Detailed Description

Author: Peter Kietzmann peter.nosp@m..kie.nosp@m.tzman.nosp@m.n@ha.nosp@m.w-ham.nosp@m.burg.nosp@m..de

Definition in file puf_sram.h.

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

Include dependency graph for puf_sram.h:

Macros
#define	SEED_RAM_LEN (2048 / sizeof(uint32_t))
	SRAM length considered for seeding.

#define	PUF_SRAM_MARKER (0xad3021ff)
	SRAM marker to detect reboot without power-off.

Functions
void	puf_sram_init (const uint8_t *ram, size_t len)
	checks source of reboot by `puf_sram_softreset` and conditionally calls `puf_sram_generate`

void	puf_sram_generate (const uint8_t *ram, size_t len)
	builds hash from `SEED_RAM_LEN` bytes uninitialized SRAM, writes it to the global variable `puf_sram_seed` and returns the value

bool	puf_sram_softreset (void)
	checks for a memory marker to determine whether memory contains old data.

Variables
uint32_t	puf_sram_seed
	Global seed variable, allocated in puf_sram.c.

uint32_t	puf_sram_state
	Global seed state, allocated in puf_sram.c 0 means seed was generated from SRAM pattern, 1 means missing power cycle detected, 2 means power cycle detected.

uint32_t	puf_sram_softreset_cnt
	Counter variable allocated in puf_sram.c.

Macros