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

23 files changed, 20 insertions, 92 deletions

diff --git a/scripts/atomic/atomics.tbl b/scripts/atomic/atomics.tbl
index 85ca8d9b5c27..903946cbf1b3 100644
--- a/scripts/atomic/atomics.tbl
+++ b/scripts/atomic/atomics.tbl
@@ -27,7 +27,7 @@ and			vF	i	v
 andnot			vF	i	v
 or			vF	i	v
 xor			vF	i	v
-xchg			I	v	i
+xchg			I	v	i:new
 cmpxchg			I	v	i:old	i:new
 try_cmpxchg		B	v	p:old	i:new
 sub_and_test		b	i	v
diff --git a/scripts/atomic/fallbacks/acquire b/scripts/atomic/fallbacks/acquire
index b0f732a5c46e..4da0cab3604e 100755
--- a/scripts/atomic/fallbacks/acquire
+++ b/scripts/atomic/fallbacks/acquire
@@ -1,9 +1,5 @@
 cat <<EOF
-static __always_inline ${ret}
-raw_${atomic}_${pfx}${name}${sfx}_acquire(${params})
-{
 	${ret} ret = arch_${atomic}_${pfx}${name}${sfx}_relaxed(${args});
 	__atomic_acquire_fence();
 	return ret;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/add_negative b/scripts/atomic/fallbacks/add_negative
index 16876118019e..1d3d4ab3a9d2 100755
--- a/scripts/atomic/fallbacks/add_negative
+++ b/scripts/atomic/fallbacks/add_negative
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline bool
-raw_${atomic}_add_negative${order}(${int} i, ${atomic}_t *v)
-{
 	return raw_${atomic}_add_return${order}(i, v) < 0;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/add_unless b/scripts/atomic/fallbacks/add_unless
index 88593e28b163..95ecb2b7405b 100755
--- a/scripts/atomic/fallbacks/add_unless
+++ b/scripts/atomic/fallbacks/add_unless
@@ -1,7 +1,3 @@
 cat << EOF
-static __always_inline bool
-raw_${atomic}_add_unless(${atomic}_t *v, ${int} a, ${int} u)
-{
 	return raw_${atomic}_fetch_add_unless(v, a, u) != u;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/andnot b/scripts/atomic/fallbacks/andnot
index 5b83bb63f728..66760457e67a 100755
--- a/scripts/atomic/fallbacks/andnot
+++ b/scripts/atomic/fallbacks/andnot
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline ${ret}
-raw_${atomic}_${pfx}andnot${sfx}${order}(${int} i, ${atomic}_t *v)
-{
 	${retstmt}raw_${atomic}_${pfx}and${sfx}${order}(~i, v);
-}
 EOF
diff --git a/scripts/atomic/fallbacks/cmpxchg b/scripts/atomic/fallbacks/cmpxchg
index 312ee67f1743..1c8507f62e04 100644
--- a/scripts/atomic/fallbacks/cmpxchg
+++ b/scripts/atomic/fallbacks/cmpxchg
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline ${int}
-raw_${atomic}_cmpxchg${order}(${atomic}_t *v, ${int} old, ${int} new)
-{
 	return raw_cmpxchg${order}(&v->counter, old, new);
-}
 EOF
diff --git a/scripts/atomic/fallbacks/dec b/scripts/atomic/fallbacks/dec
index a660ac65994b..60d286d40300 100755
--- a/scripts/atomic/fallbacks/dec
+++ b/scripts/atomic/fallbacks/dec
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline ${ret}
-raw_${atomic}_${pfx}dec${sfx}${order}(${atomic}_t *v)
-{
 	${retstmt}raw_${atomic}_${pfx}sub${sfx}${order}(1, v);
-}
 EOF
diff --git a/scripts/atomic/fallbacks/dec_and_test b/scripts/atomic/fallbacks/dec_and_test
index 521dfcae03f2..3a0278e0ddd7 100755
--- a/scripts/atomic/fallbacks/dec_and_test
+++ b/scripts/atomic/fallbacks/dec_and_test
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline bool
-raw_${atomic}_dec_and_test(${atomic}_t *v)
-{
 	return raw_${atomic}_dec_return(v) == 0;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/dec_if_positive b/scripts/atomic/fallbacks/dec_if_positive
index 7acb205e6ce3..f65c11b4b85b 100755
--- a/scripts/atomic/fallbacks/dec_if_positive
+++ b/scripts/atomic/fallbacks/dec_if_positive
@@ -1,7 +1,4 @@
 cat <<EOF
-static __always_inline ${ret}
-raw_${atomic}_dec_if_positive(${atomic}_t *v)
-{
 	${int} dec, c = raw_${atomic}_read(v);
 
 	do {
@@ -11,5 +8,4 @@ raw_${atomic}_dec_if_positive(${atomic}_t *v)
 	} while (!raw_${atomic}_try_cmpxchg(v, &c, dec));
 
 	return dec;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/dec_unless_positive b/scripts/atomic/fallbacks/dec_unless_positive
index bcb4f27945ea..d025361d7b85 100755
--- a/scripts/atomic/fallbacks/dec_unless_positive
+++ b/scripts/atomic/fallbacks/dec_unless_positive
@@ -1,7 +1,4 @@
 cat <<EOF
-static __always_inline bool
-raw_${atomic}_dec_unless_positive(${atomic}_t *v)
-{
 	${int} c = raw_${atomic}_read(v);
 
 	do {
@@ -10,5 +7,4 @@ raw_${atomic}_dec_unless_positive(${atomic}_t *v)
 	} while (!raw_${atomic}_try_cmpxchg(v, &c, c - 1));
 
 	return true;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/fence b/scripts/atomic/fallbacks/fence
index 067eea553f5e..40d5b397658f 100755
--- a/scripts/atomic/fallbacks/fence
+++ b/scripts/atomic/fallbacks/fence
@@ -1,11 +1,7 @@
 cat <<EOF
-static __always_inline ${ret}
-raw_${atomic}_${pfx}${name}${sfx}(${params})
-{
 	${ret} ret;
 	__atomic_pre_full_fence();
 	ret = arch_${atomic}_${pfx}${name}${sfx}_relaxed(${args});
 	__atomic_post_full_fence();
 	return ret;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/fetch_add_unless b/scripts/atomic/fallbacks/fetch_add_unless
index c18b940153df..8db7e9e17fac 100755
--- a/scripts/atomic/fallbacks/fetch_add_unless
+++ b/scripts/atomic/fallbacks/fetch_add_unless
@@ -1,7 +1,4 @@
 cat << EOF
-static __always_inline ${int}
-raw_${atomic}_fetch_add_unless(${atomic}_t *v, ${int} a, ${int} u)
-{
 	${int} c = raw_${atomic}_read(v);
 
 	do {
@@ -10,5 +7,4 @@ raw_${atomic}_fetch_add_unless(${atomic}_t *v, ${int} a, ${int} u)
 	} while (!raw_${atomic}_try_cmpxchg(v, &c, c + a));
 
 	return c;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/inc b/scripts/atomic/fallbacks/inc
index 7d838f0b6639..56c770f5919c 100755
--- a/scripts/atomic/fallbacks/inc
+++ b/scripts/atomic/fallbacks/inc
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline ${ret}
-raw_${atomic}_${pfx}inc${sfx}${order}(${atomic}_t *v)
-{
 	${retstmt}raw_${atomic}_${pfx}add${sfx}${order}(1, v);
-}
 EOF
diff --git a/scripts/atomic/fallbacks/inc_and_test b/scripts/atomic/fallbacks/inc_and_test
index de25aebee715..7d16a10f2257 100755
--- a/scripts/atomic/fallbacks/inc_and_test
+++ b/scripts/atomic/fallbacks/inc_and_test
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline bool
-raw_${atomic}_inc_and_test(${atomic}_t *v)
-{
 	return raw_${atomic}_inc_return(v) == 0;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/inc_not_zero b/scripts/atomic/fallbacks/inc_not_zero
index e02206d017f6..1fcef1e55bc9 100755
--- a/scripts/atomic/fallbacks/inc_not_zero
+++ b/scripts/atomic/fallbacks/inc_not_zero
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline bool
-raw_${atomic}_inc_not_zero(${atomic}_t *v)
-{
 	return raw_${atomic}_add_unless(v, 1, 0);
-}
 EOF
diff --git a/scripts/atomic/fallbacks/inc_unless_negative b/scripts/atomic/fallbacks/inc_unless_negative
index 7b85cc5b00d2..7b4b09868842 100755
--- a/scripts/atomic/fallbacks/inc_unless_negative
+++ b/scripts/atomic/fallbacks/inc_unless_negative
@@ -1,7 +1,4 @@
 cat <<EOF
-static __always_inline bool
-raw_${atomic}_inc_unless_negative(${atomic}_t *v)
-{
 	${int} c = raw_${atomic}_read(v);
 
 	do {
@@ -10,5 +7,4 @@ raw_${atomic}_inc_unless_negative(${atomic}_t *v)
 	} while (!raw_${atomic}_try_cmpxchg(v, &c, c + 1));
 
 	return true;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/read_acquire b/scripts/atomic/fallbacks/read_acquire
index 26d15ad92d04..e319862d2f1a 100755
--- a/scripts/atomic/fallbacks/read_acquire
+++ b/scripts/atomic/fallbacks/read_acquire
@@ -1,7 +1,4 @@
 cat <<EOF
-static __always_inline ${ret}
-raw_${atomic}_read_acquire(const ${atomic}_t *v)
-{
 	${int} ret;
 
 	if (__native_word(${atomic}_t)) {
@@ -12,5 +9,4 @@ raw_${atomic}_read_acquire(const ${atomic}_t *v)
 	}
 
 	return ret;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/release b/scripts/atomic/fallbacks/release
index cbbff708129b..1e6daf57b4ba 100755
--- a/scripts/atomic/fallbacks/release
+++ b/scripts/atomic/fallbacks/release
@@ -1,8 +1,4 @@
 cat <<EOF
-static __always_inline ${ret}
-raw_${atomic}_${pfx}${name}${sfx}_release(${params})
-{
 	__atomic_release_fence();
 	${retstmt}arch_${atomic}_${pfx}${name}${sfx}_relaxed(${args});
-}
 EOF
diff --git a/scripts/atomic/fallbacks/set_release b/scripts/atomic/fallbacks/set_release
index 104693bc3c66..16a374ae6bb1 100755
--- a/scripts/atomic/fallbacks/set_release
+++ b/scripts/atomic/fallbacks/set_release
@@ -1,12 +1,8 @@
 cat <<EOF
-static __always_inline void
-raw_${atomic}_set_release(${atomic}_t *v, ${int} i)
-{
 	if (__native_word(${atomic}_t)) {
 		smp_store_release(&(v)->counter, i);
 	} else {
 		__atomic_release_fence();
 		raw_${atomic}_set(v, i);
 	}
-}
 EOF
diff --git a/scripts/atomic/fallbacks/sub_and_test b/scripts/atomic/fallbacks/sub_and_test
index 8975a496d495..d1f746fe0ca4 100755
--- a/scripts/atomic/fallbacks/sub_and_test
+++ b/scripts/atomic/fallbacks/sub_and_test
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline bool
-raw_${atomic}_sub_and_test(${int} i, ${atomic}_t *v)
-{
 	return raw_${atomic}_sub_return(i, v) == 0;
-}
 EOF
diff --git a/scripts/atomic/fallbacks/try_cmpxchg b/scripts/atomic/fallbacks/try_cmpxchg
index 4c911a6cced9..d4da82092baf 100755
--- a/scripts/atomic/fallbacks/try_cmpxchg
+++ b/scripts/atomic/fallbacks/try_cmpxchg
@@ -1,11 +1,7 @@
 cat <<EOF
-static __always_inline bool
-raw_${atomic}_try_cmpxchg${order}(${atomic}_t *v, ${int} *old, ${int} new)
-{
 	${int} r, o = *old;
 	r = raw_${atomic}_cmpxchg${order}(v, o, new);
 	if (unlikely(r != o))
 		*old = r;
 	return likely(r == o);
-}
 EOF
diff --git a/scripts/atomic/fallbacks/xchg b/scripts/atomic/fallbacks/xchg
index bdd788aa575f..e4def1e0d092 100644
--- a/scripts/atomic/fallbacks/xchg
+++ b/scripts/atomic/fallbacks/xchg
@@ -1,7 +1,3 @@
 cat <<EOF
-static __always_inline ${int}
-raw_${atomic}_xchg${order}(${atomic}_t *v, ${int} new)
-{
 	return raw_xchg${order}(&v->counter, new);
-}
 EOF
diff --git a/scripts/atomic/gen-atomic-fallback.sh b/scripts/atomic/gen-atomic-fallback.sh
index 86aca4f9f315..2b470d31e353 100755
--- a/scripts/atomic/gen-atomic-fallback.sh
+++ b/scripts/atomic/gen-atomic-fallback.sh
@@ -60,13 +60,23 @@ gen_proto_order_variant()
 	local name="$1"; shift
 	local sfx="$1"; shift
 	local order="$1"; shift
-	local atomic="$1"
+	local atomic="$1"; shift
+	local int="$1"; shift
 
 	local atomicname="${atomic}_${pfx}${name}${sfx}${order}"
 	local basename="${atomic}_${pfx}${name}${sfx}"
 
 	local template="$(find_fallback_template "${pfx}" "${name}" "${sfx}" "${order}")"
 
+	local ret="$(gen_ret_type "${meta}" "${int}")"
+	local retstmt="$(gen_ret_stmt "${meta}")"
+	local params="$(gen_params "${int}" "${atomic}" "$@")"
+	local args="$(gen_args "$@")"
+
+	printf "static __always_inline ${ret}\n"
+	printf "raw_${atomicname}(${params})\n"
+	printf "{\n"
+
 	# Where there is no possible fallback, this order variant is mandatory
 	# and must be provided by arch code. Add a comment to the header to
 	# make this obvious.
@@ -75,33 +85,35 @@ gen_proto_order_variant()
 	# define this order variant as a C function without a preprocessor
 	# symbol.
 	if [ -z ${template} ] && [ -z "${order}" ] && ! meta_has_relaxed "${meta}"; then
-		printf "#define raw_${atomicname} arch_${atomicname}\n\n"
+		printf "\t${retstmt}arch_${atomicname}(${args});\n"
+		printf "}\n\n"
 		return
 	fi
 
 	printf "#if defined(arch_${atomicname})\n"
-	printf "#define raw_${atomicname} arch_${atomicname}\n"
+	printf "\t${retstmt}arch_${atomicname}(${args});\n"
 
 	# Allow FULL/ACQUIRE/RELEASE ops to be defined in terms of RELAXED ops
 	if [ "${order}" != "_relaxed" ] && meta_has_relaxed "${meta}"; then
 		printf "#elif defined(arch_${basename}_relaxed)\n"
-		gen_order_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "${order}" "$@"
+		gen_order_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "${order}" "${atomic}" "${int}" "$@"
 	fi
 
 	# Allow ACQUIRE/RELEASE/RELAXED ops to be defined in terms of FULL ops
 	if [ ! -z "${order}" ]; then
 		printf "#elif defined(arch_${basename})\n"
-		printf "#define raw_${atomicname} arch_${basename}\n"
+		printf "\t${retstmt}arch_${basename}(${args});\n"
 	fi
 
 	printf "#else\n"
 	if [ ! -z "${template}" ]; then
-		gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "${order}" "$@"
+		gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "${order}" "${atomic}" "${int}" "$@"
 	else
 		printf "#error \"Unable to define raw_${atomicname}\"\n"
 	fi
 
-	printf "#endif\n\n"
+	printf "#endif\n"
+	printf "}\n\n"
 }