locking/atomic: scripts: simplify raw_atomic*() definitions

Currently each ordering variant has several potential definitions,
with a mixture of preprocessor and C definitions, including several
copies of its C prototype, e.g.

| #if defined(arch_atomic_fetch_andnot_acquire)
| #define raw_atomic_fetch_andnot_acquire arch_atomic_fetch_andnot_acquire
| #elif defined(arch_atomic_fetch_andnot_relaxed)
| static __always_inline int
| raw_atomic_fetch_andnot_acquire(int i, atomic_t *v)
| {
| int ret = arch_atomic_fetch_andnot_relaxed(i, v);
| __atomic_acquire_fence();
| return ret;
| }
| #elif defined(arch_atomic_fetch_andnot)
| #define raw_atomic_fetch_andnot_acquire arch_atomic_fetch_andnot
| #else
| static __always_inline int
| raw_atomic_fetch_andnot_acquire(int i, atomic_t *v)
| {
| return raw_atomic_fetch_and_acquire(~i, v);
| }
| #endif

Make this a bit simpler by defining the C prototype once, and writing
the various potential definitions as plain C code guarded by ifdeffery.
For example, the above becomes:

| static __always_inline int
| raw_atomic_fetch_andnot_acquire(int i, atomic_t *v)
| {
| #if defined(arch_atomic_fetch_andnot_acquire)
| return arch_atomic_fetch_andnot_acquire(i, v);
| #elif defined(arch_atomic_fetch_andnot_relaxed)
| int ret = arch_atomic_fetch_andnot_relaxed(i, v);
| __atomic_acquire_fence();
| return ret;
| #elif defined(arch_atomic_fetch_andnot)
| return arch_atomic_fetch_andnot(i, v);
| #else
| return raw_atomic_fetch_and_acquire(~i, v);
| #endif
| }

Which is far easier to read. As we now always have a single copy of the
C prototype wrapping all the potential definitions, we now have an
obvious single location for kerneldoc comments.

At the same time, the fallbacks for raw_atomic*_xhcg() are made to use
'new' rather than 'i' as the name of the new value. This is what the
existing fallback template used, and is more consistent with the
raw_atomic{_try,}cmpxchg() fallbacks.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230605070124.3741859-24-mark.rutland@arm.com

atomics: Provide atomic_add_negative() variants

atomic_add_negative() does not provide the relaxed/acquire/release
variants.

Provide them in preparation for a new scalable reference count algorithm.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230323102800.101763813@linutronix.de

Fix up more non-executable files marked executable

Joe found another DT file that shouldn't be executable, and that
frustrated me enough that I went hunting with this script:

git ls-files -s |
grep '^100755' |
cut -f2 |
xargs grep -L '^#!'

and that found another file that shouldn't have been marked executable
either, despite being in the scripts directory.

Maybe these two are the last ones at least for now. But I'm sure we'll
be back in a few years, fixing things up again.

Fixes: 8c6789f4e2d4 ("ASoC: dt-bindings: Add Everest ES8326 audio CODEC")
Fixes: 4d8e5cd233db ("locking/atomics: Fix scripts/atomic/ script permissions")
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

locking/atomics: Fix scripts/atomic/ script permissions

Mark all these scripts executable.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: linuxdrivers@attotech.com
Cc: dvyukov@google.com
Cc: boqun.feng@gmail.com
Cc: arnd@arndb.de
Cc: aryabinin@virtuozzo.com
Cc: glider@google.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

locking/atomics: Add common header generation files

To minimize repetition, to allow for future rework, and to ensure
regularity of the various atomic APIs, we'd like to automatically
generate (the bulk of) a number of headers related to atomics.

This patch adds the infrastructure to do so, leaving actual conversion
of headers to subsequent patches. This infrastructure consists of:

* atomics.tbl - a table describing the functions in the atomics API,
with names, prototypes, and metadata describing the variants that
exist (e.g fetch/return, acquire/release/relaxed). Note that the
return type is dependent on the particular variant.

* atomic-tbl.sh - a library of routines useful for dealing with
atomics.tbl (e.g. querying which variants exist, or generating
argument/parameter lists for a given function variant).

* gen-atomic-fallback.sh - a script which generates a header of
fallbacks, covering cases where architecture omit certain functions
(e.g. omitting relaxed variants).

* gen-atomic-long.sh - a script which generates wrappers providing the
atomic_long API atomic of the relevant atomic or atomic64 API,
ensuring the APIs are consistent.

* gen-atomic-instrumented.sh - a script which generates atomic* wrappers
atop of arch_atomic* functions, with automatically generated KASAN
instrumentation.

* fallbacks/* - a set of fallback implementations for atomics, which
should be used when no implementation of a given atomic is provided.
These are used by gen-atomic-fallback.sh to generate fallbacks, and
these are also used by other scripts to determine the set of optional
atomics (as required to generate preprocessor guards correctly).

Fallbacks may use the following variables:

${atomic} atomic prefix: atomic/atomic64/atomic_long, which can be
used to derive the atomic type, and to prefix functions

${int} integer type: int/s64/long

${pfx} variant prefix, e.g. fetch_

${name} base function name, e.g. add

${sfx} variant suffix, e.g. _return

${order} order suffix, e.g. _relaxed

${atomicname} full name, e.g. atomic64_fetch_add_relaxed

${ret} return type of the function, e.g. void

${retstmt} a return statement (with a trailing space), unless the
variant returns void

${params} parameter list for the function declaration, e.g.
"int i, atomic_t *v"

${args} argument list for invoking the function, e.g. "i, v"

... for clarity, ${ret}, ${retstmt}, ${params}, and ${args} are
open-coded for fallbacks where these do not vary, or are critical to
understanding the logic of the fallback.

The MAINTAINERS entry for the atomic infrastructure is updated to cover
the new scripts.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: catalin.marinas@arm.com
Cc: Will Deacon <will.deacon@arm.com>
Cc: linuxdrivers@attotech.com
Cc: dvyukov@google.com
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: arnd@arndb.de
Cc: aryabinin@virtuozzo.com
Cc: glider@google.com
Link: http://lkml.kernel.org/r/20180904104830.2975-2-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>