[U-Boot] efi_loader: LoadOptions (bootargs)

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Wed, Sep 11, 2019 at 07:39:07PM +0200, Heinrich Schuchardt wrote:
> On 9/11/19 8:14 AM, AKASHI Takahiro wrote:
> >Heinrich,
> >
> >On Fri, Aug 23, 2019 at 08:42:27AM +0900, AKASHI Takahiro wrote:
> >>On Thu, Aug 22, 2019 at 07:53:46PM +0200, Heinrich Schuchardt wrote:
> >>>On 8/22/19 11:03 AM, AKASHI Takahiro wrote:
> >>>>Heinrich,
> >>>>
> >>>>I'm now wondering whether LoadedImage's LoadOptions, which comes
> >>>>from "bootargs" variable, should contain a command(application) name
> >>>>as a first argument or not.
> >>>>
> >>>>When I tried some efi application (efitools), I found that it expected
> >>>>so. For example, efitools' UpdateVars.efi takes
> >>>>     Usage: UpdateVars.efi: [-g guid] [-a] [-e] [-b] var file
> >>>>
> >>>>and I had to passed arguments by specifying "foo db DB.auth" for
> >>>>"bootargs" where foo makes no sense.
> >>>>
> >>>>What do you think about this issue?
> >>>
> >>>Do you relate to
> >>>https://git.kernel.org/pub/scm/linux/kernel/git/jejb/efitools.git?
> >>
> >>Yes.
> >>
> >>>This style of parsing LoadOptions is defined by the EFI shell. See
> >>>function ParseCommandLineToArgs() in
> >>>ShellPkg/Application/Shell/ShellParametersProtocol.c.
> >>
> >>So do you mean that Shell.efi is responsible for adding a command name
> >>to LoadOptions (or bootargs) as a first parameter or that LoadOptions
> >>is solely for Shell environment?
> 
> LoadOptions are used to communicate with any EFI binary including the
> Linux kernels. Inside the EFI shell Shell.efi takes care of passing the
> executable name as a first parameter.
> 
> If a user chooses to call an EFI binary which expects its own name as
> first parameter via bootefi, the user should simply add it to
> LoadOptions via 'setenv bootargs'.

Right, but
my concern is that a user normally doesn't care/know if an application
expects that it would be invoked from Shell or with Shell-style arguments.

> I would not change anything in bootefi. Otherwise you start passing
> 'vmlinux' or 'grubaa64.efi' as command line arguments to Linux.

How can users distinguish vmlinux or whatever else from
other apps that would expect Shell-style arguments in general?

-Takahiro Akashi


> Best regards
> 
> Heinrich
> 
> >>
> >>If so, should we do the same thing at bootefi?
> >
> >Any comment?
> >
> >-Takahiro Akashi
> >
> >
> >>>If UpdateVars.efi would work differently it could not be launched via
> >>>the shell.
> >>
> >>Well, I'm trying to run UpdateVars.efi in a standalone way
> >>by invoking it directly from bootefi/bootmgr and it obviously fails
> >>due to this issue.
> >>
> >>Thanks,
> >>-Takashiro Akashi
> >>
> >>
> >>>Best regards
> >>>
> >>>Heinrich
> >
>