[U-Boot] [RFC 2/6] efi: add RuntimeServicesSupported variable

[Heinrich Schuchardt]

On 6/13/19 9:06 AM, AKASHI Takahiro wrote:
> On Thu, Jun 13, 2019 at 07:56:19AM +0200, Heinrich Schuchardt wrote:
>>
>>
>> On 6/5/19 6:21 AM, AKASHI Takahiro wrote:
>>> This variable is defined in UEFI specification 2.8, section 8.1.
>>> Its value should be updated whenever we add any usable runtime services
>>> function.
>>
>> It is also required by the EBBR specification.
>>
>>>
>>> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
>>> ---
>>>  include/efi_api.h            | 15 +++++++++++++++
>>>  include/efi_loader.h         |  3 +++
>>>  lib/efi_loader/efi_runtime.c | 28 ++++++++++++++++++++++++++++
>>>  lib/efi_loader/efi_setup.c   |  5 +++++
>>>  4 files changed, 51 insertions(+)
>>>
>>> diff --git a/include/efi_api.h b/include/efi_api.h
>>> index 65584dd2d82a..d7d95edd4dfc 100644
>>> --- a/include/efi_api.h
>>> +++ b/include/efi_api.h
>>> @@ -213,6 +213,21 @@ struct efi_capsule_header {
>>>  	u32 capsule_image_size;
>>>  };
>>>
>>> +#define EFI_RT_SUPPORTED_GET_TIME			0x0001
>>> +#define EFI_RT_SUPPORTED_SET_TIME			0x0002
>>> +#define EFI_RT_SUPPORTED_GET_WAKEUP_TIME		0x0004
>>> +#define EFI_RT_SUPPORTED_SET_WAKEUP_TIME		0x0008
>>> +#define EFI_RT_SUPPORTED_GET_VARIABLE			0x0010
>>> +#define EFI_RT_SUPPORTED_GET_NEXT_VARIABLE_NAME		0x0020
>>> +#define EFI_RT_SUPPORTED_SET_VARIABLE			0x0040
>>> +#define EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP	0x0080
>>> +#define EFI_RT_SUPPORTED_CONVERT_POINTER		0x0100
>>> +#define EFI_RT_SUPPORTED_GET_NEXT_HIGH_MONOTONIC_COUNT	0x0200
>>> +#define EFI_RT_SUPPORTED_RESET_SYSTEM			0x0400
>>> +#define EFI_RT_SUPPORTED_UPDATE_CAPSULE			0x0800
>>> +#define EFI_RT_SUPPORTED_QUERY_CAPSULE_CAPABILITIES	0x1000
>>> +#define EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO		0x2000
>>> +
>>>  struct efi_runtime_services {
>>>  	struct efi_table_hdr hdr;
>>>  	efi_status_t (EFIAPI *get_time)(struct efi_time *time,
>>> diff --git a/include/efi_loader.h b/include/efi_loader.h
>>> index 23ce73226762..7bd8002e303e 100644
>>> --- a/include/efi_loader.h
>>> +++ b/include/efi_loader.h
>>> @@ -573,6 +573,9 @@ static inline int guidcmp(const efi_guid_t *g1, const efi_guid_t *g2)
>>>  #define __efi_runtime_data __attribute__ ((section (".data.efi_runtime")))
>>>  #define __efi_runtime __attribute__ ((section (".text.efi_runtime")))
>>>
>>> +/* Indicate supported runtime services */
>>> +efi_status_t efi_init_runtime_supported(void);
>>> +
>>>  /* Update CRC32 in table header */
>>>  void __efi_runtime efi_update_table_header_crc32(struct efi_table_hdr *table);
>>>
>>> diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
>>> index 60442cb21d37..cf202bb9ec07 100644
>>> --- a/lib/efi_loader/efi_runtime.c
>>> +++ b/lib/efi_loader/efi_runtime.c
>>> @@ -89,6 +89,34 @@ struct elf_rela {
>>>   * handle a good number of runtime callbacks
>>>   */
>>>
>>> +efi_status_t efi_init_runtime_supported(void)
>>> +{
>>> +	u16 efi_runtime_services_supported;
>>> +
>>> +	/*
>>> +	 * This value must be synced with efi_runtime_detach_list
>>> +	 * as well as efi_runtime_services.
>>> +	 */
>>> +	efi_runtime_services_supported = EFI_RT_SUPPORTED_RESET_SYSTEM;
>>
>> This support is system dependent, e.g. on RK3288 systems it does not exist.
>
> efi_reset_system() is defined as a weak function and so
> there is no easy way to determine whether this API is supported or not.
>
>>> +#ifdef CONFIG_EFI_GET_TIME
>>> +	efi_runtime_services_supported |= EFI_RT_SUPPORTED_GET_TIME;
>>
>> We do not support this at runtime.
>
> Okay, I will drop it.
>
>>> +#endif
>>> +#ifdef CONFIG_EFI_SET_TIME
>>> +	efi_runtime_services_supported |= EFI_RT_SUPPORTED_SET_TIME;
>>
>> We do not support this at runtime.
>
> ditto
>
>>> +#endif
>>> +#ifdef CONFIG_EFI_RUNTIME_SET_VIRTUAL_ADDRESS_MAP
>>> +	efi_runtime_services_supported |=
>>> +				EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP;
>>
>> Our support is incomplete as we have not implemented ConvertPointer().
>
> Incomplete?
> My patch#3 adds ConvertPointer().

That is a later patch. So I did not consider it for this patch.
Furthermore the implementation of ConvertPointer depends on
CONFIG_EFI_RUNTIME_CONVERT_POINTER.

Best regards

Heinrich

>
> -Takahiro Akashi
>
>> For unsupported services we will have to change the return value to
>> EFI_UNSUPPORTED. But that will be a separate patch.
>>
>> Best regards
>>
>> Heinrich
>>
>>> +#endif
>>> +
>>> +	return EFI_CALL(efi_set_variable(L"RuntimeServicesSupported",
>>> +					 &efi_global_variable_guid,
>>> +					 EFI_VARIABLE_BOOTSERVICE_ACCESS |
>>> +					 EFI_VARIABLE_RUNTIME_ACCESS,
>>> +					 sizeof(efi_runtime_services_supported),
>>> +					 &efi_runtime_services_supported));
>>> +}
>>> +
>>>  /**
>>>   * efi_update_table_header_crc32() - Update crc32 in table header
>>>   *
>>> diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
>>> index 45d6aca051f3..75fa344060d5 100644
>>> --- a/lib/efi_loader/efi_setup.c
>>> +++ b/lib/efi_loader/efi_setup.c
>>> @@ -123,6 +123,11 @@ efi_status_t efi_init_obj_list(void)
>>>  	if (ret != EFI_SUCCESS)
>>>  		goto out;
>>>
>>> +	/* Indicate supported runtime services */
>>> +	ret = efi_init_runtime_supported();
>>> +	if (ret != EFI_SUCCESS)
>>> +		goto out;
>>> +
>>>  	/* Initialize system table */
>>>  	ret = efi_initialize_system_table();
>>>  	if (ret != EFI_SUCCESS)
>>>
>