Re: [PATCH] initrd: Remove erroneous comment

From: Tom Rini <trini@konsulko.com>
To: ron minnich <rminnich@gmail.com>
Cc: lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Borislav Petkov <bp@suse.de>,
	Dominik Brodowski <linux@dominikbrodowski.net>,
	"H . Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] initrd: Remove erroneous comment
Date: Mon, 22 Jun 2020 17:01:45 -0400	[thread overview]
Message-ID: <20200622210145.GM27801@bill-the-cat> (raw)
In-Reply-To: <CAP6exYLd0uFbVSbn28iS1OV=jULtg2f+7t1DAn-fvGoRSd5dng@mail.gmail.com>

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On Mon, Jun 22, 2020 at 01:56:24PM -0700, ron minnich wrote:

> So, let me first add,  the comment can be removed as needed. Comments
> offered only for clarification.

Noted, thanks.

> On Mon, Jun 22, 2020 at 1:40 PM Tom Rini <trini@konsulko.com> wrote:
> 
> > But what do you mean UEFI "consumes" initrd= ?
> 
> What I mean is, there are bootloaders that will, if they see initrd=
> in the command line, remove it: the kernel will never see it.

I'm picky here because, well, there's a whole lot of moving parts in the
pre-kernel world.  In a strict sense, "UEFI" doesn't do anything with
the kernel but based on hpa's comments I assume that at least the
in-kernel UEFI stub does what Documentation/x86/booting.rst suggests to
do and consumes initrd=/file just like "initrd /file" in extlinux.conf,
etc do.  And since the EFI stub is cross-platform, it's worth noting
this too.

> >  I guess looking at
> > Documentation/x86/boot.rst is where treating initrd= as a file that
> > should be handled and ramdisk_image / ramdisk_size set came from.  I do
> > wonder what happens in the case of ARM/ARM64 + UEFI without device tree.
> 
> it is possible that the initrd= argument will not be seen by the
> kernel. That's my understanding. Will this be a problem if so? It
> would be for me :-)
> 
> >  And it doesn't provide any sort of link / context to the
> > boot loader specification project or similar that explains the cases
> > when a non-filename "initrd=" would reasonably (or unreasonably but
> > happens in reality) be removed.
> 
> But it unreasonably happens as I learned the hard way :-)
> 
> Anyway, thanks Tom, I have no objections to whatever you all feel is
> best to do with that comment. It was a failed attempt on my part to
> explain the state of things :-)

Booting up the kernel is quite the "fun" area indeed.

-- 
Tom

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