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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2020-02-04 07:33:53 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-02-05 04:22:43 -0500
commit7495e0926fdf302cb9e62a49f7c22198815624cd (patch)
tree4c3fb757786ce82fe314227f128d673080d55cc3 /Documentation
parent2b90927c77c973771cc658d639724d5b247a83eb (diff)
downloadlinux-stericsson-7495e0926fdf302cb9e62a49f7c22198815624cd.tar.gz
bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline
As the bootconfig is appended to the initrd it is not as easy to modify as the kernel command line. If there's some issue with the kernel, and the developer wants to boot a pristine kernel, it should not be needed to modify the initrd to remove the bootconfig for a single boot. As bootconfig is silently added (if the admin does not know where to look they may not know it's being loaded). It should be explicitly added to the kernel cmdline. The loading of the bootconfig is only done if "bootconfig" is on the kernel command line. This will let admins know that the kernel command line is extended. Note, after adding printk()s for when the size is too great or the checksum is wrong, exposed that the current method always looked for the boot config, and if this size and checksum matched, it would parse it (as if either is wrong a printk has been added to show this). It's better to only check this if the boot config is asked to be looked for. Link: https://lore.kernel.org/r/CAHk-=wjfjO+h6bQzrTf=YCZA53Y3EDyAs3Z4gEsT7icA3u_Psw@mail.gmail.com Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/bootconfig.rst2
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt6
2 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index 4d617693c0c8..b342a6796392 100644
--- a/Documentation/admin-guide/bootconfig.rst
+++ b/Documentation/admin-guide/bootconfig.rst
@@ -123,6 +123,8 @@ To remove the config from the image, you can use -d option as below::
# tools/bootconfig/bootconfig -d /boot/initrd.img-X.Y.Z
+Then add "bootconfig" on the normal kernel command line to tell the
+kernel to look for the bootconfig at the end of the initrd file.
Config File Limitation
======================
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index ade4e6ec23e0..b48c70ba9841 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -437,6 +437,12 @@
no delay (0).
Format: integer
+ bootconfig [KNL]
+ Extended command line options can be added to an initrd
+ and this will cause the kernel to look for it.
+
+ See Documentation/admin-guide/bootconfig.rst
+
bert_disable [ACPI]
Disable BERT OS support on buggy BIOSes.