Received-SPF: pass (google.com: domain of linux-kernel+bounces-210476-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223;
Precedence: bulk
MIME-Version: 1.0
References: <20240610204821.230388-1-torvalds@linux-foundation.org>
 <20240610204821.230388-5-torvalds@linux-foundation.org> <ZmhfNRViOhyn-Dxi@J2N7QTR9R3>
 <CAHk-=wiHp60JjTs=qZDboGnQxKSzv=hLyjEp+8StqvtjOKY64w@mail.gmail.com>
 <ZmiN_7LMp2fbKhIw@J2N7QTR9R3> <CAHk-=wipw+_LKyXpuq9X7suf1VDUX4wD6iCuxFJKm9g2+ntFkQ@mail.gmail.com>
In-Reply-To: <CAHk-=wipw+_LKyXpuq9X7suf1VDUX4wD6iCuxFJKm9g2+ntFkQ@mail.gmail.com>
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 11 Jun 2024 11:59:21 -0700
Message-ID: <CAHk-=wgq4kMyeyhSm-Hrw1cQMi81=2JGznyVugeCejJoy1QSwg@mail.gmail.com>
Subject: Re: [PATCH 4/7] arm64: add 'runtime constant' support
To: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Anvin <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>, 
	Thomas Gleixner <tglx@linutronix.de>, Rasmus Villemoes <linux@rasmusvillemoes.dk>, 
	Josh Poimboeuf <jpoimboe@kernel.org>, Catalin Marinas <catalin.marinas@arm.com>, 
	Will Deacon <will@kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, 
	"the arch/x86 maintainers" <x86@kernel.org>, linux-arm-kernel@lists.infradead.org, 
	linux-arch <linux-arch@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"

On Tue, 11 Jun 2024 at 10:59, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> So I'll look at doing this for x86 and see how it works.

Oh - and when I started looking at it, I immediately remembered why I
didn't want to use alternatives originally.

The alternatives are finalized much too early for this. By the time
the dcache code works, the alternatives have already been applied.

I guess all the arm64 alternative callbacks are basically finalized
very early, basically when the CPU models etc have been setup.

We could do a "late alternatives", I guess, but now it's even more
infrastructure just for the constants.

              Linus