From: Heiko Carstens <hca@linux.ibm.com>
Date: Fri, 17 Mar 2023 09:31:40 +0000 (+0100)
Subject: s390: enable ARCH_HAS_MEMBARRIER_SYNC_CORE
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e7615c9225d7c7562d1cd95ba8cc2cbf38c3d29e;p=linux.git

s390: enable ARCH_HAS_MEMBARRIER_SYNC_CORE

s390 trivially supports the ARCH_HAS_MEMBARRIER_SYNC_CORE requirements
since the used lpswe(y) instruction to return from any kernel context to
user space performs CPU serialization. This is very similar to arm, arm64
and powerpc.

See commit 70216e18e519 ("membarrier: Provide core serializing command,
*_SYNC_CORE") for further details.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---

diff --git a/Documentation/features/sched/membarrier-sync-core/arch-support.txt b/Documentation/features/sched/membarrier-sync-core/arch-support.txt
index 1e51614c136eb..23260ca449468 100644
--- a/Documentation/features/sched/membarrier-sync-core/arch-support.txt
+++ b/Documentation/features/sched/membarrier-sync-core/arch-support.txt
@@ -5,7 +5,7 @@
 #
 # Architecture requirements
 #
-# * arm/arm64/powerpc
+# * arm/arm64/powerpc/s390
 #
 # Rely on implicit context synchronization as a result of exception return
 # when returning from IPI handler, and when returning to user-space.
@@ -45,7 +45,7 @@
     |      parisc: | TODO |
     |     powerpc: |  ok  |
     |       riscv: | TODO |
-    |        s390: | TODO |
+    |        s390: |  ok  |
     |          sh: | TODO |
     |       sparc: | TODO |
     |          um: | TODO |
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 8f1c6da2ae4d4..d610f911677e8 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -76,6 +76,7 @@ config S390
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
+	select ARCH_HAS_MEMBARRIER_SYNC_CORE
 	select ARCH_HAS_MEM_ENCRYPT
 	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
 	select ARCH_HAS_PTE_SPECIAL