From: Thomas Gleixner <tglx@kernel.org>
Date: Tue, 2 Jun 2026 09:09:47 +0000 (+0200)
Subject: x86: Select ARCH_MEMORY_ORDER_TSO
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=7b125c44d0b7f617ee81dffd14ce116149d03cb6;p=thirdparty%2Fkernel%2Flinux.git

x86: Select ARCH_MEMORY_ORDER_TSO

The generic unsafe_atomic_store_release_user() implementation does:

    if (!IS_ENABLED(CONFIG_ARCH_MEMORY_ORDER_TSO))
        smp_mb();
    unsafe_put_user();

As x86 implements Total Store Order (TSO) which means stores imply release,
select ARCH_MEMORY_ORDER_TSO to avoid the unnecessary smp_mb().

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://patch.msgid.link/20260602090535.564499644@kernel.org
---

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f3f7cb01d69d0..1ce62a996192e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -113,6 +113,7 @@ config X86
 	select ARCH_HAS_ZONE_DMA_SET if EXPERT
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_HAVE_EXTRA_ELF_NOTES
+	select ARCH_MEMORY_ORDER_TSO
 	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
 	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
 	select ARCH_MIGHT_HAVE_PC_PARPORT