4 files changed, 23 insertions, 0 deletions

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. */