Add support for ARM to the efi boot1 and loader

[andrew]

Summary

This adds support to boot ARM with the efi loader. The kernel side
is still missing.

[emaste]

overall looks fine to me

sys/arm/include/metadata.h

37–38

What do you think about making these uint64_ts with the intent that the same metatada could be used everywhere?

sys/boot/efi/boot1/Makefile

40

Out of curiosity why does only arm boot1 need it?

sys/boot/efi/include/arm/efibind.h

1–3

can we share a common efibind.h?

[emaste]

sys/boot/efi/boot1/Makefile

40

Also, this should be LDADD+= ${LIBSTAND}, no?

[andrew]

sys/arm/include/metadata.h

37–38

They probably should be, we could have > 4GiB of ram with LPAE.

sys/boot/efi/boot1/Makefile

40

It's for the runtime functions the compiler assumes are available. As an alternative may be able to use compiler-rt. I'll add a comment explaining this.

I think this is correct, it should have DPADD+= ${LIBSTAND}. LIBSTAND is only correct when DESTDIR is set so may not be in buildenv.

sys/boot/efi/include/arm/efibind.h

1–3

I think we could share large chunks, but would need to investigate further.

[emaste]

sys/boot/efi/boot1/Makefile

40

It turns out we also need it for i386. Perhaps it makes sense to just include it unconditionally, and let the linker use it if needed or not.

sys/boot/efi/include/arm/efibind.h

1–3

Yeah, perhaps with a few #ifdefs in it.

[emaste]

sys/boot/efi/loader/arch/arm/reloc.c

38

ElfW_Dyn instead?

71–76

I think we should use a common reloc.c with a bit of #ifdefery instead, actually - the i386/amd64/arm/arm64 implementations of this file are going to be >80% common, without more divergence over time I think.

#if defined(__arm__)
case R_ARM_RELATIVE:
#elif defined(__i386__)
case R_386_RELATIVE:
#endif
    /* Address relative to the base address. */
    newaddr = (unsigned long *)(ImageBase + rel->r_offset);
    *newaddr += ImageBase;
    break;

[andrew]

Closed by commit rS281156 (authored by @andrew).