[dpdk-stable] patch 'eal/arm: fix debug build with gcc for 128-bit atomics' has been queued to stable release 20.11.1

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 20.11.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 02/07/21. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/bluca/dpdk-stable

This queued commit can be viewed at:
https://github.com/bluca/dpdk-stable/commit/e89a62391eb8d9da9e47e231bbae339d94df5b90

Thanks.

Luca Boccassi

---
>From e89a62391eb8d9da9e47e231bbae339d94df5b90 Mon Sep 17 00:00:00 2001
From: Joyce Kong <joyce.kong at arm.com>
Date: Fri, 15 Jan 2021 17:58:21 +0800
Subject: [PATCH] eal/arm: fix debug build with gcc for 128-bit atomics
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

[ upstream commit 36d406c5139fa0160a1d3686f5b2413a2f9ee83b ]

Compiling with "meson build -Dbuildtype=debug --cross-file
config/arm/arm64_thunderx2_linux_gcc" shows the warnings
"function returns an aggregate [-Waggregate-return]":
../../dpdk/lib/librte_eal/arm/include/rte_atomic_64.h: In
function ‘__cas_128_relaxed’:
../../dpdk/lib/librte_eal/arm/include/rte_atomic_64.h:81:20:
error: function returns an aggregate [-Werror=aggregate-return]
 __ATOMIC128_CAS_OP(__cas_128_relaxed, "casp")
                    ^~~~~~~~~~~~~~~~~

Fix the compiling issue by defining __ATOMIC128_CAS_OP as a void
function and passing the address pointer into it.

Fixes: 7e2c3e17fe2c ("eal/arm64: add 128-bit atomic compare exchange")

Signed-off-by: Joyce Kong <joyce.kong at arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
Acked-by: Jerin Jacob <jerinj at marvell.com>
---
 lib/librte_eal/arm/include/rte_atomic_64.h | 28 +++++++++++-----------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/lib/librte_eal/arm/include/rte_atomic_64.h b/lib/librte_eal/arm/include/rte_atomic_64.h
index 467d32a455..fa6f334c0d 100644
--- a/lib/librte_eal/arm/include/rte_atomic_64.h
+++ b/lib/librte_eal/arm/include/rte_atomic_64.h
@@ -53,15 +53,15 @@ rte_atomic_thread_fence(int memorder)
 #endif
 
 #define __ATOMIC128_CAS_OP(cas_op_name, op_string)                          \
-static __rte_noinline rte_int128_t                                          \
-cas_op_name(rte_int128_t *dst, rte_int128_t old, rte_int128_t updated)      \
+static __rte_noinline void                                                  \
+cas_op_name(rte_int128_t *dst, rte_int128_t *old, rte_int128_t updated)     \
 {                                                                           \
 	/* caspX instructions register pair must start from even-numbered
 	 * register at operand 1.
 	 * So, specify registers for local variables here.
 	 */                                                                 \
-	register uint64_t x0 __asm("x0") = (uint64_t)old.val[0];            \
-	register uint64_t x1 __asm("x1") = (uint64_t)old.val[1];            \
+	register uint64_t x0 __asm("x0") = (uint64_t)old->val[0];           \
+	register uint64_t x1 __asm("x1") = (uint64_t)old->val[1];           \
 	register uint64_t x2 __asm("x2") = (uint64_t)updated.val[0];        \
 	register uint64_t x3 __asm("x3") = (uint64_t)updated.val[1];        \
 	asm volatile(                                                       \
@@ -73,9 +73,8 @@ cas_op_name(rte_int128_t *dst, rte_int128_t old, rte_int128_t updated)      \
 		[upd1] "r" (x3),                                            \
 		[dst] "r" (dst)                                             \
 		: "memory");                                                \
-	old.val[0] = x0;                                                    \
-	old.val[1] = x1;                                                    \
-	return old;                                                         \
+	old->val[0] = x0;                                                   \
+	old->val[1] = x1;                                                   \
 }
 
 __ATOMIC128_CAS_OP(__cas_128_relaxed, "casp")
@@ -113,13 +112,14 @@ rte_atomic128_cmp_exchange(rte_int128_t *dst, rte_int128_t *exp,
 
 #if defined(__ARM_FEATURE_ATOMICS) || defined(RTE_ARM_FEATURE_ATOMICS)
 	if (success == __ATOMIC_RELAXED)
-		old = __cas_128_relaxed(dst, expected, desired);
+		__cas_128_relaxed(dst, exp, desired);
 	else if (success == __ATOMIC_ACQUIRE)
-		old = __cas_128_acquire(dst, expected, desired);
+		__cas_128_acquire(dst, exp, desired);
 	else if (success == __ATOMIC_RELEASE)
-		old = __cas_128_release(dst, expected, desired);
+		__cas_128_release(dst, exp, desired);
 	else
-		old = __cas_128_acq_rel(dst, expected, desired);
+		__cas_128_acq_rel(dst, exp, desired);
+	old = *exp;
 #else
 #define __HAS_ACQ(mo) ((mo) != __ATOMIC_RELAXED && (mo) != __ATOMIC_RELEASE)
 #define __HAS_RLS(mo) ((mo) == __ATOMIC_RELEASE || (mo) == __ATOMIC_ACQ_REL || \
@@ -183,12 +183,12 @@ rte_atomic128_cmp_exchange(rte_int128_t *dst, rte_int128_t *exp,
 #undef __STORE_128
 
 	} while (unlikely(ret));
-#endif
 
-	/* Unconditionally updating expected removes an 'if' statement.
-	 * expected should already be in register if not in the cache.
+	/* Unconditionally updating the value of exp removes an 'if' statement.
+	 * The value of exp should already be in register if not in the cache.
 	 */
 	*exp = old;
+#endif
 
 	return (old.int128 == expected.int128);
 }
-- 
2.29.2

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2021-02-05 11:18:37.927166041 +0000
+++ 0196-eal-arm-fix-debug-build-with-gcc-for-128-bit-atomics.patch	2021-02-05 11:18:29.150697661 +0000
@@ -1 +1 @@
-From 36d406c5139fa0160a1d3686f5b2413a2f9ee83b Mon Sep 17 00:00:00 2001
+From e89a62391eb8d9da9e47e231bbae339d94df5b90 Mon Sep 17 00:00:00 2001
@@ -8,0 +9,2 @@
+[ upstream commit 36d406c5139fa0160a1d3686f5b2413a2f9ee83b ]
+
@@ -23 +24,0 @@
-Cc: stable at dpdk.org