Re: [PATCH v3 2/9] ARM: tlbflush: Make TLB flushes into static inlines

From: Sami Tolvanen <samitolvanen@google.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Ard Biesheuvel <ardb@kernel.org>,
	"Russell King (Oracle)" <linux@armlinux.org.uk>,
	 Kees Cook <keescook@chromium.org>,
	Nathan Chancellor <nathan@kernel.org>,
	 Nick Desaulniers <ndesaulniers@google.com>,
	Arnd Bergmann <arnd@arndb.de>,
	 linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev
Subject: Re: [PATCH v3 2/9] ARM: tlbflush: Make TLB flushes into static inlines
Date: Mon, 11 Mar 2024 21:36:58 +0000	[thread overview]
Message-ID: <CABCJKuf7xmCBs8UrpEbeRtQnofuq2Pp4M=RGT4TUw1+HsvS_CA@mail.gmail.com> (raw)
In-Reply-To: <CACRpkdbjjbRP5cED+qX5PGpvjvBEK9AxnGekVab=7WMrAPe+pQ@mail.gmail.com>

On Mon, Mar 11, 2024 at 7:51 PM Linus Walleij <linus.walleij@linaro.org> wrote:
>
> On Mon, Mar 11, 2024 at 4:35 PM Sami Tolvanen <samitolvanen@google.com> wrote:
> > On Mon, Mar 11, 2024 at 3:04 AM Ard Biesheuvel <ardb@kernel.org> wrote:
> >>
> > > This works for some function attributes (e.g., __efiapi is used like
> > > this), but the attribute specifier to which __nocfi resolves does not
> > > appear to be usable in the same manner.
> > >
> > > Best would be to annotate the asm code using
> > > SYM_TYPED_FUNC_START/_END, so that the CFI machinery is invoked at the
> > > call site to validate the function type of the destination.
> >
> > Agreed, ideally we would annotate indirectly called assembly functions
> > with CFI types and avoid __nocfi wrappers.
>
> I'm taking a stab at SYM_TYPED_FUNC_* for ARM, as we don't have them
> yet.

Does the default implementation in include/linux/cfi_types.h not work
on arm for some reason?

Sami