[U-Boot] [PATCH v2 1/1] efi_loader: unload applications upon Exit()

[Heinrich Schuchardt]

Implement unloading of images in the Exit() boot services:

* unload images that are not yet started,
* unload started applications,
* unload drivers returning an error.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
v2
	Images that are no yet started can be unloaded by calling Exit().
	In this case they are not the current image. Move the test for
	current down in the code.

	A started driver that called Exit() should still be considered a
	started image. Exit cannot be called by another image afterwards,
	cf. UEFI SCT 2.6 (2017), 3.5.1 Exit(), 5.1.4.5.8 - 5.1.4.5.10.
---
 include/efi_loader.h              |  1 +
 lib/efi_loader/efi_boottime.c     | 36 +++++++++++++++++++++++++------
 lib/efi_loader/efi_image_loader.c |  2 ++
 3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/include/efi_loader.h b/include/efi_loader.h
index 3b50cd28ef..4e4cffa799 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -234,6 +234,7 @@ struct efi_loaded_image_obj {
 	struct jmp_buf_data exit_jmp;
 	EFIAPI efi_status_t (*entry)(efi_handle_t image_handle,
 				     struct efi_system_table *st);
+	u16 image_type;
 };

 /**
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 0385883ded..1ea96dab6c 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -13,6 +13,7 @@
 #include <linux/libfdt_env.h>
 #include <u-boot/crc.h>
 #include <bootm.h>
+#include <pe.h>
 #include <watchdog.h>

 DECLARE_GLOBAL_DATA_PTR;
@@ -2798,7 +2799,7 @@ static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
 	 *	 image protocol.
 	 */
 	efi_status_t ret;
-	void *info;
+	struct efi_loaded_image *loaded_image_protocol;
 	struct efi_loaded_image_obj *image_obj =
 		(struct efi_loaded_image_obj *)image_handle;

@@ -2806,13 +2807,33 @@ static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
 		  exit_data_size, exit_data);

 	/* Check parameters */
-	if (image_handle != current_image)
-		goto out;
 	ret = EFI_CALL(efi_open_protocol(image_handle, &efi_guid_loaded_image,
-					 &info, NULL, NULL,
+					 (void **)&loaded_image_protocol,
+					 NULL, NULL,
 					 EFI_OPEN_PROTOCOL_GET_PROTOCOL));
-	if (ret != EFI_SUCCESS)
+	if (ret != EFI_SUCCESS) {
+		ret = EFI_INVALID_PARAMETER;
 		goto out;
+	}
+
+	/* Unloading of unstarted images */
+	switch (image_obj->header.type) {
+	case EFI_OBJECT_TYPE_STARTED_IMAGE:
+		break;
+	case EFI_OBJECT_TYPE_LOADED_IMAGE:
+		efi_delete_image(image_obj, loaded_image_protocol);
+		ret = EFI_SUCCESS;
+		goto out;
+	default:
+		/* Handle does not refer to loaded image */
+		ret = EFI_INVALID_PARAMETER;
+		goto out;
+	}
+	/* A started image can only be unloaded it is the last one started. */
+	if (image_handle != current_image) {
+		ret = EFI_INVALID_PARAMETER;
+		goto out;
+	}

 	/* Exit data is only foreseen in case of failure. */
 	if (exit_status != EFI_SUCCESS) {
@@ -2822,6 +2843,9 @@ static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
 		if (ret != EFI_SUCCESS)
 			EFI_PRINT("%s: out of memory\n", __func__);
 	}
+	if (image_obj->image_type == IMAGE_SUBSYSTEM_EFI_APPLICATION ||
+	    exit_status != EFI_SUCCESS)
+		efi_delete_image(image_obj, loaded_image_protocol);

 	/* Make sure entry/exit counts for EFI world cross-overs match */
 	EFI_EXIT(exit_status);
@@ -2837,7 +2861,7 @@ static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,

 	panic("EFI application exited");
 out:
-	return EFI_EXIT(EFI_INVALID_PARAMETER);
+	return EFI_EXIT(ret);
 }

 /**
diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
index f8092b6202..13541cfa7a 100644
--- a/lib/efi_loader/efi_image_loader.c
+++ b/lib/efi_loader/efi_image_loader.c
@@ -273,6 +273,7 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi,
 		IMAGE_OPTIONAL_HEADER64 *opt = &nt64->OptionalHeader;
 		image_base = opt->ImageBase;
 		efi_set_code_and_data_type(loaded_image_info, opt->Subsystem);
+		handle->image_type = opt->Subsystem;
 		efi_reloc = efi_alloc(virt_size,
 				      loaded_image_info->image_code_type);
 		if (!efi_reloc) {
@@ -288,6 +289,7 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi,
 		IMAGE_OPTIONAL_HEADER32 *opt = &nt->OptionalHeader;
 		image_base = opt->ImageBase;
 		efi_set_code_and_data_type(loaded_image_info, opt->Subsystem);
+		handle->image_type = opt->Subsystem;
 		efi_reloc = efi_alloc(virt_size,
 				      loaded_image_info->image_code_type);
 		if (!efi_reloc) {
--
2.20.1