Commit 9dc8313c authored by Will Deacon's avatar Will Deacon
Browse files

Merge branch 'for-next/rng' into for-next/core 

Add support for the TRNG firmware call introduced by Arm spec DEN0098.

* for-next/rng:
  arm64: Add support for SMCCC TRNG entropy source
  firmware: smccc: Introduce SMCCC TRNG framework
  firmware: smccc: Add SMCCC TRNG function call IDs
parents cf6a85a8 38db9873

arch/arm/include/asm/archrandom.h

0 → 100644
+10 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _ASM_ARCHRANDOM_H

#define _ASM_ARCHRANDOM_H



static inline bool __init smccc_probe_trng(void)

{

	return false;

}



#endif /* _ASM_ARCHRANDOM_H */

arch/arm64/include/asm/archrandom.h

+72 −10
Original line number Diff line number Diff line
@@ -4,10 +4,26 @@ 


#ifdef CONFIG_ARCH_RANDOM



#include <linux/arm-smccc.h>

#include <linux/bug.h>

#include <linux/kernel.h>

#include <asm/cpufeature.h>



#define ARM_SMCCC_TRNG_MIN_VERSION	0x10000UL



extern bool smccc_trng_available;



static inline bool __init smccc_probe_trng(void)

{

	struct arm_smccc_res res;



	arm_smccc_1_1_invoke(ARM_SMCCC_TRNG_VERSION, &res);

	if ((s32)res.a0 < 0)

		return false;



	return res.a0 >= ARM_SMCCC_TRNG_MIN_VERSION;

}



static inline bool __arm64_rndr(unsigned long *v)

{

	bool ok;
@@ -38,26 +54,55 @@ static inline bool __must_check arch_get_random_int(unsigned int *v) 


static inline bool __must_check arch_get_random_seed_long(unsigned long *v)

{

	struct arm_smccc_res res;



	/*

	 * We prefer the SMCCC call, since its semantics (return actual

	 * hardware backed entropy) is closer to the idea behind this

	 * function here than what even the RNDRSS register provides

	 * (the output of a pseudo RNG freshly seeded by a TRNG).

	 */

	if (smccc_trng_available) {

		arm_smccc_1_1_invoke(ARM_SMCCC_TRNG_RND64, 64, &res);

		if ((int)res.a0 >= 0) {

			*v = res.a3;

			return true;

		}

	}



	/*

	 * 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))

		return false;

	if (cpus_have_const_cap(ARM64_HAS_RNG) && __arm64_rndr(v))

		return true;



	return __arm64_rndr(v);

	return false;

}





static inline bool __must_check arch_get_random_seed_int(unsigned int *v)

{

	struct arm_smccc_res res;

	unsigned long val;

	bool ok = arch_get_random_seed_long(&val);



	if (smccc_trng_available) {

		arm_smccc_1_1_invoke(ARM_SMCCC_TRNG_RND64, 32, &res);

		if ((int)res.a0 >= 0) {

			*v = res.a3 & GENMASK(31, 0);

			return true;

		}

	}



	if (cpus_have_const_cap(ARM64_HAS_RNG)) {

		if (__arm64_rndr(&val)) {

			*v = val;

	return ok;

			return true;

		}

	}



	return false;

}



static inline bool __init __early_cpu_has_rndr(void)
@@ -72,12 +117,29 @@ arch_get_random_seed_long_early(unsigned long *v) 
{

	WARN_ON(system_state != SYSTEM_BOOTING);



	if (!__early_cpu_has_rndr())

		return false;

	if (smccc_trng_available) {

		struct arm_smccc_res res;



		arm_smccc_1_1_invoke(ARM_SMCCC_TRNG_RND64, 64, &res);

		if ((int)res.a0 >= 0) {

			*v = res.a3;

			return true;

		}

	}



	if (__early_cpu_has_rndr() && __arm64_rndr(v))

		return true;



	return __arm64_rndr(v);

	return false;

}

#define arch_get_random_seed_long_early arch_get_random_seed_long_early



#else /* !CONFIG_ARCH_RANDOM */



static inline bool __init smccc_probe_trng(void)

{

	return false;

}



#endif /* CONFIG_ARCH_RANDOM */

#endif /* _ASM_ARCHRANDOM_H */

drivers/firmware/smccc/smccc.c

+6 −0
Original line number Diff line number Diff line
@@ -5,16 +5,22 @@ 


#define pr_fmt(fmt) "smccc: " fmt



#include <linux/cache.h>

#include <linux/init.h>

#include <linux/arm-smccc.h>

#include <asm/archrandom.h>



static u32 smccc_version = ARM_SMCCC_VERSION_1_0;

static enum arm_smccc_conduit smccc_conduit = SMCCC_CONDUIT_NONE;



bool __ro_after_init smccc_trng_available = false;



void __init arm_smccc_version_init(u32 version, enum arm_smccc_conduit conduit)

{

	smccc_version = version;

	smccc_conduit = conduit;



	smccc_trng_available = smccc_probe_trng();

}



enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)

include/linux/arm-smccc.h

+31 −0
Original line number Diff line number Diff line
@@ -102,6 +102,37 @@ 
			   ARM_SMCCC_OWNER_STANDARD_HYP,	\

			   0x21)



/* TRNG entropy source calls (defined by ARM DEN0098) */

#define ARM_SMCCC_TRNG_VERSION					\

	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\

			   ARM_SMCCC_SMC_32,			\

			   ARM_SMCCC_OWNER_STANDARD,		\

			   0x50)



#define ARM_SMCCC_TRNG_FEATURES					\

	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\

			   ARM_SMCCC_SMC_32,			\

			   ARM_SMCCC_OWNER_STANDARD,		\

			   0x51)



#define ARM_SMCCC_TRNG_GET_UUID					\

	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\

			   ARM_SMCCC_SMC_32,			\

			   ARM_SMCCC_OWNER_STANDARD,		\

			   0x52)



#define ARM_SMCCC_TRNG_RND32					\

	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\

			   ARM_SMCCC_SMC_32,			\

			   ARM_SMCCC_OWNER_STANDARD,		\

			   0x53)



#define ARM_SMCCC_TRNG_RND64					\

	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\

			   ARM_SMCCC_SMC_64,			\

			   ARM_SMCCC_OWNER_STANDARD,		\

			   0x53)



/*

 * Return codes defined in ARM DEN 0070A

 * ARM DEN 0070A is now merged/consolidated into ARM DEN 0028 C