Attention is currently required from: Peter Marheine.

Matti Finder has uploaded this change for review.

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rpmc: add rpmc commands feature

Added optional support for all the commands specified in JESD260.
Added a new optional dependency to openssls libcrypto.
Added parsing for the rpmc parameter sfdp table.
Added necessary rpmc parameter information to flashchips struct and the
flash hardening feature to enable rpmc commands.

Enables future use of these commands in the cli_client and also
libflashrom.

Change-Id: I6ab3d0446e9fd674b20550fdbfaf499b8d4a9b38
Signed-off-by: Matti Finder <matti.finder@gmail.com>
---
M include/flash.h
A include/rpmc.h
M meson.build
M meson_options.txt
A rpmc.c
M sfdp.c
6 files changed, 666 insertions(+), 15 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/34/84934/1

diff --git a/include/flash.h b/include/flash.h
index d0e55af..ccac994 100644
--- a/include/flash.h
+++ b/include/flash.h
@@ -172,6 +172,11 @@
 /* Whether chip has configuration register (RDCR/WRSR_EXT2 commands) */
 #define FEATURE_CFGR	    (1 << 25)
 
+/*
+ * Whether the chip supports serial flash hardening specified in JESD260
+ */
+#define FEATURE_FLASH_HARDENING (1 << 26)
+
 #define ERASED_VALUE(flash)	(((flash)->chip->feature_bits & FEATURE_ERASED_ZERO) ? 0x00 : 0xff)
 #define UNERASED_VALUE(flash)	(((flash)->chip->feature_bits & FEATURE_ERASED_ZERO) ? 0xff : 0x00)
 
@@ -543,6 +548,32 @@
 	 * and determines what protection range they select.
 	 */
 	enum decode_range_func decode_range;
+
+	struct rpmc_config {
+		uint8_t op1_opcode;
+		uint8_t op2_opcode;
+
+		unsigned int num_counters;
+
+		/*
+		 * Busy Polling Method :
+		 * ‘0’: Poll for OP1 busy using OP2 Extended Status[0].
+		 *      No OP1 Suspended State Support.
+		 * ‘1’: Poll for OP1 busy using Read Status (05H).
+		 *      Suspended State is supported.
+		 */
+		enum busy_polling_methods {
+			POLL_OP2_EXTENDED_STATUS = 0,
+			POLL_READ_STATUS = 1
+		} busy_polling_method;
+
+		unsigned int update_rate;
+
+		/* All times in microsecond (us) */
+		unsigned int polling_delay_read_counter_us;
+		unsigned int polling_short_delay_write_counter_us;
+		unsigned int polling_long_delay_write_counter_us;
+	} rpmc_ctx;
 };
 
 typedef int (*chip_restore_fn_cb_t)(struct flashctx *flash, void *data);
diff --git a/include/rpmc.h b/include/rpmc.h
new file mode 100644
index 0000000..fa5c46d
--- /dev/null
+++ b/include/rpmc.h
@@ -0,0 +1,117 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2024 Matti Finder
+ * (written by Matti Finder <matti.finder@gmail.com>)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __RPMC_H__
+#define __RPMC_H__ 1
+
+#include <stdint.h>
+#include "flash.h" // for flashctx
+
+/**
+ * @defgroup flashrom-rpmc Write Protect
+ * @{
+ */
+
+#define RPMC_OP1_MSG_HEADER_LENGTH 4
+#define RPMC_SIGNATURE_LENGTH 32
+#define RPMC_COUNTER_LENGTH 4
+#define RPMC_KEY_DATA_LENGTH 4
+#define RPMC_TAG_LENGTH 12
+#define RPMC_HMAC_KEY_LENGTH 32
+#define RPMC_TRUNCATED_SIG_LENGTH 28
+
+struct rpmc_status_register {
+	uint8_t status;
+	unsigned char tag[RPMC_TAG_LENGTH];
+	uint32_t counter_data;
+	unsigned char signature[RPMC_SIGNATURE_LENGTH];
+};
+
+/**
+ * @brief Write root key on flashchip
+ *q
+ * @param[in] flash Flash context which rpmc options will be used
+ * @param[in] keyfile Location of 32-byte key to use
+ * @param[in] counter_address Address of counter (starts at 0)
+ *
+ * @return Rpmc extended status value, or -1 on general error
+ */
+int rpmc_write_root_key(struct flashrom_flashctx * flash,
+			const char * const keyfile,
+			const unsigned int counter_address);
+
+/**
+ * @brief Update hmac key register
+ *
+ * @param[in] flash Flash context which rpmc options will be used
+ * @param[in] keyfile Location of 32-byte key to use
+ * @param[in] key_data 4-bytes of data to use as key data
+ * @param[in] counter_address Address of counter (starts at 0)
+ *
+ * @return Rpmc extended status value, or -1 on general error
+ */
+int rpmc_update_hmac_key(struct flashrom_flashctx * flash,
+			 const char * const keyfile,
+			 const uint32_t key_data,
+			 const unsigned int counter_address);
+
+/**
+ * @brief Increment monotonic counter value
+ *
+ * @param[in] flash Flash context which rpmc options will be used
+ * @param[in] keyfile Location of 32-byte key to use
+ * @param[in] key_data 4-bytes of data to use as key data
+ * @param[in] counter_address Address of counter (starts at 0)
+ * @param[in] previous_value Previous value of counter
+ *
+ * @return Rpmc extended status value, or -1 on general error
+ */
+int rpmc_increment_counter(struct flashrom_flashctx * flash,
+			   const char * const keyfile,
+			   const uint32_t key_data,
+			   const unsigned int counter_address,
+			   const uint32_t previous_value);
+
+/**
+ * @brief Get monotonic counter value
+ *
+ * @param[in] flash Flash context which rpmc options will be used
+ * @param[in] keyfile Location of 32-byte key to use
+ * @param[in] key_data 4-bytes of data to use as key data
+ * @param[in] counter_address Address of counter (starts at 0)
+ * @param[out] counter_value Pointer to write the counter value to
+ *
+ * @return Rpmc extended status value, or -1 on general error
+ */
+int rpmc_get_monotonic_counter(struct flashrom_flashctx * flash,
+			       const char * const keyfile,
+			       const uint32_t key_data,
+			       const unsigned int counter_address,
+			       uint32_t * const counter_value);
+
+/**
+ * @brief Update hmac key register
+ *
+ * @param[in] flash Flash context which rpmc options will be used
+ * @param[out] status Status register to write data into
+ *
+ * @return 0 on success, otherwise 1
+ */
+int rpmc_read_data(struct flashrom_flashctx * flash, struct rpmc_status_register * status);
+
+/** @} */ /* end flashrom-rpmc */
+
+#endif /* !__RPMC_H__ */
diff --git a/meson.build b/meson.build
index 26d96d9..9cf2ffc 100644
--- a/meson.build
+++ b/meson.build
@@ -164,6 +164,7 @@
 libusb1    = dependency('libusb-1.0', required : group_usb)
 libftdi1   = dependency('libftdi1', required : group_ftdi)
 libjaylink = dependency('libjaylink', required : group_jlink, version : '>=0.3.0')
+libcrypto = dependency('libcrypto', required : get_option('rpmc'), version : '>=3.0.0')
 
 # ECAM is supported in libpci after 3.13.0
 if libpci.version().version_compare('>=3.13.0')
@@ -172,6 +173,13 @@
     add_project_arguments('-DCONFIG_USE_LIBPCI_ECAM=0', language: 'c')
 endif
 
+# Support additional rpmc commands if libcrypto is installed
+if get_option('rpmc').enabled() and libcrypto.found()
+    add_project_arguments('-DCONFIG_RPMC_ENABLED=1', language : 'c')
+    srcs += 'rpmc.c'
+    deps += libcrypto
+endif
+
 if host_machine.system() == 'windows'
   # Specifying an include_path that doesn't exist is an error,
   # but we only use this if the library is found in the same directory.
diff --git a/meson_options.txt b/meson_options.txt
index 6df95ba..87456a9 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -24,3 +24,4 @@
 option('delay_minimum_sleep_us', type : 'integer', min : 0, value : 100,
        description : 'Minimum time in microseconds to suspend execution for (rather than polling) when a delay is required.'
                    + ' Larger values may perform better on machines with low timer resolution, at the cost of increased power.')
+option('rpmc', type : 'feature', value : 'auto', description : 'Support for Replay Protected Monotonic Counter (RPMC) commands as specified by JESD260')
diff --git a/rpmc.c b/rpmc.c
new file mode 100644
index 0000000..7f9fcaa
--- /dev/null
+++ b/rpmc.c
@@ -0,0 +1,398 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2024 Matti Finder
+ * (written by Matti Finder <matti.finder@gmail.com>)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "rpmc.h"
+#include "flash.h"
+#include <stdint.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <openssl/hmac.h>
+#include <openssl/evp.h>
+#include <openssl/rand.h>
+#include <string.h>
+
+// OP1 commands
+#define RPMC_WRITE_ROOT_KEY_MSG_LENGTH (RPMC_OP1_MSG_HEADER_LENGTH + RPMC_HMAC_KEY_LENGTH + RPMC_TRUNCATED_SIG_LENGTH)
+#define RPMC_UPDATE_HMAC_KEY_MSG_LENGTH (RPMC_OP1_MSG_HEADER_LENGTH + RPMC_KEY_DATA_LENGTH + RPMC_SIGNATURE_LENGTH)
+#define RPMC_INCREMENT_MONOTONIC_COUNTER_MSG_LENGTH (RPMC_OP1_MSG_HEADER_LENGTH + RPMC_COUNTER_LENGTH + RPMC_SIGNATURE_LENGTH)
+#define RPMC_GET_MONOTONIC_COUNTER_MSG_LENGTH (RPMC_OP1_MSG_HEADER_LENGTH + RPMC_TAG_LENGTH + RPMC_SIGNATURE_LENGTH)
+
+// OP2 commands
+#define RPMC_READ_DATA_MSG_LENGTH 2
+#define RPMC_READ_DATA_ANSWER_LENGTH (1 + RPMC_TAG_LENGTH + RPMC_COUNTER_LENGTH + RPMC_SIGNATURE_LENGTH)
+
+static int rpmc_get_extended_status(struct flashrom_flashctx * flash, uint8_t * status)
+{
+	const unsigned char extended_status_msg[RPMC_READ_DATA_MSG_LENGTH] = {
+		flash->chip->rpmc_ctx.op2_opcode,
+		0 // dummy
+	};
+
+	if (spi_send_command(flash, RPMC_READ_DATA_MSG_LENGTH, 1, extended_status_msg, status)) {
+		msg_gerr("Reading extended status failed\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+static int rpmc_get_extended_status_long(struct flashrom_flashctx * flash,
+					 struct rpmc_status_register * status,
+					 // optional to check values tag and signature against
+					 const unsigned char * const tag,
+					 const unsigned char * const key)
+{
+	const unsigned int tag_offset = 1;
+	const unsigned int counter_data_offset = tag_offset + RPMC_TAG_LENGTH;
+	const unsigned int signature_offset = counter_data_offset + RPMC_COUNTER_LENGTH;
+	const unsigned char cmd[RPMC_READ_DATA_MSG_LENGTH] = {
+		flash->chip->rpmc_ctx.op2_opcode,
+		0 // dummy
+	};
+	unsigned char answer[RPMC_READ_DATA_ANSWER_LENGTH];
+
+	int ret = spi_send_command(flash, RPMC_READ_DATA_MSG_LENGTH, RPMC_READ_DATA_ANSWER_LENGTH, cmd, answer);
+	if (ret) {
+		msg_gerr("reading extended status failed\n");
+		return ret;
+	}
+
+	status->status = answer[0];
+
+	memcpy(status->tag, answer + tag_offset, RPMC_TAG_LENGTH);
+
+	status->counter_data = answer[counter_data_offset];
+	status->counter_data = (status->counter_data << 8) | answer[counter_data_offset + 1];
+	status->counter_data = (status->counter_data << 8) | answer[counter_data_offset + 2];
+	status->counter_data = (status->counter_data << 8) | answer[counter_data_offset + 3];
+
+	memcpy(status->signature, answer + signature_offset, RPMC_SIGNATURE_LENGTH);
+
+	if (tag != NULL) {
+		if (memcmp(tag, status->tag, RPMC_TAG_LENGTH) != 0) {
+			msg_gwarn("Tag doesn't match counter might be false\n");
+		}
+	}
+
+	if (key != NULL) {
+		unsigned char * signature = HMAC(EVP_sha256(),
+						 key, RPMC_HMAC_KEY_LENGTH,
+						 answer + tag_offset, RPMC_TAG_LENGTH + RPMC_COUNTER_LENGTH,
+						 NULL, NULL);
+		if (signature == NULL) {
+			msg_gerr("Could not generate signature\n");
+			ret = 1;
+		} else if (memcmp(signature, status->signature, RPMC_SIGNATURE_LENGTH) != 0) {
+			msg_gwarn("Signature doesn't match, counter might be false\n");
+		}
+	}
+
+	return ret;
+}
+
+static int rpmc_poll_until_finished(struct flashrom_flashctx * flash)
+{
+	unsigned char poll_response;
+
+	do {
+		const unsigned char status_poll_msg = 0x05;
+
+		// since we aren't really a time critical application we just sleep for the longest time
+		if (usleep(flash->chip->rpmc_ctx.polling_long_delay_write_counter_us)) {
+			msg_gdbg("%s: usleep failed\n", __func__);
+		}
+
+		switch (flash->chip->rpmc_ctx.busy_polling_method) {
+			case POLL_READ_STATUS:
+				if (spi_send_command(flash, 1, 1, &status_poll_msg, &poll_response)) {
+					msg_gerr("Polling Status-Register-1 failed\n");
+					return 1;
+				}
+				break;
+			case POLL_OP2_EXTENDED_STATUS:
+				if (rpmc_get_extended_status(flash, &poll_response)) {
+					return 1;
+				}
+				break;
+			default:
+				msg_gerr("Unsupported busy polling method found, this should not happen. Exiting...\n");
+				return 1;
+		}
+	} while ((poll_response & 1) != 0);
+
+	return 0;
+}
+
+static int rpmc_calculate_hmac_key_register(const char * const keyfile,
+					    const uint32_t key_data,
+					    unsigned char * hmac_key_register)
+{
+	unsigned char key[RPMC_HMAC_KEY_LENGTH];
+	unsigned char key_data_buf[RPMC_KEY_DATA_LENGTH];
+	key_data_buf[0] = (key_data >> 24) & 0xff;
+	key_data_buf[1] = (key_data >> 16) & 0xff;
+	key_data_buf[2] = (key_data >> 8) & 0xff;
+	key_data_buf[3] = key_data & 0xff;
+
+	if (keyfile == NULL || read_buf_from_file(key, RPMC_HMAC_KEY_LENGTH, keyfile) != 0) {
+		return 1;
+	}
+
+	unsigned char * key_ptr = HMAC(EVP_sha256(),
+				       key, RPMC_HMAC_KEY_LENGTH,
+				       key_data_buf, RPMC_KEY_DATA_LENGTH,
+				       hmac_key_register, NULL);
+	if (key_ptr == NULL) {
+		msg_gerr("Could not calculate HMAC signature for hmac storage\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+static int rpmc_basic_checks(struct flashrom_flashctx * flash, const unsigned int counter_address)
+{
+	if ((flash->chip->feature_bits & FEATURE_FLASH_HARDENING) == 0) {
+		msg_gerr("Flash hardening is not supported on this chip, aborting.\n");
+		return 1;
+	}
+
+	if (counter_address >= flash->chip->rpmc_ctx.num_counters) {
+		msg_gerr("Counter address is not in range, should be between 0 and %d.\n",
+			 flash->chip->rpmc_ctx.num_counters - 1);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int rpmc_send_and_wait(struct flashrom_flashctx * flash,
+			      const unsigned char * const msg,
+			      const size_t length)
+{
+	msg_gdbg("sending rpmc command\n");
+	int ret = spi_send_command(flash, length, 0, msg, NULL);
+	if (ret)
+		return ret;
+
+	// check operation status
+	ret = rpmc_poll_until_finished(flash);
+	if (ret)
+		return ret;
+
+	msg_gdbg("done sending rpmc command\n");
+
+	return 0;
+}
+
+static int rpmc_sign_send_wait_check(struct flashrom_flashctx * flash,
+				     unsigned char * const msg,
+				     const size_t msg_length,
+				     const size_t signature_offset,
+				     const char * const keyfile,
+				     const uint32_t key_data)
+{
+	unsigned char hmac_key_register[RPMC_HMAC_KEY_LENGTH];
+
+	if (rpmc_calculate_hmac_key_register(keyfile, key_data, hmac_key_register)) {
+		return -1;
+	}
+
+	if (HMAC(EVP_sha256(),
+		 hmac_key_register, RPMC_HMAC_KEY_LENGTH,
+		 msg, signature_offset,
+		 msg + signature_offset, NULL) == NULL) {
+		msg_gerr("Could not generate HMAC signature\n");
+		return -1;
+	}
+
+	if (rpmc_send_and_wait(flash, msg, msg_length)) {
+		return -1;
+	}
+
+	uint8_t return_status;
+	if (rpmc_get_extended_status(flash, &return_status)){
+		return -1;
+	}
+
+	return return_status;
+}
+
+int rpmc_write_root_key(struct flashrom_flashctx * flash,
+			const char * const keyfile,
+			const unsigned int counter_address)
+{
+	const unsigned int key_offset = RPMC_OP1_MSG_HEADER_LENGTH;
+	const unsigned int signature_offset = key_offset + RPMC_HMAC_KEY_LENGTH;
+	const unsigned int signature_cutoff = RPMC_SIGNATURE_LENGTH - RPMC_TRUNCATED_SIG_LENGTH;
+
+	unsigned char msg[RPMC_WRITE_ROOT_KEY_MSG_LENGTH];
+	msg[0] = flash->chip->rpmc_ctx.op1_opcode; // Opcode
+	msg[1] = 0x00; // CmdType
+	msg[2] = counter_address; // CounterAddr
+	msg[3] = 0; // Reserved
+
+	if (rpmc_basic_checks(flash, counter_address)) {
+		return -1;
+	}
+
+	if (keyfile == NULL ||
+	    read_buf_from_file(msg + key_offset, RPMC_HMAC_KEY_LENGTH, keyfile) != 0) {
+		return -1;
+	}
+
+	unsigned char * signature = HMAC(EVP_sha256(),
+					 msg + key_offset, RPMC_HMAC_KEY_LENGTH,
+					 msg, RPMC_OP1_MSG_HEADER_LENGTH,
+					 NULL, NULL);
+	if (signature == NULL) {
+		msg_gerr("Could not calculate HMAC signature for message\n");
+		return -1;
+	}
+
+	// need to truncate the signature a bit
+	memcpy(msg + signature_offset, signature + signature_cutoff, RPMC_TRUNCATED_SIG_LENGTH);
+
+	if (rpmc_send_and_wait(flash, msg, RPMC_WRITE_ROOT_KEY_MSG_LENGTH)) {
+		return -1;
+	}
+
+	uint8_t return_status;
+	if (rpmc_get_extended_status(flash, &return_status)){
+		return -1;
+	}
+
+	return return_status;
+}
+
+int rpmc_update_hmac_key(struct flashrom_flashctx * flash,
+			 const char * const keyfile,
+			 const uint32_t key_data,
+			 const unsigned int counter_address)
+{
+	const unsigned int signature_offset = RPMC_OP1_MSG_HEADER_LENGTH + RPMC_KEY_DATA_LENGTH;
+	unsigned char msg[RPMC_UPDATE_HMAC_KEY_MSG_LENGTH];
+	msg[0] = flash->chip->rpmc_ctx.op1_opcode; // Opcode
+	msg[1] = 0x01; // CmdType
+	msg[2] = counter_address; // CounterAddr
+	msg[3] = 0; // Reserved
+	msg[4] = (key_data >> 24) & 0xff;
+	msg[5] = (key_data >> 16) & 0xff;
+	msg[6] = (key_data >> 8) & 0xff;
+	msg[7] = key_data & 0xff;
+
+	if (rpmc_basic_checks(flash, counter_address)) {
+		return -1;
+	}
+
+	return rpmc_sign_send_wait_check(flash, msg, RPMC_UPDATE_HMAC_KEY_MSG_LENGTH,
+					 signature_offset, keyfile, key_data);
+}
+
+int rpmc_increment_counter(struct flashrom_flashctx * flash,
+			   const char * const keyfile,
+			   const uint32_t key_data,
+			   const unsigned int counter_address,
+			   const uint32_t previous_value)
+{
+	const unsigned int signature_offset = RPMC_OP1_MSG_HEADER_LENGTH + RPMC_COUNTER_LENGTH;
+	unsigned char msg[RPMC_INCREMENT_MONOTONIC_COUNTER_MSG_LENGTH];
+	msg[0] = flash->chip->rpmc_ctx.op1_opcode; // Opcode
+	msg[1] = 0x02; // CmdType
+	msg[2] = counter_address; // CounterAddr
+	msg[3] = 0; // Reserved
+	// CounterData
+	msg[4] = (previous_value >> 24) & 0xff;
+	msg[5] = (previous_value >> 16) & 0xff;
+	msg[6] = (previous_value >> 8) & 0xff;
+	msg[7] = previous_value & 0xff;
+
+	if (rpmc_basic_checks(flash, counter_address)) {
+		return 1;
+	}
+
+	return rpmc_sign_send_wait_check(flash, msg, RPMC_INCREMENT_MONOTONIC_COUNTER_MSG_LENGTH,
+					 signature_offset, keyfile, key_data);
+}
+
+int rpmc_get_monotonic_counter(struct flashrom_flashctx * flash,
+			       const char * const keyfile,
+			       const uint32_t key_data,
+			       const unsigned int counter_address,
+			       uint32_t * const counter_value)
+{
+	unsigned char hmac_key_register[RPMC_HMAC_KEY_LENGTH];
+	const unsigned int tag_offset = RPMC_OP1_MSG_HEADER_LENGTH;
+	const unsigned int signature_offset = tag_offset + RPMC_TAG_LENGTH;
+	unsigned char msg[RPMC_GET_MONOTONIC_COUNTER_MSG_LENGTH];
+	msg[0] = flash->chip->rpmc_ctx.op1_opcode; // Opcode
+	msg[1] = 0x03; // CmdType
+	msg[2] = counter_address; // CounterAddr
+	msg[3] = 0; // Reserved
+
+	if (rpmc_basic_checks(flash, counter_address)) {
+		return -1;
+	}
+
+	if (RAND_bytes(msg + tag_offset, RPMC_TAG_LENGTH) != 1) {
+		msg_gerr("Could not generate random tag.\n");
+		return -1;
+	}
+
+	msg_gdbg("Random tag is:");
+	for (size_t i = 0; i < RPMC_TAG_LENGTH; i++) {
+		msg_gdbg(" 0x%02x", msg[tag_offset + i]);
+	}
+	msg_gdbg("\n");
+
+	if (rpmc_calculate_hmac_key_register(keyfile, key_data, hmac_key_register)) {
+		return -1;
+	}
+
+	if (HMAC(EVP_sha256(),
+		 hmac_key_register, RPMC_HMAC_KEY_LENGTH,
+		 msg, signature_offset,
+		 msg + signature_offset, NULL) == NULL) {
+		msg_gerr("Could not generate HMAC signature\n");
+		return -1;
+	}
+
+	if (rpmc_send_and_wait(flash, msg, RPMC_GET_MONOTONIC_COUNTER_MSG_LENGTH)) {
+		return -1;
+	}
+
+	struct rpmc_status_register status;
+	if (rpmc_get_extended_status_long(flash, &status, msg + tag_offset, hmac_key_register)) {
+		return -1;
+	}
+
+	*counter_value = status.counter_data;
+	return status.status;
+}
+
+int rpmc_read_data(struct flashrom_flashctx * flash, struct rpmc_status_register * status)
+{
+	// hack around not having a counter address
+	if (rpmc_basic_checks(flash, 0)) {
+		return 1;
+	}
+
+	if (rpmc_get_extended_status_long(flash, status, NULL, NULL)) {
+		return 1;
+	}
+
+	return 0;
+}
diff --git a/sfdp.c b/sfdp.c
index 8683779..110738c 100644
--- a/sfdp.c
+++ b/sfdp.c
@@ -252,6 +252,88 @@
 	return 0;
 }
 
+static unsigned int bits_to_counter_delay(const uint8_t bits)
+{
+	unsigned int value = bits & 0xf;
+
+	switch ((bits & (0b11 << 4)) >> 4) {
+		case 0b00:
+			value *= 1;
+			break;
+		case 0b01:
+			value *= 16;
+			break;
+		case 0b10:
+			value *= 128;
+			break;
+		case 0b11:
+			value *= 1000;
+			break;
+	}
+
+	return value;
+}
+
+static int parse_rpmc_parameter_table(struct flashchip * const chip, const uint8_t * const buf, const uint16_t len)
+{
+	if (len != 2 * 4) {
+		msg_cdbg("Length of RPMC parameter table is wrong, skipping it\n");
+		return 1;
+	}
+
+	msg_cdbg("Parsing rpmc parameter table...\n");
+
+	// first dword
+	uint32_t first_dword =	((unsigned int)buf[(4 * 0) + 0]);
+	first_dword |=		((unsigned int)buf[(4 * 0) + 1]) << 8;
+	first_dword |=		((unsigned int)buf[(4 * 0) + 2]) << 16;
+	first_dword |=		((unsigned int)buf[(4 * 0) + 3]) << 24;
+
+	if ((first_dword & 0b1) != 0) {
+		// flash hardening is not supported
+		msg_cdbg("Flash Hardening not supported\n");
+		goto done;
+	}
+
+	chip->feature_bits |= FEATURE_FLASH_HARDENING;
+
+	chip->rpmc_ctx.busy_polling_method = (first_dword & (1 << 2)) >> 2;
+	msg_cspew("Busy polling method: %u\n", chip->rpmc_ctx.busy_polling_method);
+
+	chip->rpmc_ctx.num_counters = ((first_dword & (0xf << 4)) >> 4) + 1;
+	msg_cspew("Number of counters: %u\n", chip->rpmc_ctx.num_counters);
+
+	chip->rpmc_ctx.op1_opcode = (first_dword & (0xff << 8)) >> 8;
+	msg_cspew("OP1 opcode: 0x%02x\n", chip->rpmc_ctx.op1_opcode);
+
+	chip->rpmc_ctx.op2_opcode = (first_dword & (0xff << 16)) >> 16;
+	msg_cspew("OP2 opcode: 0x%02x\n", chip->rpmc_ctx.op2_opcode);
+
+	chip->rpmc_ctx.update_rate = 5 * (1 << ((first_dword & (0xf << 24)) >> 24));
+	msg_cspew("Update rate: %u seconds\n", chip->rpmc_ctx.update_rate);
+
+	// second dword
+	uint32_t second_dword =	((unsigned int)buf[(4 * 1) + 0]);
+	second_dword |=		((unsigned int)buf[(4 * 1) + 1]) << 8;
+	second_dword |=		((unsigned int)buf[(4 * 1) + 2]) << 16;
+	second_dword |=		((unsigned int)buf[(4 * 1) + 3]) << 24;
+
+	chip->rpmc_ctx.polling_delay_read_counter_us = bits_to_counter_delay(second_dword & 0xf);
+	msg_cspew("Read counter polling delay: %u us\n", chip->rpmc_ctx.polling_delay_read_counter_us);
+
+	chip->rpmc_ctx.polling_short_delay_write_counter_us = bits_to_counter_delay((second_dword >> 8) & 0xf);
+	msg_cspew("Write counter short polling delay: %u us\n",
+		  chip->rpmc_ctx.polling_short_delay_write_counter_us);
+
+	chip->rpmc_ctx.polling_long_delay_write_counter_us = bits_to_counter_delay((second_dword >> 16) & 0xf) * 1000;
+	msg_cspew("Write counter long polling delay: %u us\n",
+		  chip->rpmc_ctx.polling_long_delay_write_counter_us);
+
+done:
+	msg_cdbg("done.\n");
+	return 0;
+}
+
 int probe_spi_sfdp(struct flashctx *flash)
 {
 	int ret = 0;
@@ -359,23 +441,37 @@
 		}
 		msg_cspew("\n");
 
-		if (i == 0) { /* Mandatory JEDEC SFDP parameter table */
-			if (hdrs[i].id != 0)
-				msg_cdbg("ID of the mandatory JEDEC SFDP "
-					 "parameter table is not 0 as demanded "
-					 "by JESD216 (warning only).\n");
 
-			if (hdrs[i].v_major != 0x01) {
-				msg_cdbg("The chip contains an unknown "
-					  "version of the JEDEC flash "
-					  "parameters table, skipping it.\n");
-			} else if (len != 4 * 4 && len < 9 * 4) {
-				msg_cdbg("Length of the mandatory JEDEC SFDP "
-					 "parameter table is wrong (%d B), "
-					 "skipping it.\n", len);
-			} else if (sfdp_fill_flash(flash->chip, tbuf, len) == 0)
-				ret = 1;
+		// TODO: implement parsing for other pages
+		switch (hdrs[i].id){
+			case 0: // Mandatory JEDEC SFDP parameter table
+				if (hdrs[i].v_major != 0x01) {
+					msg_cdbg("The chip contains an unknown "
+						 "version of the JEDEC flash "
+						 "parameters table, skipping it.\n");
+				} else if (len != 4 * 4 && len < 9 * 4) {
+					msg_cdbg("Length of the mandatory JEDEC SFDP "
+						 "parameter table is wrong (%d B), "
+						 "skipping it.\n", len);
+				} else if (sfdp_fill_flash(flash->chip, tbuf, len) == 0) {
+					ret = 1;
+				}
+				break;
+			case 0x03: // RPMC parameter table as specified in JESD260
+				if (hdrs[i].v_major != 1) {
+					msg_cdbg("The chip contains an unknown "
+						 "version of the JEDEC flash "
+						 "parameters table, skipping it.\n");
+				} else if (parse_rpmc_parameter_table(flash->chip, tbuf, len) == 0) {
+					ret = 1;
+				}
+				break;
+			default:
+				msg_cdbg("Support for SFDP Page with ID 0x%02x not implemented, skipping it.\n",
+					 hdrs[i].id);
+				break;
 		}
+
 		free(tbuf);
 	}
 

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