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>
This commit is contained in:
Mark Rutland 2019-02-11 13:20:35 +00:00 committed by Ingo Molnar
parent b14e77f89a
commit 0cf264b313
5 changed files with 43 additions and 6 deletions

View File

@ -1785,3 +1785,4 @@ atomic64_dec_if_positive(atomic64_t *v)
})
#endif /* _ASM_GENERIC_ATOMIC_INSTRUMENTED_H */
// b29b625d5de9280f680e42c7be859b55b15e5f6a

View File

@ -1010,3 +1010,4 @@ atomic_long_dec_if_positive(atomic_long_t *v)
#endif /* CONFIG_64BIT */
#endif /* _ASM_GENERIC_ATOMIC_LONG_H */
// 77558968132ce4f911ad53f6f52ce423006f6268

View File

@ -2292,3 +2292,4 @@ atomic64_dec_if_positive(atomic64_t *v)
#define atomic64_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c))
#endif /* _LINUX_ATOMIC_FALLBACK_H */
// 25de4a2804d70f57e994fe3b419148658bb5378a

View File

@ -7,13 +7,27 @@ ATOMICDIR=$(dirname $0)
ATOMICTBL=${ATOMICDIR}/atomics.tbl
LINUXDIR=${ATOMICDIR}/../..
echo '' | sha1sum - > /dev/null 2>&1
if [ $? -ne 0 ]; then
printf "sha1sum not available, skipping atomic header checks.\n"
exit 0
fi
cat <<EOF |
gen-atomic-instrumented.sh asm-generic/atomic-instrumented.h
gen-atomic-long.sh asm-generic/atomic-long.h
gen-atomic-fallback.sh linux/atomic-fallback.h
asm-generic/atomic-instrumented.h
asm-generic/atomic-long.h
linux/atomic-fallback.h
EOF
while read script header; do
if ! (${ATOMICDIR}/${script} ${ATOMICTBL} | diff - ${LINUXDIR}/include/${header} > /dev/null); then
printf "warning: include/${header} is out-of-date.\n"
while read header; do
OLDSUM="$(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

View File

@ -0,0 +1,20 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# Generate atomic headers
ATOMICDIR=$(dirname $0)
ATOMICTBL=${ATOMICDIR}/atomics.tbl
LINUXDIR=${ATOMICDIR}/../..
cat <<EOF |
gen-atomic-instrumented.sh asm-generic/atomic-instrumented.h
gen-atomic-long.sh asm-generic/atomic-long.h
gen-atomic-fallback.sh linux/atomic-fallback.h
EOF
while read script header; do
${ATOMICDIR}/${script} ${ATOMICTBL} > ${LINUXDIR}/include/${header}
HASH="$(sha1sum ${LINUXDIR}/include/${header})"
HASH="${HASH%% *}"
printf "// %s\n" "${HASH}" >> ${LINUXDIR}/include/${header}
done