git: b2f8b2dc8736 - main - sys: Add an SMCCC Random Number Generator driver
- Go to: [ bottom of page ] [ top of archives ] [ this month ]
Date: Tue, 15 Oct 2024 17:25:14 UTC
The branch main has been updated by andrew:
URL: https://cgit.FreeBSD.org/src/commit/?id=b2f8b2dc87368d3f0a99865b2df13f5ad79f763a
commit b2f8b2dc87368d3f0a99865b2df13f5ad79f763a
Author: Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2024-10-14 14:34:13 +0000
Commit: Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2024-10-15 17:24:42 +0000
sys: Add an SMCCC Random Number Generator driver
The Arm True Random Number Generator Firmware Interface provides a way
to query the SMCCC firmware for up to 192 bits of entropy. Use it to
provide another source of randomness to the kernel.
Reviewed by: cem, markm
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D46989
---
sys/conf/files.arm64 | 1 +
sys/dev/psci/smccc_trng.c | 143 +++++++++++++++++++++++++++++++++++++++
sys/dev/random/random_harvestq.c | 1 +
sys/sys/random.h | 1 +
4 files changed, 146 insertions(+)
diff --git a/sys/conf/files.arm64 b/sys/conf/files.arm64
index 9c435405e1e9..16d70e1addb6 100644
--- a/sys/conf/files.arm64
+++ b/sys/conf/files.arm64
@@ -418,6 +418,7 @@ dev/pci/pci_dw_if.m optional pci fdt
dev/psci/psci.c standard
dev/psci/smccc_arm64.S standard
+dev/psci/smccc_trng.c standard
dev/psci/smccc.c standard
dev/pwm/controller/allwinner/aw_pwm.c optional fdt aw_pwm
diff --git a/sys/dev/psci/smccc_trng.c b/sys/dev/psci/smccc_trng.c
new file mode 100644
index 000000000000..67939f3422fa
--- /dev/null
+++ b/sys/dev/psci/smccc_trng.c
@@ -0,0 +1,143 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2024 Arm Ltd
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * A driver for the Arm True Random Number Generator Firmware Interface.
+ * This queries into the SMCCC firmware for random numbers using the
+ * interface documented in den0098 [1].
+ *
+ * [1] https://developer.arm.com/documentation/den0098/latest
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/random.h>
+
+#include <dev/psci/psci.h>
+#include <dev/psci/smccc.h>
+
+#include <dev/random/randomdev.h>
+
+#define TRNG_VERSION SMCCC_FUNC_ID(SMCCC_FAST_CALL, \
+ SMCCC_32BIT_CALL, SMCCC_STD_SECURE_SERVICE_CALLS, 0x50)
+#define TRNG_VERSION_MIN 0x10000L
+#define TRNG_RND64 SMCCC_FUNC_ID(SMCCC_FAST_CALL, \
+ SMCCC_64BIT_CALL, SMCCC_STD_SECURE_SERVICE_CALLS, 0x53)
+
+static device_identify_t trng_identify;
+static device_probe_t trng_probe;
+static device_attach_t trng_attach;
+
+static unsigned trng_read(void *, unsigned);
+
+static struct random_source random_trng = {
+ .rs_ident = "Arm SMCCC TRNG",
+ .rs_source = RANDOM_PURE_ARM_TRNG,
+ .rs_read = trng_read,
+};
+
+static void
+trng_identify(driver_t *driver, device_t parent)
+{
+ int32_t version;
+
+ /* TRNG depends on SMCCC 1.1 (per the spec) */
+ if (smccc_get_version() < SMCCC_MAKE_VERSION(1, 1))
+ return;
+
+ /* Check we have TRNG 1.0 or later */
+ version = psci_call(TRNG_VERSION, 0, 0, 0);
+ if (version < TRNG_VERSION_MIN)
+ return;
+
+ if (BUS_ADD_CHILD(parent, 0, "trng", -1) == NULL)
+ device_printf(parent, "add TRNG child failed\n");
+}
+
+static int
+trng_probe(device_t dev)
+{
+ device_set_desc(dev, "Arm SMCCC TRNG");
+ return (BUS_PROBE_NOWILDCARD);
+}
+
+static int
+trng_attach(device_t dev)
+{
+ struct arm_smccc_res res;
+ int32_t ret;
+
+ ret = arm_smccc_invoke(TRNG_RND64, 192, &res);
+ if (ret < 0) {
+ device_printf(dev, "Failed to read fron TRNG\n");
+ } else {
+ random_source_register(&random_trng);
+ }
+
+ return (0);
+}
+
+static unsigned
+trng_read(void *buf, unsigned usz)
+{
+ struct arm_smccc_res res;
+ register_t len;
+ int32_t ret;
+
+ len = usz;
+ if (len > sizeof(uint64_t))
+ len = sizeof(uint64_t);
+ if (len == 0)
+ return (0);
+
+ ret = arm_smccc_invoke(TRNG_RND64, len * 8, &res);
+ if (ret < 0)
+ return (0);
+
+ memcpy(buf, &res.a0, len);
+ return (len);
+}
+
+static device_method_t trng_methods[] = {
+ DEVMETHOD(device_identify, trng_identify),
+ DEVMETHOD(device_probe, trng_probe),
+ DEVMETHOD(device_attach, trng_attach),
+
+ DEVMETHOD_END
+};
+
+static driver_t trng_driver = {
+ "trng",
+ trng_methods,
+ 0
+};
+
+DRIVER_MODULE(trng, smccc, trng_driver, 0, 0);
diff --git a/sys/dev/random/random_harvestq.c b/sys/dev/random/random_harvestq.c
index a8ccabd1a902..379b64ac15f1 100644
--- a/sys/dev/random/random_harvestq.c
+++ b/sys/dev/random/random_harvestq.c
@@ -386,6 +386,7 @@ static const char *random_source_descr[ENTROPYSOURCE] = {
[RANDOM_PURE_VMGENID] = "PURE_VMGENID",
[RANDOM_PURE_QUALCOMM] = "PURE_QUALCOMM",
[RANDOM_PURE_ARMV8] = "PURE_ARMV8",
+ [RANDOM_PURE_ARM_TRNG] = "PURE_ARM_TRNG",
/* "ENTROPYSOURCE" */
};
diff --git a/sys/sys/random.h b/sys/sys/random.h
index 31071d356714..67aae93630b5 100644
--- a/sys/sys/random.h
+++ b/sys/sys/random.h
@@ -103,6 +103,7 @@ enum random_entropy_source {
RANDOM_PURE_VMGENID,
RANDOM_PURE_QUALCOMM,
RANDOM_PURE_ARMV8,
+ RANDOM_PURE_ARM_TRNG,
ENTROPYSOURCE
};
_Static_assert(ENTROPYSOURCE <= 32,