Re: [PATCH RFC bootconfig 0/2] Distinguish bootloader and embedded kernel parameters

Paul E. McKenney
2023-07-28T21:05:30Z

On Thu, Jul 27, 2023 at 09:25:06PM -0700, Randy Dunlap wrote:
>
>
> On 7/27/23 20:35, Paul E. McKenney wrote:
> > Hello!
> >
> > This series provides /proc interfaces parallel to /proc/cmdline that
> > provide only those kernel boot parameters that were provided by the
> > bootloader (/proc/cmdline_load) and only those parameters that were
> > embedded in the kernel image (/proc/cmdline_image, in boot-config format).
> > This is especially important when these parameters are presented to the
> > boot loader by automation that might gather them from diverse sources,
> > and also when a kexec-based reboot process pulls the kernel boot
> > parameters from /proc. If such a reboot process uses /proc/cmdline,
> > the kernel parameters from the image are replicated on every reboot,
> > which can be frustrating when the new kernel has different embedded
> > kernel boot parameters.
> >
> > Why put these in /proc? Because they is quite similar to /proc/cmdline,
> > so it makes sense to put it in the same place that /proc/cmdline is
> > located.
> >
> > 1. fs/proc: Add /proc/cmdline_load for boot loader arguments.
> >
> > 2. fs/proc: Add /proc/cmdline_image for embedded arguments.
> >
> > Thanx, Paul
> >
>
> Hi Paul,
>
> This series seems to be missing updates to
> Documentation/filesystems/proc.rst.
>
> Please add them.

Good catch, thank you!

I will fold the diff below into the three respective commits on my next
rebase, but in the meantime, please let me know what you think.

Thanx, Paul

diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 7897a7dafcbc..98c43c5ef1ee 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -686,7 +686,10 @@ files are there, and which are missing.
apm Advanced power management info
buddyinfo Kernel memory allocator information (see text) (2.5)
bus Directory containing bus specific information
- cmdline Kernel command line
+ cmdline Kernel command line, both from bootloader and embedded
+ in the kernel image
+ cmdline_image Kernel command line obtained from boot loader (6.6)
+ cmdline_load Kernel command line obtained from kernel image (6.6)
cpuinfo Info about the CPU
devices Available devices (block and character)
dma Used DMS channels