efi: Add ESRT to the EFI system table

The ESRT is initialised during efi_init_objlist after
efi_initialize_system_table().

The ESRT is recreated from scratch at the following events:
- successful UpdateCapsule;
- FMP instance install.

The code ensures that every ESRT entry has a unique fw_class value.

Limitations:
- The ESRT is not updated if an FMP instance is uninstalled;
- the fields image_type and flags are in the current implementation left
undefined. Setting these values will require a per-platform function
that returns the image_type/flags as a function of the image fw_class.

CC: Heinrich Schuchardt	<xypron.glpk@gmx.de>
CC: Sughosh Ganu <sughosh.ganu@linaro.org>
CC: AKASHI Takahiro <takahiro.akashi@linaro.org>
CC: Ilias Apalodimas <ilias.apalodimas@linaro.org>
CC: Andre Przywara <andre.przywara@arm.com>
CC: Alexander Graf <agraf@csgraf.de>
CC: nd@arm.com
Signed-off-by: Jose Marinho <jose.marinho@arm.com>

Remove two EFI_CALL() indirections.
Move ESRT GUID in efidebug's list of GUIDs.

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

6 files changed, 535 insertions, 4 deletions

diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index 0a41244..e44f004 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -342,4 +342,11 @@ config EFI_SECURE_BOOT
 	  it is signed with a trusted key. To do that, you need to install,
 	  at least, PK, KEK and db.
 
+config EFI_ESRT
+	bool "Enable the UEFI ESRT generation"
+	depends on EFI_CAPSULE_FIRMWARE_MANAGEMENT
+	default y
+	help
+	  Enabling this option creates the ESRT UEFI system table.
+
 endif
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index da2741a..8bd343e 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -53,6 +53,7 @@ obj-y += efi_variable.o
 obj-$(CONFIG_EFI_VARIABLES_PRESEED) += efi_var_seed.o
 endif
 obj-y += efi_watchdog.o
+obj-$(CONFIG_EFI_ESRT) += efi_esrt.o
 obj-$(CONFIG_LCD) += efi_gop.o
 obj-$(CONFIG_DM_VIDEO) += efi_gop.o
 obj-$(CONFIG_PARTITIONS) += efi_disk.o
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 41b8949..8e8b0a9 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -1406,10 +1406,9 @@ out:
  *
  * Return: status code
  */
-static efi_status_t EFIAPI efi_register_protocol_notify(
-						const efi_guid_t *protocol,
-						struct efi_event *event,
-						void **registration)
+efi_status_t EFIAPI efi_register_protocol_notify(const efi_guid_t *protocol,
+						 struct efi_event *event,
+						 void **registration)
 {
 	struct efi_register_notify_event *item;
 	efi_status_t ret = EFI_SUCCESS;
diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
index 7ba1ced..9df9c35 100644
--- a/lib/efi_loader/efi_capsule.c
+++ b/lib/efi_loader/efi_capsule.c
@@ -482,6 +482,14 @@ efi_status_t EFIAPI efi_update_capsule(
 			goto out;
 	}
 out:
+
+	if (IS_ENABLED(CONFIG_EFI_ESRT)) {
+		/* Rebuild the ESRT to reflect any updated FW images. */
+		ret = efi_esrt_populate();
+		if (ret != EFI_SUCCESS)
+			log_warning("EFI Capsule: failed to update ESRT\n");
+	}
+
 	return EFI_EXIT(ret);
 }
 
diff --git a/lib/efi_loader/efi_esrt.c b/lib/efi_loader/efi_esrt.c
new file mode 100644
index 0000000..947bdb5
--- /dev/null
+++ b/lib/efi_loader/efi_esrt.c
@@ -0,0 +1,510 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  EFI application ESRT tables support
+ *
+ *  Copyright (C) 2021 Arm Ltd.
+ */
+
+#include <common.h>
+#include <efi_loader.h>
+#include <log.h>
+#include <efi_api.h>
+#include <malloc.h>
+
+const efi_guid_t efi_esrt_guid = EFI_SYSTEM_RESOURCE_TABLE_GUID;
+
+static struct efi_system_resource_table *esrt;
+
+#define EFI_ESRT_VERSION 1
+
+/**
+ * efi_esrt_image_info_to_entry() - copy the information present in a fw image
+ * descriptor to a ESRT entry.
+ * The function ensures the ESRT entry matches the image_type_id in @img_info.
+ * In case of a mismatch we leave the entry unchanged.
+ *
+ * @img_info:     the source image info descriptor
+ * @entry:        pointer to the ESRT entry to be filled
+ * @desc_version: the version of the elements in img_info
+ * @image_type:   the image type value to be set in the ESRT entry
+ * @flags:        the capsule flags value to be set in the ESRT entry
+ *
+ * Return:
+ * - EFI_SUCCESS if the entry is correctly updated
+ * - EFI_INVALID_PARAMETER if entry does not match image_type_id in @img_info.
+ */
+static efi_status_t
+efi_esrt_image_info_to_entry(struct efi_firmware_image_descriptor *img_info,
+			     struct efi_system_resource_entry *entry,
+			     u32 desc_version, u32 image_type, u32 flags)
+{
+	if (guidcmp(&entry->fw_class, &img_info->image_type_id)) {
+		EFI_PRINT("ESRT entry %pUL mismatches img_type_id %pUL\n",
+			  &entry->fw_class, &img_info->image_type_id);
+		return EFI_INVALID_PARAMETER;
+	}
+
+	entry->fw_version = img_info->version;
+
+	entry->fw_type = image_type;
+	entry->capsule_flags = flags;
+
+	/*
+	 * The field lowest_supported_image_version is only present
+	 * on image info structure of version 2 or greater.
+	 * See the EFI_FIRMWARE_IMAGE_DESCRIPTOR definition in UEFI.
+	 */
+	if (desc_version >= 2)
+		entry->lowest_supported_fw_version =
+			img_info->lowest_supported_image_version;
+	else
+		entry->lowest_supported_fw_version = 0;
+
+	/*
+	 * The fields last_attempt_version and last_attempt_status
+	 * are only present on image info structure of version 3 or
+	 * greater.
+	 * See the EFI_FIRMWARE_IMAGE_DESCRIPTOR definition in UEFI.
+	 */
+	if (desc_version >= 3) {
+		entry->last_attempt_version =
+			img_info->last_attempt_version;
+
+		entry->last_attempt_status =
+			img_info->last_attempt_status;
+	} else {
+		entry->last_attempt_version = 0;
+		entry->last_attempt_status = LAST_ATTEMPT_STATUS_SUCCESS;
+	}
+
+	return EFI_SUCCESS;
+}
+
+/**
+ * efi_esrt_entries_to_size() - Obtain the bytes used by an ESRT
+ * datastructure with @num_entries.
+ *
+ * @num_entries: the number of entries in the ESRT.
+ *
+ * Return: the number of bytes an ESRT with @num_entries occupies in memory.
+ */
+static
+inline u32 efi_esrt_entries_to_size(u32 num_entries)
+{
+	u32 esrt_size = sizeof(struct efi_system_resource_table) +
+		num_entries * sizeof(struct efi_system_resource_entry);
+
+	return esrt_size;
+}
+
+/**
+ * efi_esrt_allocate_install() - Allocates @num_entries for the ESRT and
+ * performs basic ESRT initialization.
+ *
+ * @num_entries: the number of entries that the ESRT will hold.
+ *
+ * Return:
+ * - pointer to the ESRT if successful.
+ * - NULL otherwise.
+ */
+static
+efi_status_t efi_esrt_allocate_install(u32 num_entries)
+{
+	efi_status_t ret;
+	struct efi_system_resource_table *new_esrt;
+	u32 size = efi_esrt_entries_to_size(num_entries);
+	efi_guid_t esrt_guid = efi_esrt_guid;
+
+	/* Reserve num_pages for ESRT */
+	ret = efi_allocate_pool(EFI_BOOT_SERVICES_DATA, size,
+				(void **)&new_esrt);
+
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("ESRT cannot allocate memory for %d entries (%d bytes)\n",
+			  num_entries, efi_esrt_entries_to_size(num_entries));
+
+		return ret;
+	}
+
+	new_esrt->fw_resource_count_max = num_entries;
+	new_esrt->fw_resource_count = 0;
+	new_esrt->fw_resource_version = EFI_ESRT_VERSION;
+
+	/* Install the ESRT in the system configuration table. */
+	ret = efi_install_configuration_table(&esrt_guid, (void *)new_esrt);
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("ESRT failed to install the ESRT in the system table\n");
+		return ret;
+	}
+
+	/* If there was a previous ESRT, deallocate its memory now. */
+	if (esrt)
+		ret = EFI_CALL(efi_free_pool(esrt));
+
+	esrt = new_esrt;
+
+	return EFI_SUCCESS;
+}
+
+/**
+ * esrt_find_entry() - Obtain the ESRT entry for the image with GUID
+ * @img_fw_class.
+ *
+ * If the img_fw_class is not yet present in the ESRT, this function
+ * reserves the tail element of the current ESRT as the entry for that fw_class.
+ * The number of elements in the ESRT is updated in that case.
+ *
+ * @img_fw_class: the GUID of the FW image which ESRT entry we want to obtain.
+ *
+ * Return:
+ *  - A pointer to the ESRT entry for the image with GUID img_fw_class,
+ *  - NULL if:
+ *   - there is no more space in the ESRT,
+ *   - ESRT is not initialized,
+ */
+static
+struct efi_system_resource_entry *esrt_find_entry(efi_guid_t *img_fw_class)
+{
+	u32 filled_entries;
+	u32 max_entries;
+	struct efi_system_resource_entry *entry;
+
+	if (!esrt) {
+		EFI_PRINT("ESRT access before initialized\n");
+		return NULL;
+	}
+
+	filled_entries = esrt->fw_resource_count;
+	entry = esrt->entries;
+
+	/* Check if the image with img_fw_class is already in the ESRT. */
+	for (u32 idx = 0; idx < filled_entries; idx++) {
+		if (!guidcmp(&entry[idx].fw_class, img_fw_class)) {
+			EFI_PRINT("ESRT found entry for image %pUl at index %d\n",
+				  img_fw_class, idx);
+			return &entry[idx];
+		}
+	}
+
+	max_entries = esrt->fw_resource_count_max;
+	/*
+	 * Since the image with img_fw_class is not present in the ESRT, check
+	 * if ESRT is full before appending the new entry to it.
+	 */
+	if (filled_entries == max_entries) {
+		EFI_PRINT("ESRT full, this should not happen\n");
+		return NULL;
+	}
+
+	/*
+	 * This is a new entry for a fw image, increment the element
+	 * number in the table and set the fw_class field.
+	 */
+	esrt->fw_resource_count++;
+	entry[filled_entries].fw_class = *img_fw_class;
+	EFI_PRINT("ESRT allocated new entry for image %pUl at index %d\n",
+		  img_fw_class, filled_entries);
+
+	return &entry[filled_entries];
+}
+
+/**
+ * efi_esrt_add_from_fmp() - Populates a sequence of ESRT entries from the FW
+ * images in the FMP.
+ *
+ * @fmp: the FMP instance from which FW images are added to the ESRT
+ *
+ * Return:
+ * - EFI_SUCCESS if all the FW images in the FMP are added to the ESRT
+ * - Error status otherwise
+ */
+static
+efi_status_t efi_esrt_add_from_fmp(struct efi_firmware_management_protocol *fmp)
+{
+	struct efi_system_resource_entry *entry = NULL;
+	size_t info_size = 0;
+	struct efi_firmware_image_descriptor *img_info = NULL;
+	u32 desc_version;
+	u8 desc_count;
+	size_t desc_size;
+	u32 package_version;
+	u16 *package_version_name;
+	efi_status_t ret = EFI_SUCCESS;
+
+	/*
+	 * TODO: set the field image_type depending on the FW image type
+	 * defined in a platform basis.
+	 */
+	u32 image_type = ESRT_FW_TYPE_UNKNOWN;
+
+	/* TODO: set the capsule flags as a function of the FW image type. */
+	u32 flags = 0;
+
+	ret = EFI_CALL(fmp->get_image_info(fmp, &info_size, img_info,
+					   &desc_version, &desc_count,
+					   &desc_size, NULL, NULL));
+
+	if (ret != EFI_BUFFER_TOO_SMALL) {
+		/*
+		 * An input of info_size=0 should always lead
+		 * fmp->get_image_info to return BUFFER_TO_SMALL.
+		 */
+		EFI_PRINT("Erroneous FMP implementation\n");
+		return EFI_INVALID_PARAMETER;
+	}
+
+	ret = EFI_CALL(efi_allocate_pool(EFI_BOOT_SERVICES_DATA, info_size,
+					 (void **)&img_info));
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("ESRT failed to allocate memory for image info.\n");
+		return ret;
+	}
+
+	ret = EFI_CALL(fmp->get_image_info(fmp, &info_size, img_info,
+					   &desc_version, &desc_count,
+					   &desc_size, &package_version,
+					   &package_version_name));
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("ESRT failed to obtain the FMP image info\n");
+		goto out;
+	}
+
+	/*
+	 * Iterate over all the FW images in the FMP.
+	 */
+	for (u32 desc_idx = 0; desc_idx < desc_count; desc_idx++) {
+		struct efi_firmware_image_descriptor *cur_img_info =
+			(struct efi_firmware_image_descriptor *)
+			((uintptr_t)img_info + desc_idx * desc_size);
+
+		/*
+		 * Obtain the ESRT entry for the FW image with fw_class
+		 * equal to cur_img_info->image_type_id.
+		 */
+		entry = esrt_find_entry(&cur_img_info->image_type_id);
+
+		if (entry) {
+			ret = efi_esrt_image_info_to_entry(cur_img_info, entry,
+							   desc_version,
+							   image_type, flags);
+			if (ret != EFI_SUCCESS)
+				EFI_PRINT("ESRT entry mismatches image_type\n");
+
+		} else {
+			EFI_PRINT("ESRT failed to add entry for %pUl\n",
+				  &cur_img_info->image_type_id);
+			continue;
+		}
+	}
+
+out:
+	EFI_CALL(efi_free_pool(img_info));
+	return EFI_SUCCESS;
+}
+
+/**
+ * efi_esrt_populate() - Populates the ESRT entries from the FMP instances
+ * present in the system.
+ * If an ESRT already exists, the old ESRT is replaced in the system table.
+ * The memory of the old ESRT is deallocated.
+ *
+ * Return:
+ * - EFI_SUCCESS if the ESRT is correctly created
+ * - error code otherwise.
+ */
+efi_status_t efi_esrt_populate(void)
+{
+	efi_handle_t *base_handle = NULL;
+	efi_handle_t *it_handle;
+	size_t no_handles = 0;
+	struct efi_firmware_management_protocol *fmp;
+	efi_status_t ret;
+	u32 num_entries = 0;
+	struct efi_handler *handler;
+
+	/*
+	 * Obtain the number of registered FMP handles.
+	 */
+	ret = EFI_CALL(efi_locate_handle_buffer(BY_PROTOCOL,
+						&efi_guid_firmware_management_protocol,
+						NULL, &no_handles,
+						(efi_handle_t **)&base_handle));
+
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("ESRT There are no FMP instances\n");
+
+		ret = efi_esrt_allocate_install(0);
+		if (ret != EFI_SUCCESS) {
+			EFI_PRINT("ESRT failed to create table with 0 entries\n");
+			return ret;
+		}
+		return EFI_SUCCESS;
+	}
+
+	EFI_PRINT("ESRT populate esrt from (%ld) available FMP handles\n",
+		  no_handles);
+
+	/*
+	 * Iterate over all FMPs to determine an upper bound on the number of
+	 * ESRT entries.
+	 */
+	it_handle = base_handle;
+	for (u32 idx = 0; idx < no_handles; idx++, it_handle++) {
+		struct efi_firmware_image_descriptor *img_info = NULL;
+		size_t info_size = 0;
+		u32 desc_version = 0;
+		u8 desc_count = 0;
+		size_t desc_size = 0;
+		u32 package_version;
+		u16 *package_version_name;
+
+		ret = efi_search_protocol(*it_handle,
+					  &efi_guid_firmware_management_protocol,
+					  &handler);
+
+		if (ret != EFI_SUCCESS) {
+			EFI_PRINT("ESRT Unable to find FMP handle (%d)\n",
+				  idx);
+			goto out;
+		}
+		fmp = handler->protocol_interface;
+
+		ret = EFI_CALL(fmp->get_image_info(fmp, &info_size, NULL,
+						   &desc_version, &desc_count,
+						   &desc_size, &package_version,
+						   &package_version_name));
+
+		if (ret != EFI_BUFFER_TOO_SMALL) {
+			/*
+			 * An input of info_size=0 should always lead
+			 * fmp->get_image_info to return BUFFER_TO_SMALL.
+			 */
+			EFI_PRINT("ESRT erroneous FMP implementation\n");
+			ret = EFI_INVALID_PARAMETER;
+			goto out;
+		}
+
+		ret = EFI_CALL(efi_allocate_pool(EFI_BOOT_SERVICES_DATA, info_size,
+						 (void **)&img_info));
+		if (ret != EFI_SUCCESS) {
+			EFI_PRINT("ESRT failed to allocate memory for image info\n");
+			goto out;
+		}
+
+		/*
+		 * Calls to a FMP get_image_info method do not return the
+		 * desc_count value if the return status differs from EFI_SUCCESS.
+		 * We need to repeat the call to get_image_info with a properly
+		 * sized buffer in order to obtain the real number of images
+		 * handled by the FMP.
+		 */
+		ret = EFI_CALL(fmp->get_image_info(fmp, &info_size, img_info,
+						   &desc_version, &desc_count,
+						   &desc_size, &package_version,
+						   &package_version_name));
+
+		if (ret != EFI_SUCCESS) {
+			EFI_PRINT("ESRT failed to obtain image info from FMP\n");
+			EFI_CALL(efi_free_pool(img_info));
+			goto out;
+		}
+
+		num_entries += desc_count;
+
+		EFI_CALL(efi_free_pool(img_info));
+	}
+
+	EFI_PRINT("ESRT create table with %d entries\n", num_entries);
+	/*
+	 * Allocate an ESRT with the sufficient number of entries to accommodate
+	 * all the FMPs in the system.
+	 */
+	ret = efi_esrt_allocate_install(num_entries);
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("ESRT failed to initialize table\n");
+		goto out;
+	}
+
+	/*
+	 * Populate the ESRT entries with all existing FMP.
+	 */
+	it_handle = base_handle;
+	for (u32 idx = 0; idx < no_handles; idx++, it_handle++) {
+		ret = EFI_CALL(efi_search_protocol(*it_handle,
+						   &efi_guid_firmware_management_protocol,
+						   &handler));
+
+		if (ret != EFI_SUCCESS) {
+			EFI_PRINT("ESRT unable to find FMP handle (%d)\n",
+				  idx);
+			break;
+		}
+		fmp = handler->protocol_interface;
+
+		ret = efi_esrt_add_from_fmp(fmp);
+		if (ret != EFI_SUCCESS)
+			EFI_PRINT("ESRT failed to add FMP to the table\n");
+	}
+
+out:
+
+	EFI_CALL(efi_free_pool(base_handle));
+
+	return ret;
+}
+
+/**
+ * efi_esrt_new_fmp_notify() - Callback for the EVT_NOTIFY_SIGNAL event raised
+ * when a new FMP protocol instance is registered in the system.
+ */
+static void EFIAPI efi_esrt_new_fmp_notify(struct efi_event *event,
+					   void *context)
+{
+	efi_status_t ret;
+
+	EFI_ENTRY();
+
+	ret = efi_esrt_populate();
+	if (ret != EFI_SUCCESS)
+		EFI_PRINT("ESRT failed to populate ESRT entry\n");
+
+	EFI_EXIT(ret);
+}
+
+/**
+ * efi_esrt_register() - Install the ESRT system table.
+ *
+ * Return: status code
+ */
+efi_status_t efi_esrt_register(void)
+{
+	struct efi_event *ev = NULL;
+	void *registration;
+	efi_status_t ret;
+
+	EFI_PRINT("ESRT creation start\n");
+
+	ret = efi_esrt_populate();
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("ESRT failed to initiate the table\n");
+		return ret;
+	}
+
+	ret = EFI_CALL(efi_create_event(EVT_NOTIFY_SIGNAL, TPL_CALLBACK,
+					efi_esrt_new_fmp_notify, NULL, NULL, &ev));
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("ESRT failed to create event\n");
+		return ret;
+	}
+
+	ret = EFI_CALL(efi_register_protocol_notify(&efi_guid_firmware_management_protocol,
+						    ev, &registration));
+	if (ret != EFI_SUCCESS) {
+		EFI_PRINT("ESRT failed to register FMP callback\n");
+		return ret;
+	}
+
+	EFI_PRINT("ESRT table created\n");
+
+	return ret;
+}
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
index b1c5125..3c5cf9a 100644
--- a/lib/efi_loader/efi_setup.c
+++ b/lib/efi_loader/efi_setup.c
@@ -227,6 +227,12 @@ efi_status_t efi_init_obj_list(void)
 	if (ret != EFI_SUCCESS)
 		goto out;
 
+	if (IS_ENABLED(CONFIG_EFI_ESRT)) {
+		ret = efi_esrt_register();
+		if (ret != EFI_SUCCESS)
+			goto out;
+	}
+
 	if (IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)) {
 		ret = efi_tcg2_register();
 		if (ret != EFI_SUCCESS)