1 files changed, 333 insertions, 0 deletions
diff --git a/scripts/atomic/gen-atomic-fallback.sh b/scripts/atomic/gen-atomic-fallback.sh
new file mode 100755
index 000000000..a45154cef
--- /dev/null
+++ b/scripts/atomic/gen-atomic-fallback.sh
@@ -0,0 +1,333 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+ATOMICDIR=$(dirname $0)
+
+. ${ATOMICDIR}/atomic-tbl.sh
+
+#gen_template_fallback(template, meta, pfx, name, sfx, order, atomic, int, args...)
+gen_template_fallback()
+{
+	local template="$1"; shift
+	local meta="$1"; shift
+	local pfx="$1"; shift
+	local name="$1"; shift
+	local sfx="$1"; shift
+	local order="$1"; shift
+	local atomic="$1"; shift
+	local int="$1"; shift
+
+	local ret="$(gen_ret_type "${meta}" "${int}")"
+	local retstmt="$(gen_ret_stmt "${meta}")"
+	local params="$(gen_params "${int}" "${atomic}" "$@")"
+	local args="$(gen_args "$@")"
+
+	. ${template}
+}
+
+#gen_order_fallback(meta, pfx, name, sfx, order, atomic, int, args...)
+gen_order_fallback()
+{
+	local meta="$1"; shift
+	local pfx="$1"; shift
+	local name="$1"; shift
+	local sfx="$1"; shift
+	local order="$1"; shift
+
+	local tmpl_order=${order#_}
+	local tmpl="${ATOMICDIR}/fallbacks/${tmpl_order:-fence}"
+	gen_template_fallback "${tmpl}" "${meta}" "${pfx}" "${name}" "${sfx}" "${order}" "$@"
+}
+
+#gen_proto_fallback(meta, pfx, name, sfx, order, atomic, int, args...)
+gen_proto_fallback()
+{
+	local meta="$1"; shift
+	local pfx="$1"; shift
+	local name="$1"; shift
+	local sfx="$1"; shift
+	local order="$1"; shift
+
+	local tmpl="$(find_fallback_template "${pfx}" "${name}" "${sfx}" "${order}")"
+	gen_template_fallback "${tmpl}" "${meta}" "${pfx}" "${name}" "${sfx}" "${order}" "$@"
+}
+
+#gen_proto_order_variant(meta, pfx, name, sfx, order, atomic, int, args...)
+gen_proto_order_variant()
+{
+	local meta="$1"; shift
+	local pfx="$1"; shift
+	local name="$1"; shift
+	local sfx="$1"; shift
+	local order="$1"; shift
+	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="$(gen_args "$@")"
+
+	gen_kerneldoc "raw_" "${meta}" "${pfx}" "${name}" "${sfx}" "${order}" "${atomic}" "${int}" "$@"
+
+	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.
+	#
+	# Ideally we'd error on a missing definition, but arch code might
+	# define this order variant as a C function without a preprocessor
+	# symbol.
+	if [ -z ${template} ] && [ -z "${order}" ] && ! meta_has_relaxed "${meta}"; then
+		printf "\t${retstmt}arch_${atomicname}(${args});\n"
+		printf "}\n\n"
+		return
+	fi
+
+	printf "#if defined(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}" "${atomic}" "${int}" "$@"
+	fi
+
+	# Allow ACQUIRE/RELEASE/RELAXED ops to be defined in terms of FULL ops
+	if [ ! -z "${order}" ] && ! meta_is_implicitly_relaxed "${meta}"; then
+		printf "#elif defined(arch_${basename})\n"
+		printf "\t${retstmt}arch_${basename}(${args});\n"
+	fi
+
+	printf "#else\n"
+	if [ ! -z "${template}" ]; then
+		gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "${order}" "${atomic}" "${int}" "$@"
+	else
+		printf "#error \"Unable to define raw_${atomicname}\"\n"
+	fi
+
+	printf "#endif\n"
+	printf "}\n\n"
+}
+
+
+#gen_proto_order_variants(meta, pfx, name, sfx, atomic, int, args...)
+gen_proto_order_variants()
+{
+	local meta="$1"; shift
+	local pfx="$1"; shift
+	local name="$1"; shift
+	local sfx="$1"; shift
+	local atomic="$1"
+
+	gen_proto_order_variant "${meta}" "${pfx}" "${name}" "${sfx}" "" "$@"
+
+	if meta_has_acquire "${meta}"; then
+		gen_proto_order_variant "${meta}" "${pfx}" "${name}" "${sfx}" "_acquire" "$@"
+	fi
+
+	if meta_has_release "${meta}"; then
+		gen_proto_order_variant "${meta}" "${pfx}" "${name}" "${sfx}" "_release" "$@"
+	fi
+
+	if meta_has_relaxed "${meta}"; then
+		gen_proto_order_variant "${meta}" "${pfx}" "${name}" "${sfx}" "_relaxed" "$@"
+	fi
+}
+
+#gen_basic_fallbacks(basename)
+gen_basic_fallbacks()
+{
+	local basename="$1"; shift
+cat << EOF
+#define raw_${basename}_acquire arch_${basename}
+#define raw_${basename}_release arch_${basename}
+#define raw_${basename}_relaxed arch_${basename}
+EOF
+}
+
+gen_order_fallbacks()
+{
+	local xchg="$1"; shift
+
+cat <<EOF
+
+#define raw_${xchg}_relaxed arch_${xchg}_relaxed
+
+#ifdef arch_${xchg}_acquire
+#define raw_${xchg}_acquire arch_${xchg}_acquire
+#else
+#define raw_${xchg}_acquire(...) \\
+	__atomic_op_acquire(arch_${xchg}, __VA_ARGS__)
+#endif
+
+#ifdef arch_${xchg}_release
+#define raw_${xchg}_release arch_${xchg}_release
+#else
+#define raw_${xchg}_release(...) \\
+	__atomic_op_release(arch_${xchg}, __VA_ARGS__)
+#endif
+
+#ifdef arch_${xchg}
+#define raw_${xchg} arch_${xchg}
+#else
+#define raw_${xchg}(...) \\
+	__atomic_op_fence(arch_${xchg}, __VA_ARGS__)
+#endif
+
+EOF
+}
+
+gen_xchg_order_fallback()
+{
+	local xchg="$1"; shift
+	local order="$1"; shift
+	local forder="${order:-_fence}"
+
+	printf "#if defined(arch_${xchg}${order})\n"
+	printf "#define raw_${xchg}${order} arch_${xchg}${order}\n"
+
+	if [ "${order}" != "_relaxed" ]; then
+		printf "#elif defined(arch_${xchg}_relaxed)\n"
+		printf "#define raw_${xchg}${order}(...) \\\\\n"
+		printf "	__atomic_op${forder}(arch_${xchg}, __VA_ARGS__)\n"
+	fi
+
+	if [ ! -z "${order}" ]; then
+		printf "#elif defined(arch_${xchg})\n"
+		printf "#define raw_${xchg}${order} arch_${xchg}\n"
+	fi
+
+	printf "#else\n"
+	printf "extern void raw_${xchg}${order}_not_implemented(void);\n"
+	printf "#define raw_${xchg}${order}(...) raw_${xchg}${order}_not_implemented()\n"
+	printf "#endif\n\n"
+}
+
+gen_xchg_fallbacks()
+{
+	local xchg="$1"; shift
+
+	for order in "" "_acquire" "_release" "_relaxed"; do
+		gen_xchg_order_fallback "${xchg}" "${order}"
+	done
+}
+
+gen_try_cmpxchg_fallback()
+{
+	local cmpxchg="$1"; shift;
+	local order="$1"; shift;
+
+cat <<EOF
+#define raw_try_${cmpxchg}${order}(_ptr, _oldp, _new) \\
+({ \\
+	typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \\
+	___r = raw_${cmpxchg}${order}((_ptr), ___o, (_new)); \\
+	if (unlikely(___r != ___o)) \\
+		*___op = ___r; \\
+	likely(___r == ___o); \\
+})
+EOF
+}
+
+gen_try_cmpxchg_order_fallback()
+{
+	local cmpxchg="$1"; shift
+	local order="$1"; shift
+	local forder="${order:-_fence}"
+
+	printf "#if defined(arch_try_${cmpxchg}${order})\n"
+	printf "#define raw_try_${cmpxchg}${order} arch_try_${cmpxchg}${order}\n"
+
+	if [ "${order}" != "_relaxed" ]; then
+		printf "#elif defined(arch_try_${cmpxchg}_relaxed)\n"
+		printf "#define raw_try_${cmpxchg}${order}(...) \\\\\n"
+		printf "	__atomic_op${forder}(arch_try_${cmpxchg}, __VA_ARGS__)\n"
+	fi
+
+	if [ ! -z "${order}" ]; then
+		printf "#elif defined(arch_try_${cmpxchg})\n"
+		printf "#define raw_try_${cmpxchg}${order} arch_try_${cmpxchg}\n"
+	fi
+
+	printf "#else\n"
+	gen_try_cmpxchg_fallback "${cmpxchg}" "${order}"
+	printf "#endif\n\n"
+}
+
+gen_try_cmpxchg_fallbacks()
+{
+	local cmpxchg="$1"; shift;
+
+	for order in "" "_acquire" "_release" "_relaxed"; do
+		gen_try_cmpxchg_order_fallback "${cmpxchg}" "${order}"
+	done
+}
+
+gen_cmpxchg_local_fallbacks()
+{
+	local cmpxchg="$1"; shift
+
+	printf "#define raw_${cmpxchg} arch_${cmpxchg}\n\n"
+	printf "#ifdef arch_try_${cmpxchg}\n"
+	printf "#define raw_try_${cmpxchg} arch_try_${cmpxchg}\n"
+	printf "#else\n"
+	gen_try_cmpxchg_fallback "${cmpxchg}" ""
+	printf "#endif\n\n"
+}
+
+cat << EOF
+// SPDX-License-Identifier: GPL-2.0
+
+// Generated by $0
+// DO NOT MODIFY THIS FILE DIRECTLY
+
+#ifndef _LINUX_ATOMIC_FALLBACK_H
+#define _LINUX_ATOMIC_FALLBACK_H
+
+#include <linux/compiler.h>
+
+EOF
+
+for xchg in "xchg" "cmpxchg" "cmpxchg64" "cmpxchg128"; do
+	gen_xchg_fallbacks "${xchg}"
+done
+
+for cmpxchg in "cmpxchg" "cmpxchg64" "cmpxchg128"; do
+	gen_try_cmpxchg_fallbacks "${cmpxchg}"
+done
+
+for cmpxchg in "cmpxchg_local" "cmpxchg64_local" "cmpxchg128_local"; do
+	gen_cmpxchg_local_fallbacks "${cmpxchg}" ""
+done
+
+for cmpxchg in "sync_cmpxchg"; do
+	printf "#define raw_${cmpxchg} arch_${cmpxchg}\n\n"
+done
+
+grep '^[a-z]' "$1" | while read name meta args; do
+	gen_proto "${meta}" "${name}" "atomic" "int" ${args}
+done
+
+cat <<EOF
+#ifdef CONFIG_GENERIC_ATOMIC64
+#include <asm-generic/atomic64.h>
+#endif
+
+EOF
+
+grep '^[a-z]' "$1" | while read name meta args; do
+	gen_proto "${meta}" "${name}" "atomic64" "s64" ${args}
+done
+
+cat <<EOF
+#endif /* _LINUX_ATOMIC_FALLBACK_H */
+EOF