From nobody Fri Sep 25 10:36:34 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC9E43AA19B; Mon, 14 Sep 2026 06:05:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789365932; cv=none; b=BOveDZ+qJbxqIwbo1EWpYk9osD9XID/AZXy8sPlopjOM6u8xMekhyvFfyejO5zppmu6i/0qvFlvFy/Jt95Z/BF649A2tBKrxwTrGrsOnNtplxABw+YLBummRoIgU9YQ3/bvcS1njJRsuyElDi5Pr3EHbzd9rnAv/WvOFXt6jH1I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789365932; c=relaxed/simple; bh=NgR71CS7TMBTwhhn9vN4yOcTVsuPu2+/fmjXg0l30/s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=k3nPnrs9isUQ9DxpwivCdQ8LuvOuMYKCN/Y60uua5RSDUhjdd5DD2tTQaNI1R9nqfuluVym9zfmvRv3BuKDTX4tXN7bwXoKNdxwOHcEMTEwQo/o4zj7BQ5ht6YHzywQAvSK44P74u+5HeecP+YFqUq21JRqx4IPAfuSJxsyzBpk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oZOBHATM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oZOBHATM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D33321F00893; Mon, 14 Sep 2026 06:05:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789365928; bh=ZcIQ/j6jngQU4pqR+oILh/o4b2CteWgR3HPJyPNCyfU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=oZOBHATM+mcPoxMX8iMxvr0SRTskmiMeOaXwIsh4sAbIDf3AK+r2v7f6qQpV7SAKR LHtCAzmI8L7ui9SS3iHYASV1js4RKjy5cHQ/5crhXtyd956+peGuurWooaOxSFnXf0 5XssmRQwrf03Y+WdvdAqX1utBBYy7Bf1tSrpxX/mZJ6Nr1gNhGXBZM8iHkSjIx6aRu bJsT7l4zkQBQPFaJlqrgAv5gO1jMMgw5RyGRVsGSZWmo8tapFlV2k2oUFDnMfdKjb4 c8swGYcZ6da6kxioW++4GKx40GN7OZCqYqXYaQflfCDBM0N5gJRioRawDTSV3AtPWT vVLxujuLghymw== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Jason Gunthorpe , Catalin Marinas , Greg KH , Jeremy Linton , Jonathan Cameron , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Will Deacon , Steven Price , Suzuki K Poulose , Andre Przywara , Sudeep Holla Subject: [PATCH v11 1/7] firmware: smccc: Add an Arm SMCCC bus Date: Mon, 14 Sep 2026 11:35:05 +0530 Message-ID: <20260914060511.277948-2-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260914060511.277948-1-aneesh.kumar@kernel.org> References: <20260914060511.277948-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" SMCCC-discovered firmware services are currently represented by separate platform devices, such as smccc_trng and arm-cca-dev. Those devices do not represent independent DT/ACPI-described platform resources; they are features of the SMCCC firmware interface. Add an Arm SMCCC bus for services discovered through the SMCCC firmware interface. The bus provides SMCCC device and driver registration helpers, name-based matching, modalias generation, and a sysfs modalias attribute so SMCCC service drivers can bind to discovered firmware services and autoload as modules. Follow-up changes can then register SMCCC firmware services as arm-smccc devices instead of creating independent per-feature platform devices. Based on arm_ffa code Reviewed-by: Jason Gunthorpe Reviewed-by: Sudeep Holla Signed-off-by: Aneesh Kumar K.V (Arm) Reviewed-by: Catalin Marinas Reviewed-by: Jonathan Cameron --- drivers/firmware/smccc/Makefile | 2 +- drivers/firmware/smccc/bus.c | 151 ++++++++++++++++++++++++++++ include/linux/arm-smccc-bus.h | 48 +++++++++ include/linux/device-id/arm_smccc.h | 19 ++++ include/linux/mod_devicetable.h | 1 + scripts/mod/devicetable-offsets.c | 3 + scripts/mod/file2alias.c | 8 ++ 7 files changed, 231 insertions(+), 1 deletion(-) create mode 100644 drivers/firmware/smccc/bus.c create mode 100644 include/linux/arm-smccc-bus.h create mode 100644 include/linux/device-id/arm_smccc.h diff --git a/drivers/firmware/smccc/Makefile b/drivers/firmware/smccc/Makef= ile index 40d19144a860..68bbff1407b8 100644 --- a/drivers/firmware/smccc/Makefile +++ b/drivers/firmware/smccc/Makefile @@ -1,4 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 # -obj-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY) +=3D smccc.o kvm_guest.o +obj-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY) +=3D bus.o smccc.o kvm_guest.o obj-$(CONFIG_ARM_SMCCC_SOC_ID) +=3D soc_id.o diff --git a/drivers/firmware/smccc/bus.c b/drivers/firmware/smccc/bus.c new file mode 100644 index 000000000000..caba1a03c997 --- /dev/null +++ b/drivers/firmware/smccc/bus.c @@ -0,0 +1,151 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2026 Arm Limited + */ + +#include +#include + +static int arm_smccc_bus_match(struct device *dev, + const struct device_driver *drv) +{ + const struct arm_smccc_device_id *id_table; + struct arm_smccc_device *smccc_dev =3D to_arm_smccc_device(dev); + + id_table =3D to_arm_smccc_driver(drv)->id_table; + if (!id_table) + return 0; + + while (id_table->func_id) { + if (smccc_dev->func_id =3D=3D id_table->func_id) + return 1; + id_table++; + } + + return 0; +} + +static int arm_smccc_bus_probe(struct device *dev) +{ + struct arm_smccc_driver *smccc_drv =3D to_arm_smccc_driver(dev->driver); + + return smccc_drv->probe(to_arm_smccc_device(dev)); +} + +static void arm_smccc_bus_remove(struct device *dev) +{ + struct arm_smccc_driver *smcc_drv =3D to_arm_smccc_driver(dev->driver); + + if (smcc_drv->remove) + smcc_drv->remove(to_arm_smccc_device(dev)); +} + +static int arm_smccc_bus_uevent(const struct device *dev, + struct kobj_uevent_env *env) +{ + const struct arm_smccc_device *smccc_dev =3D to_arm_smccc_device(dev); + + return add_uevent_var(env, "MODALIAS=3D" ARM_SMCCC_MODULE_PREFIX "f%08X", + smccc_dev->func_id); +} + +static ssize_t modalias_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct arm_smccc_device *smccc_dev =3D to_arm_smccc_device(dev); + + return sysfs_emit(buf, ARM_SMCCC_MODULE_PREFIX "f%08X\n", + smccc_dev->func_id); +} +static DEVICE_ATTR_RO(modalias); + +static struct attribute *arm_smccc_device_attrs[] =3D { + &dev_attr_modalias.attr, + NULL, +}; +ATTRIBUTE_GROUPS(arm_smccc_device); + +const struct bus_type arm_smccc_bus_type =3D { + .name =3D "arm_smccc", + .match =3D arm_smccc_bus_match, + .probe =3D arm_smccc_bus_probe, + .remove =3D arm_smccc_bus_remove, + .uevent =3D arm_smccc_bus_uevent, + .dev_groups =3D arm_smccc_device_groups, +}; +EXPORT_SYMBOL_GPL(arm_smccc_bus_type); + +int arm_smccc_driver_register(struct arm_smccc_driver *driver, + struct module *owner, const char *mod_name) +{ + if (!driver->probe || !driver->id_table) + return -EINVAL; + + driver->driver.bus =3D &arm_smccc_bus_type; + driver->driver.name =3D driver->name; + driver->driver.owner =3D owner; + driver->driver.mod_name =3D mod_name; + + return driver_register(&driver->driver); +} +EXPORT_SYMBOL_GPL(arm_smccc_driver_register); + +void arm_smccc_driver_unregister(struct arm_smccc_driver *driver) +{ + driver_unregister(&driver->driver); +} +EXPORT_SYMBOL_GPL(arm_smccc_driver_unregister); + +static void arm_smccc_release_device(struct device *dev) +{ + struct arm_smccc_device *smccc_dev =3D to_arm_smccc_device(dev); + + kfree(smccc_dev); +} + +struct arm_smccc_device *arm_smccc_device_register(const char *name, u32 f= unc_id) +{ + int ret; + struct arm_smccc_device *smccc_dev; + + if (!name) + return ERR_PTR(-EINVAL); + + smccc_dev =3D kzalloc_obj(*smccc_dev); + if (!smccc_dev) + return ERR_PTR(-ENOMEM); + + smccc_dev->func_id =3D func_id; + smccc_dev->dev.bus =3D &arm_smccc_bus_type; + smccc_dev->dev.release =3D arm_smccc_release_device; + + ret =3D dev_set_name(&smccc_dev->dev, "%s", name); + if (ret) { + kfree(smccc_dev); + return ERR_PTR(ret); + } + + ret =3D device_register(&smccc_dev->dev); + if (ret) { + put_device(&smccc_dev->dev); + return ERR_PTR(ret); + } + + return smccc_dev; +} +EXPORT_SYMBOL_GPL(arm_smccc_device_register); + +void arm_smccc_device_unregister(struct arm_smccc_device *smccc_dev) +{ + if (!smccc_dev) + return; + + device_unregister(&smccc_dev->dev); +} +EXPORT_SYMBOL_GPL(arm_smccc_device_unregister); + +static int __init arm_smccc_bus_init(void) +{ + return bus_register(&arm_smccc_bus_type); +} +subsys_initcall(arm_smccc_bus_init); diff --git a/include/linux/arm-smccc-bus.h b/include/linux/arm-smccc-bus.h new file mode 100644 index 000000000000..cde268fc2930 --- /dev/null +++ b/include/linux/arm-smccc-bus.h @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2026 Arm Limited + */ +#ifndef __LINUX_ARM_SMCCC_BUS_H +#define __LINUX_ARM_SMCCC_BUS_H + +#include +#include +#include + +struct arm_smccc_device { + struct device dev; + u32 func_id; +}; + +#define to_arm_smccc_device(d) container_of(d, struct arm_smccc_device, de= v) + +struct arm_smccc_driver { + struct device_driver driver; + + const char *name; + int (*probe)(struct arm_smccc_device *sdev); + void (*remove)(struct arm_smccc_device *sdev); + const struct arm_smccc_device_id *id_table; +}; + +#define to_arm_smccc_driver(d) \ + container_of_const(d, struct arm_smccc_driver, driver) + +int arm_smccc_driver_register(struct arm_smccc_driver *driver, + struct module *owner, const char *mod_name); +void arm_smccc_driver_unregister(struct arm_smccc_driver *driver); +struct arm_smccc_device *arm_smccc_device_register(const char *name, u32 f= unc_id); +void arm_smccc_device_unregister(struct arm_smccc_device *smcc_dev); + +#define arm_smccc_register(driver) \ + arm_smccc_driver_register(driver, THIS_MODULE, KBUILD_MODNAME) +#define arm_smccc_unregister(driver) \ + arm_smccc_driver_unregister(driver) + +#define module_arm_smccc_driver(__arm_smccc_driver) \ + module_driver(__arm_smccc_driver, arm_smccc_register, \ + arm_smccc_unregister) + +extern const struct bus_type arm_smccc_bus_type; + +#endif /* __LINUX_ARM_SMCCC_BUS_H */ diff --git a/include/linux/device-id/arm_smccc.h b/include/linux/device-id/= arm_smccc.h new file mode 100644 index 000000000000..a8579832fc1c --- /dev/null +++ b/include/linux/device-id/arm_smccc.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __LINUX_DEVICE_ID_ARM_SMCCC_H +#define __LINUX_DEVICE_ID_ARM_SMCCC_H + +#ifdef __KERNEL__ +#include +#endif + +#define ARM_SMCCC_MODULE_PREFIX "arm_smccc:" + +/** + * struct arm_smccc_device_id - Arm SMCCC bus device identifier + * @func_id: SMCCC function identifier + */ +struct arm_smccc_device_id { + __u32 func_id; +}; + +#endif /* __LINUX_DEVICE_ID_ARM_SMCCC_H */ diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetabl= e.h index a397213bedac..318c4b5c3451 100644 --- a/include/linux/mod_devicetable.h +++ b/include/linux/mod_devicetable.h @@ -16,6 +16,7 @@ #include "device-id/amba.h" #include "device-id/ap.h" #include "device-id/apr.h" +#include "device-id/arm_smccc.h" #include "device-id/auxiliary.h" #include "device-id/bcma.h" #include "device-id/ccw.h" diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-of= fsets.c index b4178c42d08f..1492e9fdc7cb 100644 --- a/scripts/mod/devicetable-offsets.c +++ b/scripts/mod/devicetable-offsets.c @@ -254,6 +254,9 @@ int main(void) DEVID(auxiliary_device_id); DEVID_FIELD(auxiliary_device_id, name); =20 + DEVID(arm_smccc_device_id); + DEVID_FIELD(arm_smccc_device_id, func_id); + DEVID(ssam_device_id); DEVID_FIELD(ssam_device_id, match_flags); DEVID_FIELD(ssam_device_id, domain); diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index 8d36c74dec2d..980d7da456bb 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -1349,6 +1349,13 @@ static void do_auxiliary_entry(struct module *mod, v= oid *symval) module_alias_printf(mod, false, AUXILIARY_MODULE_PREFIX "%s", *name); } =20 +static void do_arm_smccc_entry(struct module *mod, void *symval) +{ + DEF_FIELD(symval, arm_smccc_device_id, func_id); + + module_alias_printf(mod, false, ARM_SMCCC_MODULE_PREFIX "f%08X", func_id); +} + /* * Looks like: ssam:dNcNtNiNfN * @@ -1519,6 +1526,7 @@ static const struct devtable devtable[] =3D { {"mhi", SIZE_mhi_device_id, do_mhi_entry}, {"mhi_ep", SIZE_mhi_device_id, do_mhi_ep_entry}, {"auxiliary", SIZE_auxiliary_device_id, do_auxiliary_entry}, + {"arm_smccc", SIZE_arm_smccc_device_id, do_arm_smccc_entry}, {"ssam", SIZE_ssam_device_id, do_ssam_entry}, {"dfl", SIZE_dfl_device_id, do_dfl_entry}, {"ishtp", SIZE_ishtp_device_id, do_ishtp_entry}, --=20 2.43.0 From nobody Fri Sep 25 10:36:34 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 143CD3B8949; Mon, 14 Sep 2026 06:05:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Mon, 14 Sep 2026 06:05:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789365935; bh=Xu0gx+tOD/5BT5Zbp+2v/0A892BL8cgFfQ/WZALUYzM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GUxw0ignJSereD7IqZMtSh2O9gEfnegw/sKwbAxzQYQ3oYYSC8sC8geiu8Oum/xNn vIDRi8IyvXWeso0Gx7FV3HHcOry9RjYEHObGtT5BxIk3kAklxJyBe5weIz/JbZV7nK kMQGm3axNY3f39lJfuqZNTEs7LmjTEKxZILeYbPBop0WlHbkm5i5A2+l7FeOGx0IQp /GhIAXY0tktnAPvBSQVHt+1lwh0LR3HZPO6DF8b8jC+HXx2GsHjZobqkEhSUQD0XzL 3cOFuY8E2lEJUeaaVcx2h38eUEmMEtc+oOyxBcm2n876x8LNykrCvvV7WnTGcM5E3q kGMcyWTKduEqQ== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Jason Gunthorpe , Catalin Marinas , Greg KH , Jeremy Linton , Jonathan Cameron , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Will Deacon , Steven Price , Suzuki K Poulose , Andre Przywara Subject: [PATCH v11 2/7] firmware: hwrng: arm_smccc_trng: Register as an SMCCC device Date: Mon, 14 Sep 2026 11:35:06 +0530 Message-ID: <20260914060511.277948-3-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260914060511.277948-1-aneesh.kumar@kernel.org> References: <20260914060511.277948-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The SMCCC TRNG interface is a firmware-provided SMCCC service rather than a standalone platform device. Now that the SMCCC core has an SMCCC bus, create an arm-smccc-trng device for the discovered TRNG service and convert the hwrng driver to an SMCCC driver. The SMCCC id table preserves module autoloading for systems where the TRNG driver is built as a module. The sysfs device path changes from the old smccc_trng platform-device path to an arm-smccc device path. No known userspace dependency on the old path was found; a Debian Code Search lookup for the existing platform-device name/path did not find any users. Reviewed-by: Jason Gunthorpe Tested-by: Andre Przywara Signed-off-by: Aneesh Kumar K.V (Arm) Reviewed-by: Catalin Marinas Reviewed-by: Jonathan Cameron Reviewed-by: Sudeep Holla --- arch/arm/include/asm/archrandom.h | 2 +- arch/arm64/include/asm/archrandom.h | 2 +- drivers/char/hw_random/arm_smccc_trng.c | 32 ++++++++----- drivers/firmware/smccc/smccc.c | 62 +++++++++++++++++++++---- 4 files changed, 76 insertions(+), 22 deletions(-) diff --git a/arch/arm/include/asm/archrandom.h b/arch/arm/include/asm/archr= andom.h index cc4714eb1a75..ee39a03ddf8a 100644 --- a/arch/arm/include/asm/archrandom.h +++ b/arch/arm/include/asm/archrandom.h @@ -2,7 +2,7 @@ #ifndef _ASM_ARCHRANDOM_H #define _ASM_ARCHRANDOM_H =20 -static inline bool __init smccc_probe_trng(void) +static inline bool smccc_probe_trng(void) { return false; } diff --git a/arch/arm64/include/asm/archrandom.h b/arch/arm64/include/asm/a= rchrandom.h index 8babfbe31f95..7605dd81bd1e 100644 --- a/arch/arm64/include/asm/archrandom.h +++ b/arch/arm64/include/asm/archrandom.h @@ -12,7 +12,7 @@ =20 extern bool smccc_trng_available; =20 -static inline bool __init smccc_probe_trng(void) +static inline bool smccc_probe_trng(void) { struct arm_smccc_res res; =20 diff --git a/drivers/char/hw_random/arm_smccc_trng.c b/drivers/char/hw_rand= om/arm_smccc_trng.c index dcb8e7f37f25..01c1a30cbab8 100644 --- a/drivers/char/hw_random/arm_smccc_trng.c +++ b/drivers/char/hw_random/arm_smccc_trng.c @@ -16,8 +16,10 @@ #include #include #include -#include #include +#include + +#include =20 #ifdef CONFIG_ARM64 #define ARM_SMCCC_TRNG_RND ARM_SMCCC_TRNG_RND64 @@ -94,29 +96,37 @@ static int smccc_trng_read(struct hwrng *rng, void *dat= a, size_t max, bool wait) return copied; } =20 -static int smccc_trng_probe(struct platform_device *pdev) +static int smccc_trng_probe(struct arm_smccc_device *sdev) { struct hwrng *trng; =20 - trng =3D devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL); + /* validate the minimum version requirement */ + if (!smccc_probe_trng()) + return -ENODEV; + + trng =3D devm_kzalloc(&sdev->dev, sizeof(*trng), GFP_KERNEL); if (!trng) return -ENOMEM; =20 trng->name =3D "smccc_trng"; trng->read =3D smccc_trng_read; =20 - return devm_hwrng_register(&pdev->dev, trng); + return devm_hwrng_register(&sdev->dev, trng); } =20 -static struct platform_driver smccc_trng_driver =3D { - .driver =3D { - .name =3D "smccc_trng", - }, - .probe =3D smccc_trng_probe, +static const struct arm_smccc_device_id smccc_trng_id_table[] =3D { + { .func_id =3D ARM_SMCCC_TRNG_VERSION }, + {} +}; +MODULE_DEVICE_TABLE(arm_smccc, smccc_trng_id_table); + +static struct arm_smccc_driver smccc_trng_driver =3D { + .name =3D KBUILD_MODNAME, + .probe =3D smccc_trng_probe, + .id_table =3D smccc_trng_id_table, }; -module_platform_driver(smccc_trng_driver); +module_arm_smccc_driver(smccc_trng_driver); =20 -MODULE_ALIAS("platform:smccc_trng"); MODULE_AUTHOR("Andre Przywara"); MODULE_DESCRIPTION("Arm SMCCC TRNG firmware interface support"); MODULE_LICENSE("GPL"); diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c index bdee057db2fd..756c79204e44 100644 --- a/drivers/firmware/smccc/smccc.c +++ b/drivers/firmware/smccc/smccc.c @@ -9,7 +9,8 @@ #include #include #include -#include +#include + #include =20 static u32 smccc_version =3D ARM_SMCCC_VERSION_1_0; @@ -81,16 +82,59 @@ bool arm_smccc_hypervisor_has_uuid(const uuid_t *hyp_uu= id) } EXPORT_SYMBOL_GPL(arm_smccc_hypervisor_has_uuid); =20 +struct smccc_device_info { + u32 func_id; + bool requires_smc; + const char *device_name; +}; + +static const struct smccc_device_info smccc_devices[] __initconst =3D { + { + .func_id =3D ARM_SMCCC_TRNG_VERSION, + .requires_smc =3D false, + .device_name =3D "arm-smccc-trng", + }, +}; + +static bool __init smccc_probe_smccc_device(const struct smccc_device_info= *smccc_dev) +{ + int ret; + struct arm_smccc_res res =3D {}; + + if (smccc_conduit =3D=3D SMCCC_CONDUIT_NONE) + return false; + + if (smccc_dev->requires_smc && smccc_conduit !=3D SMCCC_CONDUIT_SMC) + return false; + + if (IS_ENABLED(CONFIG_ARM) && ARM_SMCCC_IS_64(smccc_dev->func_id)) + return false; + + arm_smccc_1_1_invoke(smccc_dev->func_id, + 0, 0, 0, 0, 0, 0, 0, &res); + ret =3D res.a0; + + if (ret =3D=3D SMCCC_RET_NOT_SUPPORTED) + return false; + + return true; +} + static int __init smccc_devices_init(void) { - struct platform_device *pdev; - - if (smccc_trng_available) { - pdev =3D 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)); + struct arm_smccc_device *sdev; + const struct smccc_device_info *smccc_dev; + + for (int i =3D 0; i < ARRAY_SIZE(smccc_devices); i++) { + smccc_dev =3D &smccc_devices[i]; + + if (!smccc_probe_smccc_device(smccc_dev)) + continue; + + sdev =3D arm_smccc_device_register(smccc_dev->device_name, smccc_dev->fu= nc_id); + if (IS_ERR(sdev)) + pr_err("%s: could not register device: %ld\n", + smccc_dev->device_name, PTR_ERR(sdev)); } =20 return 0; --=20 2.43.0 From nobody Fri Sep 25 10:36:34 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 677613DF019; Mon, 14 Sep 2026 06:05:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Mon, 14 Sep 2026 06:05:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789365941; bh=BDLs56GbfdaghW6+Ojs30rCNMbDvkWBrRf/SwASI79Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SZxBGJMsvG21OsGPt9V2/vQ6Mv5KdHOs88gMQBPv6nEntWLLL1USw52CLzcPovdSc vzGAdtsABt2s+GcQwhqfJkKfM8D9IsNrj0uO6TmHMkRRzb8TTSewrric1WzPNPvJSD WjTlKN164IEz5b6IvlruUlnPnqvhfuQUuzgnYmvX4AhUY2RVWKzgaCSRlqKY0e34HM jLfnIdSFhcsUlnUz9cfjtt2w0l1WalY1iUUTo+ppj02hyx7CXqzNp7UoJ5z8pU1CCo jOuOdCW028WLHKg7pn0/Kw3QAoxaHdNZ+E/9Mz+wCEPlc/cBQudao5b68Tg8Dh75V5 TDN5npXrznpDA== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Jason Gunthorpe , Catalin Marinas , Greg KH , Jeremy Linton , Jonathan Cameron , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Will Deacon , Steven Price , Suzuki K Poulose , Andre Przywara , Suzuki K Poulose Subject: [PATCH v11 3/7] firmware: arm_rmm: Move RSI support out of arch/arm64 Date: Mon, 14 Sep 2026 11:35:07 +0530 Message-ID: <20260914060511.277948-4-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260914060511.277948-1-aneesh.kumar@kernel.org> References: <20260914060511.277948-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The RSI SMCCC function IDs describe a firmware ABI and are not arm64 architecture specific definitions. Follow-up changes need to use them from non-arch code, including drivers/firmware/smccc and the Arm CCA guest driver. Move the complete Realm Service Interface (RSI) implementation from arch/arm64 to drivers/firmware/arm_rmm. The RSI SMCCC definitions and command helpers are also moved to include/linux so they can be shared by architecture code and firmware or driver code. This also keeps the firmware interface outside architecture code, as requested [1]. [1] https://lore.kernel.org/all/agsNO9cc7H-b0H8L@willie-the-truck Reviewed-by: Jason Gunthorpe Acked-by: Suzuki K Poulose Signed-off-by: Aneesh Kumar K.V (Arm) Reviewed-by: Catalin Marinas Reviewed-by: Jonathan Cameron --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/io.h | 2 +- arch/arm64/include/asm/mem_encrypt.h | 2 +- arch/arm64/include/asm/pgtable-prot.h | 2 +- arch/arm64/include/asm/rsi.h | 70 ----------------- arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/setup.c | 2 +- arch/arm64/mm/init.c | 3 +- drivers/firmware/Kconfig | 1 + drivers/firmware/Makefile | 1 + drivers/firmware/arm_rmm/Kconfig | 17 ++++ drivers/firmware/arm_rmm/Makefile | 2 + .../kernel =3D> drivers/firmware/arm_rmm}/rsi.c | 2 +- drivers/virt/coco/arm-cca-guest/Kconfig | 2 +- .../virt/coco/arm-cca-guest/arm-cca-guest.c | 5 +- .../linux/arm-rsi-cmds.h | 77 +++++++++++++++++-- .../linux/arm-smccc-rsi.h | 6 +- 17 files changed, 108 insertions(+), 89 deletions(-) delete mode 100644 arch/arm64/include/asm/rsi.h create mode 100644 drivers/firmware/arm_rmm/Kconfig create mode 100644 drivers/firmware/arm_rmm/Makefile rename {arch/arm64/kernel =3D> drivers/firmware/arm_rmm}/rsi.c (99%) rename arch/arm64/include/asm/rsi_cmds.h =3D> include/linux/arm-rsi-cmds.h= (69%) rename arch/arm64/include/asm/rsi_smc.h =3D> include/linux/arm-smccc-rsi.h= (98%) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b5a51b0ef944..ff9565d3ffa5 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -38,6 +38,7 @@ config ARM64 select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_MEM_ENCRYPT select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS + select ARCH_SUPPORTS_RMM select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_HAS_NONLEAF_PMD_YOUNG if ARM64_HAFT diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h index 49a7002661a9..1620537f0332 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -8,6 +8,7 @@ #ifndef __ASM_IO_H #define __ASM_IO_H =20 +#include #include #include =20 @@ -17,7 +18,6 @@ #include #include #include -#include =20 /* * Generic IO read/write. These perform native-endian accesses. diff --git a/arch/arm64/include/asm/mem_encrypt.h b/arch/arm64/include/asm/= mem_encrypt.h index 636f45b4d8af..f03b9d7b83b4 100644 --- a/arch/arm64/include/asm/mem_encrypt.h +++ b/arch/arm64/include/asm/mem_encrypt.h @@ -2,8 +2,8 @@ #ifndef __ASM_MEM_ENCRYPT_H #define __ASM_MEM_ENCRYPT_H =20 +#include #include -#include =20 struct device; =20 diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm= /pgtable-prot.h index 09d7c00cf405..58e71e592175 100644 --- a/arch/arm64/include/asm/pgtable-prot.h +++ b/arch/arm64/include/asm/pgtable-prot.h @@ -66,9 +66,9 @@ =20 #ifndef __ASSEMBLER__ =20 +#include #include #include -#include =20 extern bool arm64_use_ng_mappings; extern unsigned long prot_ns_shared; diff --git a/arch/arm64/include/asm/rsi.h b/arch/arm64/include/asm/rsi.h deleted file mode 100644 index 88b50d660e85..000000000000 --- a/arch/arm64/include/asm/rsi.h +++ /dev/null @@ -1,70 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ -/* - * Copyright (C) 2024 ARM Ltd. - */ - -#ifndef __ASM_RSI_H_ -#define __ASM_RSI_H_ - -#include -#include -#include - -#define RSI_PDEV_NAME "arm-cca-dev" - -DECLARE_STATIC_KEY_FALSE(rsi_present); - -void __init arm64_rsi_init(void); - -bool arm64_rsi_is_protected(phys_addr_t base, size_t size); - -static inline bool is_realm_world(void) -{ - return static_branch_unlikely(&rsi_present); -} - -static inline int rsi_set_memory_range(phys_addr_t start, phys_addr_t end, - enum ripas state, unsigned long flags) -{ - unsigned long ret; - phys_addr_t top; - - while (start !=3D end) { - ret =3D rsi_set_addr_range_state(start, end, state, flags, &top); - if (ret || top < start || top > end) - return -EINVAL; - start =3D top; - } - - return 0; -} - -/* - * Convert the specified range to RAM. Do not use this if you rely on the - * contents of a page that may already be in RAM state. - */ -static inline int rsi_set_memory_range_protected(phys_addr_t start, - phys_addr_t end) -{ - return rsi_set_memory_range(start, end, RSI_RIPAS_RAM, - RSI_CHANGE_DESTROYED); -} - -/* - * Convert the specified range to RAM. Do not convert any pages that may h= ave - * been DESTROYED, without our permission. - */ -static inline int rsi_set_memory_range_protected_safe(phys_addr_t start, - phys_addr_t end) -{ - return rsi_set_memory_range(start, end, RSI_RIPAS_RAM, - RSI_NO_CHANGE_DESTROYED); -} - -static inline int rsi_set_memory_range_shared(phys_addr_t start, - phys_addr_t end) -{ - return rsi_set_memory_range(start, end, RSI_RIPAS_EMPTY, - RSI_CHANGE_DESTROYED); -} -#endif /* __ASM_RSI_H_ */ diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index d2690c3ec528..21fc3a3d25c9 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -34,7 +34,7 @@ obj-y :=3D debug-monitors.o entry.o irq.o fpsimd.o \ cpufeature.o alternative.o cacheinfo.o \ smp.o smp_spin_table.o topology.o smccc-call.o \ syscall.o proton-pack.o idle.o patching.o pi/ \ - rsi.o jump_label.o + jump_label.o =20 obj-$(CONFIG_COMPAT) +=3D sys32.o signal32.o \ sys_compat.o diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 29c6100f0c50..a707deba6ae7 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -7,6 +7,7 @@ */ =20 #include +#include #include #include #include @@ -43,7 +44,6 @@ #include #include #include -#include #include #include #include diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index fbf215ecc7d0..2a8de20d2b44 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -34,6 +34,8 @@ #include #include #include +#include + =20 #include #include @@ -43,7 +45,6 @@ #include #include #include -#include #include #include #include diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig index b7cc11e4fbfa..62660bf520a8 100644 --- a/drivers/firmware/Kconfig +++ b/drivers/firmware/Kconfig @@ -310,5 +310,6 @@ source "drivers/firmware/samsung/Kconfig" source "drivers/firmware/smccc/Kconfig" source "drivers/firmware/tegra/Kconfig" source "drivers/firmware/xilinx/Kconfig" +source "drivers/firmware/arm_rmm/Kconfig" =20 endmenu diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile index be46f1e1dc77..196a650ccf02 100644 --- a/drivers/firmware/Makefile +++ b/drivers/firmware/Makefile @@ -39,3 +39,4 @@ obj-y +=3D samsung/ obj-y +=3D smccc/ obj-y +=3D tegra/ obj-y +=3D xilinx/ +obj-y +=3D arm_rmm/ diff --git a/drivers/firmware/arm_rmm/Kconfig b/drivers/firmware/arm_rmm/Kc= onfig new file mode 100644 index 000000000000..e981e12fdbe6 --- /dev/null +++ b/drivers/firmware/arm_rmm/Kconfig @@ -0,0 +1,17 @@ + +config ARCH_SUPPORTS_RMM + bool + +config ARM_RMM_RSI + bool "Realm Service Interface (RSI) Support" + depends on ARCH_SUPPORTS_RMM + default y + help + Enable support for running Linux as a Realm guest under a Realm + Management Monitor (RMM), as defined by the Arm Confidential + Compute Architecture. + + The RMM exposes the Realm Service Interface (RSI) to Realm guests. + Linux uses RSI to negotiate the interface version, obtain the Realm + configuration, and manage the protected or shared state of guest + memory. diff --git a/drivers/firmware/arm_rmm/Makefile b/drivers/firmware/arm_rmm/M= akefile new file mode 100644 index 000000000000..3708b37a9aaf --- /dev/null +++ b/drivers/firmware/arm_rmm/Makefile @@ -0,0 +1,2 @@ + +obj-$(CONFIG_ARM_RMM_RSI) =3D rsi.o diff --git a/arch/arm64/kernel/rsi.c b/drivers/firmware/arm_rmm/rsi.c similarity index 99% rename from arch/arm64/kernel/rsi.c rename to drivers/firmware/arm_rmm/rsi.c index 25ca75ce1a4d..8e716f1c1e31 100644 --- a/arch/arm64/kernel/rsi.c +++ b/drivers/firmware/arm_rmm/rsi.c @@ -8,11 +8,11 @@ #include #include #include +#include =20 #include #include #include -#include =20 static struct realm_config config; =20 diff --git a/drivers/virt/coco/arm-cca-guest/Kconfig b/drivers/virt/coco/ar= m-cca-guest/Kconfig index 3f0f013f03f1..2582ebb36922 100644 --- a/drivers/virt/coco/arm-cca-guest/Kconfig +++ b/drivers/virt/coco/arm-cca-guest/Kconfig @@ -1,6 +1,6 @@ config ARM_CCA_GUEST tristate "Arm CCA Guest driver" - depends on ARM64 + depends on ARM_RMM_RSI select TSM_REPORTS help The driver provides userspace interface to request and diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c b/drivers/virt= /coco/arm-cca-guest/arm-cca-guest.c index 0eeddd1ff05b..b741643d1364 100644 --- a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c +++ b/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c @@ -3,7 +3,8 @@ * Copyright (C) 2023 ARM Ltd. */ =20 -#include +#include +#include #include #include #include @@ -12,8 +13,6 @@ #include #include =20 -#include - /** * struct arm_cca_token_info - a descriptor for the token buffer. * @granule: PA of the granule to which the token will be written diff --git a/arch/arm64/include/asm/rsi_cmds.h b/include/linux/arm-rsi-cmds= .h similarity index 69% rename from arch/arm64/include/asm/rsi_cmds.h rename to include/linux/arm-rsi-cmds.h index c1fab41f671e..9e8a8c189ca1 100644 --- a/arch/arm64/include/asm/rsi_cmds.h +++ b/include/linux/arm-rsi-cmds.h @@ -3,14 +3,36 @@ * Copyright (C) 2023 ARM Ltd. */ =20 -#ifndef __ASM_RSI_CMDS_H -#define __ASM_RSI_CMDS_H +#ifndef __LINUX_ARM_RSI_CMDS_H_ +#define __LINUX_ARM_RSI_CMDS_H_ =20 -#include +#include +#include #include #include =20 -#include +#define RSI_PDEV_NAME "arm-cca-dev" +#ifdef CONFIG_ARM_RMM_RSI +DECLARE_STATIC_KEY_FALSE(rsi_present); + +void __init arm64_rsi_init(void); + +bool arm64_rsi_is_protected(phys_addr_t base, size_t size); + +static inline bool is_realm_world(void) +{ + return static_branch_unlikely(&rsi_present); +} +#else +static inline void arm64_rsi_init(void) { } + +static inline bool arm64_rsi_is_protected(phys_addr_t base, size_t size) +{ + return false; +} + +static inline bool is_realm_world(void) { return false; } +#endif =20 #define RSI_GRANULE_SHIFT 12 #define RSI_GRANULE_SIZE (_AC(1, UL) << RSI_GRANULE_SHIFT) @@ -88,6 +110,51 @@ static inline long rsi_set_addr_range_state(phys_addr_t= start, return res.a0; } =20 +static inline int rsi_set_memory_range(phys_addr_t start, phys_addr_t end, + enum ripas state, unsigned long flags) +{ + unsigned long ret; + phys_addr_t top; + + while (start !=3D end) { + ret =3D rsi_set_addr_range_state(start, end, state, flags, &top); + if (ret || top < start || top > end) + return -EINVAL; + start =3D top; + } + + return 0; +} + +/* + * Convert the specified range to RAM. Do not use this if you rely on the + * contents of a page that may already be in RAM state. + */ +static inline int rsi_set_memory_range_protected(phys_addr_t start, + phys_addr_t end) +{ + return rsi_set_memory_range(start, end, RSI_RIPAS_RAM, + RSI_CHANGE_DESTROYED); +} + +/* + * Convert the specified range to RAM. Do not convert any pages that may h= ave + * been DESTROYED, without our permission. + */ +static inline int rsi_set_memory_range_protected_safe(phys_addr_t start, + phys_addr_t end) +{ + return rsi_set_memory_range(start, end, RSI_RIPAS_RAM, + RSI_NO_CHANGE_DESTROYED); +} + +static inline int rsi_set_memory_range_shared(phys_addr_t start, + phys_addr_t end) +{ + return rsi_set_memory_range(start, end, RSI_RIPAS_EMPTY, + RSI_CHANGE_DESTROYED); +} + #define RSI_ATTEST_CHALLENGE_MIN_SIZE 32 #define RSI_ATTEST_CHALLENGE_MAX_SIZE 64 =20 @@ -170,4 +237,4 @@ static inline unsigned long rsi_attestation_token_conti= nue(phys_addr_t granule, return res.a0; } =20 -#endif /* __ASM_RSI_CMDS_H */ +#endif /* __LINUX_ARM_RSI_CMDS_H_ */ diff --git a/arch/arm64/include/asm/rsi_smc.h b/include/linux/arm-smccc-rsi= .h similarity index 98% rename from arch/arm64/include/asm/rsi_smc.h rename to include/linux/arm-smccc-rsi.h index e19253f96c94..fddb77986f70 100644 --- a/arch/arm64/include/asm/rsi_smc.h +++ b/include/linux/arm-smccc-rsi.h @@ -3,8 +3,8 @@ * Copyright (C) 2023 ARM Ltd. */ =20 -#ifndef __ASM_RSI_SMC_H_ -#define __ASM_RSI_SMC_H_ +#ifndef __LINUX_ARM_SMCCC_RSI_H_ +#define __LINUX_ARM_SMCCC_RSI_H_ =20 #include =20 @@ -190,4 +190,4 @@ struct realm_config { */ #define SMC_RSI_HOST_CALL SMC_RSI_FID(0x199) =20 -#endif /* __ASM_RSI_SMC_H_ */ +#endif /* __LINUX_ARM_SMCCC_RSI_H_ */ --=20 2.43.0 From nobody Fri Sep 25 10:36:34 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F69E368D76; Mon, 14 Sep 2026 06:05:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789365954; cv=none; b=Mz3CCMI9G/gIoJf2/VDJ+wmAIte0o/hSk0dSKsyaVLUeoupcmRJKlmGzXoV8FqkVWmw8ysNwMxPnMYkLhV6dhnZfigqw7RCsdsPMQXBFgVc0Ki7VWtkDDSAO+fOpGTG+4NSFP90rncfrqMI743ebtFdpwRJHsSw94yqj9hV3w7c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789365954; c=relaxed/simple; bh=pMwVbkp82WwqMD+fRFDKhESSdXxnjz0LHZEzr7pPA1Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RmX048oz1oOllYRonADF3Py5ZKIlkik2a6/7YZfNBtpDtsCKJFkZqLUz4TfABN9kvzR+Exqkg+MFv1wlHXOTBCGrXnnGfjLsBp6H5pO9bNayuPKQggN63lssOGlbAUeMbdUe280E61tmAv3MnEiF1Yu+xqpTh+5Et8ZO0ewJqRg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TjRd+HIF; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TjRd+HIF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 556711F000FF; Mon, 14 Sep 2026 06:05:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789365948; bh=ejtM7hb19Fdx1Vz6IdIqz6XjKIpNAf5ysZyl7dRaz/8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TjRd+HIFopwyfRzpb88qYRhn7IQ37uB1AtN2T9+lBFSlypjMpDRf50dlPxUVWG+gK 6nLsMgsUC4atO6qnGvsbUyAYVpONse5fcPJSZHXXhW2GEaAU1vQkvtGjPOqBa/sx5F NutBTScAQKPW6dbqHn4KWLHA6aA6Ly3r/9P4cb1vqZZMrTHPC5o55nx112cv31DnFS 8hRzzzJhuwZkpbmbIKoryJyHGloKIlU2in0WLwjf0hRK9kseAldjRi3VfeZSVHXqb4 pzpmDm1sFVfhOR7kleYNdfiExEceM8totT2KEbFkWm52vnyGWkQtdQeh1jkQLGYfDf UArcnfK5Q5jfw== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Jason Gunthorpe , Catalin Marinas , Greg KH , Jeremy Linton , Jonathan Cameron , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Will Deacon , Steven Price , Suzuki K Poulose , Andre Przywara Subject: [PATCH v11 4/7] arm64: realm: Move Realm memory encryption ops to RSI code Date: Mon, 14 Sep 2026 11:35:08 +0530 Message-ID: <20260914060511.277948-5-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260914060511.277948-1-aneesh.kumar@kernel.org> References: <20260914060511.277948-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Realm memory encryption callbacks are CCA-specific. Keep the Realm callback registration with the RSI initialization code instead of pageattr.c, which only needs to provide the low-level page-attribute transition helper. Export __set_memory_enc_dec() within arm64 so the RSI code can wrap it with the Realm-specific encrypt/decrypt callbacks and warning policy. No functional changes in this patch. Reviewed-by: Jason Gunthorpe Signed-off-by: Aneesh Kumar K.V (Arm) Reviewed-by: Catalin Marinas Reviewed-by: Suzuki K Poulose --- arch/arm64/include/asm/mem_encrypt.h | 3 +-- arch/arm64/mm/pageattr.c | 38 +--------------------------- drivers/firmware/arm_rmm/rsi.c | 34 +++++++++++++++++++++++++ 3 files changed, 36 insertions(+), 39 deletions(-) diff --git a/arch/arm64/include/asm/mem_encrypt.h b/arch/arm64/include/asm/= mem_encrypt.h index f03b9d7b83b4..ef8b8463e52b 100644 --- a/arch/arm64/include/asm/mem_encrypt.h +++ b/arch/arm64/include/asm/mem_encrypt.h @@ -16,8 +16,7 @@ int arm64_mem_crypt_ops_register(const struct arm64_mem_c= rypt_ops *ops); =20 int set_memory_encrypted(unsigned long addr, int numpages); int set_memory_decrypted(unsigned long addr, int numpages); - -int realm_register_memory_enc_ops(void); +int __set_memory_enc_dec(unsigned long addr, int numpages, bool encrypt); =20 static inline bool force_dma_unencrypted(struct device *dev) { diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index bbe98ac9ad8c..14b2a3801f40 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -275,9 +275,7 @@ int set_direct_map_default_noflush(struct page *page) PAGE_SIZE, set_mask, clear_mask); } =20 -static int __set_memory_enc_dec(unsigned long addr, - int numpages, - bool encrypt) +int __set_memory_enc_dec(unsigned long addr, int numpages, bool encrypt) { unsigned long set_prot =3D 0, clear_prot =3D 0; phys_addr_t start, end; @@ -321,40 +319,6 @@ static int __set_memory_enc_dec(unsigned long addr, __pgprot(PTE_PRESENT_INVALID)); } =20 -static int realm_set_memory_encrypted(unsigned long addr, int numpages) -{ - int ret =3D __set_memory_enc_dec(addr, numpages, true); - - /* - * If the request to change state fails, then the only sensible cause - * of action for the caller is to leak the memory - */ - WARN(ret, "Failed to encrypt memory, %d pages will be leaked", - numpages); - - return ret; -} - -static int realm_set_memory_decrypted(unsigned long addr, int numpages) -{ - int ret =3D __set_memory_enc_dec(addr, numpages, false); - - WARN(ret, "Failed to decrypt memory, %d pages will be leaked", - numpages); - - return ret; -} - -static const struct arm64_mem_crypt_ops realm_crypt_ops =3D { - .encrypt =3D realm_set_memory_encrypted, - .decrypt =3D realm_set_memory_decrypted, -}; - -int realm_register_memory_enc_ops(void) -{ - return arm64_mem_crypt_ops_register(&realm_crypt_ops); -} - int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool vali= d) { unsigned long addr =3D (unsigned long)page_address(page); diff --git a/drivers/firmware/arm_rmm/rsi.c b/drivers/firmware/arm_rmm/rsi.c index 8e716f1c1e31..ada139d0e344 100644 --- a/drivers/firmware/arm_rmm/rsi.c +++ b/drivers/firmware/arm_rmm/rsi.c @@ -127,6 +127,40 @@ static int realm_ioremap_hook(phys_addr_t phys, size_t= size, pgprot_t *prot) return 0; } =20 +static int realm_set_memory_encrypted(unsigned long addr, int numpages) +{ + int ret =3D __set_memory_enc_dec(addr, numpages, true); + + /* + * If the request to change state fails, then the only sensible cause + * of action for the caller is to leak the memory + */ + WARN(ret, "Failed to encrypt memory, %d pages will be leaked", + numpages); + + return ret; +} + +static int realm_set_memory_decrypted(unsigned long addr, int numpages) +{ + int ret =3D __set_memory_enc_dec(addr, numpages, false); + + WARN(ret, "Failed to decrypt memory, %d pages will be leaked", + numpages); + + return ret; +} + +static const struct arm64_mem_crypt_ops realm_crypt_ops =3D { + .encrypt =3D realm_set_memory_encrypted, + .decrypt =3D realm_set_memory_decrypted, +}; + +static int realm_register_memory_enc_ops(void) +{ + return arm64_mem_crypt_ops_register(&realm_crypt_ops); +} + void __init arm64_rsi_init(void) { if (arm_smccc_1_1_get_conduit() !=3D SMCCC_CONDUIT_SMC) --=20 2.43.0 From nobody Fri Sep 25 10:36:34 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EEB50378838; Mon, 14 Sep 2026 06:05:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789365960; cv=none; b=s+gOmtxMNarTAldLvCNNYK5sA9aDBibGsn23LFyaSXcuO1PZFlJiuHs7xVKbBZs5pOIdlxDLwV/CARCkPmXbD68yTNwF/TFjwRZm7vn/MCHxxAauPi3JDme21+GrtSOcRXrwfjz3VgMYqw4z1axfANskoXMKHUre0J3rWFOBgWs= ARC-Message-Signature: i=1; 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b=SVEahWpwGKf7hfU1NjhUJ4yCGlqR4i33qJrs4QkHXqVfPMTvj3lPt2cNrFOyvqDVY 7p9mzIJJ8tfx88EUOABAyojg9DZJhUAroC9+/zDI71LpUW7Unc4xUpEHdBtxk8Xv8m 7GDNmfgxe4MfbGpgbXZr/S23Gg1qVNCw1+Dfvcnv+z+ynfACwHRkXZ3PrSt1D1Vj8A GROofYmu7gVko/aJS82h/UtokIZGGO1z6wrpOxMpRfJFP09slalwlJsv8KIwf7PdLv WbDsZ7Zh7K/dJ80/U2oYSoC0ua0VzQcAUDbuPkMf76qKHtLwGGKO23NzdP3A+Oed0h ramw8nNhlCR9A== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Jason Gunthorpe , Catalin Marinas , Greg KH , Jeremy Linton , Jonathan Cameron , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Will Deacon , Steven Price , Suzuki K Poulose , Andre Przywara Subject: [PATCH v11 5/7] virt: coco: arm-cca-guest: Rename TSM report source file Date: Mon, 14 Sep 2026 11:35:09 +0530 Message-ID: <20260914060511.277948-6-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260914060511.277948-1-aneesh.kumar@kernel.org> References: <20260914060511.277948-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The Arm CCA guest driver currently only implements TSM report support, but follow-up changes will add more TSM-related functionality to the same module. Rename arm-cca-guest.c to main.c and build it as an object of the arm-cca-guest module. This leaves room for the module to grow additional source files. Reviewed-by: Jason Gunthorpe Signed-off-by: Aneesh Kumar K.V (Arm) Reviewed-by: Catalin Marinas Reviewed-by: Suzuki K Poulose --- drivers/virt/coco/arm-cca-guest/Makefile | 2 ++ drivers/virt/coco/arm-cca-guest/{arm-cca-guest.c =3D> main.c} | 6 +++--- 2 files changed, 5 insertions(+), 3 deletions(-) rename drivers/virt/coco/arm-cca-guest/{arm-cca-guest.c =3D> main.c} (97%) diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/a= rm-cca-guest/Makefile index 69eeba08e98a..7564f4fcc4a4 100644 --- a/drivers/virt/coco/arm-cca-guest/Makefile +++ b/drivers/virt/coco/arm-cca-guest/Makefile @@ -1,2 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only obj-$(CONFIG_ARM_CCA_GUEST) +=3D arm-cca-guest.o + +arm-cca-guest-y +=3D main.o diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c b/drivers/virt= /coco/arm-cca-guest/main.c similarity index 97% rename from drivers/virt/coco/arm-cca-guest/arm-cca-guest.c rename to drivers/virt/coco/arm-cca-guest/main.c index b741643d1364..80659f0885e9 100644 --- a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c +++ b/drivers/virt/coco/arm-cca-guest/main.c @@ -156,7 +156,7 @@ static int arm_cca_report_new(struct tsm_report *report= , void *data) return ret; } =20 -static const struct tsm_report_ops arm_cca_tsm_ops =3D { +static const struct tsm_report_ops arm_cca_tsm_report_ops =3D { .name =3D KBUILD_MODNAME, .report_new =3D arm_cca_report_new, }; @@ -177,7 +177,7 @@ static int __init arm_cca_guest_init(void) if (!is_realm_world()) return -ENODEV; =20 - ret =3D tsm_report_register(&arm_cca_tsm_ops, NULL); + ret =3D tsm_report_register(&arm_cca_tsm_report_ops, NULL); if (ret < 0) pr_err("Error %d registering with TSM\n", ret); =20 @@ -191,7 +191,7 @@ module_init(arm_cca_guest_init); */ static void __exit arm_cca_guest_exit(void) { - tsm_report_unregister(&arm_cca_tsm_ops); + tsm_report_unregister(&arm_cca_tsm_report_ops); } module_exit(arm_cca_guest_exit); =20 --=20 2.43.0 From nobody Fri Sep 25 10:36:34 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9883A3C3789; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DJs4tkKY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4FAF1F000FF; Mon, 14 Sep 2026 06:05:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789365960; bh=/o9pGv3CK3tPFfl+wZlXp3a7PvqxlttD/V/umrpbIfQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DJs4tkKYp9nOK2wmGxEpAkH7ghJiBVHobOz3Fs88VQyGD85UVn9Yr4i7Ia/94jgyw GN2BQ0psgfBe++jCne91oQEQf5otHACH9kOwU6/oHhfCvnbvuGx3mIjpD+6GppYEhp 95RdswKAp+Gl1p97cDiwshqbPCeC0ZtRccns2EXTtF26u9zPdX86oXIKWoBQr8kiG5 VE1bJs/81ImDbsXUQ7SCYbmQT63KuZWgaqplplMcTCFLpfpT5w1F+fULKL/O9oezrC bYIpF/y4waw6mjPRqZdC2tTPh3FxqPYPf0qvEiP8E6dUtqLnSOcotsumTZa1lBQgim QsUfK5d5NqgmA== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Jason Gunthorpe , Catalin Marinas , Greg KH , Jeremy Linton , Jonathan Cameron , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Will Deacon , Steven Price , Suzuki K Poulose , Andre Przywara Subject: [PATCH v11 6/7] firmware: smccc: arm-cca-guest: Bind the TSM provider to an SMCCC device Date: Mon, 14 Sep 2026 11:35:10 +0530 Message-ID: <20260914060511.277948-7-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260914060511.277948-1-aneesh.kumar@kernel.org> References: <20260914060511.277948-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The Arm CCA guest TSM provider currently binds through the arm-cca-dev platform device. Like arm-smccc-trng, this device is not an independent platform resource; it is a software representation of the RSI firmware service discovered through SMCCC. Move RSI discovery into the SMCCC firmware driver. When the SMCCC conduit is SMC and if RSI ABI version call is supported, create an arm-rsi-dev SMCCC device. Convert the Arm CCA guest TSM provider to an SMCCC driver so it binds to that discovered RSI service and keeps module autoloading through the SMCCC device id table. Keep the old arm-cca-dev platform-device registration for now. Userspace has used that device as a Realm-guest indicator, so removing it is left to a follow-up patch that adds a replacement sysfs ABI. Signed-off-by: Aneesh Kumar K.V (Arm) Reviewed-by: Catalin Marinas Reviewed-by: Jason Gunthorpe Reviewed-by: Jonathan Cameron Reviewed-by: Sudeep Holla --- drivers/firmware/arm_rmm/rsi.c | 2 +- drivers/firmware/smccc/smccc.c | 6 ++++ drivers/virt/coco/arm-cca-guest/Kconfig | 1 + drivers/virt/coco/arm-cca-guest/main.c | 44 +++++++++++-------------- include/linux/arm-rsi-cmds.h | 1 - 5 files changed, 27 insertions(+), 27 deletions(-) diff --git a/drivers/firmware/arm_rmm/rsi.c b/drivers/firmware/arm_rmm/rsi.c index ada139d0e344..2dd69febedbd 100644 --- a/drivers/firmware/arm_rmm/rsi.c +++ b/drivers/firmware/arm_rmm/rsi.c @@ -183,7 +183,7 @@ void __init arm64_rsi_init(void) } =20 static struct platform_device rsi_dev =3D { - .name =3D RSI_PDEV_NAME, + .name =3D "arm-cca-dev", .id =3D PLATFORM_DEVID_NONE }; =20 diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c index 756c79204e44..e1b16a09a265 100644 --- a/drivers/firmware/smccc/smccc.c +++ b/drivers/firmware/smccc/smccc.c @@ -10,6 +10,7 @@ #include #include #include +#include =20 #include =20 @@ -94,6 +95,11 @@ static const struct smccc_device_info smccc_devices[] __= initconst =3D { .requires_smc =3D false, .device_name =3D "arm-smccc-trng", }, + { + .func_id =3D SMC_RSI_ABI_VERSION, + .requires_smc =3D true, + .device_name =3D "arm-rsi", + }, }; =20 static bool __init smccc_probe_smccc_device(const struct smccc_device_info= *smccc_dev) diff --git a/drivers/virt/coco/arm-cca-guest/Kconfig b/drivers/virt/coco/ar= m-cca-guest/Kconfig index 2582ebb36922..0d4ce72e2d86 100644 --- a/drivers/virt/coco/arm-cca-guest/Kconfig +++ b/drivers/virt/coco/arm-cca-guest/Kconfig @@ -1,6 +1,7 @@ config ARM_CCA_GUEST tristate "Arm CCA Guest driver" depends on ARM_RMM_RSI + depends on HAVE_ARM_SMCCC_DISCOVERY select TSM_REPORTS help The driver provides userspace interface to request and diff --git a/drivers/virt/coco/arm-cca-guest/main.c b/drivers/virt/coco/arm= -cca-guest/main.c index 80659f0885e9..7b1fa008a8f4 100644 --- a/drivers/virt/coco/arm-cca-guest/main.c +++ b/drivers/virt/coco/arm-cca-guest/main.c @@ -4,6 +4,7 @@ */ =20 #include +#include #include #include #include @@ -161,16 +162,7 @@ static const struct tsm_report_ops arm_cca_tsm_report_= ops =3D { .report_new =3D arm_cca_report_new, }; =20 -/** - * arm_cca_guest_init - Register with the Trusted Security Module (TSM) - * interface. - * - * Return: - * * %0 - Registered successfully with the TSM interface. - * * %-ENODEV - The execution context is not an Arm Realm. - * * %-EBUSY - Already registered. - */ -static int __init arm_cca_guest_init(void) +static int cca_tsm_probe(struct arm_smccc_device *sdev) { int ret; =20 @@ -178,30 +170,32 @@ static int __init arm_cca_guest_init(void) return -ENODEV; =20 ret =3D tsm_report_register(&arm_cca_tsm_report_ops, NULL); - if (ret < 0) - pr_err("Error %d registering with TSM\n", ret); + if (ret < 0) { + dev_err_probe(&sdev->dev, ret, "Error registering with TSM\n"); + return ret; + } =20 - return ret; + return 0; } -module_init(arm_cca_guest_init); =20 -/** - * arm_cca_guest_exit - unregister with the Trusted Security Module (TSM) - * interface. - */ -static void __exit arm_cca_guest_exit(void) +static void cca_tsm_remove(struct arm_smccc_device *sdev) { tsm_report_unregister(&arm_cca_tsm_report_ops); } -module_exit(arm_cca_guest_exit); =20 -/* modalias, so userspace can autoload this module when RSI is available */ -static const struct platform_device_id arm_cca_match[] __maybe_unused =3D { - { .name =3D RSI_PDEV_NAME }, - { } +static const struct arm_smccc_device_id cca_tsm_id_table[] =3D { + { .func_id =3D SMC_RSI_ABI_VERSION }, + {} }; +MODULE_DEVICE_TABLE(arm_smccc, cca_tsm_id_table); =20 -MODULE_DEVICE_TABLE(platform, arm_cca_match); +static struct arm_smccc_driver cca_tsm_driver =3D { + .name =3D KBUILD_MODNAME, + .probe =3D cca_tsm_probe, + .remove =3D cca_tsm_remove, + .id_table =3D cca_tsm_id_table, +}; +module_arm_smccc_driver(cca_tsm_driver); MODULE_AUTHOR("Sami Mujawar "); MODULE_DESCRIPTION("Arm CCA Guest TSM Driver"); MODULE_LICENSE("GPL"); diff --git a/include/linux/arm-rsi-cmds.h b/include/linux/arm-rsi-cmds.h index 9e8a8c189ca1..3f7a6a833993 100644 --- a/include/linux/arm-rsi-cmds.h +++ b/include/linux/arm-rsi-cmds.h @@ -11,7 +11,6 @@ #include #include =20 -#define RSI_PDEV_NAME "arm-cca-dev" #ifdef CONFIG_ARM_RMM_RSI DECLARE_STATIC_KEY_FALSE(rsi_present); =20 --=20 2.43.0 From nobody Fri Sep 25 10:36:34 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EC5CB3DB323; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CzoYt5Vg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40CAB1F00893; Mon, 14 Sep 2026 06:06:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789365966; bh=zQhmhJMTXwneX/RqH3DzVF+nOtJL2DGWLLD8wsqyKPs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CzoYt5VgNmseKdHJScMgJ8A7M8ysbwdkORR7hRm7LXrvSVI3h/67n0xvtBU/aPYNW 8mmsqszPwekSJGVQJZdFUmrSGpRp8jBuvLq29DvAOs3d/h+Yen4iUYv7QxV9Lfjdy0 pxJ6VBuvl/wVhJ2f3zxLH8Z0HkKBzm+uniWMzDcTgVJZ2Q+TfQoGzcfO4x7IlhAVGk x1R7MqIXgSiSApdrLEu4j2LL5fl2S9lakRjkFtmRhqQ78MyeseWSwKXi/0u70cvSt9 KirrPdP720sKVFcrvwCJlDG+xP9gZ0RZs/YFkPzlFxQc9On7xC+cnWturF8FMZlHNy yzPcqWSRdUGOw== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Jason Gunthorpe , Catalin Marinas , Greg KH , Jeremy Linton , Jonathan Cameron , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Will Deacon , Steven Price , Suzuki K Poulose , Andre Przywara Subject: [PATCH v11 7/7] coco: guest: arm64: Replace dummy CCA device with sysfs ABI Date: Mon, 14 Sep 2026 11:35:11 +0530 Message-ID: <20260914060511.277948-8-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260914060511.277948-1-aneesh.kumar@kernel.org> References: <20260914060511.277948-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The SMCCC firmware driver now creates the arm-smccc platform device and instantiates the CCA RSI auxiliary devices once the RSI ABI is discovered. The arm64-specific arm-cca-dev platform device stub is therefore no longer needed. However, userspace has used the arm-cca-dev platform device to detect Arm CCA Realm guests [1]. Removing it without a replacement would break that detection and would also leave userspace depending on kernel device-model details. Add /sys/firmware/cca/realm_guest as a stable, architecture-provided ABI for detecting whether the kernel is running as an Arm CCA Realm guest. The file returns 1 in Realm world and 0 otherwise, similar to the existing s390 /sys/firmware/uv/prot_virt_guest interface for protected virtualization guests. Remove the dummy arm-cca-dev registration now that userspace has a dedicated CCA Realm guest indicator, and document the new ABI in Documentation/ABI/testing/sysfs-firmware-cca. [1] https://lore.kernel.org/all/4a7d84b2-2ec4-4773-a2d5-7b63d5c683cf@arm.com Reviewed-by: Jason Gunthorpe Signed-off-by: Aneesh Kumar K.V (Arm) Reviewed-by: Catalin Marinas Reviewed-by: Jonathan Cameron --- Documentation/ABI/testing/sysfs-firmware-cca | 10 +++++ drivers/firmware/arm_rmm/rsi.c | 42 +++++++++++++++----- 2 files changed, 42 insertions(+), 10 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-firmware-cca diff --git a/Documentation/ABI/testing/sysfs-firmware-cca b/Documentation/A= BI/testing/sysfs-firmware-cca new file mode 100644 index 000000000000..bf177d636b92 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-firmware-cca @@ -0,0 +1,10 @@ +What: /sys/firmware/cca/realm_guest +Date: May 2026 +Contact: Linux ARM Kernel Mailing list +Description: Read-only. Indicates whether the kernel is running as an + Arm Confidential Compute Architecture (CCA) Realm guest. + + The value is one of: + + 0: the kernel is not running as a Realm guest + 1: the kernel is running as a Realm guest diff --git a/drivers/firmware/arm_rmm/rsi.c b/drivers/firmware/arm_rmm/rsi.c index 2dd69febedbd..52f40256bd78 100644 --- a/drivers/firmware/arm_rmm/rsi.c +++ b/drivers/firmware/arm_rmm/rsi.c @@ -9,12 +9,15 @@ #include #include #include +#include +#include =20 #include #include #include =20 static struct realm_config config; +static struct kobject *cca_kobj; =20 unsigned long prot_ns_shared; EXPORT_SYMBOL(prot_ns_shared); @@ -182,17 +185,36 @@ void __init arm64_rsi_init(void) static_branch_enable(&rsi_present); } =20 -static struct platform_device rsi_dev =3D { - .name =3D "arm-cca-dev", - .id =3D PLATFORM_DEVID_NONE +static ssize_t cca_is_realm_guest(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%d\n", is_realm_world()); +} + +static struct kobj_attribute cca_realm_guest =3D + __ATTR(realm_guest, 0444, cca_is_realm_guest, NULL); + +static const struct attribute *cca_realm_attrs[] =3D { + &cca_realm_guest.attr, + NULL, }; =20 -static int __init arm64_create_dummy_rsi_dev(void) +static int __init realm_sysfs_init(void) { - if (is_realm_world() && - platform_device_register(&rsi_dev)) - pr_err("failed to register rsi platform device\n"); - return 0; -} + int ret; =20 -arch_initcall(arm64_create_dummy_rsi_dev) + if (!static_branch_unlikely(&rsi_present)) + return 0; + + cca_kobj =3D kobject_create_and_add("cca", firmware_kobj); + if (!cca_kobj) + return -ENOMEM; + + ret =3D sysfs_create_files(cca_kobj, cca_realm_attrs); + if (!ret) + return 0; + + kobject_put(cca_kobj); + return ret; +} +device_initcall(realm_sysfs_init); --=20 2.43.0