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efi/libstub: Describe RNG functions

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Provide descriptions for the functions invoking the EFI_RNG_PROTOCOL.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Link: https://lore.kernel.org/r/20200221114716.4372-1-xypron.glpk@gmx.de
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Heinrich Schuchardt 2020-02-21 12:47:16 +01:00 committed by Ard Biesheuvel
parent 0255973bd6
commit ba832f68dc
1 changed files with 24 additions and 0 deletions
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24
drivers/firmware/efi/libstub/random.c
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@ -25,6 +25,17 @@ union efi_rng_protocol {
} mixed_mode;
};
/**
* efi_get_random_bytes() - fill a buffer with random bytes
* @size: size of the buffer
* @out: caller allocated buffer to receive the random bytes
*
* The call will fail if either the firmware does not implement the
* EFI_RNG_PROTOCOL or there are not enough random bytes available to fill
* the buffer.
*
* Return: status code
*/
efi_status_t efi_get_random_bytes(unsigned long size, u8 *out)
{
efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;
@ -38,6 +49,19 @@ efi_status_t efi_get_random_bytes(unsigned long size, u8 *out)
return efi_call_proto(rng, get_rng, NULL, size, out);
}
/**
* efi_random_get_seed() - provide random seed as configuration table
*
* The EFI_RNG_PROTOCOL is used to read random bytes. These random bytes are
* saved as a configuration table which can be used as entropy by the kernel
* for the initialization of its pseudo random number generator.
*
* If the EFI_RNG_PROTOCOL is not available or there are not enough random bytes
* available, the configuration table will not be installed and an error code
* will be returned.
*
* Return: status code
*/
efi_status_t efi_random_get_seed(void)
{
efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;