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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 C3A95C43381 for ; Fri, 22 Feb 2019 18:51:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9B62D2070B for ; Fri, 22 Feb 2019 18:51:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727625AbfBVSvW (ORCPT ); Fri, 22 Feb 2019 13:51:22 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:39532 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726368AbfBVSvV (ORCPT ); Fri, 22 Feb 2019 13:51:21 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A3C831688; Fri, 22 Feb 2019 10:51:20 -0800 (PST) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 68E593F5C1; Fri, 22 Feb 2019 10:51:17 -0800 (PST) From: Will Deacon To: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Will Deacon , "Paul E. McKenney" , Benjamin Herrenschmidt , Michael Ellerman , Arnd Bergmann , Peter Zijlstra , Andrea Parri , Palmer Dabbelt , Daniel Lustig , David Howells , Alan Stern , Linus Torvalds , "Maciej W. Rozycki" , Paul Burton , Ingo Molnar , Yoshinori Sato , Rich Felker , Tony Luck Subject: [RFC PATCH 13/20] riscv: mmiowb: Hook up mmwiob() implementation to asm-generic code Date: Fri, 22 Feb 2019 18:50:19 +0000 Message-Id: <20190222185026.10973-14-will.deacon@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190222185026.10973-1-will.deacon@arm.com> References: <20190222185026.10973-1-will.deacon@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In a bid to kill off explicit mmiowb() usage in driver code, hook up the asm-generic mmiowb() tracking code for riscv, so that an mmiowb() is automatically issued from spin_unlock() if an I/O write was performed in the critical section. Signed-off-by: Will Deacon --- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/Kbuild | 1 - arch/riscv/include/asm/io.h | 15 ++------------- arch/riscv/include/asm/mmiowb.h | 14 ++++++++++++++ 4 files changed, 17 insertions(+), 14 deletions(-) create mode 100644 arch/riscv/include/asm/mmiowb.h diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 515fc3cc9687..3e7acb997235 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -49,6 +49,7 @@ config RISCV select RISCV_TIMER select GENERIC_IRQ_MULTI_HANDLER select ARCH_HAS_PTE_SPECIAL + select ARCH_HAS_MMIOWB if SMP config MMU def_bool y diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild index 221cd2ec78a4..cccd12cf27d4 100644 --- a/arch/riscv/include/asm/Kbuild +++ b/arch/riscv/include/asm/Kbuild @@ -21,7 +21,6 @@ generic-y += kvm_para.h generic-y += local.h generic-y += local64.h generic-y += mm-arch-hooks.h -generic-y += mmiowb.h generic-y += mutex.h generic-y += percpu.h generic-y += preempt.h diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h index 1d9c1376dc64..744fd92e77bc 100644 --- a/arch/riscv/include/asm/io.h +++ b/arch/riscv/include/asm/io.h @@ -20,6 +20,7 @@ #define _ASM_RISCV_IO_H #include +#include extern void __iomem *ioremap(phys_addr_t offset, unsigned long size); @@ -100,18 +101,6 @@ static inline u64 __raw_readq(const volatile void __iomem *addr) #endif /* - * FIXME: I'm flip-flopping on whether or not we should keep this or enforce - * the ordering with I/O on spinlocks like PowerPC does. The worry is that - * drivers won't get this correct, but I also don't want to introduce a fence - * into the lock code that otherwise only uses AMOs (and is essentially defined - * by the ISA to be correct). For now I'm leaving this here: "o,w" is - * sufficient to ensure that all writes to the device have completed before the - * write to the spinlock is allowed to commit. I surmised this from reading - * "ACQUIRES VS I/O ACCESSES" in memory-barriers.txt. - */ -#define mmiowb() __asm__ __volatile__ ("fence o,w" : : : "memory"); - -/* * Unordered I/O memory access primitives. These are even more relaxed than * the relaxed versions, as they don't even order accesses between successive * operations to the I/O regions. @@ -165,7 +154,7 @@ static inline u64 __raw_readq(const volatile void __iomem *addr) #define __io_br() do {} while (0) #define __io_ar(v) __asm__ __volatile__ ("fence i,r" : : : "memory"); #define __io_bw() __asm__ __volatile__ ("fence w,o" : : : "memory"); -#define __io_aw() do {} while (0) +#define __io_aw() mmiowb_set_pending() #define readb(c) ({ u8 __v; __io_br(); __v = readb_cpu(c); __io_ar(__v); __v; }) #define readw(c) ({ u16 __v; __io_br(); __v = readw_cpu(c); __io_ar(__v); __v; }) diff --git a/arch/riscv/include/asm/mmiowb.h b/arch/riscv/include/asm/mmiowb.h new file mode 100644 index 000000000000..5d7e3a2b4e3b --- /dev/null +++ b/arch/riscv/include/asm/mmiowb.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_RISCV_MMIOWB_H +#define _ASM_RISCV_MMIOWB_H + +/* + * "o,w" is sufficient to ensure that all writes to the device have completed + * before the write to the spinlock is allowed to commit. + */ +#define mmiowb() __asm__ __volatile__ ("fence o,w" : : : "memory"); + +#include + +#endif /* ASM_RISCV_MMIOWB_H */ -- 2.11.0