From 7b878d4b48c4e04b936918bb83836a107ba453b3 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Mon, 17 Mar 2014 16:36:30 -0700 Subject: [PATCH] random: Add arch_has_random[_seed]() Add predicate functions for having arch_get_random[_seed]*(). The only current use is to avoid the loop in arch_random_refill() when arch_get_random_seed_long() is unavailable. Signed-off-by: H. Peter Anvin Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Signed-off-by: Theodore Ts'o --- arch/powerpc/include/asm/archrandom.h | 9 +++++++++ arch/x86/include/asm/archrandom.h | 3 +++ drivers/char/random.c | 3 +++ include/linux/random.h | 8 ++++++++ 4 files changed, 23 insertions(+) diff --git a/arch/powerpc/include/asm/archrandom.h b/arch/powerpc/include/asm/archrandom.h index 801beba4e64b..bde531103638 100644 --- a/arch/powerpc/include/asm/archrandom.h +++ b/arch/powerpc/include/asm/archrandom.h @@ -25,6 +25,11 @@ static inline int arch_get_random_int(unsigned int *v) return rc; } +static inline int arch_has_random(void) +{ + return !!ppc_md.get_random_long; +} + int powernv_get_random_long(unsigned long *v); static inline int arch_get_random_seed_long(unsigned long *v) @@ -35,6 +40,10 @@ static inline int arch_get_random_seed_int(unsigned int *v) { return 0; } +static inline int arch_has_random_seed(void) +{ + return 0; +} #endif /* CONFIG_ARCH_RANDOM */ diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h index 6ad7f6d3f97f..69f1366f1aa3 100644 --- a/arch/x86/include/asm/archrandom.h +++ b/arch/x86/include/asm/archrandom.h @@ -114,6 +114,9 @@ GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4); #endif /* CONFIG_X86_64 */ +#define arch_has_random() static_cpu_has(X86_FEATURE_RDRAND) +#define arch_has_random_seed() static_cpu_has(X86_FEATURE_RDSEED) + #else static inline int rdrand_long(unsigned long *v) diff --git a/drivers/char/random.c b/drivers/char/random.c index c35cee268e13..6b75713d953a 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1307,6 +1307,9 @@ static int arch_random_refill(void) unsigned int i; unsigned long buf[nlongs]; + if (!arch_has_random_seed()) + return 0; + for (i = 0; i < nlongs; i++) { if (arch_get_random_seed_long(&buf[n])) n++; diff --git a/include/linux/random.h b/include/linux/random.h index c2f08131050d..57fbbffd77a0 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -88,6 +88,10 @@ static inline int arch_get_random_int(unsigned int *v) { return 0; } +static inline int arch_has_random(void) +{ + return 0; +} static inline int arch_get_random_seed_long(unsigned long *v) { return 0; @@ -96,6 +100,10 @@ static inline int arch_get_random_seed_int(unsigned int *v) { return 0; } +static inline int arch_has_random_seed(void) +{ + return 0; +} #endif /* Pseudo random number generator from numerical recipes. */ -- 2.20.1