linux-kernel - Re: [PATCH 09/10] efi/x86: Support builtin command line

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Date:   Wed, 29 Apr 2020 17:39:44 -0400
From:   Arvind Sankar <nivedita@...m.mit.edu>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     Arvind Sankar <nivedita@...m.mit.edu>,
        linux-efi <linux-efi@...r.kernel.org>, X86 ML <x86@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 09/10] efi/x86: Support builtin command line

On Wed, Apr 29, 2020 at 09:07:32PM +0200, Ard Biesheuvel wrote:
> On Wed, 29 Apr 2020 at 19:41, Arvind Sankar <nivedita@...m.mit.edu> wrote:
> >
> > Add support for the x86 CMDLINE_BOOL and CMDLINE_OVERRIDE configuration
> > options.
> >
> > Signed-off-by: Arvind Sankar <nivedita@...m.mit.edu>
> > ---
> >  drivers/firmware/efi/libstub/x86-stub.c | 12 ++++++++----
> >  1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
> > index 85a924fecc87..0faba30d6406 100644
> > --- a/drivers/firmware/efi/libstub/x86-stub.c
> > +++ b/drivers/firmware/efi/libstub/x86-stub.c
> > @@ -680,7 +680,6 @@ unsigned long efi_main(efi_handle_t handle,
> >         unsigned long buffer_start, buffer_end;
> >         struct setup_header *hdr = &boot_params->hdr;
> >         efi_status_t status;
> > -       unsigned long cmdline_paddr;
> >
> >         efi_system_table = sys_table_arg;
> >
> > @@ -739,9 +738,14 @@ unsigned long efi_main(efi_handle_t handle,
> >                 image_offset = 0;
> >         }
> >
> > -       cmdline_paddr = ((u64)hdr->cmd_line_ptr |
> > -                        ((u64)boot_params->ext_cmd_line_ptr << 32));
> > -       efi_parse_options((char *)cmdline_paddr);
> > +#ifdef CONFIG_CMDLINE_BOOL
> > +       efi_parse_options(CONFIG_CMDLINE);
> > +#endif
> 
> Can we use IS_ENABLED() here as well?

Unfortunately on x86, CONFIG_CMDLINE is not defined if
CONFIG_CMDLINE_BOOL isn't enabled. So turning this into an
IS_ENABLED(CONFIG_CMDLINE_BOOL) causes a compile error when it's
disabled due to CONFIG_CMDLINE being an undeclared symbol.

> 
> > +       if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
> > +               unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
> > +                                              ((u64)boot_params->ext_cmd_line_ptr << 32));
> > +               efi_parse_options((char *)cmdline_paddr);
> > +       }
> >
> >         /*
> >          * At this point, an initrd may already have been loaded by the
> > --
> > 2.26.2
> >