diff mbox series

[v3,4/4] efi: add EFI_DEBUG_IMAGE_INFO for debug

Message ID 20250522011749.3498970-5-paulliu@debian.org
State New
Headers show
Series Add EFI Debug Support Table feature | expand

Commit Message

Ying-Chun Liu (PaulLiu) May 22, 2025, 1:17 a.m. UTC
From: "Ying-Chun Liu (PaulLiu)" <paul.liu@linaro.org>

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.

Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Peter Robinson <pbrobinson@gmail.com>
---
V2: use Kconfig options to turn on/off this feature.
V3: Use efi_realloc to realloc the tables. Move tables to boot time.
---
 include/efi_api.h             |   2 +
 include/efi_loader.h          |   5 ++
 lib/efi_loader/efi_boottime.c | 142 ++++++++++++++++++++++++++++++++++
 3 files changed, 149 insertions(+)
diff mbox series

Patch

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 ff7ca5a0480..649bfc36f22 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -650,6 +650,11 @@  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 5a4349f8679..58fe3416817 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -2129,6 +2129,14 @@  efi_status_t EFIAPI efi_load_image(bool boot_policy,
 		*image_handle = NULL;
 		free(info);
 	}
+
+	if (IS_ENABLED(CONFIG_EFI_DEBUG_SUPPORT_TABLE)) {
+		if (*image_handle) {
+			efi_core_new_debug_image_info_entry(EFI_DEBUG_IMAGE_INFO_TYPE_NORMAL,
+							    info,
+							    *image_handle);
+		}
+	}
 error:
 	return EFI_EXIT(ret);
 }
@@ -3359,6 +3367,9 @@  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_TABLE)) {
+		efi_core_remove_debug_image_info_entry(image_handle);
+	}
 	switch (efiobj->type) {
 	case EFI_OBJECT_TYPE_STARTED_IMAGE:
 		/* Call the unload function */
@@ -4038,6 +4049,13 @@  efi_status_t efi_initialize_system_table(void)
 	return ret;
 }
 
+/* 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() - Initialize system table pointer
  *
@@ -4081,3 +4099,127 @@  efi_status_t efi_initialize_system_table_pointer(void)
 
 	return ret;
 }
+
+/**
+ * Add a new efi_loaded_image structure to the efi_debug_image_info Table.
+ * Re-Allocates the table if it's not large enough to accomidate another
+ * entry.
+ *
+ * @param image_info_type  type of debug image information
+ * @param loaded_image     pointer to the loaded image protocol for the image
+ *                         being loaded
+ * @param image_handle     image handle for the image being loaded
+ * @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;
+	union efi_debug_image_info *new_table;
+	u32 index;
+	u32 table_size;
+
+	/* 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;
+
+		new_table = efi_realloc(table, table_size + EFI_PAGE_SIZE);
+
+		if (!new_table) {
+			efi_m_debug_info_table_header.update_status &=
+				~EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
+			return EFI_OUT_OF_RESOURCES;
+		}
+
+		/* Update the table header. */
+		table = new_table;
+		efi_m_debug_info_table_header.efi_debug_image_info_table =
+			new_table;
+
+		/* 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. */
+	efi_allocate_pool(EFI_BOOT_SERVICES_DATA,
+			  sizeof(union efi_debug_image_info),
+			  (void **)(&table[index].normal_image));
+	if (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;
+	}
+
+	efi_m_debug_info_table_header.update_status &=
+		~EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
+
+	return EFI_SUCCESS;
+}
+
+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);
+
+			memcpy(&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;
+}