locking/atomic: add arch_atomic_long*()

Now that all architectures provide arch_{atomic,atomic64}_*(), we can
build arch_atomic_long_*() atop these, which can be safely used in
noinstr code. The regular atomic_long_*() wrappers are built atop these,
as we do for {atomic,atomic64}_*() atop arch_{atomic,atomic64}_*().

We don't provide arch_* versions of the cond_read*() variants, as we
don't have arch_* versions of the underlying atomic/atomic64 functions
(nor the smp_cond_load*() helpers these are typically based on).

Note that the headers in this patch under include/linux/atomic/ are
generated by the scripts in scripts/atomic/.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210713105253.7615-5-mark.rutland@arm.com

include/linux/atomic.h

@@ -78,7 +78,7 @@
 })
 
 #include <linux/atomic/atomic-arch-fallback.h>
-#include <linux/atomic/atomic-instrumented.h>
 #include <linux/atomic/atomic-long.h>
+#include <linux/atomic/atomic-instrumented.h>
 
 #endif /* _LINUX_ATOMIC_H */

scripts/atomic/gen-atomic-instrumented.sh

@@ -138,6 +138,11 @@ grep '^[a-z]' "$1" | while read name meta args; do
 	gen_proto "${meta}" "${name}" "atomic64" "s64" ${args}
 done
 
+grep '^[a-z]' "$1" | while read name meta args; do
+	gen_proto "${meta}" "${name}" "atomic_long" "long" ${args}
+done
+
+
 for xchg in "xchg" "cmpxchg" "cmpxchg64" "try_cmpxchg"; do
 	for order in "" "_acquire" "_release" "_relaxed"; do
 		gen_xchg "${xchg}${order}" ""

scripts/atomic/gen-atomic-long.sh

@@ -47,9 +47,9 @@ gen_proto_order_variant()
 
 cat <<EOF
 static __always_inline ${ret}
-atomic_long_${name}(${params})
+arch_atomic_long_${name}(${params})
 {
-	${retstmt}${atomic}_${name}(${argscast});
+	${retstmt}arch_${atomic}_${name}(${argscast});
 }
 
 EOF