linux/scripts/atomic/atomic-tbl.sh
Mark Rutland ace9bad4df 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.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-11-01 11:00:36 +01:00

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#!/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
}