[U-Boot] [RFC v2 10/11] efi_loader: rework bootmgr/bootefi using load_image API

Heinrich Schuchardt xypron.glpk at gmx.de
Fri Apr 12 08:55:42 UTC 2019


On 4/12/19 10:38 AM, AKASHI Takahiro wrote:
> On Fri, Apr 12, 2019 at 07:53:25AM +0200, Heinrich Schuchardt wrote:
>> On 3/27/19 5:40 AM, AKASHI Takahiro wrote:
>>> In the current implementation, bootefi command and EFI boot manager
>>> don't use load_image API, instead, use more primitive and internal
>>> functions. This will introduce duplicated code and potentially
>>> unknown bugs as well as inconsistent behaviours.
>>>
>>> With this patch, do_efibootmgr() and do_boot_efi() are completely
>>> overhauled and re-implemented using load_image API.
>>>
>>> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
>>> ---
>>>  cmd/bootefi.c                 | 199 +++++++++++++++++++---------------
>>>  include/efi_loader.h          |   5 +-
>>>  lib/efi_loader/efi_bootmgr.c  |  43 ++++----
>>>  lib/efi_loader/efi_boottime.c |   1 +
>>>  4 files changed, 138 insertions(+), 110 deletions(-)
>>>
>>> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
>>> index 39a0712af6ad..17dccd718008 100644
>>> --- a/cmd/bootefi.c
>>> +++ b/cmd/bootefi.c
>>> @@ -224,88 +224,43 @@ static efi_status_t efi_install_fdt(const char *fdt_opt)
>>>  /**
>>>   * do_bootefi_exec() - execute EFI binary
>>>   *
>>> - * @efi:		address of the binary
>>> - * @device_path:	path of the device from which the binary was loaded
>>> - * @image_path:		device path of the binary
>>> + * @handle:		handle of loaded image
>>>   * Return:		status code
>>>   *
>>>   * Load the EFI binary into a newly assigned memory unwinding the relocation
>>>   * information, install the loaded image protocol, and call the binary.
>>>   */
>>> -static efi_status_t do_bootefi_exec(void *efi,
>>> -				    struct efi_device_path *device_path,
>>> -				    struct efi_device_path *image_path)
>>> +static efi_status_t do_bootefi_exec(efi_handle_t handle)
>>>  {
>>> -	efi_handle_t mem_handle = NULL;
>>> -	struct efi_device_path *memdp = NULL;
>>> -	efi_status_t ret;
>>>  	struct efi_loaded_image_obj *image_obj = NULL;
>>>  	struct efi_loaded_image *loaded_image_info = NULL;
>>> -
>>> -	/*
>>> -	 * Special case for efi payload not loaded from disk, such as
>>> -	 * 'bootefi hello' or for example payload loaded directly into
>>> -	 * memory via JTAG, etc:
>>> -	 */
>>> -	if (!device_path && !image_path) {
>>> -		printf("WARNING: using memory device/image path, this may confuse some payloads!\n");
>>> -		/* actual addresses filled in after efi_load_pe() */
>>> -		memdp = efi_dp_from_mem(EFI_RESERVED_MEMORY_TYPE, 0, 0);
>>> -		device_path = image_path = memdp;
>>> -		/*
>>> -		 * Grub expects that the device path of the loaded image is
>>> -		 * installed on a handle.
>>> -		 */
>>> -		ret = efi_create_handle(&mem_handle);
>>> -		if (ret != EFI_SUCCESS)
>>> -			return ret; /* TODO: leaks device_path */
>>> -		ret = efi_add_protocol(mem_handle, &efi_guid_device_path,
>>> -				       device_path);
>>> -		if (ret != EFI_SUCCESS)
>>> -			goto err_add_protocol;
>>> -	} else {
>>> -		assert(device_path && image_path);
>>> -	}
>>> -
>>> -	ret = efi_setup_loaded_image(device_path, image_path, &image_obj,
>>> -				     &loaded_image_info);
>>> -	if (ret)
>>> -		goto err_prepare;
>>> +	efi_status_t ret;
>>>
>>>  	/* Transfer environment variable as load options */
>>> -	set_load_options(loaded_image_info, "bootargs");
>>> -
>>> -	/* Load the EFI payload */
>>> -	ret = efi_load_pe(image_obj, efi, loaded_image_info);
>>> +	ret = EFI_CALL(systab.boottime->open_protocol(
>>> +					handle,
>>> +					&efi_guid_loaded_image,
>>> +					(void **)&loaded_image_info,
>>> +					NULL, NULL,
>>> +					EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL));
>>>  	if (ret != EFI_SUCCESS)
>>> -		goto err_prepare;
>>> -
>>> -	if (memdp) {
>>> -		struct efi_device_path_memory *mdp = (void *)memdp;
>>> -		mdp->memory_type = loaded_image_info->image_code_type;
>>> -		mdp->start_address = (uintptr_t)loaded_image_info->image_base;
>>> -		mdp->end_address = mdp->start_address +
>>> -				loaded_image_info->image_size;
>>> -	}
>>> +		goto err;
>>> +	set_load_options(loaded_image_info, "bootargs");
>>>
>>>  	/* we don't support much: */
>>>  	env_set("efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_OsIndicationsSupported",
>>>  		"{ro,boot}(blob)0000000000000000");
>>>
>>>  	/* Call our payload! */
>>> +	image_obj = container_of(handle, struct efi_loaded_image_obj, header);
>> This is not needed, if we remove the debug statement.
>>
>>>  	debug("%s: Jumping to 0x%p\n", __func__, image_obj->entry);
>> That line should go to StartImage() if needed. Please, drop it here.
>>
>>> -	ret = EFI_CALL(efi_start_image(&image_obj->header, NULL, NULL));
>>> +	ret = EFI_CALL(efi_start_image(handle, NULL, NULL));
>>>
>>> -err_prepare:
>>> -	/* image has returned, loaded-image obj goes *poof*: */
>>>  	efi_restore_gd();
>>>  	free(loaded_image_info->load_options);
>>> -	efi_delete_handle(&image_obj->header);
>>> -
>>> -err_add_protocol:
>>> -	if (mem_handle)
>>> -		efi_delete_handle(mem_handle);
>>> +	efi_free_pool(loaded_image_info);
>>
>> Wouldn't this be done by unload_image()?
>
> but we should not call unload_image(), efi_exit() does. Right?
> Yes, correct.

>>>
>>> +err:
>>>  	return ret;
>>>  }
>>>
>>> @@ -319,8 +274,7 @@ err_add_protocol:
>>>   */
>>>  static int do_efibootmgr(const char *fdt_opt)
>>>  {
>>> -	struct efi_device_path *device_path, *file_path;
>>> -	void *addr;
>>> +	efi_handle_t handle;
>>>  	efi_status_t ret;
>>>
>>>  	/* Allow unaligned memory access */
>>> @@ -340,19 +294,21 @@ static int do_efibootmgr(const char *fdt_opt)
>>>  	if (ret != EFI_SUCCESS)
>>>  		return CMD_RET_FAILURE;
>>>
>>> -	addr = efi_bootmgr_load(&device_path, &file_path);
>>> -	if (!addr)
>>> -		return 1;
>>> +	ret = efi_bootmgr_load(&handle);
>>> +	if (ret != EFI_SUCCESS) {
>>> +		printf("EFI boot manager: Cannot load any image\n");
>>> +		return CMD_RET_FAILURE;
>>> +	}
>>>
>>> -	printf("## Starting EFI application at %p ...\n", addr);
>>> -	ret = do_bootefi_exec(addr, device_path, file_path);
>>> -	printf("## Application terminated, r = %lu\n",
>>> -	       ret & ~EFI_ERROR_MASK);
>>> +	ret = do_bootefi_exec(handle);
>>> +	printf("## Application terminated, r = %lu\n", ret & ~EFI_ERROR_MASK);
>>> +
>>> +	EFI_CALL(efi_unload_image(handle));
>>
>> Only applications have to be unloaded, not drivers. Unloading is to be
>> handled by exit(), see UEFI spec.
>
> How do we know whether the loaded image is an application, or driver?

In efi_load_pe() we should evaluate the field opt->Subsystem describing
the "Windows Subsystem". I once started on this but then I saw that
cmd/bootefi.c needed to be cleaned up first:

https://github.com/xypron/u-boot-patches/blob/efi-next/0001-efi_loader-implement-UnloadImage.patch

>
>>>
>>>  	if (ret != EFI_SUCCESS)
>>> -		return 1;
>>> +		return CMD_RET_FAILURE;
>>>
>>> -	return 0;
>>> +	return CMD_RET_SUCCESS;
>>>  }
>>>
>>>  /*
>>> @@ -367,10 +323,14 @@ static int do_efibootmgr(const char *fdt_opt)
>>>   */
>>>  static int do_boot_efi(const char *image_opt, const char *fdt_opt)
>>>  {
>>> -	unsigned long addr;
>>> -	char *saddr;
>>> +	void *image_buf;
>>> +	struct efi_device_path *device_path, *image_path;
>>> +	struct efi_device_path *memdp = NULL, *file_path = NULL;
>>> +	const char *saddr;
>>> +	unsigned long addr, size;
>>> +	const char *size_str;
>>> +	efi_handle_t mem_handle = NULL, handle;
>>>  	efi_status_t ret;
>>> -	unsigned long fdt_addr;
>>>
>>>  	/* Allow unaligned memory access */
>>>  	allow_unaligned();
>>> @@ -390,36 +350,96 @@ static int do_boot_efi(const char *image_opt, const char *fdt_opt)
>>>  		return CMD_RET_FAILURE;
>>>
>>>  #ifdef CONFIG_CMD_BOOTEFI_HELLO
>>> -	if (!strcmp(argv[1], "hello")) {
>>> -		ulong size = __efi_helloworld_end - __efi_helloworld_begin;
>>> -
>>> +	if (!strcmp(image_opt, "hello")) {
>>>  		saddr = env_get("loadaddr");
>>> +		size = __efi_helloworld_end - __efi_helloworld_begin;
>>> +
>>>  		if (saddr)
>>>  			addr = simple_strtoul(saddr, NULL, 16);
>>>  		else
>>>  			addr = CONFIG_SYS_LOAD_ADDR;
>>> -		memcpy(map_sysmem(addr, size), __efi_helloworld_begin, size);
>>> +
>>> +		image_buf = map_sysmem(addr, size);
>>> +		memcpy(image_buf, __efi_helloworld_begin, size);
>>> +
>>> +		device_path = NULL;
>>> +		image_path = NULL;
>>>  	} else
>>>  #endif
>>>  	{
>>> -		saddr = argv[1];
>>> +		saddr = image_opt;
>>> +		size_str = env_get("filesize");
>>> +		if (size_str)
>>> +			size = simple_strtoul(size_str, NULL, 16);
>>> +		else
>>> +			size = 0;
>>>
>>>  		addr = simple_strtoul(saddr, NULL, 16);
>>>  		/* Check that a numeric value was passed */
>>>  		if (!addr && *saddr != '0')
>>>  			return CMD_RET_USAGE;
>>> +
>>> +		image_buf = map_sysmem(addr, size);
>>> +
>>> +		device_path = bootefi_device_path;
>>> +		image_path = bootefi_image_path;
>>> +	}
>>> +
>>> +	if (!device_path && !image_path) {
>>> +		/*
>>> +		 * Special case for efi payload not loaded from disk,
>>> +		 * such as 'bootefi hello' or for example payload
>>> +		 * loaded directly into memory via JTAG, etc:
>>> +		 */
>>> +		printf("WARNING: using memory device/image path, this may confuse some payloads!\n");
>>> +
>>> +		/* actual addresses filled in after efi_load_image() */
>>> +		memdp = efi_dp_from_mem(EFI_RESERVED_MEMORY_TYPE,
>>> +					(uint64_t)image_buf, size);
>>> +		file_path = memdp; /* append(memdp, NULL) */
>>> +
>>> +		/*
>>> +		 * Make sure that device for device_path exist
>>> +		 * in load_image(). Otherwise, shell and grub will fail.
>>> +		 */
>>> +		ret = efi_create_handle(&mem_handle);
>>> +		if (ret != EFI_SUCCESS)
>>> +			/* TODO: leaks device_path */
>>> +			goto err_add_protocol;
>>> +
>>> +		ret = efi_add_protocol(mem_handle, &efi_guid_device_path,
>>> +				       memdp);
>>> +		if (ret != EFI_SUCCESS)
>>> +			goto err_add_protocol;
>>> +	} else {
>>> +		assert(device_path && image_path);
>>> +		file_path = efi_dp_append(device_path, image_path);
>>>  	}
>>>
>>> +	ret = EFI_CALL(efi_load_image(false, (void *)0x1 /* FIXME */,
>>> +				      file_path, image_buf, size, &handle));
>>> +	if (ret != EFI_SUCCESS)
>>> +		goto err_prepare;
>>> +
>>>  	printf("## Starting EFI application at %08lx ...\n", addr);
>>> -	ret = do_bootefi_exec(map_sysmem(addr, 0), bootefi_device_path,
>>> -			      bootefi_image_path);
>>> -	printf("## Application terminated, r = %lu\n",
>>> -	       ret & ~EFI_ERROR_MASK);
>>> +	ret = do_bootefi_exec(handle);
>>> +	printf("## Application terminated, r = %lu\n", ret & ~EFI_ERROR_MASK);
>>
>> Why should we need all this duplicate code. Cant we move that to
>> do_bootefi_exec()?
>>
>>> +
>>> +	EFI_CALL(efi_unload_image(handle));
>>
>> That is the task of efi_exit().
>
> Who should be blamed for reclaiming a handle which is created
> with load_image()?
> What if an application doesn't call efi_exit() by itself?

When the last protocol interface is deleted from a handle via
UninstallProtocolInterface() the handle is deleted.

Best regards

Heinrich

>
> -Takahiro Akashi
>
>
>> Best regards
>>
>> Heinrich
>>
>>> +err_prepare:
>>> +	if (device_path)
>>> +		efi_free_pool(file_path);
>>> +
>>> +err_add_protocol:
>>> +	if (mem_handle)
>>> +		efi_delete_handle(mem_handle);
>>> +	if (memdp)
>>> +		efi_free_pool(memdp);
>>>
>>>  	if (ret != EFI_SUCCESS)
>>>  		return CMD_RET_FAILURE;
>>> -	else
>>> -		return CMD_RET_SUCCESS;
>>> +
>>> +	return CMD_RET_SUCCESS;
>>>  }
>>>
>>>  #ifdef CONFIG_CMD_BOOTEFI_SELFTEST
>>> @@ -577,7 +597,7 @@ static char bootefi_help_text[] =
>>>  	"    Use environment variable efi_selftest to select a single test.\n"
>>>  	"    Use 'setenv efi_selftest list' to enumerate all tests.\n"
>>>  #endif
>>> -	"bootefi bootmgr [fdt addr]\n"
>>> +	"bootefi bootmgr [fdt address]\n"
>>>  	"  - load and boot EFI payload based on BootOrder/BootXXXX variables.\n"
>>>  	"\n"
>>>  	"    If specified, the device tree located at <fdt address> gets\n"
>>> @@ -602,6 +622,13 @@ void efi_set_bootdev(const char *dev, const char *devnr, const char *path)
>>>  	ret = efi_dp_from_name(dev, devnr, path, &device, &image);
>>>  	if (ret == EFI_SUCCESS) {
>>>  		bootefi_device_path = device;
>>> +		if (image) {
>>> +			/* FIXME: image should not contain device */
>>> +			struct efi_device_path *image_tmp = image;
>>> +
>>> +			efi_dp_split_file_path(image, &device, &image);
>>> +			efi_free_pool(image_tmp);
>>> +		}
>>>  		bootefi_image_path = image;
>>>  	} else {
>>>  		bootefi_device_path = NULL;
>>> diff --git a/include/efi_loader.h b/include/efi_loader.h
>>> index 6dfa2fef3cf0..6c09a7f40d02 100644
>>> --- a/include/efi_loader.h
>>> +++ b/include/efi_loader.h
>>> @@ -410,8 +410,6 @@ efi_status_t efi_setup_loaded_image(struct efi_device_path *device_path,
>>>  				    struct efi_device_path *file_path,
>>>  				    struct efi_loaded_image_obj **handle_ptr,
>>>  				    struct efi_loaded_image **info_ptr);
>>> -efi_status_t efi_load_image_from_path(struct efi_device_path *file_path,
>>> -				      void **buffer, efi_uintn_t *size);
>>>  /* Print information about all loaded images */
>>>  void efi_print_image_infos(void *pc);
>>>
>>> @@ -565,8 +563,7 @@ struct efi_load_option {
>>>
>>>  void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data);
>>>  unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data);
>>> -void *efi_bootmgr_load(struct efi_device_path **device_path,
>>> -		       struct efi_device_path **file_path);
>>> +efi_status_t efi_bootmgr_load(efi_handle_t *handle);
>>>
>>>  #else /* CONFIG_IS_ENABLED(EFI_LOADER) */
>>>
>>> diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
>>> index 4fccadc5483d..13ec79b2098b 100644
>>> --- a/lib/efi_loader/efi_bootmgr.c
>>> +++ b/lib/efi_loader/efi_bootmgr.c
>>> @@ -120,14 +120,14 @@ static void *get_var(u16 *name, const efi_guid_t *vendor,
>>>   * if successful.  This checks that the EFI_LOAD_OPTION is active (enabled)
>>>   * and that the specified file to boot exists.
>>>   */
>>> -static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
>>> -			    struct efi_device_path **file_path)
>>> +static efi_status_t try_load_entry(u16 n, efi_handle_t *handle)
>>>  {
>>>  	struct efi_load_option lo;
>>>  	u16 varname[] = L"Boot0000";
>>>  	u16 hexmap[] = L"0123456789ABCDEF";
>>> -	void *load_option, *image = NULL;
>>> +	void *load_option;
>>>  	efi_uintn_t size;
>>> +	efi_status_t ret;
>>>
>>>  	varname[4] = hexmap[(n & 0xf000) >> 12];
>>>  	varname[5] = hexmap[(n & 0x0f00) >> 8];
>>> @@ -136,19 +136,19 @@ static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
>>>
>>>  	load_option = get_var(varname, &efi_global_variable_guid, &size);
>>>  	if (!load_option)
>>> -		return NULL;
>>> +		return EFI_LOAD_ERROR;
>>>
>>>  	efi_deserialize_load_option(&lo, load_option);
>>>
>>>  	if (lo.attributes & LOAD_OPTION_ACTIVE) {
>>>  		u32 attributes;
>>> -		efi_status_t ret;
>>>
>>>  		debug("%s: trying to load \"%ls\" from %pD\n",
>>>  		      __func__, lo.label, lo.file_path);
>>>
>>> -		ret = efi_load_image_from_path(lo.file_path, &image, &size);
>>> -
>>> +		ret = EFI_CALL(efi_load_image(false, (void *)0x1 /* FIXME */,
>>> +					      lo.file_path, NULL, 0,
>>> +					      handle));
>>>  		if (ret != EFI_SUCCESS)
>>>  			goto error;
>>>
>>> @@ -159,17 +159,22 @@ static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
>>>  				L"BootCurrent",
>>>  				(efi_guid_t *)&efi_global_variable_guid,
>>>  				attributes, size, &n));
>>> -		if (ret != EFI_SUCCESS)
>>> +		if (ret != EFI_SUCCESS) {
>>> +			if (EFI_CALL(efi_unload_image(*handle))
>>> +			    != EFI_SUCCESS)
>>> +				printf("Unloading image failed\n");
>>>  			goto error;
>>> +		}
>>>
>>>  		printf("Booting: %ls\n", lo.label);
>>> -		efi_dp_split_file_path(lo.file_path, device_path, file_path);
>>> +	} else {
>>> +		ret = EFI_LOAD_ERROR;
>>>  	}
>>>
>>>  error:
>>>  	free(load_option);
>>>
>>> -	return image;
>>> +	return ret;
>>>  }
>>>
>>>  /*
>>> @@ -177,12 +182,10 @@ error:
>>>   * EFI variable, the available load-options, finding and returning
>>>   * the first one that can be loaded successfully.
>>>   */
>>> -void *efi_bootmgr_load(struct efi_device_path **device_path,
>>> -		       struct efi_device_path **file_path)
>>> +efi_status_t efi_bootmgr_load(efi_handle_t *handle)
>>>  {
>>>  	u16 bootnext, *bootorder;
>>>  	efi_uintn_t size;
>>> -	void *image = NULL;
>>>  	int i, num;
>>>  	efi_status_t ret;
>>>
>>> @@ -209,10 +212,9 @@ void *efi_bootmgr_load(struct efi_device_path **device_path,
>>>  		/* load BootNext */
>>>  		if (ret == EFI_SUCCESS) {
>>>  			if (size == sizeof(u16)) {
>>> -				image = try_load_entry(bootnext, device_path,
>>> -						       file_path);
>>> -				if (image)
>>> -					return image;
>>> +				ret = try_load_entry(bootnext, handle);
>>> +				if (ret == EFI_SUCCESS)
>>> +					return ret;
>>>  			}
>>>  		} else {
>>>  			printf("Deleting BootNext failed\n");
>>> @@ -223,19 +225,20 @@ void *efi_bootmgr_load(struct efi_device_path **device_path,
>>>  	bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
>>>  	if (!bootorder) {
>>>  		printf("BootOrder not defined\n");
>>> +		ret = EFI_NOT_FOUND;
>>>  		goto error;
>>>  	}
>>>
>>>  	num = size / sizeof(uint16_t);
>>>  	for (i = 0; i < num; i++) {
>>>  		debug("%s: trying to load Boot%04X\n", __func__, bootorder[i]);
>>> -		image = try_load_entry(bootorder[i], device_path, file_path);
>>> -		if (image)
>>> +		ret = try_load_entry(bootorder[i], handle);
>>> +		if (ret == EFI_SUCCESS)
>>>  			break;
>>>  	}
>>>
>>>  	free(bootorder);
>>>
>>>  error:
>>> -	return image;
>>> +	return ret;
>>>  }
>>> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
>>> index 74da6b01054a..8e2fa0111591 100644
>>> --- a/lib/efi_loader/efi_boottime.c
>>> +++ b/lib/efi_loader/efi_boottime.c
>>> @@ -1610,6 +1610,7 @@ failure:
>>>   * @size:	size of the loaded image
>>>   * Return:	status code
>>>   */
>>> +static
>>>  efi_status_t efi_load_image_from_path(struct efi_device_path *file_path,
>>>  				      void **buffer, efi_uintn_t *size)
>>>  {
>>>
>>
>


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