Re: [PATCH 4/9] x86/alternative: Implement .retpoline_sites support

[Josh Poimboeuf]

On Wed, Oct 13, 2021 at 02:22:21PM +0200, Peter Zijlstra wrote:
>  	/*
> +	 * Rewrite the retpolines, must be done before alternatives since
> +	 * those can rewrite the retpoline thunks.
> +	 */

Why exactly is that a problem?  This code doesn't read the thunks.

BTW, CALL_NOSPEC results in a retpoline site in .altinstr_replacement:

Relocation section [40] '.rela.retpoline_sites' for section [39] '.retpoline_sites' at offset 0x8d28 contains 1 entry:
  Offset              Type            Value               Addend Name
  000000000000000000  X86_64_PC32     000000000000000000     +10 .altinstr_replacement

Which I assume we don't want.

-- 
Josh