From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5B3A1C433F5 for ; Sun, 20 Feb 2022 15:07:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=PajYMC3nKd7Hv0QqZ2PMA9NjMALyrwK8+xOgcszNCrI=; b=pQzgumkGWHcc4D bK6FBgWs87rpUFIBYvxBniADrATL6T+TjkVPbrs/KfQfG3tI64K3o5DFFWoJ3AxdWQwicYxAydUI3 heTsRKwXa6F3IduZ35cMuQgM1EdmLAoZanmYst0iOtk7n+3nNJQj9Vbz4SOjgn86Ly+8MxplTnuer H/4H3I35K17LfEOwGQcdG/gKOQFr0TumhRNMNjelL39E3hXcAMkZl+8zNbtV1fW1NNxxxDlTkaIlE h8J1vXGgDC7NllT457Q8VlbhmtQnjhJI+H+mbEWwa4Fo7nvB6IMQuRNY+w0JGOn/Z+oxvEupnxdX6 34aLHHkZPnGwUDLW1CDg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nLnnN-001b3g-5U; Sun, 20 Feb 2022 15:06:41 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nLnnI-001afa-1T for linux-arm-kernel@lists.infradead.org; Sun, 20 Feb 2022 15:06:37 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=1adgmye6FZ2zQFuk/q4+n4x9dXXIaAhx2pGahFGCNHg=; b=LfcR975FHg0DlzDVRLyShx+0dS Oj72AFCCf+IlswF4U2Yk4tT5hFQejNQRd6NB0t+Q43H9W9slRb5PNnXubJkGmz8QRmYXat0hBoH2e zzCs82kcVQ/ECE0OBcZogpw/Zu3YSTNobVAPmiCr2/LKK0K5nqoY3/WcfG4Hy0eT0TzsD2TSMj+W3 W06LVicDbP2c2/VIaOwyMszpk5ilaaVdy+w29isivK1/qVbpc9fFtLpISFp5IX++ZRoGOE8VF3/v6 +NYEO9cBHnMkQSHRbAJdvi1SZedFdPG4lAM06AwRiBoxV1i/QHyDNGUu3fKCpzXWZc1DbpKGdeo9b e6IxeWcg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:57378) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nLnl8-0007lp-Oq; Sun, 20 Feb 2022 15:04:22 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1nLnl4-0006RE-HH; Sun, 20 Feb 2022 15:04:18 +0000 Date: Sun, 20 Feb 2022 15:04:18 +0000 From: "Russell King (Oracle)" To: Barry Song <21cnbao@gmail.com> Cc: maz@kernel.org, tglx@linutronix.de, will@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxarm@huawei.com, Barry Song Subject: Re: [PATCH] irqchip/gic-v3: use dsb(ishst) to synchronize data to smp before issuing ipi Message-ID: References: <20220218215549.4274-1-song.bao.hua@hisilicon.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220218215549.4274-1-song.bao.hua@hisilicon.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220220_070636_093585_E371C632 X-CRM114-Status: GOOD ( 16.16 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, Feb 19, 2022 at 05:55:49AM +0800, Barry Song wrote: > dsb(ishst) should be enough here as we only need to guarantee the > visibility of data to other CPUs in smp inner domain before we > send the ipi. > > Signed-off-by: Barry Song > --- > drivers/irqchip/irq-gic-v3.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c > index 5e935d97207d..0efe1a9a9f3b 100644 > --- a/drivers/irqchip/irq-gic-v3.c > +++ b/drivers/irqchip/irq-gic-v3.c > @@ -1211,7 +1211,7 @@ static void gic_ipi_send_mask(struct irq_data *d, const struct cpumask *mask) > * Ensure that stores to Normal memory are visible to the > * other CPUs before issuing the IPI. > */ > - wmb(); > + dsb(ishst); On ARM, wmb() is a dsb(st) followed by other operations which may include a sync operation at the L2 cache, and SoC specific barriers for the bus. Hopefully, nothing will break if the sledge hammer is replaced by the tack hammer. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel