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fw: break out trng and xorwow to rng.[ch]

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This commit is contained in:
Daniel Jobson 2024-09-04 13:43:57 +02:00
parent 5188584fcf
commit 8c0f66282e
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GPG Key ID: 3707A9DBF4BB8F1A
4 changed files with 53 additions and 29 deletions
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9
hw/application_fpga/Makefile
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@ -116,7 +116,8 @@ FIRMWARE_DEPS = \
$(P)/fw/tk1/partition_table.h \
$(P)/fw/tk1/preload_app.h \
$(P)/fw/tk1/auth_app.h \
$(P)/fw/tk1/htif.h
$(P)/fw/tk1/htif.h \
$(P)/fw/tk1/rng.h
FIRMWARE_OBJS = \
$(P)/fw/tk1/main.o \
@ -131,7 +132,8 @@ FIRMWARE_OBJS = \
$(P)/fw/tk1/partition_table.o \
$(P)/fw/tk1/preload_app.o \
$(P)/fw/tk1/auth_app.o \
$(P)/fw/tk1/htif.o
$(P)/fw/tk1/htif.o \
$(P)/fw/tk1/rng.o
FIRMWARE_SOURCES = \
$(P)/fw/tk1/main.c \
@ -145,7 +147,8 @@ FIRMWARE_SOURCES = \
$(P)/fw/tk1/partition_table.c \
$(P)/fw/tk1/preload_app.c \
$(P)/fw/tk1/auth_app.c \
$(P)/fw/tk1/htif.c
$(P)/fw/tk1/htif.c \
$(P)/fw/tk1/rng.c
TESTFW_OBJS = \
$(P)/fw/testfw/main.o \

33
hw/application_fpga/fw/tk1/main.c
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@ -11,6 +11,7 @@
#include "partition_table.h"
#include "preload_app.h"
#include "proto.h"
#include "rng.h"
#include "state.h"
#include <stdbool.h>
@ -28,8 +29,6 @@ static volatile uint32_t *cdi = (volatile uint32_t *)TK1_MMIO_TK1_C
static volatile uint32_t *app_addr = (volatile uint32_t *)TK1_MMIO_TK1_APP_ADDR;
static volatile uint32_t *app_size = (volatile uint32_t *)TK1_MMIO_TK1_APP_SIZE;
static volatile uint32_t *fw_blake2s_addr = (volatile uint32_t *)TK1_MMIO_TK1_BLAKE2S;
static volatile uint32_t *trng_status = (volatile uint32_t *)TK1_MMIO_TRNG_STATUS;
static volatile uint32_t *trng_entropy = (volatile uint32_t *)TK1_MMIO_TRNG_ENTROPY;
static volatile uint32_t *timer = (volatile uint32_t *)TK1_MMIO_TIMER_TIMER;
static volatile uint32_t *timer_prescaler = (volatile uint32_t *)TK1_MMIO_TIMER_PRESCALER;
static volatile uint32_t *timer_status = (volatile uint32_t *)TK1_MMIO_TIMER_STATUS;
@ -49,7 +48,6 @@ struct context {
static void print_hw_version(void);
static void print_digest(uint8_t *md);
static uint32_t rnd_word(void);
static int compute_app_digest(uint8_t *digest);
static void compute_cdi(const uint8_t *digest, const bool use_uss,
const uint8_t *uss);
@ -61,7 +59,6 @@ static enum state loading_commands(const struct frame_header *hdr,
const uint8_t *cmd, enum state state,
struct context *ctx);
static void run(const struct context *ctx);
static uint32_t xorwow(uint32_t state, uint32_t acc);
static void scramble_ram(void);
static void print_hw_version(void)
@ -88,13 +85,6 @@ static void print_digest(uint8_t *md)
htif_lf();
}
static uint32_t rnd_word(void)
{
while ((*trng_status & (1 << TK1_MMIO_TRNG_STATUS_READY_BIT)) == 0) {
}
return *trng_entropy;
}
/* Computes the blake2s digest of the app loaded into RAM */
static int compute_app_digest(uint8_t *digest)
{
@ -115,7 +105,7 @@ static void compute_cdi(const uint8_t *digest, const bool use_uss,
// Prepare to sleep a random number of cycles before reading out UDS
*timer_prescaler = 1;
rnd_sleep = rnd_word();
rnd_sleep = rng_get_word();
// Up to 65536 cycles
rnd_sleep &= 0xffff;
*timer = (uint32_t)(rnd_sleep == 0 ? 1 : rnd_sleep);
@ -381,32 +371,23 @@ static void run(const struct context *ctx)
__builtin_unreachable();
}
static uint32_t xorwow(uint32_t state, uint32_t acc)
{
state ^= state << 13;
state ^= state >> 17;
state ^= state << 5;
state += acc;
return state;
}
static void scramble_ram(void)
{
uint32_t *ram = (uint32_t *)(TK1_RAM_BASE);
// Fill RAM with random data
// Get random state and accumulator seeds.
uint32_t data_state = rnd_word();
uint32_t data_acc = rnd_word();
uint32_t data_state = rng_get_word();
uint32_t data_acc = rng_get_word();
for (uint32_t w = 0; w < TK1_RAM_SIZE / 4; w++) {
data_state = xorwow(data_state, data_acc);
data_state = rng_xorwow(data_state, data_acc);
ram[w] = data_state;
}
// Set RAM address and data scrambling parameters
*ram_addr_rand = rnd_word();
*ram_data_rand = rnd_word();
*ram_addr_rand = rng_get_word();
*ram_data_rand = rng_get_word();
}
int main(void)

29
hw/application_fpga/fw/tk1/rng.c Normal file
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@ -0,0 +1,29 @@
// Copyright (C) 2024 - Tillitis AB
// SPDX-License-Identifier: GPL-2.0-only
#include "rng.h"
#include "../tk1_mem.h"
#include <stdint.h>
// clang-format off
static volatile uint32_t *trng_status = (volatile uint32_t *)TK1_MMIO_TRNG_STATUS;
static volatile uint32_t *trng_entropy = (volatile uint32_t *)TK1_MMIO_TRNG_ENTROPY;
// clang-format on
//
//
uint32_t rng_get_word(void)
{
while ((*trng_status & (1 << TK1_MMIO_TRNG_STATUS_READY_BIT)) == 0) {
}
return *trng_entropy;
}
uint32_t rng_xorwow(uint32_t state, uint32_t acc)
{
state ^= state << 13;
state ^= state >> 17;
state ^= state << 5;
state += acc;
return state;
}

11
hw/application_fpga/fw/tk1/rng.h Normal file
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@ -0,0 +1,11 @@
// Copyright (C) 2024 - Tillitis AB
// SPDX-License-Identifier: GPL-2.0-only
#ifndef RNG_H
#define RNG_H
#include <stdint.h>
uint32_t rng_get_word(void);
uint32_t rng_xorwow(uint32_t state, uint32_t acc);
#endif