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Date: Thu, 23 Feb 2023 11:14:40 -0800
From: Jeffrey Kardatzke <jkardatzke@...omium.org>
To: op-tee@...ts.trustedfirmware.org
Cc: Jeffrey Kardatzke <jkardatzke@...gle.com>,
Jeffrey Kardatzke <jkardatzke@...omium.org>,
Jens Wiklander <jens.wiklander@...aro.org>,
Sumit Garg <sumit.garg@...aro.org>,
linux-kernel@...r.kernel.org
Subject: [PATCH v2] tee: optee: Add SMC for loading OP-TEE image
Adds an SMC call that will pass an OP-TEE binary image to EL3 and
instruct it to load it as the BL32 payload. This works in conjunction
with a feature added to Trusted Firmware for ARM that supports this.
Signed-off-by: Jeffrey Kardatzke <jkardatzke@...omium.org>
Signed-off-by: Jeffrey Kardatzke <jkardatzke@...gle.com>
---
Changes in v2:
- Fixed compile issue when feature is disabled
- Addressed minor comments
- Added state tracking for driver reload
drivers/tee/optee/Kconfig | 10 +++++
drivers/tee/optee/optee_smc.h | 22 ++++++++++
drivers/tee/optee/smc_abi.c | 82 +++++++++++++++++++++++++++++++++++
3 files changed, 114 insertions(+)
diff --git a/drivers/tee/optee/Kconfig b/drivers/tee/optee/Kconfig
index f121c224e682..f0f12b146add 100644
--- a/drivers/tee/optee/Kconfig
+++ b/drivers/tee/optee/Kconfig
@@ -7,3 +7,13 @@ config OPTEE
help
This implements the OP-TEE Trusted Execution Environment (TEE)
driver.
+
+config OPTEE_LOAD_IMAGE
+ bool "Load OP-TEE image as firmware"
+ default n
+ depends on OPTEE
+ help
+ This loads the BL32 image for OP-TEE as firmware when the driver is probed.
+ This returns -EPROBE_DEFER until the firmware is loadable from the
+ filesystem which is determined by checking the system_state until it is in
+ SYSTEM_RUNNING.
diff --git a/drivers/tee/optee/optee_smc.h b/drivers/tee/optee/optee_smc.h
index 73b5e7760d10..a24c524b44fa 100644
--- a/drivers/tee/optee/optee_smc.h
+++ b/drivers/tee/optee/optee_smc.h
@@ -104,6 +104,28 @@ struct optee_smc_call_get_os_revision_result {
unsigned long reserved1;
};
+/*
+ * Load Trusted OS from optee/tee.bin in the Linux firmware.
+ *
+ * WARNING: Use this cautiously as it could lead to insecure loading of the
+ * Trusted OS.
+ * This SMC instructs EL3 to load a binary and execute it as the Trusted OS.
+ *
+ * Call register usage:
+ * a0 SMC Function ID, OPTEE_SMC_CALL_LOAD_IMAGE
+ * a1 Upper 32bit of a 64bit size for the payload
+ * a2 Lower 32bit of a 64bit size for the payload
+ * a3 Upper 32bit of the physical address for the payload
+ * a4 Lower 32bit of the physical address for the payload
+ *
+ * The payload is in the OP-TEE image format.
+ *
+ * Returns result in a0, 0 on success and an error code otherwise.
+ */
+#define OPTEE_SMC_FUNCID_LOAD_IMAGE 2
+#define OPTEE_SMC_CALL_LOAD_IMAGE \
+ OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_LOAD_IMAGE)
+
/*
* Call with struct optee_msg_arg as argument
*
diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
index a1c1fa1a9c28..79ddfb0f9aca 100644
--- a/drivers/tee/optee/smc_abi.c
+++ b/drivers/tee/optee/smc_abi.c
@@ -8,9 +8,11 @@
#include <linux/arm-smccc.h>
#include <linux/errno.h>
+#include <linux/firmware.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irqdomain.h>
+#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/of.h>
@@ -1354,6 +1356,82 @@ static void optee_shutdown(struct platform_device *pdev)
optee_disable_shm_cache(optee);
}
+#ifdef CONFIG_OPTEE_LOAD_IMAGE
+
+#define OPTEE_FW_IMAGE "optee/tee.bin"
+
+static int optee_load_fw(struct platform_device *pdev,
+ optee_invoke_fn *invoke_fn)
+{
+ const struct firmware *fw = NULL;
+ struct arm_smccc_res res;
+ phys_addr_t data_pa;
+ u8 *data_buf = NULL;
+ u64 data_size;
+ u32 data_pa_high, data_pa_low;
+ u32 data_size_high, data_size_low;
+ static int rc;
+ static bool already_loaded;
+
+ if (already_loaded)
+ return rc;
+
+ rc = request_firmware(&fw, OPTEE_FW_IMAGE, &pdev->dev);
+ if (rc) {
+ /*
+ * The firmware in the rootfs will not be accessible until we
+ * are in the SYSTEM_RUNNING state, so return EPROBE_DEFER until
+ * that point.
+ */
+ if (system_state < SYSTEM_RUNNING)
+ return -EPROBE_DEFER;
+ goto fw_err;
+ }
+
+ data_size = fw->size;
+ /*
+ * This uses the GFP_DMA flag to ensure we are allocated memory in the
+ * 32-bit space since TF-A cannot map memory beyond the 32-bit boundary.
+ */
+ data_buf = kmalloc(fw->size, GFP_KERNEL | GFP_DMA);
+ if (!data_buf) {
+ rc = -ENOMEM;
+ goto fw_err;
+ }
+ memcpy(data_buf, fw->data, fw->size);
+ data_pa = virt_to_phys(data_buf);
+ reg_pair_from_64(&data_pa_high, &data_pa_low, data_pa);
+ reg_pair_from_64(&data_size_high, &data_size_low, data_size);
+ goto fw_load;
+
+fw_err:
+ pr_warn("image loading failed\n");
+ data_pa_high = data_pa_low = data_size_high = data_size_low = 0;
+
+fw_load:
+ /*
+ * Always invoke the SMC, even if loading the image fails, to indicate
+ * to EL3 that we have passed the point where it should allow invoking
+ * this SMC.
+ */
+ invoke_fn(OPTEE_SMC_CALL_LOAD_IMAGE, data_size_high, data_size_low,
+ data_pa_high, data_pa_low, 0, 0, 0, &res);
+ if (!rc)
+ rc = res.a0;
+ if (fw)
+ release_firmware(fw);
+ kfree(data_buf);
+ already_loaded = true;
+
+ return rc;
+}
+#else
+static inline int optee_load_fw(struct platform_device *__unused1,
+ optee_invoke_fn *__unused2) {
+ return 0;
+}
+#endif
+
static int optee_probe(struct platform_device *pdev)
{
optee_invoke_fn *invoke_fn;
@@ -1372,6 +1450,10 @@ static int optee_probe(struct platform_device *pdev)
if (IS_ERR(invoke_fn))
return PTR_ERR(invoke_fn);
+ rc = optee_load_fw(pdev, invoke_fn);
+ if (rc)
+ return rc;
+
if (!optee_msg_api_uid_is_optee_api(invoke_fn)) {
pr_warn("api uid mismatch\n");
return -EINVAL;
--
2.39.2.637.g21b0678d19-goog
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