devtools: prevent use of legacy atomic API

In order to deprecate the rte_atomic and rte_smp barrier APIs [1], prevent
the patches from using these APIs and __sync builtins in new code.
Please use __atomic builtins instead of __sync builtins, rte_atomicNN_xxx
and rte_smp_[r/w]mb APIs.

On x86 the __atomic_thread_fence(__ATOMIC_SEQ_CST) is quite expensive for
SMP case. Flag the new code which use __atomic_thread_fence API.
Please use rte_thread_fence API instead of __atomic_thread_fence builtins.

1: Refer to the locks-and-atomic-operations section in
https://doc.dpdk.org/guides/prog_guide/writing_efficient_code.html

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
index 58021aa..6966922 100755 (executable)
--- a/devtools/checkpatches.sh
+++ b/devtools/checkpatches.sh
@@ -77,6 +77,39 @@ check_forbidden_additions() { # <patch>
                -f $(dirname $(readlink -f $0))/check-forbidden-tokens.awk \
                "$1" || res=1
 
+       # refrain from new additions of 16/32/64 bits rte_atomicNN_xxx()
+       awk -v FOLDERS="lib drivers app examples" \
+               -v EXPRESSIONS="rte_atomic[0-9][0-9]_.*\\\(" \
+               -v RET_ON_FAIL=1 \
+               -v MESSAGE='Using rte_atomicNN_xxx' \
+               -f $(dirname $(readlink -f $0))/check-forbidden-tokens.awk \
+               "$1" || res=1
+
+       # refrain from new additions of rte_smp_[r/w]mb()
+       awk -v FOLDERS="lib drivers app examples" \
+               -v EXPRESSIONS="rte_smp_(r|w)?mb\\\(" \
+               -v RET_ON_FAIL=1 \
+               -v MESSAGE='Using rte_smp_[r/w]mb' \
+               -f $(dirname $(readlink -f $0))/check-forbidden-tokens.awk \
+               "$1" || res=1
+
+       # refrain from using compiler __sync_xxx builtins
+       awk -v FOLDERS="lib drivers app examples" \
+               -v EXPRESSIONS="__sync_.*\\\(" \
+               -v RET_ON_FAIL=1 \
+               -v MESSAGE='Using __sync_xxx builtins' \
+               -f $(dirname $(readlink -f $0))/check-forbidden-tokens.awk \
+               "$1" || res=1
+
+       # refrain from using compiler __atomic_thread_fence()
+       # It should be avoided on x86 for SMP case.
+       awk -v FOLDERS="lib drivers app examples" \
+               -v EXPRESSIONS="__atomic_thread_fence\\\(" \
+               -v RET_ON_FAIL=1 \
+               -v MESSAGE='Using __atomic_thread_fence' \
+               -f $(dirname $(readlink -f $0))/check-forbidden-tokens.awk \
+               "$1" || res=1
+
        # svg figures must be included with wildcard extension
        # because of png conversion for pdf docs
        awk -v FOLDERS='doc' \