1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
--------------
NXP Platforms:
--------------
TRUSTED_BOARD_BOOT option can be enabled by specifying TRUSTED_BOARD_BOOT=1 on command line during make.
Bare-Minimum Preparation to run TBBR on NXP Platforms:
=======================================================
- OTPMK(One Time Programable Key) needs to be burnt in fuses.
-- It is the 256 bit key that stores a secret value used by the NXP SEC 4.0 IP in Trusted or Secure mode.
Note: It is primarily for the purpose of decrypting additional secrets stored in system non-volatile memory.
-- NXP CST tool gives an option to generate it.
Use the below command from directory 'cst', with correct options.
.. code:: shell
./gen_otpmk_drbg
- SRKH (Super Root Key Hash) needs to be burnt in fuses.
-- It is the 256 bit hash of the list of the public keys of the SRK key pair.
-- NXP CST tool gives an option to generate the RSA key pair and its hash.
Use the below command from directory 'cst', with correct options.
.. code:: shell
./gen_keys
Refer fuse frovisioning readme 'nxp-ls-fuse-prov.rst' for steps to blow these keys.
Two options are provided for TRUSTED_BOARD_BOOT:
================================================
-------------------------------------------------------------------------
Option 1: CoT using X 509 certificates
-------------------------------------------------------------------------
- This CoT is as provided by ARM.
- To use this option user needs to specify mbedtld dir path in MBEDTLS_DIR.
- To generate CSF header, path of CST repository needs to be specified as CST_DIR
- CSF header is embedded to each of the BL2 image.
- GENERATE_COT=1 adds the tool 'cert_create' to the build environment to generate:
-- X509 Certificates as (.crt) files.
-- X509 Pem key file as (.pem) files.
- SAVE_KEYS=1 saves the keys and certificates, if GENERATE_COT=1.
-- For this to work, file name for cert and keys are provided as part of compilation or build command.
--- default file names will be used, incase not provided as part compilation or build command.
--- default folder 'BUILD_PLAT' will be used to store them.
- ROTPK for x.509 certificates is generated and embedded in bl2.bin and
verified as part of CoT by Boot ROM during secure boot.
- Compilation steps:
All Images
.. code:: shell
make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 GENERATE_COT=1 MBEDTLS_DIR=$MBEDTLS_PATH CST_DIR=$CST_DIR_PATH \
BOOT_MODE=<platform_supported_boot_mode> \
RCW=$RCW_BIN \
BL32=$TEE_BIN SPD=opteed\
BL33=$UBOOT_SECURE_BIN \
pbl \
fip
Additional FIP_DDR Image (For NXP platforms like lx2160a)
.. code:: shell
make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 GENERATE_COT=1 MBEDTLS_DIR=$MBEDTLS_PATH fip_ddr
Note: make target 'fip_ddr' should never be combine with other make target 'fip', 'pbl' & 'bl2'.
-------------------------------------------------------------------------
Option 2: CoT using NXP CSF headers.
-------------------------------------------------------------------------
- This option is automatically selected when TRUSTED_BOARD_BOOT is set but MBEDTLS_DIR path is not specified.
- CSF header is embedded to each of the BL31, BL32 and BL33 image.
- To generate CSF header, path of CST repository needs to be specified as CST_DIR
- Default input files for CSF header generation is added in this repo.
- Default input file requires user to generate RSA key pair named
-- srk.pri, and
-- srk.pub, and add them in ATF repo.
-- These keys can be generated using gen_keys tool of CST.
- To change the input file , user can use the options BL33_INPUT_FILE, BL32_INPUT_FILE, BL31_INPUT_FILE
- There are 2 paths in secure boot flow :
-- Development Mode (sb_en in RCW = 1, SFP->OSPR, ITS = 0)
--- In this flow , even on ROTPK comparison failure, flow would continue.
--- However SNVS is transitioned to non-secure state
-- Production mode (SFP->OSPR, ITS = 1)
--- Any failure is fatal failure
- Compilation steps:
All Images
.. code:: shell
make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 CST_DIR=$CST_DIR_PATH \
BOOT_MODE=<platform_supported_boot_mode> \
RCW=$RCW_BIN \
BL32=$TEE_BIN SPD=opteed\
BL33=$UBOOT_SECURE_BIN \
pbl \
fip
Additional FIP_DDR Image (For NXP platforms like lx2160a)
.. code:: shell
make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 CST_DIR=$CST_DIR_PATH fip_ddr
- Compilation Steps with build option for generic image processing filters to prepend CSF header:
-- Generic image processing filters to prepend CSF header
BL32_INPUT_FILE = < file name>
BL33_INPUT_FILE = <file name>
.. code:: shell
make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 CST_DIR=$CST_DIR_PATH \
BOOT_MODE=<platform_supported_boot_mode> \
RCW=$RCW_BIN \
BL32=$TEE_BIN SPD=opteed\
BL33=$UBOOT_SECURE_BIN \
BL33_INPUT_FILE = <ip file> \
BL32_INPUT_FILE = <ip_file> \
BL31_INPUT_FILE = <ip file> \
pbl \
fip
Deploy ATF Images
=================
Same steps as mentioned in the readme "nxp-layerscape.rst".
Verification to check if Secure state is achieved:
==================================================
+---+----------------+-----------------+------------------------+----------------------------------+-------------------------------+
| | Platform | SNVS_HPSR_REG | SYS_SECURE_BIT(=value) | SYSTEM_SECURE_CONFIG_BIT(=value) | SSM_STATE |
+===+================+=================+========================+==================================+===============================+
| 1.| lx2160ardb or | 0x01E90014 | 15 | 14-12 | 11-8 |
| | lx2160aqds or | | ( = 1, BootROM Booted) | ( = 010 means Intent to Secure, | (=1111 means secure boot) |
| | lx2162aqds | | | ( = 000 Unsecure) | (=1011 means Non-secure Boot) |
+---+----------------+-----------------+------------------------+----------------------------------+-------------------------------+
- Production mode (SFP->OSPR, ITS = 1)
-- Linux prompt will successfully come. if the TBBR is successful.
--- Else, Linux boot will be successful.
-- For secure-boot status, read SNVS Register $SNVS_HPSR_REG from u-boot prompt:
.. code:: shell
md $SNVS_HPSR_REG
Command Output:
1e90014: 8000AF00
In case it is read as 00000000, then read this register using jtag (in development mode only through CW tap).
+0 +4 +8 +C
[0x01E90014] 8000AF00
- Development Mode (sb_en in RCW = 1, SFP->OSPR, ITS = 0)
-- Refer the SoC specific table to read the register to interpret whether the secure boot is achieved or not.
-- Using JTAG (in development environment only, using CW tap):
--- For secure-boot status, read SNVS Register $SNVS_HPSR_REG
.. code:: shell
ccs::display_regs 86 0x01E90014 4 0 1
Command Output:
Using the SAP chain position number 86, following is the output.
+0 +4 +8 +C
[0x01E90014] 8000AF00
Note: Chain position number will vary from one SoC to other SoC.
- Interpretation of the value:
-- 0xA indicates BootROM booted, with intent to secure.
-- 0xF = secure boot, as SSM_STATE.
|
