1 What: /sys/kernel/boot_params 1 What: /sys/kernel/boot_params
2 Date: December 2013 2 Date: December 2013
3 Contact: Dave Young <dyoung@redhat.com> 3 Contact: Dave Young <dyoung@redhat.com>
4 Description: The /sys/kernel/boot_params di 4 Description: The /sys/kernel/boot_params directory contains two
5 files: "data" and "version" an 5 files: "data" and "version" and one subdirectory "setup_data".
6 It is used to export the kerne 6 It is used to export the kernel boot parameters of an x86
7 platform to userspace for kexe 7 platform to userspace for kexec and debugging purpose.
8 8
9 If there's no setup_data in bo 9 If there's no setup_data in boot_params the subdirectory will
10 not be created. 10 not be created.
11 11
12 "data" file is the binary repr 12 "data" file is the binary representation of struct boot_params.
13 13
14 "version" file is the string r 14 "version" file is the string representation of boot
15 protocol version. 15 protocol version.
16 16
17 "setup_data" subdirectory cont 17 "setup_data" subdirectory contains the setup_data data
18 structure in boot_params. setu 18 structure in boot_params. setup_data is maintained in kernel
19 as a link list. In "setup_data 19 as a link list. In "setup_data" subdirectory there's one
20 subdirectory for each link lis 20 subdirectory for each link list node named with the number
21 of the list nodes. The list no 21 of the list nodes. The list node subdirectory contains two
22 files "type" and "data". "type 22 files "type" and "data". "type" file is the string
23 representation of setup_data t 23 representation of setup_data type. "data" file is the binary
24 representation of setup_data p 24 representation of setup_data payload.
25 25
26 The whole boot_params director 26 The whole boot_params directory structure is like below::
27 27
28 /sys/kernel/boot_params 28 /sys/kernel/boot_params
29 |__ data 29 |__ data
30 |__ setup_data 30 |__ setup_data
31 | |__ 0 31 | |__ 0
32 | | |__ data 32 | | |__ data
33 | | |__ type 33 | | |__ type
34 | |__ 1 34 | |__ 1
35 | |__ data 35 | |__ data
36 | |__ type 36 | |__ type
37 |__ version 37 |__ version
38 38
39 Users: Kexec 39 Users: Kexec
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