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.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

MAINTAINERS

@@ -2579,6 +2579,7 @@ L:	linux-kernel@vger.kernel.org
 S:	Maintained
 F:	arch/*/include/asm/atomic*.h
 F:	include/*/atomic*.h
+F:	scripts/atomic/
 
 ATTO EXPRESSSAS SAS/SATA RAID SCSI DRIVER
 M:	Bradley Grove <linuxdrivers@attotech.com>

scripts/atomic/atomic-tbl.sh

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# helpers for dealing with atomics.tbl
+
+#meta_in(meta, match)
+meta_in()
+{
+	case "$1" in
+	[$2]) return 0;;
+	esac
+
+	return 1
+}
+
+#meta_has_ret(meta)
+meta_has_ret()
+{
+	meta_in "$1" "bBiIfFlR"
+}
+
+#meta_has_acquire(meta)
+meta_has_acquire()
+{
+	meta_in "$1" "BFIlR"
+}
+
+#meta_has_release(meta)
+meta_has_release()
+{
+	meta_in "$1" "BFIRs"
+}
+
+#meta_has_relaxed(meta)
+meta_has_relaxed()
+{
+	meta_in "$1" "BFIR"
+}
+
+#find_fallback_template(pfx, name, sfx, order)
+find_fallback_template()
+{
+	local pfx="$1"; shift
+	local name="$1"; shift
+	local sfx="$1"; shift
+	local order="$1"; shift
+
+	local base=""
+	local file=""
+
+	# We may have fallbacks for a specific case (e.g. read_acquire()), or
+	# an entire class, e.g. *inc*().
+	#
+	# Start at the most specific, and fall back to the most general. Once
+	# we find a specific fallback, don't bother looking for more.
+	for base in "${pfx}${name}${sfx}${order}" "${name}"; do
+		file="${ATOMICDIR}/fallbacks/${base}"
+
+		if [ -f "${file}" ]; then
+			printf "${file}"
+			break
+		fi
+	done
+}
+
+#gen_ret_type(meta, int)
+gen_ret_type() {
+	local meta="$1"; shift
+	local int="$1"; shift
+
+	case "${meta}" in
+	[sv]) printf "void";;
+	[bB]) printf "bool";;
+	[aiIfFlR]) printf "${int}";;
+	esac
+}
+
+#gen_ret_stmt(meta)
+gen_ret_stmt()
+{
+	if meta_has_ret "${meta}"; then
+		printf "return ";
+	fi
+}
+
+# gen_param_name(arg)
+gen_param_name()
+{
+	# strip off the leading 'c' for 'cv'
+	local name="${1#c}"
+	printf "${name#*:}"
+}
+
+# gen_param_type(arg, int, atomic)
+gen_param_type()
+{
+	local type="${1%%:*}"; shift
+	local int="$1"; shift
+	local atomic="$1"; shift
+
+	case "${type}" in
+	i) type="${int} ";;
+	p) type="${int} *";;
+	v) type="${atomic}_t *";;
+	cv) type="const ${atomic}_t *";;
+	esac
+
+	printf "${type}"
+}
+
+#gen_param(arg, int, atomic)
+gen_param()
+{
+	local arg="$1"; shift
+	local int="$1"; shift
+	local atomic="$1"; shift
+	local name="$(gen_param_name "${arg}")"
+	local type="$(gen_param_type "${arg}" "${int}" "${atomic}")"
+
+	printf "${type}${name}"
+}
+
+#gen_params(int, atomic, arg...)
+gen_params()
+{
+	local int="$1"; shift
+	local atomic="$1"; shift
+
+	while [ "$#" -gt 0 ]; do
+		gen_param "$1" "${int}" "${atomic}"
+		[ "$#" -gt 1 ] && printf ", "
+		shift;
+	done
+}
+
+#gen_args(arg...)
+gen_args()
+{
+	while [ "$#" -gt 0 ]; do
+		printf "$(gen_param_name "$1")"
+		[ "$#" -gt 1 ] && printf ", "
+		shift;
+	done
+}
+
+#gen_proto_order_variants(meta, pfx, name, sfx, ...)
+gen_proto_order_variants()
+{
+	local meta="$1"; shift
+	local pfx="$1"; shift
+	local name="$1"; shift
+	local sfx="$1"; shift
+
+	gen_proto_order_variant "${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_proto_variants(meta, name, ...)
+gen_proto_variants()
+{
+	local meta="$1"; shift
+	local name="$1"; shift
+	local pfx=""
+	local sfx=""
+
+	meta_in "${meta}" "fF" && pfx="fetch_"
+	meta_in "${meta}" "R" && sfx="_return"
+
+	gen_proto_order_variants "${meta}" "${pfx}" "${name}" "${sfx}" "$@"
+}
+
+#gen_proto(meta, ...)
+gen_proto() {
+	local meta="$1"; shift
+	for m in $(echo "${meta}" | fold -w1); do
+		gen_proto_variants "${m}" "$@"
+	done
+}

scripts/atomic/atomics.tbl

+# name	meta	args...
+#
+# Where meta contains a string of variants to generate.
+# Upper-case implies _{acquire,release,relaxed} variants.
+# Valid meta values are:
+# * B/b	- bool: returns bool
+# * v	- void: returns void
+# * I/i	- int: returns base type
+# * R	- return: returns base type (has _return variants)
+# * F/f	- fetch: returns base type (has fetch_ variants)
+# * l	- load: returns base type (has _acquire order variant)
+# * s	- store: returns void (has _release order variant)
+#
+# Where args contains list of type[:name], where type is:
+# * cv	- const pointer to atomic base type (atomic_t/atomic64_t/atomic_long_t)
+# * v	- pointer to atomic base type (atomic_t/atomic64_t/atomic_long_t)
+# * i	- base type (int/s64/long)
+# * p	- pointer to base type (int/s64/long)
+#
+read			l	cv
+set			s	v	i
+add			vRF	i	v
+sub			vRF	i	v
+inc			vRF	v
+dec			vRF	v
+and			vF	i	v
+andnot			vF	i	v
+or			vF	i	v
+xor			vF	i	v
+xchg			I	v	i
+cmpxchg			I	v	i:old	i:new
+try_cmpxchg		B	v	p:old	i:new
+sub_and_test		b	i	v
+dec_and_test		b	v
+inc_and_test		b	v
+add_negative		b	i	v
+add_unless		fb	v	i:a	i:u
+inc_not_zero		b	v
+inc_unless_negative	b	v
+dec_unless_positive	b	v
+dec_if_positive		i	v

scripts/atomic/fallbacks/acquire

+cat <<EOF
+static inline ${ret}
+${atomic}_${pfx}${name}${sfx}_acquire(${params})
+{
+	${ret} ret = ${atomic}_${pfx}${name}${sfx}_relaxed(${args});
+	__atomic_acquire_fence();
+	return ret;
+}
+EOF

scripts/atomic/fallbacks/add_negative

+cat <<EOF
+/**
+ * ${atomic}_add_negative - add and test if negative
+ * @i: integer value to add
+ * @v: pointer of type ${atomic}_t
+ *
+ * Atomically adds @i to @v and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.
+ */
+static inline bool
+${atomic}_add_negative(${int} i, ${atomic}_t *v)
+{
+	return ${atomic}_add_return(i, v) < 0;
+}
+EOF

scripts/atomic/fallbacks/add_unless

+cat << EOF
+/**
+ * ${atomic}_add_unless - add unless the number is already a given value
+ * @v: pointer of type ${atomic}_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, if @v was not already @u.
+ * Returns true if the addition was done.
+ */
+static inline bool
+${atomic}_add_unless(${atomic}_t *v, ${int} a, ${int} u)
+{
+	return ${atomic}_fetch_add_unless(v, a, u) != u;
+}
+EOF

scripts/atomic/fallbacks/andnot

+cat <<EOF
+static inline ${ret}
+${atomic}_${pfx}andnot${sfx}${order}(${int} i, ${atomic}_t *v)
+{
+	${retstmt}${atomic}_${pfx}and${sfx}${order}(~i, v);
+}
+EOF

scripts/atomic/fallbacks/dec

+cat <<EOF
+static inline ${ret}
+${atomic}_${pfx}dec${sfx}${order}(${atomic}_t *v)
+{
+	${retstmt}${atomic}_${pfx}sub${sfx}${order}(1, v);
+}
+EOF

scripts/atomic/fallbacks/dec_and_test

+cat <<EOF
+/**
+ * ${atomic}_dec_and_test - decrement and test
+ * @v: pointer of type ${atomic}_t
+ *
+ * Atomically decrements @v by 1 and
+ * returns true if the result is 0, or false for all other
+ * cases.
+ */
+static inline bool
+${atomic}_dec_and_test(${atomic}_t *v)
+{
+	return ${atomic}_dec_return(v) == 0;
+}
+EOF

scripts/atomic/fallbacks/dec_if_positive

+cat <<EOF
+static inline ${ret}
+${atomic}_dec_if_positive(${atomic}_t *v)
+{
+	${int} dec, c = ${atomic}_read(v);
+
+	do {
+		dec = c - 1;
+		if (unlikely(dec < 0))
+			break;
+	} while (!${atomic}_try_cmpxchg(v, &c, dec));
+
+	return dec;
+}
+EOF

scripts/atomic/fallbacks/dec_unless_positive

+cat <<EOF
+static inline bool
+${atomic}_dec_unless_positive(${atomic}_t *v)
+{
+	${int} c = ${atomic}_read(v);
+
+	do {
+		if (unlikely(c > 0))
+			return false;
+	} while (!${atomic}_try_cmpxchg(v, &c, c - 1));
+
+	return true;
+}
+EOF

scripts/atomic/fallbacks/fence

+cat <<EOF
+static inline ${ret}
+${atomic}_${pfx}${name}${sfx}(${params})
+{
+	${ret} ret;
+	__atomic_pre_full_fence();
+	ret = ${atomic}_${pfx}${name}${sfx}_relaxed(${args});
+	__atomic_post_full_fence();
+	return ret;
+}
+EOF

scripts/atomic/fallbacks/fetch_add_unless

+cat << EOF
+/**
+ * ${atomic}_fetch_add_unless - add unless the number is already a given value
+ * @v: pointer of type ${atomic}_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, so long as @v was not already @u.
+ * Returns original value of @v
+ */
+static inline ${int}
+${atomic}_fetch_add_unless(${atomic}_t *v, ${int} a, ${int} u)
+{
+	${int} c = ${atomic}_read(v);
+
+	do {
+		if (unlikely(c == u))
+			break;
+	} while (!${atomic}_try_cmpxchg(v, &c, c + a));
+
+	return c;
+}
+EOF

scripts/atomic/fallbacks/inc

+cat <<EOF
+static inline ${ret}
+${atomic}_${pfx}inc${sfx}${order}(${atomic}_t *v)
+{
+	${retstmt}${atomic}_${pfx}add${sfx}${order}(1, v);
+}
+EOF

scripts/atomic/fallbacks/inc_and_test

+cat <<EOF
+/**
+ * ${atomic}_inc_and_test - increment and test
+ * @v: pointer of type ${atomic}_t
+ *
+ * Atomically increments @v by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.
+ */
+static inline bool
+${atomic}_inc_and_test(${atomic}_t *v)
+{
+	return ${atomic}_inc_return(v) == 0;
+}
+EOF

scripts/atomic/fallbacks/inc_not_zero

+cat <<EOF
+/**
+ * ${atomic}_inc_not_zero - increment unless the number is zero
+ * @v: pointer of type ${atomic}_t
+ *
+ * Atomically increments @v by 1, if @v is non-zero.
+ * Returns true if the increment was done.
+ */
+static inline bool
+${atomic}_inc_not_zero(${atomic}_t *v)
+{
+	return ${atomic}_add_unless(v, 1, 0);
+}
+EOF

scripts/atomic/fallbacks/inc_unless_negative

+cat <<EOF
+static inline bool
+${atomic}_inc_unless_negative(${atomic}_t *v)
+{
+	${int} c = ${atomic}_read(v);
+
+	do {
+		if (unlikely(c < 0))
+			return false;
+	} while (!${atomic}_try_cmpxchg(v, &c, c + 1));
+
+	return true;
+}
+EOF

scripts/atomic/fallbacks/read_acquire

+cat <<EOF
+static inline ${ret}
+${atomic}_read_acquire(const ${atomic}_t *v)
+{
+	return smp_load_acquire(&(v)->counter);
+}
+EOF

scripts/atomic/fallbacks/release

+cat <<EOF
+static inline ${ret}
+${atomic}_${pfx}${name}${sfx}_release(${params})
+{
+	__atomic_release_fence();
+	${retstmt}${atomic}_${pfx}${name}${sfx}_relaxed(${args});
+}
+EOF

scripts/atomic/fallbacks/set_release

+cat <<EOF
+static inline void
+${atomic}_set_release(${atomic}_t *v, ${int} i)
+{
+	smp_store_release(&(v)->counter, i);
+}
+EOF

scripts/atomic/fallbacks/sub_and_test

+cat <<EOF
+/**
+ * ${atomic}_sub_and_test - subtract value from variable and test result
+ * @i: integer value to subtract
+ * @v: pointer of type ${atomic}_t
+ *
+ * Atomically subtracts @i from @v and returns
+ * true if the result is zero, or false for all
+ * other cases.
+ */
+static inline bool
+${atomic}_sub_and_test(${int} i, ${atomic}_t *v)
+{
+	return ${atomic}_sub_return(i, v) == 0;
+}
+EOF

scripts/atomic/fallbacks/try_cmpxchg

+cat <<EOF
+static inline bool
+${atomic}_try_cmpxchg${order}(${atomic}_t *v, ${int} *old, ${int} new)
+{
+	${int} r, o = *old;
+	r = ${atomic}_cmpxchg${order}(v, o, new);
+	if (unlikely(r != o))
+		*old = r;
+	return likely(r == o);
+}
+EOF

scripts/atomic/gen-atomic-fallback.sh

+#!/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="$1"; shift
+
+	local atomicname="${atomic}_${pfx}${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 "$@")"
+
+	if [ ! -z "${template}" ]; then
+		printf "#ifndef ${atomicname}\n"
+		. ${template}
+		printf "#define ${atomicname} ${atomicname}\n"
+		printf "#endif\n\n"
+	fi
+}
+
+#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_basic_fallbacks(basename)
+gen_basic_fallbacks()
+{
+	local basename="$1"; shift
+cat << EOF
+#define ${basename}_acquire ${basename}
+#define ${basename}_release ${basename}
+#define ${basename}_relaxed ${basename}
+EOF
+}
+
+#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="$1"
+
+	local basename="${atomic}_${pfx}${name}${sfx}"
+
+	local template="$(find_fallback_template "${pfx}" "${name}" "${sfx}" "${order}")"
+
+	# If we don't have relaxed atomics, then we don't bother with ordering fallbacks
+	# read_acquire and set_release need to be templated, though
+	if ! meta_has_relaxed "${meta}"; then
+		gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "" "$@"
+
+		if meta_has_acquire "${meta}"; then
+			gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "_acquire" "$@"
+		fi
+
+		if meta_has_release "${meta}"; then
+			gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "_release" "$@"
+		fi
+
+		return
+	fi
+
+	printf "#ifndef ${basename}_relaxed\n"
+
+	if [ ! -z "${template}" ]; then
+		printf "#ifdef ${basename}\n"
+	fi
+
+	gen_basic_fallbacks "${basename}"
+
+	if [ ! -z "${template}" ]; then
+		printf "#endif /* ${atomic}_${pfx}${name}${sfx} */\n\n"
+		gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "" "$@"
+		gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "_acquire" "$@"
+		gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "_release" "$@"
+		gen_proto_fallback "${meta}" "${pfx}" "${name}" "${sfx}" "_relaxed" "$@"
+	fi
+
+	printf "#else /* ${basename}_relaxed */\n\n"
+
+	gen_template_fallback "${ATOMICDIR}/fallbacks/acquire"  "${meta}" "${pfx}" "${name}" "${sfx}" "_acquire" "$@"
+	gen_template_fallback "${ATOMICDIR}/fallbacks/release"  "${meta}" "${pfx}" "${name}" "${sfx}" "_release" "$@"
+	gen_template_fallback "${ATOMICDIR}/fallbacks/fence"  "${meta}" "${pfx}" "${name}" "${sfx}" "" "$@"
+
+	printf "#endif /* ${basename}_relaxed */\n\n"
+}
+
+gen_xchg_fallbacks()
+{
+	local xchg="$1"; shift
+cat <<EOF
+#ifndef ${xchg}_relaxed
+#define ${xchg}_relaxed		${xchg}
+#define ${xchg}_acquire		${xchg}
+#define ${xchg}_release		${xchg}
+#else /* ${xchg}_relaxed */
+
+#ifndef ${xchg}_acquire
+#define ${xchg}_acquire(...) \\
+	__atomic_op_acquire(${xchg}, __VA_ARGS__)
+#endif
+
+#ifndef ${xchg}_release
+#define ${xchg}_release(...) \\
+	__atomic_op_release(${xchg}, __VA_ARGS__)
+#endif
+
+#ifndef ${xchg}
+#define ${xchg}(...) \\
+	__atomic_op_fence(${xchg}, __VA_ARGS__)
+#endif
+
+#endif /* ${xchg}_relaxed */
+
+EOF
+}
+
+cat << EOF
+// SPDX-License-Identifier: GPL-2.0
+
+// Generated by $0
+// DO NOT MODIFY THIS FILE DIRECTLY
+
+#ifndef _LINUX_ATOMIC_FALLBACK_H
+#define _LINUX_ATOMIC_FALLBACK_H
+
+EOF
+
+for xchg in "xchg" "cmpxchg" "cmpxchg64"; do
+	gen_xchg_fallbacks "${xchg}"
+done
+
+grep '^[a-z]' "$1" | while read name meta args; do
+	gen_proto "${meta}" "${name}" "atomic" "int" ${args}
+done
+
+cat <<EOF
+#define atomic_cond_read_acquire(v, c) smp_cond_load_acquire(&(v)->counter, (c))
+#define atomic_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c))
+
+#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
+#define atomic64_cond_read_acquire(v, c) smp_cond_load_acquire(&(v)->counter, (c))
+#define atomic64_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c))
+
+#endif /* _LINUX_ATOMIC_FALLBACK_H */
+EOF

scripts/atomic/gen-atomic-instrumented.sh

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+ATOMICDIR=$(dirname $0)
+
+. ${ATOMICDIR}/atomic-tbl.sh
+
+#gen_param_check(arg)
+gen_param_check()
+{
+	local arg="$1"; shift
+	local type="${arg%%:*}"
+	local name="$(gen_param_name "${arg}")"
+	local rw="write"
+
+	case "${type#c}" in
+	i) return;;
+	esac
+
+	# We don't write to constant parameters
+	[ ${type#c} != ${type} ] && rw="read"
+
+	printf "\tkasan_check_${rw}(${name}, sizeof(*${name}));\n"
+}
+
+#gen_param_check(arg...)
+gen_params_checks()
+{
+	while [ "$#" -gt 0 ]; do
+		gen_param_check "$1"
+		shift;
+	done
+}
+
+# gen_guard(meta, atomic, pfx, name, sfx, order)
+gen_guard()
+{
+	local meta="$1"; shift
+	local atomic="$1"; shift
+	local pfx="$1"; shift
+	local name="$1"; shift
+	local sfx="$1"; shift
+	local order="$1"; shift
+
+	local atomicname="arch_${atomic}_${pfx}${name}${sfx}${order}"
+
+	local template="$(find_fallback_template "${pfx}" "${name}" "${sfx}" "${order}")"
+
+	# We definitely need a preprocessor symbol for this atomic if it is an
+	# ordering variant, or if there's a generic fallback.
+	if [ ! -z "${order}" ] || [ ! -z "${template}" ]; then
+		printf "defined(${atomicname})"
+		return
+	fi
+
+	# If this is a base variant, but a relaxed variant *may* exist, then we
+	# only have a preprocessor symbol if the relaxed variant isn't defined
+	if meta_has_relaxed "${meta}"; then
+		printf "!defined(${atomicname}_relaxed) || defined(${atomicname})"
+	fi
+}
+
+#gen_proto_order_variant(meta, pfx, name, sfx, order, atomic, int, arg...)
+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 guard="$(gen_guard "${meta}" "${atomic}" "${pfx}" "${name}" "${sfx}" "${order}")"
+
+	local ret="$(gen_ret_type "${meta}" "${int}")"
+	local params="$(gen_params "${int}" "${atomic}" "$@")"
+	local checks="$(gen_params_checks "$@")"
+	local args="$(gen_args "$@")"
+	local retstmt="$(gen_ret_stmt "${meta}")"
+
+	[ ! -z "${guard}" ] && printf "#if ${guard}\n"
+
+cat <<EOF
+static inline ${ret}
+${atomicname}(${params})
+{
+${checks}
+	${retstmt}arch_${atomicname}(${args});
+}
+#define ${atomicname} ${atomicname}
+EOF
+
+	[ ! -z "${guard}" ] && printf "#endif\n"
+
+	printf "\n"
+}
+
+gen_xchg()
+{
+	local xchg="$1"; shift
+	local mult="$1"; shift
+
+cat <<EOF
+#define ${xchg}(ptr, ...)						\\
+({									\\
+	typeof(ptr) __ai_ptr = (ptr);					\\
+	kasan_check_write(__ai_ptr, ${mult}sizeof(*__ai_ptr));		\\
+	arch_${xchg}(__ai_ptr, __VA_ARGS__);				\\
+})
+EOF
+}
+
+gen_optional_xchg()
+{
+	local name="$1"; shift
+	local sfx="$1"; shift
+	local guard="defined(arch_${name}${sfx})"
+
+	[ -z "${sfx}" ] && guard="!defined(arch_${name}_relaxed) || defined(arch_${name})"
+
+	printf "#if ${guard}\n"
+	gen_xchg "${name}${sfx}" ""
+	printf "#endif\n\n"
+}
+
+cat << EOF
+// SPDX-License-Identifier: GPL-2.0
+
+// Generated by $0
+// DO NOT MODIFY THIS FILE DIRECTLY
+
+/*
+ * This file provides wrappers with KASAN instrumentation for atomic operations.
+ * To use this functionality an arch's atomic.h file needs to define all
+ * atomic operations with arch_ prefix (e.g. arch_atomic_read()) and include
+ * this file at the end. This file provides atomic_read() that forwards to
+ * arch_atomic_read() for actual atomic operation.
+ * Note: if an arch atomic operation is implemented by means of other atomic
+ * operations (e.g. atomic_read()/atomic_cmpxchg() loop), then it needs to use
+ * arch_ variants (i.e. arch_atomic_read()/arch_atomic_cmpxchg()) to avoid
+ * double instrumentation.
+ */
+#ifndef _ASM_GENERIC_ATOMIC_INSTRUMENTED_H
+#define _ASM_GENERIC_ATOMIC_INSTRUMENTED_H
+
+#include <linux/build_bug.h>
+#include <linux/kasan-checks.h>
+
+EOF
+
+grep '^[a-z]' "$1" | while read name meta args; do
+	gen_proto "${meta}" "${name}" "atomic" "int" ${args}
+done
+
+grep '^[a-z]' "$1" | while read name meta args; do
+	gen_proto "${meta}" "${name}" "atomic64" "s64" ${args}
+done
+
+for xchg in "xchg" "cmpxchg" "cmpxchg64"; do
+	for order in "" "_acquire" "_release" "_relaxed"; do
+		gen_optional_xchg "${xchg}" "${order}"
+	done
+done
+
+for xchg in "cmpxchg_local" "cmpxchg64_local" "sync_cmpxchg"; do
+	gen_xchg "${xchg}" ""
+	printf "\n"
+done
+
+gen_xchg "cmpxchg_double" "2 * "
+
+printf "\n\n"
+
+gen_xchg "cmpxchg_double_local" "2 * "
+
+cat <<EOF
+
+#endif /* _ASM_GENERIC_ATOMIC_INSTRUMENTED_H */
+EOF

scripts/atomic/gen-atomic-long.sh

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+ATOMICDIR=$(dirname $0)
+
+. ${ATOMICDIR}/atomic-tbl.sh
+
+#gen_cast(arg, int, atomic)
+gen_cast()
+{
+	local arg="$1"; shift
+	local int="$1"; shift
+	local atomic="$1"; shift
+
+	[ "${arg%%:*}" = "p" ] || return
+
+	printf "($(gen_param_type "${arg}" "${int}" "${atomic}"))"
+}
+
+#gen_args_cast(int, atomic, arg...)
+gen_args_cast()
+{
+	local int="$1"; shift
+	local atomic="$1"; shift
+
+	while [ "$#" -gt 0 ]; do
+		local cast="$(gen_cast "$1" "${int}" "${atomic}")"
+		local arg="$(gen_param_name "$1")"
+		printf "${cast}${arg}"
+		[ "$#" -gt 1 ] && printf ", "
+		shift;
+	done
+}
+
+#gen_proto_order_variant(meta, pfx, name, sfx, order, atomic, int, arg...)
+gen_proto_order_variant()
+{
+	local meta="$1"; shift
+	local name="$1$2$3$4"; shift; shift; shift; shift
+	local atomic="$1"; shift
+	local int="$1"; shift
+
+	local ret="$(gen_ret_type "${meta}" "long")"
+	local params="$(gen_params "long" "atomic_long" "$@")"
+	local argscast="$(gen_args_cast "${int}" "${atomic}" "$@")"
+	local retstmt="$(gen_ret_stmt "${meta}")"
+
+cat <<EOF
+static inline ${ret}
+atomic_long_${name}(${params})
+{
+	${retstmt}${atomic}_${name}(${argscast});
+}
+
+EOF
+}
+
+cat << EOF
+// SPDX-License-Identifier: GPL-2.0
+
+// Generated by $0
+// DO NOT MODIFY THIS FILE DIRECTLY
+
+#ifndef _ASM_GENERIC_ATOMIC_LONG_H
+#define _ASM_GENERIC_ATOMIC_LONG_H
+
+#include <asm/types.h>
+
+#ifdef CONFIG_64BIT
+typedef atomic64_t atomic_long_t;
+#define ATOMIC_LONG_INIT(i)		ATOMIC64_INIT(i)
+#define atomic_long_cond_read_acquire	atomic64_cond_read_acquire
+#define atomic_long_cond_read_relaxed	atomic64_cond_read_relaxed
+#else
+typedef atomic_t atomic_long_t;
+#define ATOMIC_LONG_INIT(i)		ATOMIC_INIT(i)
+#define atomic_long_cond_read_acquire	atomic_cond_read_acquire
+#define atomic_long_cond_read_relaxed	atomic_cond_read_relaxed
+#endif
+
+#ifdef CONFIG_64BIT
+
+EOF
+
+grep '^[a-z]' "$1" | while read name meta args; do
+	gen_proto "${meta}" "${name}" "atomic64" "s64" ${args}
+done
+
+cat <<EOF
+#else /* CONFIG_64BIT */
+
+EOF
+
+grep '^[a-z]' "$1" | while read name meta args; do
+	gen_proto "${meta}" "${name}" "atomic" "int" ${args}
+done
+
+cat <<EOF
+#endif /* CONFIG_64BIT */
+#endif /* _ASM_GENERIC_ATOMIC_LONG_H */
+EOF