Re: [PATCH 4/4] x86/percpu: Use C for percpu read/write accessors

[Uros Bizjak]

On Mon, Oct 9, 2023 at 2:21 PM Nadav Amit <namit@xxxxxxxxxx> wrote:
>
>
>
> > On Oct 9, 2023, at 3:00 PM, Uros Bizjak <ubizjak@xxxxxxxxx> wrote:
> >
> > !! External Email
> >
> > On Mon, Oct 9, 2023 at 1:51 PM Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> >>
> >> BTW., while this OK for testing, this is too heavy handed for release
> >> purposes, so please only disable the KASAN instrumentation for the affected
> >> percpu accessors.
> >>
> >> See the various __no_sanitize* attributes available.
> >
> > These attributes are for function declarations. The percpu casts can
> > not be implemented with separate static inline functions. Also,
> > __no_sanitize_address is mutually exclusive with __always_inline.
>
> Right, but for GCC you may be able to do something like:
>
>     #pragma GCC diagnostic push
>     #pragma GCC diagnostic ignored "-fsanitize=address"
>
>     // Your code here...
>     #pragma GCC diagnostic pop
>
> Not sure if there is something equivalent in CLANG, and it should be done with
> the kernel’s _Pragma.

Unfortunately, this is only for diagnostics and expects "-W..." to
suppress warnings. Here we want to disable kernel sanitizer just for
the enclosing access and I'm sure it won't work with diagnostics
pragmas. I don't think that "-fsanitize=..." is included in target or
optimization options allowed in Pragma.

Uros.