mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Andre Przywara](/assets/img/avatar_default.png)
At the moment we probe for the Random Number Generator SMCCC service, and use that in the core code (arch_get_random). However the hardware entropy can also be useful to access from userland, and be it to assess its quality. Register a platform device when the SMCCC TRNG service is detected, to allow a hw_random driver to hook onto this. The function registering the device is deliberately made in a way which allows expansion, so other services that could be exposed via a platform device (or some other interface), can be added here easily. Signed-off-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (C) 2020 Arm Limited
|
|
*/
|
|
|
|
#define pr_fmt(fmt) "smccc: " fmt
|
|
|
|
#include <linux/cache.h>
|
|
#include <linux/init.h>
|
|
#include <linux/arm-smccc.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/platform_device.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;
|
|
u64 __ro_after_init smccc_has_sve_hint = 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();
|
|
if (IS_ENABLED(CONFIG_ARM64_SVE) &&
|
|
smccc_version >= ARM_SMCCC_VERSION_1_3)
|
|
smccc_has_sve_hint = true;
|
|
}
|
|
|
|
enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
|
|
{
|
|
if (smccc_version < ARM_SMCCC_VERSION_1_1)
|
|
return SMCCC_CONDUIT_NONE;
|
|
|
|
return smccc_conduit;
|
|
}
|
|
EXPORT_SYMBOL_GPL(arm_smccc_1_1_get_conduit);
|
|
|
|
u32 arm_smccc_get_version(void)
|
|
{
|
|
return smccc_version;
|
|
}
|
|
EXPORT_SYMBOL_GPL(arm_smccc_get_version);
|
|
|
|
static int __init smccc_devices_init(void)
|
|
{
|
|
struct platform_device *pdev;
|
|
|
|
if (smccc_trng_available) {
|
|
pdev = platform_device_register_simple("smccc_trng", -1,
|
|
NULL, 0);
|
|
if (IS_ERR(pdev))
|
|
pr_err("smccc_trng: could not register device: %ld\n",
|
|
PTR_ERR(pdev));
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
device_initcall(smccc_devices_init);
|