[PATCH v2 2/3] lib: random: get_random_bytes from HWRNG if present

[Sascha Hauer]

On Thu, Mar 16, 2017 at 06:31:45AM +0100, Oleksij Rempel wrote:
> From: Steffen Trumtrar <s.trumtrar at pengutronix.de>
> 
> Instead of generating pseudo random numbers, get random bytes
> from an optional HW generator, if enabled and registered.
> 
> Signed-off-by: Steffen Trumtrar <s.trumtrar at pengutronix.de>
> Signed-off-by: Oleksij Rempel <o.rempel at pengutronix.de>
> ---
>  lib/random.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/lib/random.c b/lib/random.c
> index 210fea994..42c0f83b7 100644
> --- a/lib/random.c
> +++ b/lib/random.c
> @@ -1,5 +1,6 @@
>  #include <common.h>
>  #include <stdlib.h>
> +#include <linux/hw_random.h>
>  
>  static unsigned int random_seed;
>  
> @@ -22,6 +23,24 @@ void get_random_bytes(void *_buf, int len)
>  {
>  	char *buf = _buf;
>  
> +	if (IS_ENABLED(CONFIG_HWRNG)) {
> +		struct hwrng *rng;
> +		int bytes;
> +
> +		rng = hwrng_get_first();
> +		if (!IS_ERR(rng)) {
> +			while (len) {
> +				bytes = hwrng_get_data(rng, _buf, len, 1);
> +				if (!bytes)
> +					goto sw_fallback;

hwrng_get_data() looks like it could return a negative error code.

Sascha


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