Re: git: e605b87a9e75 - main - Save only callee-saved registers in pcb

From: John Baldwin <jhb_at_FreeBSD.org>
Date: Wed, 25 May 2022 18:11:41 UTC 
On 5/25/22 3:38 AM, Andrew Turner wrote:
> The branch main has been updated by andrew:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=e605b87a9e75a7f693527f0aad8189ae9db20f16
> 
> commit e605b87a9e75a7f693527f0aad8189ae9db20f16
> Author:     Dapeng Gao <peter@dpgao.cc>
> AuthorDate: 2022-05-25 10:25:06 +0000
> Commit:     Andrew Turner <andrew@FreeBSD.org>
> CommitDate: 2022-05-25 10:26:30 +0000
> 
>      Save only callee-saved registers in pcb
>      
>      On AArch64, registers x9-x18 are not callee-saved, yet they are
>      preserved at many placed in swtch.S. This patch removes code that
>      preserves these registers.

Do you plan to alter the layout of struct pcb?  I'll need to make changes to
kgdb to not read these registers on newer kernels (and so probably need a
__FreeBSD_version bump to cue from, though I can probably just reuse the
previous bump).  If you are going to alter the layout of struct pcb I'd
rather just do one change that handles both than trying to support all three
states.

-- 
John Baldwin