Re: [PATCH v15 07/16] arm64: add image head flag definitions

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

Hi Mark,

On Mon, Oct 01, 2018 at 01:52:26PM +0100, Mark Rutland wrote:
> On Fri, Sep 28, 2018 at 03:48:32PM +0900, AKASHI Takahiro wrote:
> > Those image head's flags will be used later by kexec_file loader.
> > 
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: Will Deacon <will.deacon@arm.com>
> > Acked-by: James Morse <james.morse@arm.com>
> > ---
> >  arch/arm64/include/asm/boot.h | 15 +++++++++++++++
> >  arch/arm64/kernel/head.S      |  2 +-
> >  2 files changed, 16 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm64/include/asm/boot.h b/arch/arm64/include/asm/boot.h
> > index 355e552a9175..0bab7eed3012 100644
> > --- a/arch/arm64/include/asm/boot.h
> > +++ b/arch/arm64/include/asm/boot.h
> > @@ -5,6 +5,21 @@
> >  
> >  #include <asm/sizes.h>
> >  
> > +#define ARM64_MAGIC		"ARM\x64"
> > +
> > +#define HEAD_FLAG_BE_SHIFT		0
> > +#define HEAD_FLAG_PAGE_SIZE_SHIFT	1
> > +#define HEAD_FLAG_BE_MASK		0x1
> > +#define HEAD_FLAG_PAGE_SIZE_MASK	0x3
> > +
> > +#define HEAD_FLAG_BE			1
> 
> These already exist in some form in arch/arm64/kernel/image.h; can we
> please factor those out rather than duplicating them?

Sure.

> I'd be happy if you'd update image.h to use the new HEAD_FLAG_* names,
> and removed the old definitions.

I want to make sure two things;

1. Do you assume all the existing __HEAD_FLAG_xyz's NOT be renamed
   (say, to HEAD_FLAG_xyz)?

2. Do you mind removing this check in image.h?
   (we also need to manage 'CONFIG_EFI' part of image.h.)

>       #ifndef LINKER_SCRIPT
>       #error This file should only be included in vmlinux.lds.S
>       #endif


Thanks,
-Takahiro Akashi

> > +#define HEAD_FLAG_PAGE_SIZE_4K		1
> > +#define HEAD_FLAG_PAGE_SIZE_16K		2
> > +#define HEAD_FLAG_PAGE_SIZE_64K		3
> 
> I appreciate these are new, since we didn't previously need definitions.
> 
> Thanks,
> Mark.
> 
> > +
> > +#define head_flag_field(flags, field) \
> > +		(((flags) >> field##_SHIFT) & field##_MASK)
> > +
> >  /*
> >   * arm64 requires the DTB to be 8 byte aligned and
> >   * not exceed 2MB in size.
> > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
> > index b0853069702f..8cbac6232ed1 100644
> > --- a/arch/arm64/kernel/head.S
> > +++ b/arch/arm64/kernel/head.S
> > @@ -91,7 +91,7 @@ _head:
> >  	.quad	0				// reserved
> >  	.quad	0				// reserved
> >  	.quad	0				// reserved
> > -	.ascii	"ARM\x64"			// Magic number
> > +	.ascii	ARM64_MAGIC			// Magic number
> >  #ifdef CONFIG_EFI
> >  	.long	pe_header - _head		// Offset to the PE header.
> >  
> > -- 
> > 2.19.0
> >