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authorMark Rutland <mark.rutland@arm.com>2019-02-11 13:20:35 +0000
committerIngo Molnar <mingo@kernel.org>2019-02-13 08:07:31 +0100
commit0cf264b3133dce56a60ca8b4335d1f76fe26870a (patch)
tree9afbe4db4847974c5f357fde4fd76f92aaa37b01
parentb14e77f89aca1c2763f65dc274b5837a185ab13f (diff)
downloadlinux-0cf264b3133dce56a60ca8b4335d1f76fe26870a.tar.bz2
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>
-rw-r--r--include/asm-generic/atomic-instrumented.h1
-rw-r--r--include/asm-generic/atomic-long.h1
-rw-r--r--include/linux/atomic-fallback.h1
-rwxr-xr-xscripts/atomic/check-atomics.sh26
-rw-r--r--scripts/atomic/gen-atomics.sh20
5 files changed, 43 insertions, 6 deletions
diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h
index b8f5b35216e1..e8730c6b9fe2 100644
--- a/include/asm-generic/atomic-instrumented.h
+++ b/include/asm-generic/atomic-instrumented.h
@@ -1785,3 +1785,4 @@ atomic64_dec_if_positive(atomic64_t *v)
})
#endif /* _ASM_GENERIC_ATOMIC_INSTRUMENTED_H */
+// b29b625d5de9280f680e42c7be859b55b15e5f6a
diff --git a/include/asm-generic/atomic-long.h b/include/asm-generic/atomic-long.h
index a833d385a70b..881c7e27af28 100644
--- a/include/asm-generic/atomic-long.h
+++ b/include/asm-generic/atomic-long.h
@@ -1010,3 +1010,4 @@ atomic_long_dec_if_positive(atomic_long_t *v)
#endif /* CONFIG_64BIT */
#endif /* _ASM_GENERIC_ATOMIC_LONG_H */
+// 77558968132ce4f911ad53f6f52ce423006f6268
diff --git a/include/linux/atomic-fallback.h b/include/linux/atomic-fallback.h
index 1c02c0112fbb..a7d240e465c0 100644
--- a/include/linux/atomic-fallback.h
+++ b/include/linux/atomic-fallback.h
@@ -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
diff --git a/scripts/atomic/check-atomics.sh b/scripts/atomic/check-atomics.sh
index c30101cddf2d..cfa0c2f71c84 100755
--- a/scripts/atomic/check-atomics.sh
+++ b/scripts/atomic/check-atomics.sh
@@ -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
diff --git a/scripts/atomic/gen-atomics.sh b/scripts/atomic/gen-atomics.sh
new file mode 100644
index 000000000000..27400b0cd732
--- /dev/null
+++ b/scripts/atomic/gen-atomics.sh
@@ -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