From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4A11B3E9592 for ; Thu, 2 Apr 2026 15:21:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775143294; cv=none; b=ctWecF9oMLx4YVHhz8hPrbpYEgbKK35JusEL8gddvl0zaM4qUpas/s4KX1zmfx8IQQ6T9RakDBtY5unCDmtR7ICE1S/G5apTUM7mMyo0nVbPz6JiKpVn2XcegML9kRFmYUhF0zwm3d0yhvkyJuLSS03ekgZO+JO/krUS8DFAW/c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775143294; c=relaxed/simple; bh=Honbj/gYMh+IblqW9oRvdR1XlTDAuDZ6TXXb8z+iKe0=; h=Date:Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=dB/lhyqiREWgyP4xWcOyxTuX8StxNvCtPjF4JeHP7mxdEhaDHjsHrmb0antKpFW6c/K4lVgsr/NgbryQZD5TNEljrhb2j/1WqfJsSKyjEzu5qzMDWndYaBnO0Eu6bGCmU3vGbHkT/4zw8xw34LYtYRI3mqmXtq8MIFk/TdjJ1iE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E8B+gXTN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="E8B+gXTN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F7D1C116C6; Thu, 2 Apr 2026 15:21:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775143293; bh=Honbj/gYMh+IblqW9oRvdR1XlTDAuDZ6TXXb8z+iKe0=; h=Date:From:To:Cc:Subject:References:From; b=E8B+gXTNq1n/4mql3X+xwfltILrwH+XlAcGHb9YPYBG7yqynID9aLJZFSxdPQmX3q D2HQEi1f8VOxOQRfcvhcOWInwv0t5LNJFTvlMHcnpd6zYLB/6MvqfElX8s7fxLhvLm Yqu3gpKs1iR9IGvyGjKuTckdP3ejG+xBQr+R/k05/A7Ss0uKzkhjmbO5l1Y84oRfiD G4vOTz5KTlplOX7P0QS/l4w/N3Z5fnzVQ6osBaChYsRz2pP+0n52ZXk1+0DjAx/qIW Chz27+ac4RARodxQoHdzTcggwHgjWOCm2S70h+revAkN1Af8pUlIK4GBREt/xsPcDP MUZjlrQtXsXBA== Date: Thu, 02 Apr 2026 17:21:30 +0200 Message-ID: <20260402151940.006105560@kernel.org> User-Agent: quilt/0.68 From: Thomas Gleixner To: LKML Cc: Mathieu Desnoyers , =?UTF-8?q?Andr=C3=A8=20Almeida?= , Sebastian Andrzej Siewior , Carlos O'Donell , Peter Zijlstra , Florian Weimer , Rich Felker , Torvald Riegel , Darren Hart , Ingo Molnar , Davidlohr Bueso , Arnd Bergmann , "Liam R . Howlett" , Uros Bizjak , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Subject: [patch V4 06/14] x86: Select ARCH_MEMORY_ORDER_TSO References: <20260402151131.876492985@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 Reviewed-by: André Almeida --- V4: Rename it correctly V3: Rename to TOS - Peter V2: New patch --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -114,6 +114,7 @@ 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