Re: [PATCH bpf-next v6 2/4] arm64: Add LDR (literal) instruction

[Will Deacon]

On Sat, Jun 25, 2022 at 12:12:53PM -0400, Xu Kuohai wrote:
> Add LDR (literal) instruction to load data from address relative to PC.
> This instruction will be used to implement long jump from bpf prog to
> bpf rampoline in the follow-up patch.

typo: trampoline

> 
> The instruction encoding:
> 
>     3       2   2     2                                     0        0
>     0       7   6     4                                     5        0
> +-----+-------+---+-----+-------------------------------------+--------+
> | 0 x | 0 1 1 | 0 | 0 0 |                imm19                |   Rt   |
> +-----+-------+---+-----+-------------------------------------+--------+
> 
> for 32-bit, variant x == 0; for 64-bit, x == 1.
> 
> branch_imm_common() is used to check the distance between pc and target
> address, since it's reused by this patch and LDR (literal) is not a branch
> instruction, rename it to aarch64_imm_common().

nit, but I think "label_imm_common()" would be a better name.

Anyway, I checked the encodings and the code looks good, so:

Acked-by: Will Deacon <will@xxxxxxxxxx>

Will