[PATCH v9 1/5] rust: add generic static_key_false

[Alice Ryhl]

On Tue, Oct 1, 2024 at 4:11 PM Steven Rostedt <rostedt at goodmis.org> wrote:
>
> On Tue, 01 Oct 2024 13:29:58 +0000
> Alice Ryhl <aliceryhl at google.com> wrote:
>
> > Add just enough support for static key so that we can use it from
> > tracepoints. Tracepoints rely on `static_key_false` even though it is
> > deprecated, so we add the same functionality to Rust.
> >
> > This patch only provides a generic implementation without code patching
> > (matching the one used when CONFIG_JUMP_LABEL is disabled). Later
> > patches add support for inline asm implementations that use runtime
> > patching.
> >
> > When CONFIG_JUMP_LABEL is unset, `static_key_count` is a static inline
> > function, so a Rust helper is defined for `static_key_count` in this
> > case. If Rust is compiled with LTO, this call should get inlined. The
> > helper can be eliminated once we have the necessary inline asm to make
> > atomic operations from Rust.
> >
> > Reviewed-by: Boqun Feng <boqun.feng at gmail.com>
> > Signed-off-by: Alice Ryhl <aliceryhl at google.com>
> > ---
> >  rust/bindings/bindings_helper.h |  1 +
> >  rust/helpers/helpers.c          |  1 +
> >  rust/helpers/jump_label.c       | 15 +++++++++++++++
> >  rust/kernel/jump_label.rs       | 29 +++++++++++++++++++++++++++++
> >  rust/kernel/lib.rs              |  1 +
> >  5 files changed, 47 insertions(+)
> >
> > diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
> > index ae82e9c941af..e0846e7e93e6 100644
> > --- a/rust/bindings/bindings_helper.h
> > +++ b/rust/bindings/bindings_helper.h
> > @@ -14,6 +14,7 @@
> >  #include <linux/ethtool.h>
> >  #include <linux/firmware.h>
> >  #include <linux/jiffies.h>
> > +#include <linux/jump_label.h>
> >  #include <linux/mdio.h>
> >  #include <linux/phy.h>
> >  #include <linux/refcount.h>
> > diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
> > index 30f40149f3a9..17e1b60d178f 100644
> > --- a/rust/helpers/helpers.c
> > +++ b/rust/helpers/helpers.c
> > @@ -12,6 +12,7 @@
> >  #include "build_assert.c"
> >  #include "build_bug.c"
> >  #include "err.c"
> > +#include "jump_label.c"
> >  #include "kunit.c"
> >  #include "mutex.c"
> >  #include "page.c"
> > diff --git a/rust/helpers/jump_label.c b/rust/helpers/jump_label.c
> > new file mode 100644
> > index 000000000000..0e9ed15903f6
> > --- /dev/null
> > +++ b/rust/helpers/jump_label.c
> > @@ -0,0 +1,15 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +/*
> > + * Copyright (C) 2024 Google LLC.
> > + */
> > +
> > +#include <linux/jump_label.h>
> > +
>
> Nit, the above line has a spurious space.

Thanks. Looks like the function body also uses 7 spaces instead of a
tab. I'll fix it.

Alice