Re: [PATCH v3 3/3] powerpc/pseries: wire up rng during setup_arch

[Christophe Leroy]

Le 11/06/2022 à 17:10, Jason A. Donenfeld a écrit :
> The platform's RNG must be available before random_init() in order to be
> useful for initial seeding, which in turn means that it needs to be
> called from setup_arch(), rather than from an init call. Fortunately,
> each platform already has a setup_arch function pointer, which means
> it's easy to wire this up. This commit also removes some noisy log
> messages that don't add much.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> Fixes: a489043f4626 ("powerpc/pseries: Implement arch_get_random_long() based on H_RANDOM")
> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>

Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>

> ---
>   arch/powerpc/platforms/pseries/pseries.h |  2 ++
>   arch/powerpc/platforms/pseries/rng.c     | 11 +++--------
>   arch/powerpc/platforms/pseries/setup.c   |  1 +
>   3 files changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
> index f5c916c839c9..1d75b7742ef0 100644
> --- a/arch/powerpc/platforms/pseries/pseries.h
> +++ b/arch/powerpc/platforms/pseries/pseries.h
> @@ -122,4 +122,6 @@ void pseries_lpar_read_hblkrm_characteristics(void);
>   static inline void pseries_lpar_read_hblkrm_characteristics(void) { }
>   #endif
>   
> +void pseries_rng_init(void);
> +
>   #endif /* _PSERIES_PSERIES_H */
> diff --git a/arch/powerpc/platforms/pseries/rng.c b/arch/powerpc/platforms/pseries/rng.c
> index 6268545947b8..6ddfdeaace9e 100644
> --- a/arch/powerpc/platforms/pseries/rng.c
> +++ b/arch/powerpc/platforms/pseries/rng.c
> @@ -10,6 +10,7 @@
>   #include <asm/archrandom.h>
>   #include <asm/machdep.h>
>   #include <asm/plpar_wrappers.h>
> +#include "pseries.h"
>   
>   
>   static int pseries_get_random_long(unsigned long *v)
> @@ -24,19 +25,13 @@ static int pseries_get_random_long(unsigned long *v)
>   	return 0;
>   }
>   
> -static __init int rng_init(void)
> +void __init pseries_rng_init(void)
>   {
>   	struct device_node *dn;
>   
>   	dn = of_find_compatible_node(NULL, NULL, "ibm,random");
>   	if (!dn)
> -		return -ENODEV;
> -
> -	pr_info("Registering arch random hook.\n");
> -
> +		return;
>   	ppc_md.get_random_seed = pseries_get_random_long;
> -
>   	of_node_put(dn);
> -	return 0;
>   }
> -machine_subsys_initcall(pseries, rng_init);
> diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
> index afb074269b42..ee4f1db49515 100644
> --- a/arch/powerpc/platforms/pseries/setup.c
> +++ b/arch/powerpc/platforms/pseries/setup.c
> @@ -839,6 +839,7 @@ static void __init pSeries_setup_arch(void)
>   	}
>   
>   	ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;
> +	pseries_rng_init();
>   }
>   
>   static void pseries_panic(char *str)