efi: add EFI_DEBUG_IMAGE_INFO for debug

This commit adds the functionality of generate EFI_DEBUG_IMAGE_INFO
while loading the image.

This feature is described in UEFI Spec 2.10. Section 18.4.3.
The implementation ensures support for hardware-assisted debugging and
provides a standardized mechanism for debuggers to discover the load
address of an EFI application.

Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Peter Robinson <pbrobinson@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Tested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

4 files changed, 151 insertions, 0 deletions

diff --git a/include/efi_api.h b/include/efi_api.h
index 8da0a350ce3..77a05f752e5 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -581,6 +581,8 @@ struct efi_loaded_image {
 #define EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS 0x01
 #define EFI_DEBUG_IMAGE_INFO_TABLE_MODIFIED     0x02
 
+#define EFI_DEBUG_IMAGE_INFO_TYPE_NORMAL  0x01
+
 /**
  * struct efi_debug_image_info_normal - Store Debug Information for normal
  * image.
diff --git a/include/efi_loader.h b/include/efi_loader.h
index b60ea58d71f..3e70ac07055 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -647,6 +647,11 @@ efi_status_t efi_root_node_register(void);
 efi_status_t efi_initialize_system_table(void);
 /* Called by bootefi to initialize debug */
 efi_status_t efi_initialize_system_table_pointer(void);
+/* Called by efi_load_image for register debug info */
+efi_status_t efi_core_new_debug_image_info_entry(u32 image_info_type,
+						 struct efi_loaded_image *loaded_image,
+						 efi_handle_t image_handle);
+void efi_core_remove_debug_image_info_entry(efi_handle_t image_handle);
 /* efi_runtime_detach() - detach unimplemented runtime functions */
 void efi_runtime_detach(void);
 /* efi_convert_pointer() - convert pointer to virtual address */
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 754bc6a6519..ddc935d2240 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -2130,6 +2130,11 @@ efi_status_t EFIAPI efi_load_image(bool boot_policy,
 		*image_handle = NULL;
 		free(info);
 	}
+
+	if (IS_ENABLED(CONFIG_EFI_DEBUG_SUPPORT) && *image_handle)
+		efi_core_new_debug_image_info_entry(EFI_DEBUG_IMAGE_INFO_TYPE_NORMAL,
+						    info,
+						    *image_handle);
 error:
 	return EFI_EXIT(ret);
 }
@@ -3360,6 +3365,8 @@ efi_status_t EFIAPI efi_unload_image(efi_handle_t image_handle)
 		ret = EFI_INVALID_PARAMETER;
 		goto out;
 	}
+	if (IS_ENABLED(CONFIG_EFI_DEBUG_SUPPORT))
+		efi_core_remove_debug_image_info_entry(image_handle);
 	switch (efiobj->type) {
 	case EFI_OBJECT_TYPE_STARTED_IMAGE:
 		/* Call the unload function */
diff --git a/lib/efi_loader/efi_debug_support.c b/lib/efi_loader/efi_debug_support.c
index 597592fbd1c..186bdbce750 100644
--- a/lib/efi_loader/efi_debug_support.c
+++ b/lib/efi_loader/efi_debug_support.c
@@ -17,6 +17,13 @@ struct efi_debug_image_info_table_header efi_m_debug_info_table_header = {
 	NULL
 };
 
+/* efi_m_max_table_entries is the maximum entries allocated for
+ * the efi_m_debug_info_table_header.efi_debug_image_info_table.
+ */
+static u32 efi_m_max_table_entries;
+
+#define EFI_DEBUG_TABLE_ENTRY_SIZE  (sizeof(union efi_debug_image_info *))
+
 /**
  * efi_initialize_system_table_pointer() - Initialize system table pointer
  *
@@ -44,3 +51,133 @@ efi_status_t efi_initialize_system_table_pointer(void)
 
 	return EFI_SUCCESS;
 }
+
+/**
+ * efi_core_new_debug_image_info_entry() - Add a new efi_loaded_image structure to the
+ *                                         efi_debug_image_info table.
+ *
+ * @image_info_type: type of debug image information
+ * @loaded_image:    pointer to the loaded image protocol for the image
+ *                   being loaded
+ * @image_handle:    image handle for the image being loaded
+ *
+ * Re-Allocates the table if it's not large enough to accommodate another
+ * entry.
+ *
+ * Return: status code
+ **/
+efi_status_t efi_core_new_debug_image_info_entry(u32 image_info_type,
+						 struct efi_loaded_image *loaded_image,
+						 efi_handle_t image_handle)
+{
+	union efi_debug_image_info **table;
+	u32 index;
+	u32 table_size;
+	efi_status_t ret;
+
+	/* Set the flag indicating that we're in the process of updating
+	 * the table.
+	 */
+	efi_m_debug_info_table_header.update_status |=
+		EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
+
+	table = &efi_m_debug_info_table_header.efi_debug_image_info_table;
+
+	if (efi_m_debug_info_table_header.table_size >= efi_m_max_table_entries) {
+		/* table is full, re-allocate the buffer increasing the size
+		 * by 4 KiB.
+		 */
+		table_size = efi_m_max_table_entries * EFI_DEBUG_TABLE_ENTRY_SIZE;
+
+		ret = efi_realloc((void **)table, table_size + EFI_PAGE_SIZE);
+
+		if (ret != EFI_SUCCESS) {
+			efi_m_debug_info_table_header.update_status &=
+				~EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
+			return ret;
+		}
+
+		/* Enlarge the max table entries and set the first empty
+		 * entry index to be the original max table entries.
+		 */
+		efi_m_max_table_entries +=
+			EFI_PAGE_SIZE / EFI_DEBUG_TABLE_ENTRY_SIZE;
+	}
+
+	/* We always put the next entry at the end of the currently consumed
+	 * table (i.e. first free entry)
+	 */
+	index = efi_m_debug_info_table_header.table_size;
+
+	/* Allocate data for new entry. */
+	ret = efi_allocate_pool(EFI_BOOT_SERVICES_DATA,
+				sizeof(union efi_debug_image_info),
+				(void **)(&(*table)[index].normal_image));
+	if (ret == EFI_SUCCESS && (*table)[index].normal_image) {
+		/* Update the entry. */
+		(*table)[index].normal_image->image_info_type = image_info_type;
+		(*table)[index].normal_image->loaded_image_protocol_instance =
+			loaded_image;
+		(*table)[index].normal_image->image_handle = image_handle;
+
+		/* Increase the number of EFI_DEBUG_IMAGE_INFO elements and
+		 * set the efi_m_debug_info_table_header in modified status.
+		 */
+		efi_m_debug_info_table_header.table_size++;
+		efi_m_debug_info_table_header.update_status |=
+			EFI_DEBUG_IMAGE_INFO_TABLE_MODIFIED;
+	} else {
+		log_err("Adding new efi_debug_image_info failed\n");
+		return ret;
+	}
+
+	efi_m_debug_info_table_header.update_status &=
+		~EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
+
+	return EFI_SUCCESS;
+}
+
+/**
+ * efi_core_remove_debug_image_info_entry() - Remove an efi_debug_image_info entry.
+ *
+ * @image_handle:    image handle for the image being removed
+ **/
+void efi_core_remove_debug_image_info_entry(efi_handle_t image_handle)
+{
+	union efi_debug_image_info *table;
+	u32 index;
+
+	efi_m_debug_info_table_header.update_status |=
+		EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
+
+	table = efi_m_debug_info_table_header.efi_debug_image_info_table;
+
+	for (index = 0; index < efi_m_max_table_entries; index++) {
+		if (table[index].normal_image &&
+		    table[index].normal_image->image_handle == image_handle) {
+			/* Found a match. Free up the table entry.
+			 * Move the tail of the table one slot to the front.
+			 */
+			efi_free_pool(table[index].normal_image);
+
+			memmove(&table[index],
+				&table[index + 1],
+				(efi_m_debug_info_table_header.table_size -
+				 index - 1) * EFI_DEBUG_TABLE_ENTRY_SIZE);
+
+			/* Decrease the number of EFI_DEBUG_IMAGE_INFO
+			 * elements and set the efi_m_debug_info_table_header
+			 * in modified status.
+			 */
+			efi_m_debug_info_table_header.table_size--;
+			table[efi_m_debug_info_table_header.table_size].normal_image =
+				NULL;
+			efi_m_debug_info_table_header.update_status |=
+				EFI_DEBUG_IMAGE_INFO_TABLE_MODIFIED;
+			break;
+		}
+	}
+
+	efi_m_debug_info_table_header.update_status &=
+		~EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
+}