linux-stable/scripts/atomic/gen-atomic-fallback.sh
Peter Zijlstra 29f006fdef asm-generic/atomic: Add try_cmpxchg() fallbacks
Only x86 provides try_cmpxchg() outside of the atomic_t interfaces,
provide generic fallbacks to create this interface from the widely
available cmpxchg() function.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/159870621515.1229682.15506193091065001742.stgit@devnote2
2020-10-12 18:27:27 +02:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
ATOMICDIR=$(dirname $0)
ARCH=$2
. ${ATOMICDIR}/atomic-tbl.sh
#gen_template_fallback(template, meta, pfx, name, sfx, order, arch, 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 arch="$1"; shift
local atomic="$1"; shift
local int="$1"; shift
local atomicname="${arch}${atomic}_${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, arch, 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_variant()
{
local meta="$1"; shift
local pfx="$1"; shift
local name="$1"; shift
local sfx="$1"; shift
local order="$1"; shift
local arch="$1"
local atomic="$2"
local basename="${arch}${atomic}_${pfx}${name}${sfx}"
printf "#define arch_${basename}${order} ${basename}${order}\n"
}
#gen_proto_order_variants(meta, pfx, name, sfx, arch, atomic, int, args...)
gen_proto_order_variants()
{
local meta="$1"; shift
local pfx="$1"; shift
local name="$1"; shift
local sfx="$1"; shift
local arch="$1"
local atomic="$2"
local basename="${arch}${atomic}_${pfx}${name}${sfx}"
local template="$(find_fallback_template "${pfx}" "${name}" "${sfx}" "${order}")"
if [ -z "$arch" ]; then
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" "$@"
fi
echo ""
fi
# If we don't have relaxed atomics, then we don't bother with ordering fallbacks
# read_acquire and set_release need to be templated, though
if ! meta_has_relaxed "${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 /* ${arch}${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_order_fallbacks()
{
local xchg="$1"; shift
cat <<EOF
#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
EOF
}
gen_xchg_fallbacks()
{
local xchg="$1"; shift
printf "#ifndef ${xchg}_relaxed\n"
gen_basic_fallbacks ${xchg}
printf "#else /* ${xchg}_relaxed */\n"
gen_order_fallbacks ${xchg}
printf "#endif /* ${xchg}_relaxed */\n\n"
}
gen_try_cmpxchg_fallback()
{
local order="$1"; shift;
cat <<EOF
#ifndef ${ARCH}try_cmpxchg${order}
#define ${ARCH}try_cmpxchg${order}(_ptr, _oldp, _new) \\
({ \\
typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \\
___r = ${ARCH}cmpxchg${order}((_ptr), ___o, (_new)); \\
if (unlikely(___r != ___o)) \\
*___op = ___r; \\
likely(___r == ___o); \\
})
#endif /* ${ARCH}try_cmpxchg${order} */
EOF
}
gen_try_cmpxchg_fallbacks()
{
printf "#ifndef ${ARCH}try_cmpxchg_relaxed\n"
printf "#ifdef ${ARCH}try_cmpxchg\n"
gen_basic_fallbacks "${ARCH}try_cmpxchg"
printf "#endif /* ${ARCH}try_cmpxchg */\n\n"
for order in "" "_acquire" "_release" "_relaxed"; do
gen_try_cmpxchg_fallback "${order}"
done
printf "#else /* ${ARCH}try_cmpxchg_relaxed */\n"
gen_order_fallbacks "${ARCH}try_cmpxchg"
printf "#endif /* ${ARCH}try_cmpxchg_relaxed */\n\n"
}
cat << EOF
// SPDX-License-Identifier: GPL-2.0
// Generated by $0
// DO NOT MODIFY THIS FILE DIRECTLY
#ifndef _LINUX_ATOMIC_FALLBACK_H
#define _LINUX_ATOMIC_FALLBACK_H
#include <linux/compiler.h>
EOF
for xchg in "${ARCH}xchg" "${ARCH}cmpxchg" "${ARCH}cmpxchg64"; do
gen_xchg_fallbacks "${xchg}"
done
gen_try_cmpxchg_fallbacks
grep '^[a-z]' "$1" | while read name meta args; do
gen_proto "${meta}" "${name}" "${ARCH}" "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}" "${name}" "${ARCH}" "atomic64" "s64" ${args}
done
cat <<EOF
#endif /* _LINUX_ATOMIC_FALLBACK_H */
EOF