Re: [PATCH 09/10] commands/file: use definitions from arm/linux.h

[Daniel Kiper]

On Tue, Feb 27, 2018 at 12:36:37PM +0000, Leif Lindholm wrote:
> On Thu, Feb 15, 2018 at 11:30:32AM +0100, Daniel Kiper wrote:
> > On Thu, Feb 01, 2018 at 06:18:57PM +0000, Leif Lindholm wrote:
> > > Clean up code for matching IS_ARM slightly by making use of struct
> > > linux_arm_kernel_header and GRUB_LINUX_ARM_MAGIC_SIGNATURE.
> > >
> > > Signed-off-by: Leif Lindholm <address@hidden>
> > > ---
> > >  grub-core/commands/file.c | 14 ++++++--------
> > >  1 file changed, 6 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/grub-core/commands/file.c b/grub-core/commands/file.c
> > > index 63c84499b..fad191202 100644
> > > --- a/grub-core/commands/file.c
> > > +++ b/grub-core/commands/file.c
> > > @@ -27,6 +27,7 @@
> > >  #include <grub/elf.h>
> > >  #include <grub/xen_file.h>
> > >  #include <grub/efi/pe32.h>
> > > +#include <grub/arm/linux.h>
> > >  #include <grub/i386/linux.h>
> > >  #include <grub/xnu.h>
> > >  #include <grub/machoload.h>
> > > @@ -383,21 +384,18 @@ grub_cmd_file (grub_extcmd_context_t ctxt, int 
> > > argc, char **args)
> > >        }
> > >      case IS_ARM_LINUX:
> > >        {
> > > - grub_uint32_t sig, sig_pi;
> > > - if (grub_file_read (file, &sig_pi, 4) != 4)
> > > + struct linux_arm_kernel_header lh;
> > > + if (grub_file_read (file, &lh, sizeof (lh)) != sizeof (lh))
> > >     break;
> > >   /* Raspberry pi.  */
> > > - if (sig_pi == grub_cpu_to_le32_compile_time (0xea000006))
> > > + if (lh.code0 == grub_cpu_to_le32_compile_time (0xea000006))
> >
> > Could you define 0xea000006 as a constant? If you add the comment
> > what does it mean that will be perfect.
>
> I'll be completely honest here and say "I don't have a clue".
>
> Well, that's not true, I'm broken enough to see that that is a short
> forward branch in the A32 ("ARM") instruction set. What I don't
> understand is what significance that has for Raspberry Pi.
> I just kept the logic for compatibility.
>
> Vladimir?

If Vladimir or anybody else is not able to say then I would not like to
hold on you any longer. I am happy with your guess in the comment if you
say that it is a guess.

Daniel