Documentation: Update kernel-parameters.tx

1) __setup() is messy, prefer module_param and core_param.
2) Document --
3) Document modprobe scraping /proc/cmdline.
4) Document handing of leftover parameters to init.
5) Document use of quotes to protect whitespace.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2014-05-14 10:33:45 +09:30
parent 51e158c12a
commit 5888bcc5d2
1 changed files with 21 additions and 11 deletions

View File

@ -1,27 +1,37 @@
Kernel Parameters
~~~~~~~~~~~~~~~~~
The following is a consolidated list of the kernel parameters as implemented
(mostly) by the __setup() macro and sorted into English Dictionary order
(defined as ignoring all punctuation and sorting digits before letters in a
case insensitive manner), and with descriptions where known.
The following is a consolidated list of the kernel parameters as
implemented by the __setup(), core_param() and module_param() macros
and sorted into English Dictionary order (defined as ignoring all
punctuation and sorting digits before letters in a case insensitive
manner), and with descriptions where known.
Module parameters for loadable modules are specified only as the
parameter name with optional '=' and value as appropriate, such as:
The kernel parses parameters from the kernel command line up to "--";
if it doesn't recognize a parameter and it doesn't contain a '.', the
parameter gets passed to init: parameters with '=' go into init's
environment, others are passed as command line arguments to init.
Everything after "--" is passed as an argument to init.
modprobe usbcore blinkenlights=1
Module parameters can be specified in two ways: via the kernel command
line with a module name prefix, or via modprobe, e.g.:
Module parameters for modules that are built into the kernel image
are specified on the kernel command line with the module name plus
'.' plus parameter name, with '=' and value if appropriate, such as:
(kernel command line) usbcore.blinkenlights=1
(modprobe command line) modprobe usbcore blinkenlights=1
usbcore.blinkenlights=1
Parameters for modules which are built into the kernel need to be
specified on the kernel command line. modprobe looks through the
kernel command line (/proc/cmdline) and collects module parameters
when it loads a module, so the kernel command line can be used for
loadable modules too.
Hyphens (dashes) and underscores are equivalent in parameter names, so
log_buf_len=1M print-fatal-signals=1
can also be entered as
log-buf-len=1M print_fatal_signals=1
Double-quotes can be used to protect spaces in values, e.g.:
param="spaces in here"
This document may not be entirely up to date and comprehensive. The command
"modinfo -p ${modulename}" shows a current list of all parameters of a loadable