Hi Jason,
On Fri, Apr 29, 2022 at 02:16:48AM +0200, Jason A. Donenfeld wrote:
> As a sanity check, this series makes sure that during early boot, the
> cycle counter isn't returning all zeros. However, OpenRISC's TTCR timer
> can be rather slow and starts out as zero during stages of early boot.
> We know it works, however. So just always add 1 to random_get_entropy()
> so that it doesn't trigger these checks.
Just one nit, you might want to qualify that this is related to simulators/qemu:
* "However, in simulators OpenRISC's TTCR timer can be rather slow..."
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Jonas Bonn <jonas@xxxxxxxxxxxx>
> Cc: Stefan Kristiansson <stefan.kristiansson@xxxxxxxxxxxxx>
> Acked-by: Stafford Horne <shorne@xxxxxxxxx>
> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
> ---
> Changes v6->v7:
> - Add 1 to cycle counter to account for functional but slow-to-begin
> counter on QEMU.
>
> arch/openrisc/include/asm/timex.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/openrisc/include/asm/timex.h b/arch/openrisc/include/asm/timex.h
> index d52b4e536e3f..a78a5807c927 100644
> --- a/arch/openrisc/include/asm/timex.h
> +++ b/arch/openrisc/include/asm/timex.h
> @@ -23,6 +23,9 @@ static inline cycles_t get_cycles(void)
> {
> return mfspr(SPR_TTCR);
> }
> +#define get_cycles get_cycles
> +
> +#define random_get_entropy() ((unsigned long)get_cycles() + 1)
>
> /* This isn't really used any more */
> #define CLOCK_TICK_RATE 1000
Thanks,
-Stafford
