linux/scripts/atomic/check-atomics.sh
Mark Rutland 0cf264b313 locking/atomics: Check atomic headers with sha1sum
We currently check the atomic headers at build-time to ensure they
haven't been modified directly, and these checks require regenerating
the headers in full. As this takes a few seconds, even when
parallelized, this is too slow to run for every kernel build.

Instead, we can generate a hash of each header as we generate them,
which we can cheaply check at build time (~0.16s for all headers).

This patch does so, updating headers with their hashes using the new
gen-atomics.sh script. As some users apparently build the kernel wihout
coreutils, lacking sha1sum, the checks are skipped in this case.
Presumably, most developers have a working coreutils installation.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: anders.roxell@linaro.org
Cc: linux-kernel@vger.kernel.rg
Cc: naresh.kamboju@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-13 08:07:31 +01:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# Check if atomic headers are up-to-date
ATOMICDIR=$(dirname $0)
ATOMICTBL=${ATOMICDIR}/atomics.tbl
LINUXDIR=${ATOMICDIR}/../..
echo '' | sha1sum - > /dev/null 2>&1
if [ $? -ne 0 ]; then
printf "sha1sum not available, skipping atomic header checks.\n"
exit 0
fi
cat <<EOF |
asm-generic/atomic-instrumented.h
asm-generic/atomic-long.h
linux/atomic-fallback.h
EOF
while read header; do
OLDSUM="$(tail -n 1 ${LINUXDIR}/include/${header})"
OLDSUM="${OLDSUM#// }"
NEWSUM="$(head -n -1 ${LINUXDIR}/include/${header} | sha1sum)"
NEWSUM="${NEWSUM%% *}"
if [ "${OLDSUM}" != "${NEWSUM}" ]; then
printf "warning: generated include/${header} has been modified.\n"
fi
done
exit 0