Merge branch 'for-next/rng' into for-next/core (92051a10) · Commits · jan.koester / Linux

arch/arm64/include/asm/archrandom.h

+39 −6

Original line number	Diff line number	Diff line
		@@ -42,13 +42,47 @@ static inline bool __arm64_rndr(unsigned long *v)
		return ok;
		}

		static inline bool __arm64_rndrrs(unsigned long *v)
		{
		bool ok;

		/*
		* Reads of RNDRRS set PSTATE.NZCV to 0b0000 on success,
		* and set PSTATE.NZCV to 0b0100 otherwise.
		*/
		asm volatile(
		__mrs_s("%0", SYS_RNDRRS_EL0) "\n"
		" cset %w1, ne\n"
		: "=r" (*v), "=r" (ok)
		:
		: "cc");

		return ok;
		}

		static inline bool __must_check arch_get_random_long(unsigned long *v)
		{
		/*
		* Only support the generic interface after we have detected
		* the system wide capability, avoiding complexity with the
		* cpufeature code and with potential scheduling between CPUs
		* with and without the feature.
		*/
		if (cpus_have_const_cap(ARM64_HAS_RNG) && __arm64_rndr(v))
		return true;
		return false;
		}

		static inline bool __must_check arch_get_random_int(unsigned int *v)
		{
		if (cpus_have_const_cap(ARM64_HAS_RNG)) {
		unsigned long val;

		if (__arm64_rndr(&val)) {
		*v = val;
		return true;
		}
		}
		return false;
		}

		@@ -71,12 +105,11 @@ static inline bool __must_check arch_get_random_seed_long(unsigned long *v)
		}

		/*
		* Only support the generic interface after we have detected
		* the system wide capability, avoiding complexity with the
		* cpufeature code and with potential scheduling between CPUs
		* with and without the feature.
		* RNDRRS is not backed by an entropy source but by a DRBG that is
		* reseeded after each invocation. This is not a 100% fit but good
		* enough to implement this API if no other entropy source exists.
		*/
		if (cpus_have_const_cap(ARM64_HAS_RNG) && __arm64_rndr(v))
		if (cpus_have_const_cap(ARM64_HAS_RNG) && __arm64_rndrrs(v))
		return true;

		return false;
		@@ -96,7 +129,7 @@ static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
		}

		if (cpus_have_const_cap(ARM64_HAS_RNG)) {
		if (__arm64_rndr(&val)) {
		if (__arm64_rndrrs(&val)) {
		*v = val;
		return true;
		}