.h index a769f871b28d..40a1adc9bd03 100644 --- a/arch/nios2/include/asm/timex.h +++ b/arch/nios2/include/asm/timex.h @@ -8,5 +8,8 @@ typedef unsigned long cycles_t; extern cycles_t get_cycles(void); +#define get_cycles get_cycles + +#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback()) #endif