[U-Boot] [RFC 6/6] efi_loader: variable: support runtime variable access via cache

Heinrich Schuchardt xypron.glpk at gmx.de
Mon Jun 17 19:52:34 UTC 2019


On 6/17/19 3:51 AM, AKASHI Takahiro wrote:
> On Sat, Jun 15, 2019 at 09:01:56PM +0200, Heinrich Schuchardt wrote:
>> On 6/5/19 6:21 AM, AKASHI Takahiro wrote:
>>> With this patch, cache buffer for UEFI variables will be created
>>> so that we will still be able to access, at least retrieve,
>>> UEFI variables when we exit from boottime services,
>>>
>>> This feature is a "should" behavior described in EBBR v1.0
>>> section 2.5.3.
>>>
>>> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
>>> ---
>>>   include/efi_loader.h          |  17 ++
>>>   lib/efi_loader/Kconfig        |   9 +
>>>   lib/efi_loader/efi_boottime.c |  10 +-
>>>   lib/efi_loader/efi_runtime.c  |  13 +
>>>   lib/efi_loader/efi_variable.c | 467 ++++++++++++++++++++++++++++++++++
>>>   5 files changed, 515 insertions(+), 1 deletion(-)
>>
>> Please, put the cache into a separate file.
>
> Why?

It is a separate set of functions. In C++ programming you wouldn't put
two classes into the same file.

>
>>>
>>> diff --git a/include/efi_loader.h b/include/efi_loader.h
>>> index 93f7ece814a0..acab657b9d70 100644
>>> --- a/include/efi_loader.h
>>> +++ b/include/efi_loader.h
>>> @@ -620,6 +620,23 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
>>>   				     const efi_guid_t *vendor, u32 attributes,
>>>   				     efi_uintn_t data_size, const void *data);
>>>
>>> +#ifdef CONFIG_EFI_RUNTIME_GET_VARIABLE_CACHING
>>> +efi_status_t efi_freeze_variable_table(void);
>>> +
>>> +/* runtime version of APIs */
>>> +efi_status_t
>>> +__efi_runtime EFIAPI efi_get_variable_runtime(u16 *variable_name,
>>
>> I think one version of the functions serving at runtime and boottime is
>> enough.
>>
>> The cache should be used both at runtime and at boottime.
>
> So do you mean that we should replace the existing "boottime" version
> of get/set_variable with my code (algorithm)?
>
> This is a bit complicated work because we should be able to *udpate*
> UEFI variables at boottime, but my version of hsearch_runtime() is
> a stripped (and modified) version and doesn't support it.

Do we really need a multilevel hash table? I would not expect hundreds
of variables.

>
> Making the existing hsearch_r() executable at UEFI runtime is,
> as I said before, quite painful.

You could start the cache implementation with a less complicated data
structure like a linked list.

>
>> Essentially I
>> expect three modules working together:
>>
>> UEFI API implementation <-> Cache <-> Persistence driver
>>
>> I would suggest to put each of these into a separate file.
>>
>> Both the API implementation and the Cache have to be available at
>> Boottime and at Runtime. A first version of the persistence driver may
>> only be working at boottime.
>
> Unfortunately, this is not practical right now because there is
> already some sort of assumption (and consensus) that we would re-use
> "Standalone MM services", which is already there in EDK2, as
> secure storage for UEFI variables.
> In the case, all the cache would be bypassed.
> In my old prototype, I utilized the cache but dropped that feature
> for several reasons.

What has EDK2 code to do with it?

In case of write you could do a write-through in your cache if needed.

>
>> The NV-cache content should be written to non-volatile memory on Reset()
>> and on ExitBootServices() and if possible when updating variables at
>> runtime.
>
> I'm not sure your intent here, but are you going to write back
> the cache only once?
> It won't work as every change of UEFI variable must be flushed
> to persistent storage instantly.

The cache should support write and read. Only NV variables have to be
written to a medium. If you do not support this currently just return
some error code vor NV variables. But you could accept still accept
changes to non-NV variables. This way we can test the code at runtime
even before implementing runtime persistence.

>
>>> +					      const efi_guid_t *vendor,
>>> +					      u32 *attributes,
>>> +					      efi_uintn_t *data_size,
>>> +					      void *data);
>>> +efi_status_t
>>> +__efi_runtime EFIAPI efi_get_next_variable_name_runtime(
>>> +						efi_uintn_t *variable_name_size,
>>> +						u16 *variable_name,
>>> +						const efi_guid_t *vendor);
>>> +#endif /* CONFIG_EFI_RUNTIME_GET_VARIABLE_CACHING */
>>> +
>>>   /*
>>>    * See section 3.1.3 in the v2.7 UEFI spec for more details on
>>>    * the layout of EFI_LOAD_OPTION.  In short it is:
>>> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
>>> index e2ef43157568..3f284795648f 100644
>>> --- a/lib/efi_loader/Kconfig
>>> +++ b/lib/efi_loader/Kconfig
>>> @@ -59,6 +59,15 @@ config EFI_RUNTIME_CONVERT_POINTER
>>>   	  to be called by UEFI drivers in relocating themselves to virtual
>>>   	  address space.
>>>
>>> +config EFI_RUNTIME_GET_VARIABLE_CACHING
>>> +	bool "runtime_service: GetVariable: Enable runtime access via cache (read-only)"
>>> +	default y
>>> +	help
>>> +	  Select this option if you want to access UEFI variables at
>>> +	  runtime even though you cannot update values on the fly.
>>> +	  With or without this option, you can access UEFI variables
>>> +	  at boottime.
>>
>> Updates of volatile variables should always be possible.
>
> Why "should"?
> Give me any use case.
> UEFI spec does not describe such a variant implementation at all.

See above. I would like to be able to test setting variables at runtime
even if persisting NV variables is not yet implemented.

>
>>> +
>>>   config EFI_DEVICE_PATH_TO_TEXT
>>>   	bool "Device path to text protocol"
>>>   	default y
>>> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
>>> index e4abaf3601d9..14e343abbd43 100644
>>> --- a/lib/efi_loader/efi_boottime.c
>>> +++ b/lib/efi_loader/efi_boottime.c
>>> @@ -1892,6 +1892,9 @@ static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
>>>   						  efi_uintn_t map_key)
>>>   {
>>>   	struct efi_event *evt;
>>> +#ifdef CONFIG_EFI_RUNTIME_GET_VARIABLE_CACHING
>>> +	efi_status_t ret;
>>> +#endif
>>>
>>>   	EFI_ENTRY("%p, %zx", image_handle, map_key);
>>>
>>> @@ -1921,7 +1924,12 @@ static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
>>>   		}
>>>   	}
>>>
>>> -	/* TODO: Should persist EFI variables here */
>>> +#ifdef CONFIG_EFI_RUNTIME_GET_VARIABLE_CACHING
>>
>> Can we have weak functions for initializing and persisting the cache, e.g.
>>
>> efi_status_t __weak
>> efi_load_variable_cache(cache_entry *cache, size_t *size)
>> {
>>          cache->len = 0;
>>          return EFI_SUCCESS;
>> }
>>
>> efi_status_t __runtime __weak
>> efi_write_variable_cache(cache_entry *cache, size_t size)
>> {
>>          return EFI_UNSUPPORTED;
>> }
>>
>> Then we can override these in whatever driver we implement.
>
> What is the difference between yours and my env_efi_load/save()
> with backing-storage driver?

I cannot see that you clearly separate the functions API, cache,
persistence.

I would like to see clearly define interfaces into which we can plug
different persistence implementations.

>
>>
>>> +	/* No more variable update */
>>> +	ret = efi_freeze_variable_table();
>>> +	if (ret != EFI_SUCCESS)
>>> +		return EFI_EXIT(ret);
>>> +#endif
>>>
>>>   	board_quiesce_devices();
>>>
>>> diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
>>> index fc5bdee80e00..b60f70f04613 100644
>>> --- a/lib/efi_loader/efi_runtime.c
>>> +++ b/lib/efi_loader/efi_runtime.c
>>> @@ -111,6 +111,11 @@ efi_status_t efi_init_runtime_supported(void)
>>>   	efi_runtime_services_supported |=
>>>   				EFI_RT_SUPPORTED_CONVERT_POINTER;
>>>   #endif
>>> +#ifdef CONFIG_EFI_RUNTIME_GET_VARIABLE_CACHING
>>> +	efi_runtime_services_supported |=
>>> +				(EFI_RT_SUPPORTED_GET_VARIABLE |
>>> +				 EFI_RT_SUPPORTED_GET_NEXT_VARIABLE_NAME);
>>> +#endif
>>>
>>>   	return EFI_CALL(efi_set_variable(L"RuntimeServicesSupported",
>>>   					 &efi_global_variable_guid,
>>> @@ -469,10 +474,18 @@ static struct efi_runtime_detach_list_struct efi_runtime_detach_list[] = {
>>>   		.patchto = NULL,
>>>   	}, {
>>>   		.ptr = &efi_runtime_services.get_variable,
>>> +#ifdef CONFIG_EFI_RUNTIME_GET_VARIABLE_CACHING
>>> +		.patchto = &efi_get_variable_runtime,
>>> +#else
>>>   		.patchto = &efi_device_error,
>>> +#endif
>>>   	}, {
>>>   		.ptr = &efi_runtime_services.get_next_variable_name,
>>> +#ifdef CONFIG_EFI_RUNTIME_GET_VARIABLE_CACHING
>>> +		.patchto = &efi_get_next_variable_name,
>>> +#else
>>>   		.patchto = &efi_device_error,
>>> +#endif
>>>   	}, {
>>>   		.ptr = &efi_runtime_services.set_variable,
>>>   		.patchto = &efi_device_error,
>>> diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
>>> index d9887be938c2..ee21892dd291 100644
>>> --- a/lib/efi_loader/efi_variable.c
>>> +++ b/lib/efi_loader/efi_variable.c
>>> @@ -706,3 +706,470 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
>>>
>>>   	return EFI_EXIT(ret);
>>>   }
>>> +
>>> +#ifdef CONFIG_EFI_RUNTIME_GET_VARIABLE_CACHING
>>> +/*
>>> + * runtime version of APIs
>>> + * We only support read-only variable access.
>>> + * The table is in U-Boot's hash table format, but has its own
>>> + * _ENTRY structure for specific use.
>>> + *
>>> + * Except for efi_freeze_variable_table(), which is to be called in
>>> + * exit_boot_services(), all the functions and data below must be
>>> + * placed in either RUNTIME_SERVICES_CODE or RUNTIME_SERVICES_DATA.
>>> + */
>>> +typedef struct _ENTRY {
>>> +	unsigned int used;	/* hash value; 0 for not used */
>>> +	size_t name;		/* name offset from itself */
>>> +	efi_guid_t vendor;
>>> +	u32 attributes;
>>> +	size_t data;		/* data offset from itself */
>>> +	size_t data_size;
>>> +} _ENTRY;
>>> +
>>> +static inline u16 *entry_name(_ENTRY *e) { return (void *)e + e->name; }
>>> +static inline u16 *entry_data(_ENTRY *e) { return (void *)e + e->data; }
>>> +
>>> +static struct hsearch_data *efi_variable_table __efi_runtime_data;
>>> +
>>> +static size_t __efi_runtime u16_strlen_runtime(const u16 *s1)
>>
>>
>> Please, do not duplicate existing functions. If they have to be runtime
>> simply change the existing function to __runtime.
>
> We should do that if possible, but please note that [str|mem]xxx() functions
> are *architecture* dependent.
> Do you want to mark all the functions across all the architectures?
>
>>> +{
>>> +	size_t n = 0;
>>> +
>>> +	while (*s1) {
>>> +		n++;
>>> +		s1++;
>>> +	}
>>> +
>>> +	return n;
>>> +}
>>> +
>>> +static int __efi_runtime memcmp_runtime(const void *m1, const void *m2,
>>> +					size_t n)
>>
>> I dislike duplicate code. Can't we simply define the existing memcmp
>> function as __runtime?
>
> ditto
>
>>> +{
>>> +	while (n && *(u8 *)m1 == *(u8 *)m2) {
>>> +		n--;
>>> +		m1++;
>>> +		m2++;
>>> +	}
>>> +
>>> +	if (n)
>>> +		return *(u8 *)m1 - *(u8 *)m2;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static void __efi_runtime memcpy_runtime(void *m1, const void *m2, size_t n)
>>> +{
>>
>> Can't we simply define the existing memcpy function as __runtime?
>>
>>> +	for (; n; n--, m1++, m2++)
>>> +		*(u8 *)m1 = *(u8 *)m2;
>>> +}
>>> +
>>> +static int __efi_runtime efi_cmpkey(_ENTRY *e, const u16 *name,
>>> +				    const efi_guid_t *vendor)
>>> +{
>>> +	size_t name_len;
>>> +
>>> +	name_len = u16_strlen_runtime(entry_name(e));
>>> +
>>> +	/* return zero if matched */
>>> +	return name_len != u16_strlen_runtime(name) ||
>>> +	       memcmp_runtime(entry_name(e), name, name_len * 2) ||
>>> +	       memcmp_runtime(e->vendor.b, vendor->b, sizeof(vendor));
>>> +}
>>> +
>>> +/* simplified and slightly different version of hsearch_r() */
>>
>> These hash functions are so complicated that they really need a unit
>> test testing them rigorously.
>
> Do you know that there are no any tests for hsearch_r()?
> Moreover, this function would better be exercised well
> if we could add *runtime* tests.

Have a look at test/env/hashtable.c

I think efi_selftest could work after SetVirtualMemoryMap if we do not
change the map for memory actually used by U-Boot.

Or we use a minimum Linux kernel and put our tests into an init binary.

>
>>
>>> +static int __efi_runtime hsearch_runtime(const u16 *name,
>>> +					 const efi_guid_t *vendor,
>>> +					 ACTION action,
>>> +					 _ENTRY **retval,
>>> +					 struct hsearch_data *htab)
>>> +{
>>> +	unsigned int hval;
>>> +	unsigned int count;
>>> +	unsigned int len;
>>> +	unsigned int idx, new;
>>> +
>>> +	/* Compute an value for the given string. */
>>> +	len = u16_strlen_runtime(name);
  >>
>> Can't the same variable name exist for different GUIDs? Why is the GUID
>> not considered in the hash?
>
> efi_cmpkey() does take into consideration GUID as well as the name.

My question concerned the hash.

>
>>> +	hval = len;
>>> +	count = len;
>>> +	while (count-- > 0) {
>>> +		hval <<= 4;
>>> +		hval += name[count];
>>> +	}
>>> +
>>> +	/*
>>> +	 * First hash function:
>>> +	 * simply take the modulo but prevent zero.
>>> +	 */
>>> +	hval %= htab->size;
>>> +	if (hval == 0)
>>> +		++hval;
>>> +
>>> +	/* The first index tried. */
>>> +	new = -1; /* not found */
>>> +	idx = hval;
>>> +
>>> +	if (htab->table[idx].used) {
>>> +		/*
>>> +		 * Further action might be required according to the
>>> +		 * action value.
>>> +		 */
>>> +		unsigned int hval2;
>>> +
>>> +		if (htab->table[idx].used == hval &&
>>> +		    !efi_cmpkey(&htab->table[idx], name, vendor)) {
>>> +			if (action == FIND) {
>>> +				*retval = &htab->table[idx];
>>> +				return idx;
>>> +			}
>>> +			/* we don't need to support overwrite */
>>> +			return -1;
>>> +		}
>>> +
>>> +		/*
>>> +		 * Second hash function:
>>> +		 * as suggested in [Knuth]
>>> +		 */
>>> +		hval2 = 1 + hval % (htab->size - 2);
>>> +
>>> +		do {
>>> +			/*
>>> +			 * Because SIZE is prime this guarantees to
>>> +			 * step through all available indices.
>>> +			 */
>>> +			if (idx <= hval2)
>>> +				idx = htab->size + idx - hval2;
>>> +			else
>>> +				idx -= hval2;
>>> +
>>> +			/*
>>> +			 * If we visited all entries leave the loop
>>> +			 * unsuccessfully.
>>> +			 */
>>> +			if (idx == hval)
>>> +				break;
>>> +
>>> +			/* If entry is found use it. */
>>> +			if (htab->table[idx].used == hval &&
>>> +			    !efi_cmpkey(&htab->table[idx], name, vendor)) {
>>> +				if (action == FIND) {
>>> +					*retval = &htab->table[idx];
>>> +					return idx;
>>> +				}
>>> +				/* we don't need to support overwrite */
>>> +				return -1;
>>> +			}
>>> +		} while (htab->table[idx].used);
>>> +
>>> +		if (!htab->table[idx].used)
>>> +			new = idx;
>>> +	} else {
>>> +		new = idx;
>>> +	}
>>> +
>>> +	/*
>>> +	 * An empty bucket has been found.
>>> +	 * The following code should never be executed after
>>> +	 * exit_boot_services()
>>> +	 */
>>> +	if (action == ENTER) {
>>> +		/*
>>> +		 * If table is full and another entry should be
>>> +		 * entered return with error.
>>> +		 */
>>> +		if (htab->filled == htab->size) {
>>> +			*retval = NULL;
>>> +			return 0;
>>> +		}
>>> +
>>> +		/* Create new entry */
>>> +		htab->table[new].used = hval;
>>> +		++htab->filled;
>>> +
>>> +		/* return new entry */
>>> +		*retval = &htab->table[new];
>>> +		return 1;
>>> +	}
>>> +
>>> +	*retval = NULL;
>>> +	return 0;
>>> +}
>>> +
>>> +/* from lib/hashtable.c */
>>> +static inline int isprime(unsigned int number)
>>> +{
>>> +	/* no even number will be passed */
>>> +	unsigned int div = 3;
>>> +
>>> +	while (div * div < number && number % div != 0)
>>> +		div += 2;
>>> +
>>> +	return number % div != 0;
>>> +}
>>> +
>>> +efi_status_t efi_freeze_variable_table(void)
>>
>> Please, add comments to your functions. It is not self-evident what this
>> function is meant to do.
>>
>> I cannot imagine why a variable cache should be frozen. It is a living
>> data structure until the system is switched off.
>
> I don't get your point.

Please, explain what you mean by freeze.

I suggest that the cache is read/write at all times.

Best regards

Heinrich

>
>> For a variable cache I expect that you allocate memory before handling
>> the first variable and never again. At runtime you will not have chance
>> to allocate memory anyway.
>
> I don't get your point.
>
>> This function is way too long. Pleae, break it down.
>
> Freezing is implemented in 2-phase steps, and some complexity
> is inevitable. I suppose adding some comments would be enough.
>
> -Takahiro Akashi
>
>> Best regards
>>
>> Heinrich
>>
>>> +{
>>> +	int var_num = 0;
>>> +	size_t var_data_size = 0;
>>> +	u16 *name;
>>> +	efi_uintn_t name_buf_len, name_len;
>>> +	efi_guid_t vendor;
>>> +	u32 attributes;
>>> +	u8 *mem_pool, *var_buf = NULL;
>>> +	size_t table_size, var_size, var_buf_size;
>>> +	_ENTRY *new = NULL;
>>> +	efi_status_t ret;
>>> +
>>> +	/* phase-1 loop */
>>> +	name_buf_len = 128;
>>> +	name = malloc(name_buf_len);
>>> +	if (!name)
>>> +		return EFI_OUT_OF_RESOURCES;
>>> +	name[0] = 0;
>>> +	for (;;) {
>>> +		name_len = name_buf_len;
>>> +		ret = EFI_CALL(efi_get_next_variable_name(&name_len, name,
>>> +							  &vendor));
>>> +		if (ret == EFI_NOT_FOUND) {
>>> +			break;
>>> +		} else if (ret == EFI_BUFFER_TOO_SMALL) {
>>> +			u16 *buf;
>>> +
>>> +			name_buf_len = name_len;
>>> +			buf = realloc(name, name_buf_len);
>>> +			if (!buf) {
>>> +				free(name);
>>> +				return EFI_OUT_OF_RESOURCES;
>>> +			}
>>> +			name = buf;
>>> +			name_len = name_buf_len;
>>> +			ret = EFI_CALL(efi_get_next_variable_name(&name_len,
>>> +								  name,
>>> +								  &vendor));
>>> +		}
>>> +
>>> +		if (ret != EFI_SUCCESS)
>>> +			return ret;
>>> +
>>> +		var_size = 0;
>>> +		ret = EFI_CALL(efi_get_variable(name, &vendor, &attributes,
>>> +						&var_size, NULL));
>>> +		if (ret != EFI_BUFFER_TOO_SMALL)
>>> +			return ret;
>>> +
>>> +		if (!(attributes & EFI_VARIABLE_RUNTIME_ACCESS))
>>> +			continue;
>>> +
>>> +		var_num++;
>>> +		var_data_size += (u16_strlen_runtime(name) + 1) * sizeof(u16);
>>> +		var_data_size += var_size;
>>> +		/* mem_pool must 2-byte aligned for u16 variable name */
>>> +		if (var_data_size & 0x1)
>>> +			var_data_size++;
>>> +	}
>>> +
>>> +	/*
>>> +	 * total of entries in hash table must be a prime number.
>>> +	 * The logic below comes from lib/hashtable.c
>>> +	 */
>>> +	var_num |= 1;               /* make odd */
>>> +	while (!isprime(var_num))
>>> +		var_num += 2;
>>> +
>>> +	/* We need table[var_num] for hsearch_runtime algo */
>>> +	table_size = sizeof(*efi_variable_table)
>>> +			+ sizeof(_ENTRY) * (var_num + 1) + var_data_size;
>>> +	ret = efi_allocate_pool(EFI_RUNTIME_SERVICES_DATA,
>>> +				table_size, (void **)&efi_variable_table);
>>> +	if (ret != EFI_SUCCESS)
>>> +		return ret;
>>> +
>>> +	efi_variable_table->size = var_num;
>>> +	efi_variable_table->table = (void *)efi_variable_table
>>> +					+ sizeof(*efi_variable_table);
>>> +	mem_pool = (u8 *)efi_variable_table->table
>>> +			+ sizeof(_ENTRY) * (var_num + 1);
>>> +
>>> +	var_buf_size = 128;
>>> +	var_buf = malloc(var_buf_size);
>>> +	if (!var_buf) {
>>> +		ret = EFI_OUT_OF_RESOURCES;
>>> +		goto err;
>>> +	}
>>> +
>>> +	/* phase-2 loop */
>>> +	name[0] = 0;
>>> +	name_len = name_buf_len;
>>> +	for (;;) {
>>> +		name_len = name_buf_len;
>>> +		ret = EFI_CALL(efi_get_next_variable_name(&name_len, name,
>>> +							  &vendor));
>>> +		if (ret == EFI_NOT_FOUND)
>>> +			break;
>>> +		else if (ret != EFI_SUCCESS)
>>> +			goto err;
>>> +
>>> +		var_size = var_buf_size;
>>> +		ret = EFI_CALL(efi_get_variable(name, &vendor, &attributes,
>>> +						&var_size, var_buf));
>>> +		if (ret == EFI_BUFFER_TOO_SMALL) {
>>> +			free(var_buf);
>>> +			var_buf_size = var_size;
>>> +			var_buf = malloc(var_buf_size);
>>> +			if (!var_buf) {
>>> +				ret = EFI_OUT_OF_RESOURCES;
>>> +				goto err;
>>> +			}
>>> +			ret = EFI_CALL(efi_get_variable(name, &vendor,
>>> +							&attributes,
>>> +							&var_size, var_buf));
>>> +		}
>>> +		if (ret != EFI_SUCCESS)
>>> +			goto err;
>>> +
>>> +		if (!(attributes & EFI_VARIABLE_RUNTIME_ACCESS))
>>> +			continue;
>>> +
>>> +		if (hsearch_runtime(name, &vendor, ENTER, &new,
>>> +				    efi_variable_table) <= 0) {
>>> +			/* This should not happen */
>>> +			ret = EFI_INVALID_PARAMETER;
>>> +			goto err;
>>> +		}
>>> +
>>> +		/* allocate space from RUNTIME DATA */
>>> +		name_len = (u16_strlen_runtime(name) + 1) * sizeof(u16);
>>> +		memcpy_runtime(mem_pool, name, name_len);
>>> +		new->name = mem_pool - (u8 *)new; /* offset */
>>> +		mem_pool += name_len;
>>> +
>>> +		memcpy_runtime(&new->vendor.b, &vendor.b, sizeof(vendor));
>>> +
>>> +		new->attributes = attributes;
>>> +
>>> +		memcpy_runtime(mem_pool, var_buf, var_size);
>>> +		new->data = mem_pool - (u8 *)new; /* offset */
>>> +		new->data_size = var_size;
>>> +		mem_pool += var_size;
>>> +
>>> +		/* mem_pool must 2-byte aligned for u16 variable name */
>>> +		if ((uintptr_t)mem_pool & 0x1)
>>> +			mem_pool++;
>>> +	}
>>> +#ifdef DEBUG
>>> +	name[0] = 0;
>>> +	name_len = name_buf_len;
>>> +	for (;;) {
>>> +		name_len = name_buf_len;
>>> +		ret = efi_get_next_variable_name_runtime(&name_len, name,
>>> +							 &vendor);
>>> +		if (ret == EFI_NOT_FOUND)
>>> +			break;
>>> +		else if (ret != EFI_SUCCESS)
>>> +			goto err;
>>> +
>>> +		var_size = var_buf_size;
>>> +		ret = efi_get_variable_runtime(name, &vendor, &attributes,
>>> +					       &var_size, var_buf);
>>> +		if (ret != EFI_SUCCESS)
>>> +			goto err;
>>> +
>>> +		printf("%ls_%pUl:\n", name, &vendor);
>>> +		printf("    attributes: 0x%x\n", attributes);
>>> +		printf("    value (size: 0x%lx)\n", var_size);
>>> +	}
>>> +#endif
>>> +	ret = EFI_SUCCESS;
>>> +
>>> +err:
>>> +	free(name);
>>> +	free(var_buf);
>>> +	if (ret != EFI_SUCCESS && efi_variable_table) {
>>> +		efi_free_pool(efi_variable_table);
>>> +		efi_variable_table = NULL;
>>> +	}
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +efi_status_t
>>> +__efi_runtime EFIAPI efi_get_variable_runtime(u16 *variable_name,
>>> +					      const efi_guid_t *vendor,
>>> +					      u32 *attributes,
>>> +					      efi_uintn_t *data_size,
>>> +					      void *data)
>>> +{
>>> +	_ENTRY *new;
>>> +
>>> +	if (!variable_name || !vendor || !data_size)
>>> +		return EFI_EXIT(EFI_INVALID_PARAMETER);
>>> +
>>> +	if (hsearch_runtime(variable_name, vendor, FIND, &new,
>>> +			    efi_variable_table) <= 0)
>>> +		return EFI_NOT_FOUND;
>>> +
>>> +	if (attributes)
>>> +		*attributes = new->attributes;
>>> +	if (*data_size < new->data_size) {
>>> +		*data_size = new->data_size;
>>> +		return EFI_BUFFER_TOO_SMALL;
>>> +	}
>>> +
>>> +	*data_size = new->data_size;
>>> +	memcpy_runtime(data, entry_data(new), new->data_size);
>>> +
>>> +	return EFI_SUCCESS;
>>> +}
>>> +
>>> +static int prev_idx __efi_runtime_data;
>>> +
>>> +efi_status_t
>>> +__efi_runtime EFIAPI efi_get_next_variable_name_runtime(
>>> +						efi_uintn_t *variable_name_size,
>>> +						u16 *variable_name,
>>> +						const efi_guid_t *vendor)
>>> +{
>>> +	_ENTRY *e;
>>> +	u16 *name;
>>> +	efi_uintn_t name_size;
>>> +
>>> +	if (!variable_name_size || !variable_name || !vendor)
>>> +		return EFI_INVALID_PARAMETER;
>>> +
>>> +	if (variable_name[0]) {
>>> +		/* sanity check for previous variable */
>>> +		if (prev_idx < 0)
>>> +			return EFI_INVALID_PARAMETER;
>>> +
>>> +		e = &efi_variable_table->table[prev_idx];
>>> +		if (!e->used || efi_cmpkey(e, variable_name, vendor))
>>> +			return EFI_INVALID_PARAMETER;
>>> +	} else {
>>> +		prev_idx = -1;
>>> +	}
>>> +
>>> +	/* next variable */
>>> +	while (++prev_idx <= efi_variable_table->size) {
>>> +		e = &efi_variable_table->table[prev_idx];
>>> +		if (e->used)
>>> +			break;
>>> +	}
>>> +	if (prev_idx > efi_variable_table->size)
>>> +		return EFI_NOT_FOUND;
>>> +
>>> +	name = entry_name(e);
>>> +	name_size = (u16_strlen_runtime(name) + 1)
>>> +			* sizeof(u16);
>>> +	if (*variable_name_size < name_size) {
>>> +		*variable_name_size = name_size;
>>> +		return EFI_BUFFER_TOO_SMALL;
>>> +	}
>>> +
>>> +	memcpy_runtime(variable_name, name, name_size);
>>> +	memcpy_runtime((void *)&vendor->b, &e->vendor.b, sizeof(vendor));
>>> +
>>> +	return EFI_SUCCESS;
>>> +}
>>> +#endif /* CONFIG_EFI_RUNTIME_GET_VARIABLE_CACHING */
>>>
>>
>



More information about the U-Boot mailing list