[PATCH v5 4/4] efi: add EFI_DEBUG_IMAGE_INFO for debug
Ying-Chun Liu (PaulLiu)
paulliu at debian.org
Wed Jun 11 07:08:43 CEST 2025
From: "Ying-Chun Liu (PaulLiu)" <paul.liu at 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 at linaro.org>
Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
Cc: Ilias Apalodimas <ilias.apalodimas at linaro.org>
Cc: Peter Robinson <pbrobinson at gmail.com>
Cc: Simon Glass <sjg at chromium.org>
---
V2: use Kconfig options to turn on/off this feature.
V3: Use efi_realloc to realloc the tables. Move tables to boot time.
V4: Use new efi_realloc().
V5: Fix function comments and move the code into a separate module.
---
include/efi_api.h | 2 +
include/efi_loader.h | 5 ++
lib/efi_loader/efi_boottime.c | 11 +++
lib/efi_loader/efi_debug_support.c | 129 +++++++++++++++++++++++++++++
4 files changed, 147 insertions(+)
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 13ca2ec9a4e..22440b842e3 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 dbebb37dc04..40495c98c18 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)) {
+ 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)) {
+ 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 a6a672bc0e4..468e9e1cc83 100644
--- a/lib/efi_loader/efi_debug_support.c
+++ b/lib/efi_loader/efi_debug_support.c
@@ -16,6 +16,13 @@ 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
*
@@ -50,3 +57,125 @@ 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 accomidate 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. */
+ 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;
+}
--
2.39.5
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