Signed-off-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
CC: Peter Zijlstra <pet...@infradead.org>
CC: Andy Lutomirski <l...@kernel.org>
CC: Paul E. McKenney <paul...@linux.vnet.ibm.com>
CC: Boqun Feng <boqun.f...@gmail.com>
CC: Andrew Hunter <a...@google.com>
CC: Maged Michael <maged.mich...@gmail.com>
CC: Avi Kivity <a...@scylladb.com>
CC: Benjamin Herrenschmidt <b...@kernel.crashing.org>
CC: Paul Mackerras <pau...@samba.org>
CC: Michael Ellerman <m...@ellerman.id.au>
CC: Dave Watson <davejwat...@fb.com>
CC: Thomas Gleixner <t...@linutronix.de>
CC: Ingo Molnar <mi...@redhat.com>
CC: "H. Peter Anvin" <h...@zytor.com>
CC: Andrea Parri <parri.and...@gmail.com>
CC: Russell King <li...@armlinux.org.uk>
CC: Greg Hackmann <ghackm...@google.com>
CC: Will Deacon <will.dea...@arm.com>
CC: David Sehr <s...@google.com>
CC: x...@kernel.org
CC: linux-a...@vger.kernel.org
---
 arch/arm64/Kconfig        | 1 +
 arch/arm64/kernel/entry.S | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c9a7e9e1414f..5b0c06d8dbbe 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -16,6 +16,7 @@ config ARM64
        select ARCH_HAS_GCOV_PROFILE_ALL
        select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
        select ARCH_HAS_KCOV
+       select ARCH_HAS_MEMBARRIER_SYNC_CORE
        select ARCH_HAS_SET_MEMORY
        select ARCH_HAS_SG_CHAIN
        select ARCH_HAS_STRICT_KERNEL_RWX
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 6d14b8f29b5f..5edde1c2e93e 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -302,6 +302,10 @@ alternative_else_nop_endif
        ldp     x28, x29, [sp, #16 * 14]
        ldr     lr, [sp, #S_LR]
        add     sp, sp, #S_FRAME_SIZE           // restore sp
+       /*
+        * ARCH_HAS_MEMBARRIER_SYNC_CORE rely on eret context synchronization
+        * when returning from IPI handler, and when returning to user-space.
+        */
        eret                                    // return to kernel
        .endm
 
-- 
2.11.0

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