summaryrefslogtreecommitdiffstats
path: root/Documentation/ABI/testing/sysfs-kernel-boot_params
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/ABI/testing/sysfs-kernel-boot_params')
-rw-r--r--Documentation/ABI/testing/sysfs-kernel-boot_params39
1 files changed, 39 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-boot_params b/Documentation/ABI/testing/sysfs-kernel-boot_params
new file mode 100644
index 0000000000..7f9bda453c
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-boot_params
@@ -0,0 +1,39 @@
+What: /sys/kernel/boot_params
+Date: December 2013
+Contact: Dave Young <dyoung@redhat.com>
+Description: The /sys/kernel/boot_params directory contains two
+ files: "data" and "version" and one subdirectory "setup_data".
+ It is used to export the kernel boot parameters of an x86
+ platform to userspace for kexec and debugging purpose.
+
+ If there's no setup_data in boot_params the subdirectory will
+ not be created.
+
+ "data" file is the binary representation of struct boot_params.
+
+ "version" file is the string representation of boot
+ protocol version.
+
+ "setup_data" subdirectory contains the setup_data data
+ structure in boot_params. setup_data is maintained in kernel
+ as a link list. In "setup_data" subdirectory there's one
+ subdirectory for each link list node named with the number
+ of the list nodes. The list node subdirectory contains two
+ files "type" and "data". "type" file is the string
+ representation of setup_data type. "data" file is the binary
+ representation of setup_data payload.
+
+ The whole boot_params directory structure is like below::
+
+ /sys/kernel/boot_params
+ |__ data
+ |__ setup_data
+ | |__ 0
+ | | |__ data
+ | | |__ type
+ | |__ 1
+ | |__ data
+ | |__ type
+ |__ version
+
+Users: Kexec