[PATCH bpf-next 0/2] bpf, arm64: Simplify jited prologue/epilogue

patchwork-bot+netdevbpf at kernel.org patchwork-bot+netdevbpf at kernel.org
Wed Aug 28 08:50:30 PDT 2024


Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast at kernel.org>:

On Mon, 26 Aug 2024 15:16:22 +0800 you wrote:
> From: Xu Kuohai <xukuohai at huawei.com>
> 
> The arm64 jit blindly saves/restores all callee-saved registers, making
> the jited result looks a bit too compliated. For example, for an empty
> prog, the jited result is:
> 
>    0:   bti jc
>    4:   mov     x9, lr
>    8:   nop
>    c:   paciasp
>   10:   stp     fp, lr, [sp, #-16]!
>   14:   mov     fp, sp
>   18:   stp     x19, x20, [sp, #-16]!
>   1c:   stp     x21, x22, [sp, #-16]!
>   20:   stp     x26, x25, [sp, #-16]!
>   24:   mov     x26, #0
>   28:   stp     x26, x25, [sp, #-16]!
>   2c:   mov     x26, sp
>   30:   stp     x27, x28, [sp, #-16]!
>   34:   mov     x25, sp
>   38:   bti j 		// tailcall target
>   3c:   sub     sp, sp, #0
>   40:   mov     x7, #0
>   44:   add     sp, sp, #0
>   48:   ldp     x27, x28, [sp], #16
>   4c:   ldp     x26, x25, [sp], #16
>   50:   ldp     x26, x25, [sp], #16
>   54:   ldp     x21, x22, [sp], #16
>   58:   ldp     x19, x20, [sp], #16
>   5c:   ldp     fp, lr, [sp], #16
>   60:   mov     x0, x7
>   64:   autiasp
>   68:   ret
> 
> [...]

Here is the summary with links:
  - [bpf-next,1/2] bpf, arm64: Get rid of fpb
    https://git.kernel.org/bpf/bpf-next/c/bd737fcb6485
  - [bpf-next,2/2] bpf, arm64: Avoid blindly saving/restoring all callee-saved registers
    https://git.kernel.org/bpf/bpf-next/c/5d4fa9ec5643

You are awesome, thank you!
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