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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7999C433DF for ; Fri, 19 Jun 2020 15:05:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D96E21941 for ; Fri, 19 Jun 2020 15:05:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592579103; bh=3/6+mYIRxKeP+sGrObHom2baRgiTdP62AWg0s7YeIOs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fxzn5cr1sNqsKLiRs17YLPRN5Jxb0Qf71MeOBMQT8XEFAXI96nd/X+jnNQ7MYOx9i d+riPM03V5C76OOyneG/TCdzXVksVIhR8GgeEk0UfGszR2FyVnpI1yrAGnhn3V20Xq Ab6bxWMJgZtIk5PbPddtM9q4ld2BDFILNTP9JyOY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391219AbgFSPFC (ORCPT ); Fri, 19 Jun 2020 11:05:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:33794 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390529AbgFSPFB (ORCPT ); Fri, 19 Jun 2020 11:05:01 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2366221841; Fri, 19 Jun 2020 15:04:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592579100; bh=3/6+mYIRxKeP+sGrObHom2baRgiTdP62AWg0s7YeIOs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cri0Dbe4/4hJknioHZKTwkKPa7PGI7G8AAAWam52gjbM9PQDpKxBx5mUSQ68aSuN3 PxZ1/1jyWZtC7CSAakODCLmI9c0PCxQhZDovq31Swcfubk9sS64V6DoqHuszmgF6gm tfGCRHkLIMf9KOoIqLtw/BpOl/kYodTaC1cQP8TM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikulas Patocka , Ivan Kokshaysky , "Maciej W. Rozycki" , Matt Turner Subject: [PATCH 4.19 249/267] alpha: fix memory barriers so that they conform to the specification Date: Fri, 19 Jun 2020 16:33:54 +0200 Message-Id: <20200619141700.631893338@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141648.840376470@linuxfoundation.org> References: <20200619141648.840376470@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mikulas Patocka commit 54505a1e2083fc54cbe8779b97479f969cd30a00 upstream. The commits cd0e00c10672 and 92d7223a7423 broke boot on the Alpha Avanti platform. The patches move memory barriers after a write before the write. The result is that if there's iowrite followed by ioread, there is no barrier between them. The Alpha architecture allows reordering of the accesses to the I/O space, and the missing barrier between write and read causes hang with serial port and real time clock. This patch makes barriers confiorm to the specification. 1. We add mb() before readX_relaxed and writeX_relaxed - memory-barriers.txt claims that these functions must be ordered w.r.t. each other. Alpha doesn't order them, so we need an explicit barrier. 2. We add mb() before reads from the I/O space - so that if there's a write followed by a read, there should be a barrier between them. Signed-off-by: Mikulas Patocka Fixes: cd0e00c10672 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering") Fixes: 92d7223a7423 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering #2") Cc: stable@vger.kernel.org # v4.17+ Acked-by: Ivan Kokshaysky Reviewed-by: Maciej W. Rozycki Signed-off-by: Matt Turner Signed-off-by: Greg Kroah-Hartman --- arch/alpha/include/asm/io.h | 74 +++++++++++++++++++++++++++++++++++--------- arch/alpha/kernel/io.c | 60 +++++++++++++++++++++++++++++++---- 2 files changed, 112 insertions(+), 22 deletions(-) --- a/arch/alpha/include/asm/io.h +++ b/arch/alpha/include/asm/io.h @@ -327,14 +327,18 @@ static inline int __is_mmio(const volati #if IO_CONCAT(__IO_PREFIX,trivial_io_bw) extern inline unsigned int ioread8(void __iomem *addr) { - unsigned int ret = IO_CONCAT(__IO_PREFIX,ioread8)(addr); + unsigned int ret; + mb(); + ret = IO_CONCAT(__IO_PREFIX,ioread8)(addr); mb(); return ret; } extern inline unsigned int ioread16(void __iomem *addr) { - unsigned int ret = IO_CONCAT(__IO_PREFIX,ioread16)(addr); + unsigned int ret; + mb(); + ret = IO_CONCAT(__IO_PREFIX,ioread16)(addr); mb(); return ret; } @@ -375,7 +379,9 @@ extern inline void outw(u16 b, unsigned #if IO_CONCAT(__IO_PREFIX,trivial_io_lq) extern inline unsigned int ioread32(void __iomem *addr) { - unsigned int ret = IO_CONCAT(__IO_PREFIX,ioread32)(addr); + unsigned int ret; + mb(); + ret = IO_CONCAT(__IO_PREFIX,ioread32)(addr); mb(); return ret; } @@ -420,14 +426,18 @@ extern inline void __raw_writew(u16 b, v extern inline u8 readb(const volatile void __iomem *addr) { - u8 ret = __raw_readb(addr); + u8 ret; + mb(); + ret = __raw_readb(addr); mb(); return ret; } extern inline u16 readw(const volatile void __iomem *addr) { - u16 ret = __raw_readw(addr); + u16 ret; + mb(); + ret = __raw_readw(addr); mb(); return ret; } @@ -468,14 +478,18 @@ extern inline void __raw_writeq(u64 b, v extern inline u32 readl(const volatile void __iomem *addr) { - u32 ret = __raw_readl(addr); + u32 ret; + mb(); + ret = __raw_readl(addr); mb(); return ret; } extern inline u64 readq(const volatile void __iomem *addr) { - u64 ret = __raw_readq(addr); + u64 ret; + mb(); + ret = __raw_readq(addr); mb(); return ret; } @@ -504,14 +518,44 @@ extern inline void writeq(u64 b, volatil #define outb_p outb #define outw_p outw #define outl_p outl -#define readb_relaxed(addr) __raw_readb(addr) -#define readw_relaxed(addr) __raw_readw(addr) -#define readl_relaxed(addr) __raw_readl(addr) -#define readq_relaxed(addr) __raw_readq(addr) -#define writeb_relaxed(b, addr) __raw_writeb(b, addr) -#define writew_relaxed(b, addr) __raw_writew(b, addr) -#define writel_relaxed(b, addr) __raw_writel(b, addr) -#define writeq_relaxed(b, addr) __raw_writeq(b, addr) + +extern u8 readb_relaxed(const volatile void __iomem *addr); +extern u16 readw_relaxed(const volatile void __iomem *addr); +extern u32 readl_relaxed(const volatile void __iomem *addr); +extern u64 readq_relaxed(const volatile void __iomem *addr); + +#if IO_CONCAT(__IO_PREFIX,trivial_io_bw) +extern inline u8 readb_relaxed(const volatile void __iomem *addr) +{ + mb(); + return __raw_readb(addr); +} + +extern inline u16 readw_relaxed(const volatile void __iomem *addr) +{ + mb(); + return __raw_readw(addr); +} +#endif + +#if IO_CONCAT(__IO_PREFIX,trivial_io_lq) +extern inline u32 readl_relaxed(const volatile void __iomem *addr) +{ + mb(); + return __raw_readl(addr); +} + +extern inline u64 readq_relaxed(const volatile void __iomem *addr) +{ + mb(); + return __raw_readq(addr); +} +#endif + +#define writeb_relaxed writeb +#define writew_relaxed writew +#define writel_relaxed writel +#define writeq_relaxed writeq #define mmiowb() --- a/arch/alpha/kernel/io.c +++ b/arch/alpha/kernel/io.c @@ -16,21 +16,27 @@ unsigned int ioread8(void __iomem *addr) { - unsigned int ret = IO_CONCAT(__IO_PREFIX,ioread8)(addr); + unsigned int ret; + mb(); + ret = IO_CONCAT(__IO_PREFIX,ioread8)(addr); mb(); return ret; } unsigned int ioread16(void __iomem *addr) { - unsigned int ret = IO_CONCAT(__IO_PREFIX,ioread16)(addr); + unsigned int ret; + mb(); + ret = IO_CONCAT(__IO_PREFIX,ioread16)(addr); mb(); return ret; } unsigned int ioread32(void __iomem *addr) { - unsigned int ret = IO_CONCAT(__IO_PREFIX,ioread32)(addr); + unsigned int ret; + mb(); + ret = IO_CONCAT(__IO_PREFIX,ioread32)(addr); mb(); return ret; } @@ -148,28 +154,36 @@ EXPORT_SYMBOL(__raw_writeq); u8 readb(const volatile void __iomem *addr) { - u8 ret = __raw_readb(addr); + u8 ret; + mb(); + ret = __raw_readb(addr); mb(); return ret; } u16 readw(const volatile void __iomem *addr) { - u16 ret = __raw_readw(addr); + u16 ret; + mb(); + ret = __raw_readw(addr); mb(); return ret; } u32 readl(const volatile void __iomem *addr) { - u32 ret = __raw_readl(addr); + u32 ret; + mb(); + ret = __raw_readl(addr); mb(); return ret; } u64 readq(const volatile void __iomem *addr) { - u64 ret = __raw_readq(addr); + u64 ret; + mb(); + ret = __raw_readq(addr); mb(); return ret; } @@ -207,6 +221,38 @@ EXPORT_SYMBOL(writew); EXPORT_SYMBOL(writel); EXPORT_SYMBOL(writeq); +/* + * The _relaxed functions must be ordered w.r.t. each other, but they don't + * have to be ordered w.r.t. other memory accesses. + */ +u8 readb_relaxed(const volatile void __iomem *addr) +{ + mb(); + return __raw_readb(addr); +} + +u16 readw_relaxed(const volatile void __iomem *addr) +{ + mb(); + return __raw_readw(addr); +} + +u32 readl_relaxed(const volatile void __iomem *addr) +{ + mb(); + return __raw_readl(addr); +} + +u64 readq_relaxed(const volatile void __iomem *addr) +{ + mb(); + return __raw_readq(addr); +} + +EXPORT_SYMBOL(readb_relaxed); +EXPORT_SYMBOL(readw_relaxed); +EXPORT_SYMBOL(readl_relaxed); +EXPORT_SYMBOL(readq_relaxed); /* * Read COUNT 8-bit bytes from port PORT into memory starting at SRC.