| Message ID | 20220408182145.142506-3-Jason@zx2c4.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | archs/random: fallback to using sched_clock() if no cycle counter | expand |
diff --git a/arch/m68k/include/asm/timex.h b/arch/m68k/include/asm/timex.h index 6a21d9358280..2cd0942097f8 100644 --- a/arch/m68k/include/asm/timex.h +++ b/arch/m68k/include/asm/timex.h @@ -7,6 +7,8 @@ #ifndef _ASMm68K_TIMEX_H #define _ASMm68K_TIMEX_H +#include <linux/sched/clock.h> + #ifdef CONFIG_COLDFIRE /* * CLOCK_TICK_RATE should give the underlying frequency of the tick timer @@ -35,7 +37,7 @@ static inline unsigned long random_get_entropy(void) { if (mach_random_get_entropy) return mach_random_get_entropy(); - return 0; + return sched_clock(); } #define random_get_entropy random_get_entropy
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 sched_clock() would be preferable, because that always needs to return _something_, even falling back to jiffies eventually. It's not as though sched_clock() 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: Arnd Bergmann <arnd@arndb.de> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> --- arch/m68k/include/asm/timex.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)