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[79.53.109.127]) by smtp.gmail.com with ESMTPSA id r129-20020a1c4487000000b003a0499df21asm229785wma.25.2022.07.07.16.15.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Jul 2022 16:15:54 -0700 (PDT) From: "Fabio M. De Francesco" To: Eric Biederman , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Fabio M. De Francesco" , Ira Weiny Subject: [PATCH v2] kexec: Replace kmap() with kmap_local_page() Date: Fri, 8 Jul 2022 01:15:50 +0200 Message-Id: <20220707231550.1484-1-fmdefrancesco@gmail.com> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220707_161558_984584_AF7E40E2 X-CRM114-Status: GOOD ( 12.74 ) X-BeenThere: kexec@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: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org The use of kmap() and kmap_atomic() are being deprecated in favor of kmap_local_page(). With kmap_local_page(), the mappings are per thread, CPU local and not globally visible. Furthermore, the mappings can be acquired from any context (including interrupts). Therefore, use kmap_local_page() in kexec_core.c because these mappings are per thread, CPU local, and not globally visible. Tested on a QEMU + KVM 32-bits VM booting a kernel with HIGHMEM64GB enabled. Suggested-by: Ira Weiny Signed-off-by: Fabio M. De Francesco --- v1->v2: A sentence of the commit message contained an error due to a mistake in copy-pasting from a previous patch. Replace "aio.c" with "kexec_core.c". kernel/kexec_core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 4d34c78334ce..6f98274765d4 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -814,7 +814,7 @@ static int kimage_load_normal_segment(struct kimage *image, if (result < 0) goto out; - ptr = kmap(page); + ptr = kmap_local_page(page); /* Start with a clear page */ clear_page(ptr); ptr += maddr & ~PAGE_MASK; @@ -827,7 +827,7 @@ static int kimage_load_normal_segment(struct kimage *image, memcpy(ptr, kbuf, uchunk); else result = copy_from_user(ptr, buf, uchunk); - kunmap(page); + kunmap_local(ptr); if (result) { result = -EFAULT; goto out; @@ -878,7 +878,7 @@ static int kimage_load_crash_segment(struct kimage *image, goto out; } arch_kexec_post_alloc_pages(page_address(page), 1, 0); - ptr = kmap(page); + ptr = kmap_local_page(page); ptr += maddr & ~PAGE_MASK; mchunk = min_t(size_t, mbytes, PAGE_SIZE - (maddr & ~PAGE_MASK)); @@ -894,7 +894,7 @@ static int kimage_load_crash_segment(struct kimage *image, else result = copy_from_user(ptr, buf, uchunk); kexec_flush_icache_page(page); - kunmap(page); + kunmap_local(ptr); arch_kexec_pre_free_pages(page_address(page), 1); if (result) { result = -EFAULT; -- 2.36.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4BE33C43334 for ; Thu, 7 Jul 2022 23:16:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236729AbiGGXQB (ORCPT ); Thu, 7 Jul 2022 19:16:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236556AbiGGXP5 (ORCPT ); Thu, 7 Jul 2022 19:15:57 -0400 Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [IPv6:2a00:1450:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1F7327FD5 for ; Thu, 7 Jul 2022 16:15:56 -0700 (PDT) Received: by mail-wr1-x42f.google.com with SMTP id z12so18695048wrq.7 for ; Thu, 07 Jul 2022 16:15:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=izEW/QlWsYwAv1ZochY3FjaPww57C5kdq40cLp75WW8=; b=bN/UI+7lQeB65atynzKqp9nMLADS1qCkhGg5AFy7k9JTlnDD+Zfmk48B2FRQd+hC0Z U4CKu5nG4vjGJCXcV2zhrMRVj5UyORVGZ0Wvcq6fki/MJbwmIrZUPJ6dJ5thhHkq+45r trErrsYkpiZKrv56HldNIjMgl5ylRyWM2frA870ii9xsEWsxGBxvQw9GZER8kL4TcltL A9S9IZChyrVI1WMBCy00qnuXGolCRiTd3a6aLoa4W8Ximf+e2l9LEQ0uIXtbfAokdAId ANb1ZhVUMrfkHBXJMCKs8voDoToWbTf2WtwrcXSUQTDgagsSYKsBMdxLfxtkqPy6PGSe /AOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=izEW/QlWsYwAv1ZochY3FjaPww57C5kdq40cLp75WW8=; b=ABf0PpGHGyqHjfTa2D2zQp/7jHpqf757bJ2TchFm/V6ecRWLHP60WGbzzKaddgtuuS 14j8ZfnAbjN6QF0F2n7EBPCSjz6qrOGJ4wu8bLwySXHQ5up4V7DHfjpjf39V0kBxNP/8 X7KdTm7nV3ReMYwpfcaIBfMCnf5VjrVh5SY+D/pb4ulblvJUAfzNPVkMGO5e4aeRidQx T5PQe+aczUZaDWSrejF4RDG2it4jmWFOyE6dWAcM/8tf0316rV8poghXGNccf8Ku1lGw MXpC8VbpA3wExhAkpM1vWgn43C8HwDfpKUTsUqI4HnaYa81WHY84emVwxInNIlCNfKe9 7dfQ== X-Gm-Message-State: AJIora9vy+Ht5D+99fYBhHCqVevMsIA8bZX4v+UTdcznRZOkV/3Dfbiw EPjjBlFq2PV9Fr6JR7uzR+g= X-Google-Smtp-Source: AGRyM1vb1t9Pd03LkoGzBnp8Qn8oJ174NaaaEi0Rd2+luP9y+glv1E3K+ONHUCDrq6cJFue2klElbQ== X-Received: by 2002:adf:f9c9:0:b0:21d:2cec:63e9 with SMTP id w9-20020adff9c9000000b0021d2cec63e9mr276271wrr.301.1657235755382; Thu, 07 Jul 2022 16:15:55 -0700 (PDT) Received: from localhost.localdomain (host-79-53-109-127.retail.telecomitalia.it. [79.53.109.127]) by smtp.gmail.com with ESMTPSA id r129-20020a1c4487000000b003a0499df21asm229785wma.25.2022.07.07.16.15.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Jul 2022 16:15:54 -0700 (PDT) From: "Fabio M. De Francesco" To: Eric Biederman , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Fabio M. De Francesco" , Ira Weiny Subject: [PATCH v2] kexec: Replace kmap() with kmap_local_page() Date: Fri, 8 Jul 2022 01:15:50 +0200 Message-Id: <20220707231550.1484-1-fmdefrancesco@gmail.com> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The use of kmap() and kmap_atomic() are being deprecated in favor of kmap_local_page(). With kmap_local_page(), the mappings are per thread, CPU local and not globally visible. Furthermore, the mappings can be acquired from any context (including interrupts). Therefore, use kmap_local_page() in kexec_core.c because these mappings are per thread, CPU local, and not globally visible. Tested on a QEMU + KVM 32-bits VM booting a kernel with HIGHMEM64GB enabled. Suggested-by: Ira Weiny Signed-off-by: Fabio M. De Francesco --- v1->v2: A sentence of the commit message contained an error due to a mistake in copy-pasting from a previous patch. Replace "aio.c" with "kexec_core.c". kernel/kexec_core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 4d34c78334ce..6f98274765d4 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -814,7 +814,7 @@ static int kimage_load_normal_segment(struct kimage *image, if (result < 0) goto out; - ptr = kmap(page); + ptr = kmap_local_page(page); /* Start with a clear page */ clear_page(ptr); ptr += maddr & ~PAGE_MASK; @@ -827,7 +827,7 @@ static int kimage_load_normal_segment(struct kimage *image, memcpy(ptr, kbuf, uchunk); else result = copy_from_user(ptr, buf, uchunk); - kunmap(page); + kunmap_local(ptr); if (result) { result = -EFAULT; goto out; @@ -878,7 +878,7 @@ static int kimage_load_crash_segment(struct kimage *image, goto out; } arch_kexec_post_alloc_pages(page_address(page), 1, 0); - ptr = kmap(page); + ptr = kmap_local_page(page); ptr += maddr & ~PAGE_MASK; mchunk = min_t(size_t, mbytes, PAGE_SIZE - (maddr & ~PAGE_MASK)); @@ -894,7 +894,7 @@ static int kimage_load_crash_segment(struct kimage *image, else result = copy_from_user(ptr, buf, uchunk); kexec_flush_icache_page(page); - kunmap(page); + kunmap_local(ptr); arch_kexec_pre_free_pages(page_address(page), 1); if (result) { result = -EFAULT; -- 2.36.1