[v3,2/3] doc: update armv8-a IO barrier changes

Message ID 20200703185741.22184-2-honnappa.nagarahalli@arm.com
State Superseded
Headers show
Series
  • [v3,1/3] eal: adjust barriers for IO on Armv8-a
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Commit Message

Honnappa Nagarahalli July 3, 2020, 6:57 p.m.
Updated the use of DMB instruction in rte_*mb APIs for Armv8-a.

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

---
 doc/guides/rel_notes/release_20_08.rst | 7 +++++++
 1 file changed, 7 insertions(+)

-- 
2.17.1

Comments

Jerin Jacob July 5, 2020, 12:57 a.m. | #1
On Sat, Jul 4, 2020 at 12:28 AM Honnappa Nagarahalli
<honnappa.nagarahalli@arm.com> wrote:
>

> Updated the use of DMB instruction in rte_*mb APIs for Armv8-a.

>

> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

> ---

>  doc/guides/rel_notes/release_20_08.rst | 7 +++++++

>  1 file changed, 7 insertions(+)

>

> diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst

> index 5cbc4ce14..15c21996d 100644

> --- a/doc/guides/rel_notes/release_20_08.rst

> +++ b/doc/guides/rel_notes/release_20_08.rst

> @@ -56,6 +56,13 @@ New Features

>       Also, make sure to start the actual text at the margin.

>       =========================================================

>

> +* **rte_*mb APIs are updated to use DMB instruction.**


IMO, It is better to change to following as the end user can ignore
parsing the description if not interested in arm64.

rte_*mb APIs are updated to use DMB instruction for Armv8-a

With  above change:
Acked-by: Jerin Jacob <jerinj@marvell.com>


> +

> +  Armv8-a memory model has been strengthened to require other-multi-copy

> +  atomicity. This allows for using DMB instruction instead of DSB for IO

> +  barriers. rte_*mb APIs, for Armv8-a platforms, are changed to use DMB

> +  instruction to reflect this.

> +

>  * **Updated PCAP driver.**

>

>    Updated PCAP driver with new features and improvements, including:

> --

> 2.17.1

>

Patch

diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
index 5cbc4ce14..15c21996d 100644
--- a/doc/guides/rel_notes/release_20_08.rst
+++ b/doc/guides/rel_notes/release_20_08.rst
@@ -56,6 +56,13 @@  New Features
      Also, make sure to start the actual text at the margin.
      =========================================================
 
+* **rte_*mb APIs are updated to use DMB instruction.**
+
+  Armv8-a memory model has been strengthened to require other-multi-copy
+  atomicity. This allows for using DMB instruction instead of DSB for IO
+  barriers. rte_*mb APIs, for Armv8-a platforms, are changed to use DMB
+  instruction to reflect this.
+
 * **Updated PCAP driver.**
 
   Updated PCAP driver with new features and improvements, including: