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=-17.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 F042EC4320A for ; Wed, 11 Aug 2021 00:43:29 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9AB916056C for ; Wed, 11 Aug 2021 00:43:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 9AB916056C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org 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=Jcd/YQGNskFS1nxO1ccm1VaoDWpqKBLKbULcdev4RGM=; b=LY6Tq2f1aH8KJO iO2RiQKhYQR7mhhyOBwKoBzk0phYcCP+e01kJkblA8G1AXthy5eUC7NC3JDjrsVraQvbQIJlqcwPa E6zYH3HtpToof8ZTWvnLpXzYdBqFknk6fcdjseTHV/GdkC4mT3nhK5GoOpWAT1I9x92MJ+2SuK4BS WGSxMcB2h4NlyclYyKaNtFFRHz2Qh+6n/xP0rUucR4S/7kL8kb6RP1TqCQYZPAkeed098+UEwwTu8 qlI15jbr47qeRlizrpkRN7c7I2X0rNHD4ZnPfq0yo0QO0sQVhcAd83kIbPFTJJ1i4yepUofNiiHbH /y0mb9orslPp2IiyxGCg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDcLB-0056oN-0h; Wed, 11 Aug 2021 00:43:29 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDcL6-0056ey-49 for linux-snps-arc@lists.infradead.org; Wed, 11 Aug 2021 00:43:27 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 989E960EB7; Wed, 11 Aug 2021 00:43:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628642603; bh=7WJKlO9bHU1KTACHVSZNKYdiOMEX5YhZuZxQV/SdLuA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HRnf5A4x4/jZiHyG9ZaRzXwbGnLGx/X7Meb25l6g61b2CB/dhxZTicTnsdeBUwEq8 uPR3P/20cfHxaAzD6B2oM/PG1YvlEyleAelnhCPOKRpYyeZV9eD6HaQLNoqoMYJ5+i 2rIEeTEM6HtnRIZPN+OyVa2JIZyVIuu5RMfoHoB93BHSDxUcrtSR/Cooe+bKYGge6S pIkAR2zJuxnAB8pdDLRsZ9gNp3OBD1xCxOF+VfdJYwLfEyiceL5vlqx2BCXqvIO0fg A8qiQb2OlNVgyyjuEAHcQu5PA47i5amo6imVqNQdIHNK+WD4wY38YMUbQnEoKKcI/T 8ijDY055CsVjw== From: Vineet Gupta To: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Anshuman Khandual , Mike Rapoport , Vineet Gupta Subject: [PATCH 17/18] ARC: mm: vmalloc sync from kernel to user table to update PMD ... Date: Tue, 10 Aug 2021 17:42:57 -0700 Message-Id: <20210811004258.138075-18-vgupta@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210811004258.138075-1-vgupta@kernel.org> References: <20210811004258.138075-1-vgupta@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210810_174324_218473_D2D214CB X-CRM114-Status: GOOD ( 11.31 ) X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org ... not PGD vmalloc() sets up the kernel page table (starting from @swapper_pg_dir). But when vmalloc area is accessed in context of a user task, say opening terminal in n_tty_open(), the user page tables need to be synced from kernel page tables so that TLB entry is created in "user context". The old code was doing this incorrectly, as it was updating the user pgd entry (first level itself) to point to kernel pud table (2nd level), effectively yanking away the entire user space translation with kernel one. The correct way to do this is to ONLY update a user space pgd/pud/pmd entry if it is not popluated already. This ensures that only the missing leaf pmd entry gets updated to point to relevant kernel pte table. >From code change pov, we are chaging the pattern: p4d = p4d_offset(pgd, address); p4d_k = p4d_offset(pgd_k, address); if (!p4d_present(*p4d_k)) goto bad_area; set_p4d(p4d, *p4d_k); with p4d = p4d_offset(pgd, address); p4d_k = p4d_offset(pgd_k, address); if (p4d_none(*p4d_k)) goto bad_area; if (!p4d_present(*p4d)) set_p4d(p4d, *p4d_k); Signed-off-by: Vineet Gupta --- arch/arc/mm/fault.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c index f8994164fa36..5787c261c9a4 100644 --- a/arch/arc/mm/fault.c +++ b/arch/arc/mm/fault.c @@ -36,31 +36,31 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address) pgd = pgd_offset(current->active_mm, address); pgd_k = pgd_offset_k(address); - if (!pgd_present(*pgd_k)) + if (pgd_none (*pgd_k)) goto bad_area; - - set_pgd(pgd, *pgd_k); + if (!pgd_present(*pgd)) + set_pgd(pgd, *pgd_k); p4d = p4d_offset(pgd, address); p4d_k = p4d_offset(pgd_k, address); - if (!p4d_present(*p4d_k)) + if (p4d_none(*p4d_k)) goto bad_area; - - set_p4d(p4d, *p4d_k); + if (!p4d_present(*p4d)) + set_p4d(p4d, *p4d_k); pud = pud_offset(p4d, address); pud_k = pud_offset(p4d_k, address); - if (!pud_present(*pud_k)) + if (pud_none(*pud_k)) goto bad_area; - - set_pud(pud, *pud_k); + if (!pud_present(*pud)) + set_pud(pud, *pud_k); pmd = pmd_offset(pud, address); pmd_k = pmd_offset(pud_k, address); - if (!pmd_present(*pmd_k)) + if (pmd_none(*pmd_k)) goto bad_area; - - set_pmd(pmd, *pmd_k); + if (!pmd_present(*pmd)) + set_pmd(pmd, *pmd_k); /* XXX: create the TLB entry here */ return 0; -- 2.25.1 _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc