Commit c9268ac6 authored by Mark Rutland's avatar Mark Rutland Committed by Peter Zijlstra
Browse files

locking/atomic: scripts: add trivial raw_atomic*_<op>() 



Currently a number of arch_atomic*_<op>() functions are optional, and
where an arch does not provide a given arch_atomic*_<op>() we will
define an implementation of arch_atomic*_<op>() in
atomic-arch-fallback.h.

Filling in the missing ops requires special care as we want to select
the optimal definition of each op (e.g. preferentially defining ops in
terms of their relaxed form rather than their fully-ordered form). The
ifdeffery necessary for this requires us to group ordering variants
together, which can be a bit painful to read, and is painful for
kerneldoc generation.

It would be easier to handle this if we generated ops into a separate
namespace, as this would remove the need to take special care with the
ifdeffery, and allow each ordering variant to be generated separately.

This patch adds a new set of raw_atomic_<op>() definitions, which are
currently trivial wrappers of their arch_atomic_<op>() equivalent. This
will allow us to move treewide users of arch_atomic_<op>() over to raw
atomic op before we rework the fallback generation to generate
raw_atomic_<op> directly.

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

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230605070124.3741859-18-mark.rutland@arm.com
parent 7ed7a156

include/linux/atomic.h

+1 −0
Original line number Diff line number Diff line
@@ -79,6 +79,7 @@ 


#include <linux/atomic/atomic-arch-fallback.h>

#include <linux/atomic/atomic-long.h>

#include <linux/atomic/atomic-raw.h>

#include <linux/atomic/atomic-instrumented.h>



#endif /* _LINUX_ATOMIC_H */

include/linux/atomic/atomic-instrumented.h

+295 −300

File changed.

Preview size limit exceeded, changes collapsed.

include/linux/atomic/atomic-raw.h

0 → 100644
+1645 −0

File added.

Preview size limit exceeded, changes collapsed.

scripts/atomic/gen-atomic-instrumented.sh

+7 −12
Original line number Diff line number Diff line
@@ -73,7 +73,7 @@ static __always_inline ${ret} 
${atomicname}(${params})

{

${checks}

	${retstmt}arch_${atomicname}(${args});

	${retstmt}raw_${atomicname}(${args});

}

EOF
@@ -105,7 +105,7 @@ EOF 
cat <<EOF

	instrument_atomic_read_write(__ai_ptr, sizeof(*__ai_ptr)); \\

	instrument_read_write(__ai_oldp, sizeof(*__ai_oldp)); \\

	arch_${xchg}${order}(__ai_ptr, __ai_oldp, __VA_ARGS__); \\

	raw_${xchg}${order}(__ai_ptr, __ai_oldp, __VA_ARGS__); \\

})

EOF
@@ -119,7 +119,7 @@ EOF 
[ -n "$kcsan_barrier" ] && printf "\t${kcsan_barrier}; \\\\\n"

cat <<EOF

	instrument_atomic_read_write(__ai_ptr, sizeof(*__ai_ptr)); \\

	arch_${xchg}${order}(__ai_ptr, __VA_ARGS__); \\

	raw_${xchg}${order}(__ai_ptr, __VA_ARGS__); \\

})

EOF
@@ -133,15 +133,10 @@ cat << EOF 
// 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.

 * This file provoides atomic operations with explicit instrumentation (e.g.

 * KASAN, KCSAN), which should be used unless it is necessary to avoid

 * instrumentation. Where it is necessary to aovid instrumenation, the

 * raw_atomic*() operations should be used.

 */

#ifndef _LINUX_ATOMIC_INSTRUMENTED_H

#define _LINUX_ATOMIC_INSTRUMENTED_H

scripts/atomic/gen-atomic-raw.sh

0 → 100644
+84 −0
Original line number Diff line number Diff line 
#!/bin/sh

# SPDX-License-Identifier: GPL-2.0



ATOMICDIR=$(dirname $0)



. ${ATOMICDIR}/atomic-tbl.sh



#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 ret="$(gen_ret_type "${meta}" "${int}")"

	local params="$(gen_params "${int}" "${atomic}" "$@")"

	local args="$(gen_args "$@")"

	local retstmt="$(gen_ret_stmt "${meta}")"



cat <<EOF

static __always_inline ${ret}

raw_${atomicname}(${params})

{

	${retstmt}arch_${atomicname}(${args});

}



EOF

}



gen_xchg()

{

	local xchg="$1"; shift

	local order="$1"; shift



cat <<EOF

#define raw_${xchg}${order}(...) \\

	arch_${xchg}${order}(__VA_ARGS__)

EOF

}



cat << EOF

// SPDX-License-Identifier: GPL-2.0



// Generated by $0

// DO NOT MODIFY THIS FILE DIRECTLY



#ifndef _LINUX_ATOMIC_RAW_H

#define _LINUX_ATOMIC_RAW_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



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" "cmpxchg128" "try_cmpxchg" "try_cmpxchg64" "try_cmpxchg128"; do

	for order in "" "_acquire" "_release" "_relaxed"; do

		gen_xchg "${xchg}" "${order}"

		printf "\n"

	done

done



for xchg in "cmpxchg_local" "cmpxchg64_local" "cmpxchg128_local" "sync_cmpxchg" "try_cmpxchg_local" "try_cmpxchg64_local" "try_cmpxchg128_local"; do

	gen_xchg "${xchg}" ""

	printf "\n"

done



cat <<EOF

#endif /* _LINUX_ATOMIC_RAW_H */

EOF