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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-04-08 18:03:13 +0200 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-05-13 23:59:23 +0200 |
| commit | ff8a8f59c99f6a7c656387addc4d9f2247d75077 (patch) | |
| tree | b4b3899b772d8a4ed4403a607340d1e7c0aad518 | |
| parent | 1c99c6a7c3c599a68321b01b9ec243215ede5a68 (diff) | |
| download | linux-stable-ff8a8f59c99f6a7c656387addc4d9f2247d75077.tar.gz linux-stable-ff8a8f59c99f6a7c656387addc4d9f2247d75077.tar.bz2 linux-stable-ff8a8f59c99f6a7c656387addc4d9f2247d75077.zip | |
arm: use fallback for random_get_entropy() instead of zero
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>
| -rw-r--r-- | arch/arm/include/asm/timex.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm/include/asm/timex.h b/arch/arm/include/asm/timex.h index 7c3b3671d6c2..6d1337c169cd 100644 --- a/arch/arm/include/asm/timex.h +++ b/arch/arm/include/asm/timex.h @@ -11,5 +11,6 @@ typedef unsigned long cycles_t; #define get_cycles() ({ cycles_t c; read_current_timer(&c) ? 0 : c; }) +#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback()) #endif |