blob: b96d4b7b362fc326c6cf3ffe85b8990522f6d050 [file] [log] [blame]
Galanakis, Minos41f85972019-09-30 15:56:40 +01001###########
2Secure boot
3###########
Gyorgy Szingdb9783c2019-04-17 21:08:48 +02004For secure devices it is security critical to enforce firmware authenticity to
5protect against execution of malicious software. This is implemented by building
6a trust chain where each step in the execution chain authenticates the next
7step before execution. The chain of trust in based on a "Root of Trust" which
8is implemented using asymmetric cryptography. The Root of Trust is a combination
9of an immutable bootloader and a public key (ROTPK).
10
Tamas Ban07a11a22019-09-23 13:54:15 +010011.. Warning::
12 In order to implement a proper chain of trust functionality, it is
13 mandatory that the first stage bootloader and ROTPK is stored in an
14 **immutable** way. To achieve this the bootloader code must be stored and
15 executed from ROM or such part of flash memory which supports write
16 protection. ROTPK can be stored in a one-time-programmable (OTP) memory. If
17 the SoC has a built-in BL1 (immutable) bootloader and the immutability of
18 TF-M secure boot code is not guaranteed then TF-M secure boot code must be
19 authenticated by BL1 bootloader before execution. If immutability of root
20 of trust (first stage bootloader + ROTPK) is not ensured then there is a
21 risk that the secure boot process could be bypassed, which could lead to
22 arbitrary code execution on the device. Current TF-M secure boot code is
23 intended to be a second stage bootloader, therefore it requires
24 authentication before execution. If TF-M secure boot code is used as a first
25 stage bootloader then it must be stored according to the above requirements.
26
Gyorgy Szingdb9783c2019-04-17 21:08:48 +020027*******************************
28Second stage bootloader in TF-M
29*******************************
30To implement secure boot functionality an external project MCUBoot has been
31integrated to TF-M. For further information please refer to the
David Vincze8a2a4e22019-05-24 10:14:23 +020032`MCUBoot homepage <https://www.mcuboot.com/>`__. Original source-code is
33available at `GitHub <https://github.com/JuulLabs-OSS/mcuboot>`__. This document
34contains information about MCUBoot modifications and how MCUBoot has been
35integrated to TF-M.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +020036
37Bootloader is started when CPU is released from reset. It runs in secure mode.
38It authenticates the firmware image by hash (SHA-256) and digital signature
David Vincze9c609012019-08-22 13:37:21 +020039(RSA-3072) validation. Public key, that the checks happens against, can be built
40into the bootloader image or can be provisioned to the SoC during manufacturing.
41Metadata of the image is delivered together with the image itself in a header
42and trailer section. In case of successful authentication, bootloader passes
43execution to the secure image. Execution never returns to bootloader until
44next reset.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +020045
46A default RSA key pair is stored in the repository, public key is in ``keys.c``
Tamas Ban7801ed42019-05-20 13:21:53 +010047and private key is in ``root-rsa-3072.pem``.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +020048
David Vincze8a2a4e22019-05-24 10:14:23 +020049.. Warning::
50 DO NOT use them in production code, they are exclusively for testing!
Gyorgy Szingdb9783c2019-04-17 21:08:48 +020051
52Private key must be stored in a safe place outside of the repository.
53``Imgtool.py`` can be used to generate new key pairs.
54
David Vincze9c609012019-08-22 13:37:21 +020055The bootloader can handle the secure and non-secure images independently
56(multiple image boot) or together (single image boot). In case of multiple image
57boot they are signed independently with different keys and they can be updated
58separately. In case of single image boot the secure and non-secure image is
59handled as a single blob, therefore they must be contiguous in the device
60memory. In this case they are signed together and also they can be updated only
61together. In order to have the same artefacts at the end of the build regardless
62of how the images are handled (independently or together) the images are always
63concatenated. In case of single image boot they are concatenated first and then
64signed. In case of multiple image boot they are separately signed first and then
65concatenated. Preparation of payload is done by Python scripts:
66``bl2/ext/mcuboot/scripts/``. At the end of a successful build the signed TF-M
67payload can be found in: ``<build_dir>/install/outputs/fvp/tfm_sign.bin``
Gyorgy Szingdb9783c2019-04-17 21:08:48 +020068
69*********************
70Integration with TF-M
71*********************
72MCUBoot assumes a predefined memory layout which is described below (applicable
David Vincze8bdfc2d2019-03-18 15:49:23 +010073for AN521). It is mandatory to define the primary slot and the secondary slot
David Vincze9c609012019-08-22 13:37:21 +020074partitions, but their size and location can be changed::
Gyorgy Szingdb9783c2019-04-17 21:08:48 +020075
76 - 0x0000_0000 - 0x0007_FFFF: BL2 bootloader - MCUBoot
David Vincze8bdfc2d2019-03-18 15:49:23 +010077 - 0x0008_0000 - 0x000F_FFFF: Primary slot : Single binary blob:
78 Secure + Non-Secure image;
79 Primary memory partition
Gyorgy Szingdb9783c2019-04-17 21:08:48 +020080 - 0x0008_0000 - 0x0008_03FF: Common image header
81 - 0x0008_0400 - 0x0008_xxxx: Secure image
82 - 0x0008_xxxx - 0x0010_03FF: Padding (with 0xFF)
83 - 0x0010_0400 - 0x0010_xxxx: Non-secure image
David Vincze9c609012019-08-22 13:37:21 +020084 - 0x0010_xxxx - 0x0010_xxxx: Hash value(SHA256), RSA signature and other
85 metadata of combined image
David Vincze8a2a4e22019-05-24 10:14:23 +020086
David Vincze8bdfc2d2019-03-18 15:49:23 +010087 - 0x0018_0000 - 0x0027_FFFF: Secondary slot : Secure + Non-Secure image;
88 Secondary memory partition, structured
89 identically to the primary slot
David Vincze9c609012019-08-22 13:37:21 +020090 - 0x0028_0000 - 0x0037_FFFF: Scratch area, only used during image
91 swapping
92
93Multiple image boot requires a slightly different layout::
94
95 - 0x0000_0000 - 0x0007_FFFF: BL2 bootloader - MCUBoot
96 - 0x0008_0000 - 0x000F_FFFF: Primary slot : Secure image
97 - 0x0008_0000 - 0x0008_03FF: Secure image header
98 - 0x0008_0400 - 0x000x_xxxx: Secure image
99 - 0x000x_xxxx - 0x000x_xxxx: Hash value(SHA256), RSA signature and other
100 metadata of secure image
101
102 - 0x0010_0000 - 0x0017_FFFF: Primary slot : Non-secure image
103 - 0x0010_0000 - 0x0010_03FF: Non-secure image header
104 - 0x0010_0400 - 0x001x_xxxx: Non-secure image
105 - 0x001x_xxxx - 0x001x_xxxx: Hash value(SHA256), RSA signature and other
106 metadata of non-secure image
107
108 - 0x0018_0000 - 0x001F_FFFF: Secondary slot : Secure image
109 - 0x0020_0000 - 0x0027_FFFF: Secondary slot : Non-secure image
110
111 - 0x0028_0000 - 0x002F_FFFF: Scratch area, only used during image
112 swapping, used for secure and non-secure
113 image as well
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200114
115**************************
116Firmware upgrade operation
117**************************
118MCUBoot handles only the firmware authenticity check after start-up and the
119firmware switch part of the firmware update process. Downloading the new version
David Vincze8a2a4e22019-05-24 10:14:23 +0200120of the firmware is out-of-scope for MCUBoot. MCUBoot supports three different
121ways to switch to the new firmware and it is assumed that firmware images are
122executed-in-place (XIP). The default behaviour is the overwrite-based image
David Vincze8bdfc2d2019-03-18 15:49:23 +0100123upgrade. In this case the active firmware is always executed from the primary
124slot and the secondary slot is a staging area for new images. Before executing
125the new firmware image, the content of the primary slot must be overwritten with
126the content of the secondary slot (the new firmware image). The second option is
127the image swapping strategy when the content of the two memory slots must be
128physically swapped. This needs the scratch area to be defined in the memory
129layout. The third option is the non-swapping version, which eliminates the
130complexity of image swapping and its administration. Active image can be
131executed from either memory slot, but new firmware must be linked to the address
132space of the proper (currently inactive) memory slot.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200133
David Vincze8a2a4e22019-05-24 10:14:23 +0200134Overwrite operation
Tamas Bane7efdc62019-06-05 13:14:52 +0100135===================
David Vincze8bdfc2d2019-03-18 15:49:23 +0100136Active image is stored in the primary slot, and this image is started always by
137the bootloader. Therefore images must be linked to the primary slot. If the
138bootloader finds a valid image in the secondary slot, which is marked for
139upgrade, then the content of the primary slot will be simply overwritten with
140the content of the secondary slot, before starting the new image from the
141primary slot. After the content of the primary slot has been successfully
142overwritten, the header and trailer of the new image in the secondary slot is
David Vincze9c609012019-08-22 13:37:21 +0200143erased to prevent the triggering of another unnecessary image upgrade after a
David Vincze8bdfc2d2019-03-18 15:49:23 +0100144restart. The overwrite operation is fail-safe and resistant to power-cut
145failures. For more details please refer to the MCUBoot
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200146`documentation <https://www.mcuboot.com/mcuboot/design.html>`__.
147
David Vincze8a2a4e22019-05-24 10:14:23 +0200148Swapping operation
149==================
150This operation can be set with the ``MCUBOOT_UPGRADE_STRATEGY`` compile time
151switch (see `Build time configuration`_). With swapping image upgrade strategy
David Vincze8bdfc2d2019-03-18 15:49:23 +0100152the active image is also stored in the primary slot and it will always be
153started by the bootloader. If the bootloader finds a valid image in the
154secondary slot, which is marked for upgrade, then contents of the primary slot
155and the secondary slot will be swapped, before starting the new image from the
156primary slot. Scratch area is used as a temporary storage place during image
157swapping. Update mark from the secondary slot is removed when the swapping is
David Vincze8a2a4e22019-05-24 10:14:23 +0200158successful. The boot loader can revert the swapping as a fall-back mechanism to
159recover the previous working firmware version after a faulty update. The swap
160operation is fail-safe and resistant to power-cut failures. For more details
161please refer to the MCUBoot
162`documentation <https://www.mcuboot.com/mcuboot/design.html>`__.
163
164.. Note::
165
166 After a successful image upgrade the firmware can mark itself as "OK" at
167 runtime by setting the image_ok flag in the flash. When this happens, the
168 swap is made "permanent" and MCUBoot will then still choose to run it
169 during the next boot. Currently TF-M does not set the image_ok flag,
170 therefore the bootloader will always perform a "revert" (swap the images
171 back) during the next boot.
172
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200173Non-swapping operation
174======================
David Vincze8a2a4e22019-05-24 10:14:23 +0200175This operation can be set with the ``MCUBOOT_UPGRADE_STRATEGY`` compile time
176switch (see `Build time configuration`_). When enabling non-swapping operation
177then the active image flag is moved between slots during firmware upgrade. If
178firmware is executed-in-place (XIP), then two firmware images must be generated.
David Vincze8bdfc2d2019-03-18 15:49:23 +0100179One of them is linked to be executed from the primary slot memory region and the
180other from the secondary slot. The firmware upgrade client, which downloads the
181new image, must be aware, which slot hosts the active firmware and which acts as
182a staging area and it is responsible for downloading the proper firmware image.
183At boot time MCUBoot inspects the version number in the image header and passes
184execution to the newer firmware version. New image must be marked for upgrade
185which is automatically done by Python scripts at compile time. Image
186verification is done the same way in all operational modes. If new image fails
187during authentication then MCUBoot erases the memory slot and starts the other
188image, after successful authentication.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200189
190At build time automatically two binaries are generated::
191
David Vincze8bdfc2d2019-03-18 15:49:23 +0100192 <build_dir>/install/outputs/fvp/tfm_s_ns_signed.bin : Image linked for the primary slot memory partition
David Vincze8a2a4e22019-05-24 10:14:23 +0200193
David Vincze8bdfc2d2019-03-18 15:49:23 +0100194 <build_dir>/install/outputs/fvp/tfm_s_ns_signed_1.bin : Image linked for the secondary slot memory partition
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200195
David Vincze9c609012019-08-22 13:37:21 +0200196.. Note::
197
198 Only single image boot is supported with non-swapping upgrade mode.
199
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200200RAM Loading firmware upgrade
201============================
David Vincze8a2a4e22019-05-24 10:14:23 +0200202Musca-A supports an image upgrade mode that is separate to the other (overwrite,
203swapping and non-swapping) modes. This is the ``RAM loading`` mode (please refer
204to the table below). Like the non-swapping mode, this selects the newest image
205by reading the image version numbers in the image headers, but instead of
206executing it in place, the newest image is copied to RAM for execution. The load
207address, the location in RAM where the image is copied to, is stored in the
208image header.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200209
David Vincze9c609012019-08-22 13:37:21 +0200210.. Note::
211
212 Only single image boot is supported with RAM loading upgrade mode.
213
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200214Summary of different modes for image upgrade
215============================================
216Different implementations of the image upgrade operation (whether through
David Vincze8a2a4e22019-05-24 10:14:23 +0200217overwriting, swapping, non-swapping or loading into RAM and executing from
218there) are supported by the platforms. The table below shows which of these
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200219modes are supported by which platforms:
220
Marton Berkee9803662019-11-11 14:11:05 +0100221+-------------+-----------------+----------------------------------------------------------+
222| | Without BL2 [1]_| With BL2 [2]_ |
223+=============+=================+===============+==========+=============+=================+
224| | XIP | XIP | XIP | XIP | Not XIP |
225+-------------+-----------------+---------------+----------+-------------+-----------------+
226| | | Overwrite [3]_| Swap [4]_| No-swap [5]_| RAM loading [6]_|
227+-------------+-----------------+---------------+----------+-------------+-----------------+
228| AN521 | Yes | Yes | Yes | Yes | No |
229+-------------+-----------------+---------------+----------+-------------+-----------------+
230| AN519 | Yes | Yes | Yes | Yes | No |
231+-------------+-----------------+---------------+----------+-------------+-----------------+
232| AN539 | Yes | Yes | Yes | Yes | No |
233+-------------+-----------------+---------------+----------+-------------+-----------------+
234| Musca-A | No | No | No | No | Yes |
235+-------------+-----------------+---------------+----------+-------------+-----------------+
236| Musca-B1 | Yes | No | No | Yes | No |
237+-------------+-----------------+---------------+----------+-------------+-----------------+
238| Musca-S1 | Yes | No | No | Yes | No |
239+-------------+-----------------+---------------+----------+-------------+-----------------+
240| AN524 | Yes | No | No | Yes | No |
241+-------------+-----------------+---------------+----------+-------------+-----------------+
242| PSoC64 | Yes | No | No | No | No |
243+-------------+-----------------+---------------+----------+-------------+-----------------+
244| SSE-200_AWS | Yes | Yes | Yes | Yes | No |
245+-------------+-----------------+---------------+----------+-------------+-----------------+
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200246
247.. [1] To disable BL2, please turn off the ``BL2`` compiler switch in the
David Vincze9c609012019-08-22 13:37:21 +0200248 build configuration file (``bl2/ext/mcuboot/MCUBootConfig.cmake``) or
249 in the command line
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200250
251.. [2] BL2 is enabled by default
252
David Vincze8a2a4e22019-05-24 10:14:23 +0200253.. [3] The image executes in-place (XIP) and is in Overwrite mode for image
254 update by default
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200255
David Vincze8a2a4e22019-05-24 10:14:23 +0200256.. [4] To enable XIP Swap mode, assign the "SWAP" string to the
David Vincze9c609012019-08-22 13:37:21 +0200257 ``MCUBOOT_UPGRADE_STRATEGY`` configuration variable in the build
David Vincze8a2a4e22019-05-24 10:14:23 +0200258 configuration file, or include this macro definition in the command line
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200259
David Vincze8a2a4e22019-05-24 10:14:23 +0200260.. [5] To enable XIP No-swap, assign the "NO_SWAP" string to the
David Vincze9c609012019-08-22 13:37:21 +0200261 ``MCUBOOT_UPGRADE_STRATEGY`` configuration variable in the build
David Vincze8a2a4e22019-05-24 10:14:23 +0200262 configuration file, or include this macro definition in the command line
263
264.. [6] To enable RAM loading, assign the "RAM_LOADING" string to the
David Vincze9c609012019-08-22 13:37:21 +0200265 ``MCUBOOT_UPGRADE_STRATEGY`` configuration variable in the build
David Vincze8a2a4e22019-05-24 10:14:23 +0200266 configuration file, or include this macro definition in the command line
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200267
David Vinczec3e313a2020-01-06 17:31:11 +0100268**************************
269Using the original MCUBoot
270**************************
271The original MCUBoot from `GitHub <https://github.com/JuulLabs-OSS/mcuboot>`__
272can also be used as the bootloader in TF-M. However please note that the
273original MCUBoot doesn't support the ``No-swap`` and ``RAM loading`` upgrade
274strategies, therefore those platforms that doesn't support other upgrade
275strategies (e.g. ``Overwrite``) cannot be used with the original MCUBoot at the
276moment.
277
278To use the upstream MCUBoot it must be cloned into the TF-M base folder
279first (into which the TF-M was cloned previously). After the original MCUBoot
280code is present at the required location the ``MCUBOOT_REPO=UPSTREAM`` option
281must be added to the command line at the CMake configuration step::
282
283 cd <TF-M base folder>
284 git clone https://github.com/JuulLabs-OSS/mcuboot.git -b v1.4.0
285 cd <TF-M build folder>
286 cmake -G"Unix Makefiles" -DTARGET_PLATFORM=AN521 -DCOMPILER=ARMCLANG -DMCUBOOT_REPO=UPSTREAM ../
287
David Vincze9c609012019-08-22 13:37:21 +0200288*******************
289Multiple image boot
290*******************
291It is possible to update the firmware images independently to support the
292scenario when secure and non-secure images are provided by different vendors.
293Multiple image boot is supported only together with the overwrite and swap
294firmware upgrade modes.
295
296It is possible to describe the dependencies of the images on each other in
297order to avoid a faulty upgrade when incompatible versions would be installed.
298These dependencies are part of the image manifest area.
299The dependencies are composed from two parts:
300
301 - **Image identifier:** The number of the image which the current image (whose
302 manifest area contains the dependency entry) depends on. The image identifier
303 starts from 0.
304
305 - **Minimum version:** The minimum version of other image must be present on
306 the device by the end of the upgrade (both images might be updated at the
307 same time).
308
309Dependencies can be added to the images at compile time with the following
310compile time switches:
311
312 - ``S_IMAGE_MIN_VER`` It is added to the non-secure image and specifies the
313 minimum required version of the secure image.
314 - ``NS_IMAGE_MIN_VER`` It is added to the secure image and specifies the
315 minimum required version of the non-secure image.
316
317Example of how to provide the secure image minimum version::
318
319 cmake -G"Unix Makefiles" -DTARGET_PLATFORM=AN521 -DCOMPILER=ARMCLANG -DS_IMAGE_MIN_VER=1.2.3+4 ../
320
Tamas Ban7801ed42019-05-20 13:21:53 +0100321********************
322Signature algorithms
323********************
324MbedTLS library is used to sign the images. The list of supported signing
325algorithms:
Tamas Bane7efdc62019-06-05 13:14:52 +0100326
327 - `RSA-2048`
328 - `RSA-3072`: default
329
David Vincze9c609012019-08-22 13:37:21 +0200330Example keys stored in:
331
332 - ``root-rsa-2048.pem`` : Used to sign single image (S+NS) or secure image
333 in case of multiple image boot
334 - ``root-rsa-2048_1.pem`` : Used to sign non-secure image in case of multiple
335 image boot
336 - ``root-rsa-3072.pem`` : Used to sign single image (S+NS) or secure image
337 in case of multiple image boot
338 - ``root-rsa-3072_1.pem`` : Used to sign non-secure image in case of multiple
339 image boot
Tamas Ban7801ed42019-05-20 13:21:53 +0100340
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200341************************
342Build time configuration
343************************
David Vincze9c609012019-08-22 13:37:21 +0200344MCUBoot related compile time switches can be set in the build configuration
345file::
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200346
David Vincze9c609012019-08-22 13:37:21 +0200347 bl2/ext/mcuboot/MCUBootConfig.cmake
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200348
349Compile time switches:
350
351- BL2 (default: True):
352 - **True:** TF-M built together with bootloader. MCUBoot is executed after
353 reset and it authenticates TF-M and starts secure code.
354 - **False:** TF-M built without bootloader. Secure image linked to the
355 beginning of the device memory and executed after reset. If it is false
David Vincze9c609012019-08-22 13:37:21 +0200356 then using any of the further compile time switches is invalid.
David Vinczec3e313a2020-01-06 17:31:11 +0100357- MCUBOOT_REPO (default: "TF-M"):
358 - **"TF-M":** Use TF-M's MCUBoot fork as bootloader which is located in the
359 bl2/ext/mcuboot folder.
360 - **"UPSTREAM":** Use the original (upstream) MCUBoot as bootloader. Before
361 selecting this option please read the `Using the original MCUBoot`_
362 section for more information and the limitations of using this option.
David Vincze8a2a4e22019-05-24 10:14:23 +0200363- MCUBOOT_UPGRADE_STRATEGY (default: "OVERWRITE_ONLY"):
364 - **"OVERWRITE_ONLY":** Default firmware upgrade operation with overwrite.
365 - **"SWAP":** Activate swapping firmware upgrade operation.
366 - **"NO_SWAP":** Activate non-swapping firmware upgrade operation.
367 - **"RAM_LOADING":** Activate RAM loading firmware upgrade operation, where
David Vincze9c609012019-08-22 13:37:21 +0200368 the latest image is copied to RAM and runs from there instead of being
David Vincze8a2a4e22019-05-24 10:14:23 +0200369 executed in-place.
Tamas Ban7801ed42019-05-20 13:21:53 +0100370- MCUBOOT_SIGNATURE_TYPE (default: RSA-3072):
David Vincze9c609012019-08-22 13:37:21 +0200371 - **RSA-3072:** Image is signed with RSA-3072 algorithm
372 - **RSA-2048:** Image is signed with RSA-2048 algorithm
373- MCUBOOT_IMAGE_NUMBER (default: 2):
374 - **1:** Single image boot, secure and non-secure images are signed and
375 updated together.
376 - **2:** Multiple image boot, secure and non-secure images are signed and
377 updatable independently.
378- MCUBOOT_HW_KEY (default: True):
379 - **True:** The hash of public key is provisioned to the SoC and the image
380 manifest contains the whole public key. MCUBoot validates the key before
381 using it for firmware authentication, it calculates the hash of public key
382 from the manifest and compare against the retrieved key-hash from the
383 hardware. This way MCUBoot is independent from the public key(s).
384 Key(s) can be provisioned any time and by different parties.
385 - **False:** The whole public key is embedded to the bootloader code and the
386 image manifest contains only the hash of the public key. MCUBoot validates
387 the key before using it for firmware authentication, it calculates the
388 hash of built-in public key and compare against the retrieved key-hash
389 from the image manifest. After this the bootloader can verify that the
390 image was signed with a private key that corresponds to the retrieved
391 key-hash (it can have more public keys embedded in and it may have to look
392 for the matching one). All the public key(s) must be known at MCUBoot
393 build time.
David Vincze73dfbc52019-10-11 13:54:58 +0200394- MCUBOOT_LOG_LEVEL:
395 Can be used to configure the level of logging in MCUBoot. The possible
396 values are the following:
397
398 - **LOG_LEVEL_OFF**
399 - **LOG_LEVEL_ERROR**
400 - **LOG_LEVEL_WARNING**
401 - **LOG_LEVEL_INFO**
402 - **LOG_LEVEL_DEBUG**
403
404 The logging in MCUBoot can be disabled and thus the code size can be reduced
405 by setting it to ``LOG_LEVEL_OFF``. Its value depends on the build type. If
406 the build type is ``Debug`` and a value has been provided (e.g. through the
407 command line or the CMake GUI) then that value will be used, otherwise it is
408 ``LOG_LEVEL_INFO`` by default. In case of different kinds of ``Release``
409 builds its value is set to ``LOG_LEVEL_OFF`` (any other value will be
410 overridden).
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200411
412Image versioning
413================
David Vincze9c609012019-08-22 13:37:21 +0200414An image version number is written to its header by one of the Python scripts,
David Vincze8a2a4e22019-05-24 10:14:23 +0200415and this number is used by the bootloader when the non-swapping or RAM loading
David Vincze9c609012019-08-22 13:37:21 +0200416mode is enabled. It is also used in case of multiple image boot when the
417bootloader checks the image dependencies if any have been added to the images.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200418
David Vincze9c609012019-08-22 13:37:21 +0200419The version number of the image (single image boot) can manually be passed in
420through the command line in the cmake configuration step::
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200421
422 cmake -G"Unix Makefiles" -DTARGET_PLATFORM=AN521 -DCOMPILER=ARMCLANG -DIMAGE_VERSION=1.2.3+4 ../
423
424Alternatively, the version number can be less specific (e.g 1, 1.2, or 1.2.3),
425where the missing numbers are automatically set to zero. The image version
426number argument is optional, and if it is left out, then the version numbers of
427the image(s) being built in the same directory will automatically change. In
428this case, the last component (the build number) automatically increments from
429the previous one: 0.0.0+1 -> 0.0.0+2, for as many times as the build is re-ran,
430**until a number is explicitly provided**. If automatic versioning is in place
431and then an image version number is provided for the first time, the new number
432will take precedence and be used instead. All subsequent image versions are
433then set to the last number that has been specified, and the build number would
434stop incrementing. Any new version numbers that are provided will overwrite
435the previous one: 0.0.0+1 -> 0.0.0+2. Note: To re-apply automatic image
436versioning, please start a clean build without specifying the image version
David Vincze9c609012019-08-22 13:37:21 +0200437number at all. In case of multiple image boot there are separate compile time
438switches for both images to provide their version: ``IMAGE_VERSION_S`` and
439``IMAGE_VERSION_NS``. These must be used instead of ``IMAGE_VERSION``.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200440
David Vincze060968d2019-05-23 01:13:14 +0200441Security counter
442================
443Each signed image contains a security counter in its manifest. It is used by the
444bootloader and its aim is to have an independent (from the image version)
445counter to ensure rollback protection by comparing the new image's security
446counter against the original (currently active) image's security counter during
447the image upgrade process. It is added to the manifest (to the TLV area that is
David Vincze9c609012019-08-22 13:37:21 +0200448appended to the end of the image) by one of the Python scripts when signing the
David Vincze060968d2019-05-23 01:13:14 +0200449image. The value of the security counter is security critical data and it is in
David Vincze9c609012019-08-22 13:37:21 +0200450the integrity protected part of the image. The last valid security counter
451should always be stored in a non-volatile and trusted component of the device
452and its value should always be increased if a security flaw was fixed in the
453current image version. The value of the security counter (single image boot) can
454be specified at build time in the cmake configuration step::
David Vincze060968d2019-05-23 01:13:14 +0200455
456 cmake -G"Unix Makefiles" -DTARGET_PLATFORM=AN521 -DCOMPILER=ARMCLANG -DSECURITY_COUNTER=42 ../
457
458The security counter can be independent from the image version, but not
459necessarily. Alternatively, if it is not specified at build time with the
David Vincze9c609012019-08-22 13:37:21 +0200460``SECURITY_COUNTER`` option the Python script will automatically generate it
David Vincze060968d2019-05-23 01:13:14 +0200461from the image version number (not including the build number) and this value
David Vincze9c609012019-08-22 13:37:21 +0200462will be added to the signed image. In case of multiple image boot there are
463separate compile time switches for both images to provide their security counter
464value: ``SECURITY_COUNTER_S`` and ``SECURITY_COUNTER_NS``. These must be used
465instead of ``SECURITY_COUNTER``. If these are not defined then the security
466counter values will be derived from the corresponding image version similar to
467the single image boot.
468
469***************************
470Signing the images manually
471***************************
472Normally the build system handles the signing (computing hash over the image
473and security critical manifest data and then signing the hash) of the firmware
474images. However, the images also can be signed manually by using the ``imgtool``
475Python program which is located in the ``bl2/ext/mcuboot/scripts`` directory.
476Issue the ``python3 imgtool.py sign --help`` command in the directory for more
477information about the mandatory and optional arguments. The tool takes an image
478in binary or Intel Hex format and adds a header and trailer that MCUBoot is
479expecting. In case of single image boot after a successful build the
480``tfm_full.bin`` build artifact (contains the concatenated secure and non-secure
481images) must be passed to the script and in case of multiple image boot the
482``tfm_s.bin`` and ``tfm_ns.bin`` binaries can be passed to prepare the signed
483images.
484
485Signing the secure image manually in case of multiple image boot
486================================================================
487
488::
489
490 python3 bl2/ext/mcuboot/scripts/imgtool.py sign \
491 --layout <build_dir>/image_macros_preprocessed_s.c \
492 -k <tfm_dir>/bl2/ext/mcuboot/root-rsa-3072.pem \
493 --public-key-format full \
494 --align 1 \
495 -v 1.2.3+4 \
496 -d "(1,1.2.3+0)" \
497 -s 42 \
498 -H 0x400 \
499 <build_dir>/install/outputs/AN521/tfm_s.bin \
500 <build_dir>/tfm_s_signed.bin
David Vincze060968d2019-05-23 01:13:14 +0200501
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200502************************
503Testing firmware upgrade
504************************
505As downloading the new firmware image is out of scope for MCUBoot, the update
506process is started from a state where the original and the new image are already
507programmed to the appropriate memory slots. To generate the original and a new
508firmware package, TF-M is built twice with different build configurations.
509
David Vincze8a2a4e22019-05-24 10:14:23 +0200510Overwriting firmware upgrade
Tamas Bane7efdc62019-06-05 13:14:52 +0100511============================
David Vincze9c609012019-08-22 13:37:21 +0200512Run TF-M build twice with ``MCUBOOT_IMAGE_NUMBER`` set to "1" in both cases
513(single image boot), but with two different build configurations: default and
David Vincze8a2a4e22019-05-24 10:14:23 +0200514regression. Save the artifacts between builds, because second run can overwrite
David Vincze8bdfc2d2019-03-18 15:49:23 +0100515original binaries. Download default build to the primary slot and regression
516build to the secondary slot.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200517
518Executing firmware upgrade on FVP_MPS2_AEMv8M
519---------------------------------------------
520.. code-block:: bash
521
522 <DS5_PATH>/sw/models/bin/FVP_MPS2_AEMv8M \
523 --parameter fvp_mps2.platform_type=2 \
524 --parameter cpu0.baseline=0 \
525 --parameter cpu0.INITVTOR_S=0x10000000 \
526 --parameter cpu0.semihosting-enable=0 \
527 --parameter fvp_mps2.DISABLE_GATING=0 \
528 --parameter fvp_mps2.telnetterminal0.start_telnet=1 \
529 --parameter fvp_mps2.telnetterminal1.start_telnet=0 \
530 --parameter fvp_mps2.telnetterminal2.start_telnet=0 \
531 --parameter fvp_mps2.telnetterminal0.quiet=0 \
532 --parameter fvp_mps2.telnetterminal1.quiet=1 \
533 --parameter fvp_mps2.telnetterminal2.quiet=1 \
534 --application cpu0=<build_dir>/bl2/ext/mcuboot/mcuboot.axf \
535 --data cpu0=<default_build_dir>/install/outputs/fvp/tfm_s_ns_signed.bin@0x10080000 \
536 --data cpu0=<regresssion_build_dir>/install/outputs/fvp/tfm_s_ns_signed.bin@0x10180000
537
538Executing firmware upgrade on SSE 200 FPGA on MPS2 board
539--------------------------------------------------------
540
541::
542
543 TITLE: Versatile Express Images Configuration File
544 [IMAGES]
545 TOTALIMAGES: 3 ;Number of Images (Max: 32)
546 IMAGE0ADDRESS: 0x00000000
547 IMAGE0FILE: \Software\mcuboot.axf ; BL2 bootloader
548 IMAGE1ADDRESS: 0x10080000
David Vincze8a2a4e22019-05-24 10:14:23 +0200549 IMAGE1FILE: \Software\tfm_sig1.bin ; TF-M default test binary blob
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200550 IMAGE2ADDRESS: 0x10180000
551 IMAGE2FILE: \Software\tfm_sig2.bin ; TF-M regression test binary blob
552
David Vincze8a2a4e22019-05-24 10:14:23 +0200553The following message will be shown in case of successful firmware upgrade:
554
555::
556
557 [INF] Starting bootloader
558 [INF] Swap type: test
David Vincze8bdfc2d2019-03-18 15:49:23 +0100559 [INF] Image upgrade secondary slot -> primary slot
560 [INF] Erasing the primary slot
561 [INF] Copying the secondary slot to the primary slot: 0x100000 bytes
David Vincze8a2a4e22019-05-24 10:14:23 +0200562 [INF] Bootloader chainload address offset: 0x80000
563 [INF] Jumping to the first image slot
564 [Sec Thread] Secure image initializing!
565
566 #### Execute test suites for the Secure area ####
567 Running Test Suite PSA protected storage S interface tests (TFM_SST_TEST_2XXX)...
568 ...
569
David Vincze9c609012019-08-22 13:37:21 +0200570To update the secure and non-secure images separately (multiple image boot),
571set the ``MCUBOOT_IMAGE_NUMBER`` switch to "2" (this is the default
572configuration value) and follow the same instructions as in case of single image
573boot.
574
575Executing multiple firmware upgrades on SSE 200 FPGA on MPS2 board
576------------------------------------------------------------------
577
578::
579
580 TITLE: Versatile Express Images Configuration File
581 [IMAGES]
582 TOTALIMAGES: 4 ;Number of Images (Max: 32)
583 IMAGE0ADDRESS: 0x00000000
584 IMAGE0FILE: \Software\mcuboot.axf ; BL2 bootloader
585 IMAGE1ADDRESS: 0x10080000
586 IMAGE1FILE: \Software\tfm_sign.bin ; TF-M default test binary blob
587 IMAGE2ADDRESS: 0x10180000
588 IMAGE2FILE: \Software\tfm_ss1.bin ; TF-M regression test secure (signed) image
589 IMAGE3ADDRESS: 0x10200000
590 IMAGE3FILE: \Software\tfm_nss1.bin ; TF-M regression test non-secure (signed) image
591
592Note that both the concatenated binary blob (the images are signed separately
593and then concatenated) and the separate signed images can be downloaded to the
594device because on this platform (AN521) both the primary slots and the secondary
595slots are contiguous areas in the Flash (see `Integration with TF-M`_). The
596following message will be shown in case of successful firmware upgrades:
597
598::
599
600 [INF] Starting bootloader
601 [INF] Swap type: test
602 [INF] Swap type: test
603 [INF] Image upgrade secondary slot -> primary slot
604 [INF] Erasing the primary slot
605 [INF] Copying the secondary slot to the primary slot: 0x80000 bytes
606 [INF] Image upgrade secondary slot -> primary slot
607 [INF] Erasing the primary slot
608 [INF] Copying the secondary slot to the primary slot: 0x80000 bytes
609 [INF] Bootloader chainload address offset: 0x80000
610 [INF] Jumping to the first image slot
611 [Sec Thread] Secure image initializing!
612 TFM level is: 1
613 [Sec Thread] Jumping to non-secure code...
614
615 #### Execute test suites for the Secure area ####
616 Running Test Suite PSA protected storage S interface tests (TFM_SST_TEST_2XXX)...
617 ...
618
David Vincze8a2a4e22019-05-24 10:14:23 +0200619Swapping firmware upgrade
620=============================
621Follow the same instructions and platform related configurations as in case of
622overwriting build including these changes:
623
David Vincze9c609012019-08-22 13:37:21 +0200624- Set the ``MCUBOOT_UPGRADE_STRATEGY`` compile time switch to "SWAP"
625 before build.
626- Set the ``MCUBOOT_IMAGE_NUMBER`` compile time switch to "1" (single image
627 boot) or "2" (multiple image boot) before build.
David Vincze8a2a4e22019-05-24 10:14:23 +0200628
David Vincze9c609012019-08-22 13:37:21 +0200629During single image boot the following message will be shown in case of
630successful firmware upgrade, ``Swap type: test`` indicates that images were
631swapped:
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200632
633::
634
David Vincze8a2a4e22019-05-24 10:14:23 +0200635 [INF] Starting bootloader
636 [INF] Image 0: magic= good, copy_done=0x3, image_ok=0x3
637 [INF] Scratch: magic= bad, copy_done=0x0, image_ok=0x2
David Vincze8bdfc2d2019-03-18 15:49:23 +0100638 [INF] Boot source: primary slot
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200639 [INF] Swap type: test
640 [INF] Bootloader chainload address offset: 0x80000
641 [INF] Jumping to the first image slot
642 [Sec Thread] Secure image initializing!
643
David Vincze8a2a4e22019-05-24 10:14:23 +0200644 #### Execute test suites for the Secure area ####
645 Running Test Suite PSA protected storage S interface tests (TFM_SST_TEST_2XXX)...
646 ...
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200647
648Non-swapping firmware upgrade
649=============================
David Vincze9c609012019-08-22 13:37:21 +0200650Follow the same instructions and platform related configurations as in case of
651overwriting build including these changes:
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200652
David Vincze8a2a4e22019-05-24 10:14:23 +0200653- Set the ``MCUBOOT_UPGRADE_STRATEGY`` compile time switch to "NO_SWAP"
654 before build.
David Vincze9c609012019-08-22 13:37:21 +0200655- Make sure the image version number was increased between the two build runs
656 either by specifying it manually or by checking in the build log that it was
657 incremented automatically.
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200658
659Executing firmware upgrade on FVP_MPS2_AEMv8M
660---------------------------------------------
661
662.. code-block:: bash
663
664 <DS5_PATH>/sw/models/bin/FVP_MPS2_AEMv8M \
665 --parameter fvp_mps2.platform_type=2 \
666 --parameter cpu0.baseline=0 \
667 --parameter cpu0.INITVTOR_S=0x10000000 \
668 --parameter cpu0.semihosting-enable=0 \
669 --parameter fvp_mps2.DISABLE_GATING=0 \
670 --parameter fvp_mps2.telnetterminal0.start_telnet=1 \
671 --parameter fvp_mps2.telnetterminal1.start_telnet=0 \
672 --parameter fvp_mps2.telnetterminal2.start_telnet=0 \
673 --parameter fvp_mps2.telnetterminal0.quiet=0 \
674 --parameter fvp_mps2.telnetterminal1.quiet=1 \
675 --parameter fvp_mps2.telnetterminal2.quiet=1 \
676 --application cpu0=<build_dir>/bl2/ext/mcuboot/mcuboot.axf \
Tamas Banbba85642019-06-06 09:31:59 +0100677 --data cpu0=<default_build_dir>/install/outputs/fvp/tfm_s_ns_signed.bin@0x10080000 \
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200678 --data cpu0=<regresssion_build_dir>/install/outputs/fvp/tfm_s_ns_signed_1.bin@0x10180000
679
680Executing firmware upgrade on SSE 200 FPGA on MPS2 board
681--------------------------------------------------------
682
683::
684
685 TITLE: Versatile Express Images Configuration File
686 [IMAGES]
687 TOTALIMAGES: 3 ;Number of Images (Max: 32)
688 IMAGE0ADDRESS: 0x00000000
689 IMAGE0FILE: \Software\mcuboot.axf ; BL2 bootloader
690 IMAGE1ADDRESS: 0x10080000
Tamas Banbba85642019-06-06 09:31:59 +0100691 IMAGE1FILE: \Software\tfm_sign.bin ; TF-M default test binary blob
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200692 IMAGE2ADDRESS: 0x10180000
693 IMAGE2FILE: \Software\tfm_sig1.bin ; TF-M regression test binary blob
694
695Executing firmware upgrade on Musca-B1 board
696--------------------------------------------
David Vincze9c609012019-08-22 13:37:21 +0200697After the two images have been built, they can be concatenated to create the
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200698combined image using ``srec_cat``:
699
700- Linux::
David Vincze8a2a4e22019-05-24 10:14:23 +0200701
Tamas Bane1570bd2019-10-25 15:20:35 +0100702 srec_cat bl2/ext/mcuboot/mcuboot.bin -Binary -offset 0xA000000 tfm_sign.bin -Binary -offset 0xA020000 tfm_sign_1.bin -Binary -offset 0xA100000 -o tfm.hex -Intel
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200703
704- Windows::
David Vincze8a2a4e22019-05-24 10:14:23 +0200705
Tamas Bane1570bd2019-10-25 15:20:35 +0100706 srec_cat.exe bl2\ext\mcuboot\mcuboot.bin -Binary -offset 0xA000000 tfm_sign.bin -Binary -offset 0xA020000 tfm_sign_1.bin -Binary -offset 0xA100000 -o tfm.hex -Intel
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200707
708The following message will be shown in case of successful firmware upgrade,
709notice that image with higher version number (``version=1.2.3.5``) is executed:
710
711::
712
713 [INF] Starting bootloader
David Vincze8a2a4e22019-05-24 10:14:23 +0200714 [INF] Image 0: version=1.2.3.4, magic= good, image_ok=0x3
715 [INF] Image 1: version=1.2.3.5, magic= good, image_ok=0x3
David Vincze8bdfc2d2019-03-18 15:49:23 +0100716 [INF] Booting image from the secondary slot
David Vincze8a2a4e22019-05-24 10:14:23 +0200717 [INF] Bootloader chainload address offset: 0xa0000
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200718 [INF] Jumping to the first image slot
719 [Sec Thread] Secure image initializing!
720
David Vincze8a2a4e22019-05-24 10:14:23 +0200721 #### Execute test suites for the Secure area ####
722 Running Test Suite PSA protected storage S interface tests (TFM_SST_TEST_2XXX)...
723 ...
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200724
Kevin Peng0a142112018-09-21 10:42:22 +0800725Executing firmware upgrade on CoreLink SSE-200 Subsystem for MPS3 (AN524)
726-------------------------------------------------------------------------
727
728::
729
730 TITLE: Arm MPS3 FPGA prototyping board Images Configuration File
731
732 [IMAGES]
733 TOTALIMAGES: 3 ;Number of Images (Max: 32)
734
735 IMAGE0UPDATE: AUTO ;Image Update:NONE/AUTO/FORCE
736 IMAGE0ADDRESS: 0x00000000
737 IMAGE0FILE: \SOFTWARE\mcuboot.bin ;BL2 bootloader
738 IMAGE1UPDATE: AUTO
739 IMAGE1ADDRESS: 0x00040000
740 IMAGE1FILE: \SOFTWARE\tfm_sig0.bin ;TF-M example application binary blob
741 IMAGE2UPDATE: AUTO
742 IMAGE2ADDRESS: 0x000C0000
743 IMAGE2FILE: \SOFTWARE\tfm_sig1.bin ;TF-M regression test binary blob
744
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200745RAM loading firmware upgrade
746============================
David Vincze8a2a4e22019-05-24 10:14:23 +0200747To enable RAM loading, please set ``MCUBOOT_UPGRADE_STRATEGY`` to "RAM_LOADING"
748(either in the configuration file or through the command line), and then specify
749a destination load address in RAM where the image can be copied to and executed
750from. The ``IMAGE_LOAD_ADDRESS`` macro must be specified in the target dependent
751files, for example with Musca-A, its ``flash_layout.h`` file in the ``platform``
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200752folder should include ``#define IMAGE_LOAD_ADDRESS #0x10020000``
753
David Vincze8a2a4e22019-05-24 10:14:23 +0200754Executing firmware upgrade on Musca-A board
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200755--------------------------------------------
756After two images have been built, they can be concatenated to create the
757combined image using ``srec_cat``:
758
David Vincze8a2a4e22019-05-24 10:14:23 +0200759- Linux::
760
761 srec_cat bl2/ext/mcuboot/mcuboot.bin -Binary -offset 0x200000 tfm_sign_old.bin -Binary -offset 0x220000 tfm_sign_new.bin -Binary -offset 0x320000 -o tfm.hex -Intel
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200762
763- Windows::
David Vincze8a2a4e22019-05-24 10:14:23 +0200764
David Vincze9c609012019-08-22 13:37:21 +0200765 srec_cat.exe bl2\ext\mcuboot\mcuboot.bin -Binary -offset 0x200000 tfm_sign_old.bin -Binary -offset 0x220000 tfm_sign_new.bin -Binary -offset 0x320000 -o tfm.hex -Intel
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200766
767The following message will be shown in case of successful firmware upgrade when,
768RAM loading is enabled, notice that image with higher version number
769(``version=0.0.0.2``) is executed:
770
771::
772
David Vincze8a2a4e22019-05-24 10:14:23 +0200773 [INF] Starting bootloader
774 [INF] Image 0: version=0.0.0.1, magic= good, image_ok=0x3
775 [INF] Image 1: version=0.0.0.2, magic= good, image_ok=0x3
David Vincze8bdfc2d2019-03-18 15:49:23 +0100776 [INF] Image has been copied from the secondary slot in flash to SRAM address 0x10020000
Gyorgy Szingdb9783c2019-04-17 21:08:48 +0200777 [INF] Booting image from SRAM at address 0x10020000
778 [INF] Bootloader chainload address offset: 0x20000
779 [INF] Jumping to the first image slot
780 [Sec Thread] Secure image initializing!
781
782--------------
783
David Vinczec3e313a2020-01-06 17:31:11 +0100784*Copyright (c) 2018-2020, Arm Limited. All rights reserved.*