[PATCH] elf.h: Add aarch64 bti/pac dynamic tag constants

[Florian Weimer]

* Mark Wielaard via Libc-alpha:

> From: Mark Wielaard <mark@klomp.org>
>
> Constants double checked against binutils and the ELF for the Arm 64-bit
> Architecture (AArch64) Release 2020Q2 document.
> ---
>  elf/elf.h | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/elf/elf.h b/elf/elf.h
> index 197b557d15..ff9f1dadd5 100644
> --- a/elf/elf.h
> +++ b/elf/elf.h
> @@ -2875,6 +2875,8 @@ enum
>  #define R_AARCH64_IRELATIVE	1032	/* STT_GNU_IFUNC relocation.  */
>  
>  /* AArch64 specific values for the Dyn d_tag field.  */
> +#define DT_AARCH64_BTI_PLT	(DT_LOPROC + 1)
> +#define DT_AARCH64_PAC_PLT	(DT_LOPROC + 3)
>  #define DT_AARCH64_VARIANT_PCS	(DT_LOPROC + 5)
>  #define DT_AARCH64_NUM		6

I think DT_AARCH64_PAC_PLT isn't really used, so maybe mentioned that in
the commit message?  There's no PAC PLT with glibc, and people are
expected to use BIND_NOW.

(I hope I remember this correctly.)

Thanks,
Florian