From patchwork Mon May 23 02:00:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kefeng Wang X-Patchwork-Id: 12858580 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 13EE1C433F5 for ; Mon, 23 May 2022 08:26:29 +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:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=jSHH0razUrmdML2wzl5mD994S+CWY+1gj1Y4u9I/S/U=; b=tn/37fgcuciZRM Rf+Qe0Vx3P7XL+KrENYjMiwKCHlaects+wIWyzqvQ/t1piQtI22sNi3KO3ZlOBFww9kqCsdq6Qm+c Ay6QVT9XoHCS4WSKiXYBbBnC17Hyk1hUGm4uU+e5t6Rll181+HDHMUhzupzUaZ+MSO8iOmfrOweuj 9vtw9EmdUQgF8S/AYJLMIqmqoOx4UHcyHnGmJxsdS8TLefLTgcDvgNGQpzvQkF9X1sYKCeSQjfAtj g3FomlLLGhghRkSdvg0vbmu6C7BeJOErX+knme8GO3PVGLe1uziNRAReZKhGZM+8ZDe0t+pBFpxjg a4ynLepmjJVzTop+ysQw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nt3N7-002PiK-8i; Mon, 23 May 2022 08:25:01 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nt2tg-002CKb-5o for linux-arm-kernel@bombadil.infradead.org; Mon, 23 May 2022 07:54:37 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:Content-Transfer-Encoding :MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:CC:To:From: Sender:Reply-To:Content-ID:Content-Description; bh=H5OVmK7595cIaNSSesmROf1Pc/5lD9t1M6ZQ2lps83E=; b=Ll68OOtehZSx0Mwoj6TVx6xm2U 5AM/skB2zm6wcx31/R2RUZc0iR0GOdBU6jX0OyIwgeLJv8hu//704QHf3p5DvO++Kkl4d5d5UgYST u/wVKzcgmZqHi3SzSXpOmTlLFxlpzAOnzx8DMwYiLbS2vG56UIunumLQWsrhGfr227nEDprbJFjdD 0777cS+dOPRb/2OyNWlgfr/FElRCfQCc49mm/j0VqyXv7ANL99qXBsQHsqE9kYCz3Tjv9mfnKEHJW CLWG4FyfPt09LUxamyjioiYu/te0Ch/8TR2TLWmNf1H+mjdpMVhiNX+u++7xFnUk5J+qeDjbV4QqL 22fc/o2w==; Received: from szxga02-in.huawei.com ([45.249.212.188]) by desiato.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nsxEC-000k8G-R0 for linux-arm-kernel@lists.infradead.org; Mon, 23 May 2022 01:51:27 +0000 Received: from dggpemm500023.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4L60dH6mdkzjWyJ; Mon, 23 May 2022 09:49:55 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 23 May 2022 09:50:24 +0800 Received: from localhost.localdomain.localdomain (10.175.113.25) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 23 May 2022 09:50:24 +0800 From: Kefeng Wang To: , , , , , , Jonathan Corbet CC: , Kefeng Wang Subject: [PATCH v3 1/2] asm-generic: Add memory barrier dma_mb() Date: Mon, 23 May 2022 10:00:50 +0800 Message-ID: <20220523020051.141460-2-wangkefeng.wang@huawei.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220523020051.141460-1-wangkefeng.wang@huawei.com> References: <20220523020051.141460-1-wangkefeng.wang@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.113.25] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220523_025125_784623_C05388A5 X-CRM114-Status: GOOD ( 15.39 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The memory barrier dma_mb() is introduced by commit a76a37777f2c ("iommu/arm-smmu-v3: Ensure queue is read after updating prod pointer"), which is used to ensure that prior (both reads and writes) accesses to memory by a CPU are ordered w.r.t. a subsequent MMIO write, this is only defined on arm64, but it is a generic memory barrier, let's add dma_mb() into documentation and include/asm-generic/barrier.h. Signed-off-by: Kefeng Wang Reviewed-by: Arnd Bergmann # for asm-generic --- Documentation/memory-barriers.txt | 11 ++++++----- include/asm-generic/barrier.h | 8 ++++++++ 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index b12df9137e1c..07a8b8e1b12a 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -1894,6 +1894,7 @@ There are some more advanced barrier functions: (*) dma_wmb(); (*) dma_rmb(); + (*) dma_mb(); These are for use with consistent memory to guarantee the ordering of writes or reads of shared memory accessible to both the CPU and a @@ -1925,11 +1926,11 @@ There are some more advanced barrier functions: The dma_rmb() allows us guarantee the device has released ownership before we read the data from the descriptor, and the dma_wmb() allows us to guarantee the data is written to the descriptor before the device - can see it now has ownership. Note that, when using writel(), a prior - wmb() is not needed to guarantee that the cache coherent memory writes - have completed before writing to the MMIO region. The cheaper - writel_relaxed() does not provide this guarantee and must not be used - here. + can see it now has ownership. The dma_mb() implies both a dma_rmb() and + a dma_wmb(). Note that, when using writel(), a prior wmb() is not needed + to guarantee that the cache coherent memory writes have completed before + writing to the MMIO region. The cheaper writel_relaxed() does not provide + this guarantee and must not be used here. See the subsection "Kernel I/O barrier effects" for more information on relaxed I/O accessors and the Documentation/core-api/dma-api.rst file for diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h index fd7e8fbaeef1..961f4d88f9ef 100644 --- a/include/asm-generic/barrier.h +++ b/include/asm-generic/barrier.h @@ -38,6 +38,10 @@ #define wmb() do { kcsan_wmb(); __wmb(); } while (0) #endif +#ifdef __dma_mb +#define dma_mb() do { kcsan_mb(); __dma_mb(); } while (0) +#endif + #ifdef __dma_rmb #define dma_rmb() do { kcsan_rmb(); __dma_rmb(); } while (0) #endif @@ -65,6 +69,10 @@ #define wmb() mb() #endif +#ifndef dma_mb +#define dma_mb() mb() +#endif + #ifndef dma_rmb #define dma_rmb() rmb() #endif From patchwork Mon May 23 02:00:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kefeng Wang X-Patchwork-Id: 12858584 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 83B5DC433EF for ; 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Mon, 23 May 2022 01:51:15 +0000 Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4L60c92ywLzgYCD; Mon, 23 May 2022 09:48:57 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 23 May 2022 09:50:25 +0800 Received: from localhost.localdomain.localdomain (10.175.113.25) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 23 May 2022 09:50:24 +0800 From: Kefeng Wang To: , , , , , , Jonathan Corbet CC: , Kefeng Wang Subject: [PATCH v3 2/2] arm64: kcsan: Support detecting more missing memory barriers Date: Mon, 23 May 2022 10:00:51 +0800 Message-ID: <20220523020051.141460-3-wangkefeng.wang@huawei.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220523020051.141460-1-wangkefeng.wang@huawei.com> References: <20220523020051.141460-1-wangkefeng.wang@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.113.25] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220523_025113_399450_DC705566 X-CRM114-Status: GOOD ( 10.51 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org As "kcsan: Support detecting a subset of missing memory barriers"[1] introduced KCSAN_STRICT/KCSAN_WEAK_MEMORY which make kcsan detects more missing memory barrier, but arm64 don't have KCSAN instrumentation for barriers, so the new selftest test_barrier() and test cases for memory barrier instrumentation in kcsan_test module will fail, even panic on selftest. Let's prefix all barriers with __ on arm64, as asm-generic/barriers.h defined the final instrumented version of these barriers, which will fix the above issues. Note, barrier instrumentation can be disabled via __no_kcsan with appropriate compiler-support (and not just with objtool help), see commit bd3d5bd1a0ad ("kcsan: Support WEAK_MEMORY with Clang where no objtool support exists"), it adds disable_sanitizer_instrumentation to __no_kcsan attribute for Clang which will remove all sanitizer instrumentation fully (with Clang 14.0). Meanwhile, GCC does the same thing with no_sanitize. [1] https://lore.kernel.org/linux-mm/20211130114433.2580590-1-elver@google.com/ Signed-off-by: Kefeng Wang Acked-by: Marco Elver --- arch/arm64/include/asm/barrier.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h index 9f3e2c3d2ca0..2cfc4245d2e2 100644 --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -50,13 +50,13 @@ #define pmr_sync() do {} while (0) #endif -#define mb() dsb(sy) -#define rmb() dsb(ld) -#define wmb() dsb(st) +#define __mb() dsb(sy) +#define __rmb() dsb(ld) +#define __wmb() dsb(st) -#define dma_mb() dmb(osh) -#define dma_rmb() dmb(oshld) -#define dma_wmb() dmb(oshst) +#define __dma_mb() dmb(osh) +#define __dma_rmb() dmb(oshld) +#define __dma_wmb() dmb(oshst) #define io_stop_wc() dgh()