Merge tag 'tee-kexec-fixes-for-v5.14' of git://git.linaro.org:/people/jens.wiklander/linux-tee into arm/fixes

tee: Improve support for kexec and kdump

This fixes several bugs uncovered while exercising the OP-TEE, ftpm
(firmware TPM), and tee_bnxt_fw (Broadcom BNXT firmware manager) drivers
with kexec and kdump (emergency kexec) based workflows.

* tag 'tee-kexec-fixes-for-v5.14' of git://git.linaro.org:/people/jens.wiklander/linux-tee:
  firmware: tee_bnxt: Release TEE shm, session, and context during kexec
  tpm_ftpm_tee: Free and unregister TEE shared memory during kexec
  tee: Correct inappropriate usage of TEE_SHM_DMA_BUF flag
  tee: add tee_shm_alloc_kernel_buf()
  optee: Clear stale cache entries during initialization
  optee: fix tee out of memory failure seen during kexec reboot
  optee: Refuse to load the driver under the kdump kernel
  optee: Fix memory leak when failing to register shm pages

Link: https://lore.kernel.org/r/20210726081039.GA2482361@jade
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

9 files changed, 132 insertions, 19 deletions

diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c
index 2ccdf8ac6994..6e3235565a4d 100644
--- a/drivers/char/tpm/tpm_ftpm_tee.c
+++ b/drivers/char/tpm/tpm_ftpm_tee.c
@@ -254,11 +254,11 @@ static int ftpm_tee_probe(struct device *dev)
 	pvt_data->session = sess_arg.session;
 
 	/* Allocate dynamic shared memory with fTPM TA */
-	pvt_data->shm = tee_shm_alloc(pvt_data->ctx,
-				      MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE,
-				      TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);
+	pvt_data->shm = tee_shm_alloc_kernel_buf(pvt_data->ctx,
+						 MAX_COMMAND_SIZE +
+						 MAX_RESPONSE_SIZE);
 	if (IS_ERR(pvt_data->shm)) {
-		dev_err(dev, "%s: tee_shm_alloc failed\n", __func__);
+		dev_err(dev, "%s: tee_shm_alloc_kernel_buf failed\n", __func__);
 		rc = -ENOMEM;
 		goto out_shm_alloc;
 	}
diff --git a/drivers/firmware/broadcom/tee_bnxt_fw.c b/drivers/firmware/broadcom/tee_bnxt_fw.c
index ed10da5313e8..a5bf4c3f6dc7 100644
--- a/drivers/firmware/broadcom/tee_bnxt_fw.c
+++ b/drivers/firmware/broadcom/tee_bnxt_fw.c
@@ -212,10 +212,9 @@ static int tee_bnxt_fw_probe(struct device *dev)
 
 	pvt_data.dev = dev;
 
-	fw_shm_pool = tee_shm_alloc(pvt_data.ctx, MAX_SHM_MEM_SZ,
-				    TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);
+	fw_shm_pool = tee_shm_alloc_kernel_buf(pvt_data.ctx, MAX_SHM_MEM_SZ);
 	if (IS_ERR(fw_shm_pool)) {
-		dev_err(pvt_data.dev, "tee_shm_alloc failed\n");
+		dev_err(pvt_data.dev, "tee_shm_alloc_kernel_buf failed\n");
 		err = PTR_ERR(fw_shm_pool);
 		goto out_sess;
 	}
@@ -242,6 +241,14 @@ static int tee_bnxt_fw_remove(struct device *dev)
 	return 0;
 }
 
+static void tee_bnxt_fw_shutdown(struct device *dev)
+{
+	tee_shm_free(pvt_data.fw_shm_pool);
+	tee_client_close_session(pvt_data.ctx, pvt_data.session_id);
+	tee_client_close_context(pvt_data.ctx);
+	pvt_data.ctx = NULL;
+}
+
 static const struct tee_client_device_id tee_bnxt_fw_id_table[] = {
 	{UUID_INIT(0x6272636D, 0x2019, 0x0716,
 		    0x42, 0x43, 0x4D, 0x5F, 0x53, 0x43, 0x48, 0x49)},
@@ -257,6 +264,7 @@ static struct tee_client_driver tee_bnxt_fw_driver = {
 		.bus		= &tee_bus_type,
 		.probe		= tee_bnxt_fw_probe,
 		.remove		= tee_bnxt_fw_remove,
+		.shutdown	= tee_bnxt_fw_shutdown,
 	},
 };
 
diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index 6e6eb836e9b6..945f03da0223 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -184,7 +184,7 @@ static struct tee_shm *get_msg_arg(struct tee_context *ctx, size_t num_params,
 	struct optee_msg_arg *ma;
 
 	shm = tee_shm_alloc(ctx, OPTEE_MSG_GET_ARG_SIZE(num_params),
-			    TEE_SHM_MAPPED);
+			    TEE_SHM_MAPPED | TEE_SHM_PRIV);
 	if (IS_ERR(shm))
 		return shm;
 
@@ -416,11 +416,13 @@ void optee_enable_shm_cache(struct optee *optee)
 }
 
 /**
- * optee_disable_shm_cache() - Disables caching of some shared memory allocation
- *			      in OP-TEE
+ * __optee_disable_shm_cache() - Disables caching of some shared memory
+ *                               allocation in OP-TEE
  * @optee:	main service struct
+ * @is_mapped:	true if the cached shared memory addresses were mapped by this
+ *		kernel, are safe to dereference, and should be freed
  */
-void optee_disable_shm_cache(struct optee *optee)
+static void __optee_disable_shm_cache(struct optee *optee, bool is_mapped)
 {
 	struct optee_call_waiter w;
 
@@ -439,6 +441,13 @@ void optee_disable_shm_cache(struct optee *optee)
 		if (res.result.status == OPTEE_SMC_RETURN_OK) {
 			struct tee_shm *shm;
 
+			/*
+			 * Shared memory references that were not mapped by
+			 * this kernel must be ignored to prevent a crash.
+			 */
+			if (!is_mapped)
+				continue;
+
 			shm = reg_pair_to_ptr(res.result.shm_upper32,
 					      res.result.shm_lower32);
 			tee_shm_free(shm);
@@ -449,6 +458,27 @@ void optee_disable_shm_cache(struct optee *optee)
 	optee_cq_wait_final(&optee->call_queue, &w);
 }
 
+/**
+ * optee_disable_shm_cache() - Disables caching of mapped shared memory
+ *                             allocations in OP-TEE
+ * @optee:	main service struct
+ */
+void optee_disable_shm_cache(struct optee *optee)
+{
+	return __optee_disable_shm_cache(optee, true);
+}
+
+/**
+ * optee_disable_unmapped_shm_cache() - Disables caching of shared memory
+ *                                      allocations in OP-TEE which are not
+ *                                      currently mapped
+ * @optee:	main service struct
+ */
+void optee_disable_unmapped_shm_cache(struct optee *optee)
+{
+	return __optee_disable_shm_cache(optee, false);
+}
+
 #define PAGELIST_ENTRIES_PER_PAGE				\
 	((OPTEE_MSG_NONCONTIG_PAGE_SIZE / sizeof(u64)) - 1)
 
diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
index ddb8f9ecf307..5ce13b099d7d 100644
--- a/drivers/tee/optee/core.c
+++ b/drivers/tee/optee/core.c
@@ -6,6 +6,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/arm-smccc.h>
+#include <linux/crash_dump.h>
 #include <linux/errno.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -277,7 +278,8 @@ static void optee_release(struct tee_context *ctx)
 	if (!ctxdata)
 		return;
 
-	shm = tee_shm_alloc(ctx, sizeof(struct optee_msg_arg), TEE_SHM_MAPPED);
+	shm = tee_shm_alloc(ctx, sizeof(struct optee_msg_arg),
+			    TEE_SHM_MAPPED | TEE_SHM_PRIV);
 	if (!IS_ERR(shm)) {
 		arg = tee_shm_get_va(shm, 0);
 		/*
@@ -572,6 +574,13 @@ static optee_invoke_fn *get_invoke_func(struct device *dev)
 	return ERR_PTR(-EINVAL);
 }
 
+/* optee_remove - Device Removal Routine
+ * @pdev: platform device information struct
+ *
+ * optee_remove is called by platform subsystem to alert the driver
+ * that it should release the device
+ */
+
 static int optee_remove(struct platform_device *pdev)
 {
 	struct optee *optee = platform_get_drvdata(pdev);
@@ -602,6 +611,18 @@ static int optee_remove(struct platform_device *pdev)
 	return 0;
 }
 
+/* optee_shutdown - Device Removal Routine
+ * @pdev: platform device information struct
+ *
+ * platform_shutdown is called by the platform subsystem to alert
+ * the driver that a shutdown, reboot, or kexec is happening and
+ * device must be disabled.
+ */
+static void optee_shutdown(struct platform_device *pdev)
+{
+	optee_disable_shm_cache(platform_get_drvdata(pdev));
+}
+
 static int optee_probe(struct platform_device *pdev)
 {
 	optee_invoke_fn *invoke_fn;
@@ -612,6 +633,16 @@ static int optee_probe(struct platform_device *pdev)
 	u32 sec_caps;
 	int rc;
 
+	/*
+	 * The kernel may have crashed at the same time that all available
+	 * secure world threads were suspended and we cannot reschedule the
+	 * suspended threads without access to the crashed kernel's wait_queue.
+	 * Therefore, we cannot reliably initialize the OP-TEE driver in the
+	 * kdump kernel.
+	 */
+	if (is_kdump_kernel())
+		return -ENODEV;
+
 	invoke_fn = get_invoke_func(&pdev->dev);
 	if (IS_ERR(invoke_fn))
 		return PTR_ERR(invoke_fn);
@@ -686,6 +717,15 @@ static int optee_probe(struct platform_device *pdev)
 	optee->memremaped_shm = memremaped_shm;
 	optee->pool = pool;
 
+	/*
+	 * Ensure that there are no pre-existing shm objects before enabling
+	 * the shm cache so that there's no chance of receiving an invalid
+	 * address during shutdown. This could occur, for example, if we're
+	 * kexec booting from an older kernel that did not properly cleanup the
+	 * shm cache.
+	 */
+	optee_disable_unmapped_shm_cache(optee);
+
 	optee_enable_shm_cache(optee);
 
 	if (optee->sec_caps & OPTEE_SMC_SEC_CAP_DYNAMIC_SHM)
@@ -728,6 +768,7 @@ MODULE_DEVICE_TABLE(of, optee_dt_match);
 static struct platform_driver optee_driver = {
 	.probe  = optee_probe,
 	.remove = optee_remove,
+	.shutdown = optee_shutdown,
 	.driver = {
 		.name = "optee",
 		.of_match_table = optee_dt_match,
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index e25b216a14ef..dbdd367be156 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -159,6 +159,7 @@ int optee_cancel_req(struct tee_context *ctx, u32 cancel_id, u32 session);
 
 void optee_enable_shm_cache(struct optee *optee);
 void optee_disable_shm_cache(struct optee *optee);
+void optee_disable_unmapped_shm_cache(struct optee *optee);
 
 int optee_shm_register(struct tee_context *ctx, struct tee_shm *shm,
 		       struct page **pages, size_t num_pages,
diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c
index 1849180b0278..efbaff7ad7e5 100644
--- a/drivers/tee/optee/rpc.c
+++ b/drivers/tee/optee/rpc.c
@@ -314,7 +314,7 @@ static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
 		shm = cmd_alloc_suppl(ctx, sz);
 		break;
 	case OPTEE_RPC_SHM_TYPE_KERNEL:
-		shm = tee_shm_alloc(ctx, sz, TEE_SHM_MAPPED);
+		shm = tee_shm_alloc(ctx, sz, TEE_SHM_MAPPED | TEE_SHM_PRIV);
 		break;
 	default:
 		arg->ret = TEEC_ERROR_BAD_PARAMETERS;
@@ -502,7 +502,8 @@ void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param,
 
 	switch (OPTEE_SMC_RETURN_GET_RPC_FUNC(param->a0)) {
 	case OPTEE_SMC_RPC_FUNC_ALLOC:
-		shm = tee_shm_alloc(ctx, param->a1, TEE_SHM_MAPPED);
+		shm = tee_shm_alloc(ctx, param->a1,
+				    TEE_SHM_MAPPED | TEE_SHM_PRIV);
 		if (!IS_ERR(shm) && !tee_shm_get_pa(shm, 0, &pa)) {
 			reg_pair_from_64(&param->a1, &param->a2, pa);
 			reg_pair_from_64(&param->a4, &param->a5,
diff --git a/drivers/tee/optee/shm_pool.c b/drivers/tee/optee/shm_pool.c
index d767eebf30bd..c41a9a501a6e 100644
--- a/drivers/tee/optee/shm_pool.c
+++ b/drivers/tee/optee/shm_pool.c
@@ -27,13 +27,19 @@ static int pool_op_alloc(struct tee_shm_pool_mgr *poolm,
 	shm->paddr = page_to_phys(page);
 	shm->size = PAGE_SIZE << order;
 
-	if (shm->flags & TEE_SHM_DMA_BUF) {
+	/*
+	 * Shared memory private to the OP-TEE driver doesn't need
+	 * to be registered with OP-TEE.
+	 */
+	if (!(shm->flags & TEE_SHM_PRIV)) {
 		unsigned int nr_pages = 1 << order, i;
 		struct page **pages;
 
 		pages = kcalloc(nr_pages, sizeof(pages), GFP_KERNEL);
-		if (!pages)
-			return -ENOMEM;
+		if (!pages) {
+			rc = -ENOMEM;
+			goto err;
+		}
 
 		for (i = 0; i < nr_pages; i++) {
 			pages[i] = page;
@@ -44,15 +50,21 @@ static int pool_op_alloc(struct tee_shm_pool_mgr *poolm,
 		rc = optee_shm_register(shm->ctx, shm, pages, nr_pages,
 					(unsigned long)shm->kaddr);
 		kfree(pages);
+		if (rc)
+			goto err;
 	}
 
+	return 0;
+
+err:
+	__free_pages(page, order);
 	return rc;
 }
 
 static void pool_op_free(struct tee_shm_pool_mgr *poolm,
 			 struct tee_shm *shm)
 {
-	if (shm->flags & TEE_SHM_DMA_BUF)
+	if (!(shm->flags & TEE_SHM_PRIV))
 		optee_shm_unregister(shm->ctx, shm);
 
 	free_pages((unsigned long)shm->kaddr, get_order(shm->size));
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index 00472f5ce22e..8a9384a64f3e 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -117,7 +117,7 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
 		return ERR_PTR(-EINVAL);
 	}
 
-	if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF))) {
+	if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF | TEE_SHM_PRIV))) {
 		dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags);
 		return ERR_PTR(-EINVAL);
 	}
@@ -193,6 +193,24 @@ err_dev_put:
 }
 EXPORT_SYMBOL_GPL(tee_shm_alloc);
 
+/**
+ * tee_shm_alloc_kernel_buf() - Allocate shared memory for kernel buffer
+ * @ctx:	Context that allocates the shared memory
+ * @size:	Requested size of shared memory
+ *
+ * The returned memory registered in secure world and is suitable to be
+ * passed as a memory buffer in parameter argument to
+ * tee_client_invoke_func(). The memory allocated is later freed with a
+ * call to tee_shm_free().
+ *
+ * @returns a pointer to 'struct tee_shm'
+ */
+struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size)
+{
+	return tee_shm_alloc(ctx, size, TEE_SHM_MAPPED);
+}
+EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);
+
 struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
 				 size_t length, u32 flags)
 {
diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
index 54269e47ac9a..3ebfea0781f1 100644
--- a/include/linux/tee_drv.h
+++ b/include/linux/tee_drv.h
@@ -27,6 +27,7 @@
 #define TEE_SHM_USER_MAPPED	BIT(4)  /* Memory mapped in user space */
 #define TEE_SHM_POOL		BIT(5)  /* Memory allocated from pool */
 #define TEE_SHM_KERNEL_MAPPED	BIT(6)  /* Memory mapped in kernel space */
+#define TEE_SHM_PRIV		BIT(7)  /* Memory private to TEE driver */
 
 struct device;
 struct tee_device;
@@ -332,6 +333,7 @@ void *tee_get_drvdata(struct tee_device *teedev);
  * @returns a pointer to 'struct tee_shm'
  */
 struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags);
+struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size);
 
 /**
  * tee_shm_register() - Register shared memory buffer