From patchwork Mon Feb 4 16:54:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 10796197 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AEBD017FB for ; Mon, 4 Feb 2019 17:21:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9BF3C2BE37 for ; Mon, 4 Feb 2019 17:21:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8FFC82BE26; Mon, 4 Feb 2019 17:21:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id DE9C52BE37 for ; Mon, 4 Feb 2019 17:21:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=JNKkBcs7RJMaGk4/yqBxfVPH/HjYPKI2zcvNNDvDsT8=; b=Iul YSTl9abW92PhynsT/AtMXFfyYyo7WqyJeM1WCXkyf4nJwL8tnGkCJtpGfDZH4AbgWpaYAdnq3MUpj iT40vrKF40O2QE21YBPYmPFBoJQA6B2tFF/zDZZy6JLCXrnWYO2LLTXUXjqK/QZQXxWsz1dkR4pMz w1DYIbsqh9AspwsPJqiwHWfoWZ7jBS3GJAbbbwY+oTv2N4PfQMo/kqvEXWdTd/pk04MyN+93BsAGg ZTO8WWdENr9tvNbgHiCznKcv6sjjlSexxP7LQbmsxLPN6kTFBdpGhpYfOQtS29fF4rmmx+dsZE+0X M4SqiCscnFx7XiApzRoA7MQfjD8wvBg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gqhwM-0004xv-0N; Mon, 04 Feb 2019 17:21:50 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gqhkr-0003OJ-NY for linux-arm-kernel@bombadil.infradead.org; Mon, 04 Feb 2019 17:09:58 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Message-Id:Date:Subject:Cc:To:From: Sender:Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=IBq4f+EU57KQKEZCfnjcyljvyISxXphHzcyrCjrqINM=; b=nbHIUOV/iDUUgpL9Tn1m45AwC S1g+y8P+NOdPlsQJBID5QfRmQyef3QKXhbQe20cAhEBKzCGdUHZlSnDwUfEFnJecpaEZTh58k/xZI B4DzjpovDZ5uqkjjl8RAUP0d/x0fkVZa5wHKl9PZ9raDelgIy1Uzn2Fw9nXp5SOe0tfJMn+mKqAvN /oKNVamGY3mpaZSS+cXrgMeIRz5InN7MPnPn1MZcJ6Gkt0ZDeUtSg9PstOu6GAsCUXaNJLWVgTqdN 3ncOaTWiNMZUbTvQzSJTOQ6tJx6x3XoYr9s2zkRUqGyX0kD2wbOoJazRYKf0/Csx/BZ+lVmbrSceJ 4Eg722PtA==; Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by casper.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gqhWI-0005Gc-B1 for linux-arm-kernel@lists.infradead.org; Mon, 04 Feb 2019 16:54:56 +0000 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 3046015AD; Mon, 4 Feb 2019 08:54:53 -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 441CC3F589; Mon, 4 Feb 2019 08:54:52 -0800 (PST) From: Will Deacon To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] arm64: ptdump: Don't iterate kernel page tables using PTRS_PER_PXX Date: Mon, 4 Feb 2019 16:54:46 +0000 Message-Id: <20190204165446.23662-1-will.deacon@arm.com> X-Mailer: git-send-email 2.11.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190204_165454_676029_9C0081FC X-CRM114-Status: GOOD ( 10.67 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Will Deacon , cai@lca.pw, steve.capper@arm.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP When 52-bit virtual addressing is enabled for userspace (CONFIG_ARM64_USER_VA_BITS_52=y), the kernel continues to utilise 48-bit virtual addressing in TTBR1. Consequently, PTRS_PER_PGD reflects the larger page table size for userspace and the pgd pointer for kernel page tables is offset before being written to TTBR1. This means that we can't use PTRS_PER_PGD to iterate over kernel page tables unless we apply the same offset, which is fiddly to get right and leads to some non-idiomatic walking code. Instead, just follow the usual pattern when walking page tables by using a while loop driven by pXd_offset() and pXd_addr_end(). Reported-by: Qian Cai Tested-by: Qian Cai Acked-by: Steve Capper Tested-by: Steve Capper Signed-off-by: Will Deacon --- arch/arm64/mm/dump.c | 59 ++++++++++++++++++++++++++-------------------------- 1 file changed, 29 insertions(+), 30 deletions(-) diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c index fcb1f2a6d7c6..99bb8facb5cb 100644 --- a/arch/arm64/mm/dump.c +++ b/arch/arm64/mm/dump.c @@ -286,74 +286,73 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level, } -static void walk_pte(struct pg_state *st, pmd_t *pmdp, unsigned long start) +static void walk_pte(struct pg_state *st, pmd_t *pmdp, unsigned long start, + unsigned long end) { - pte_t *ptep = pte_offset_kernel(pmdp, 0UL); - unsigned long addr; - unsigned i; + unsigned long addr = start; + pte_t *ptep = pte_offset_kernel(pmdp, start); - for (i = 0; i < PTRS_PER_PTE; i++, ptep++) { - addr = start + i * PAGE_SIZE; + do { note_page(st, addr, 4, READ_ONCE(pte_val(*ptep))); - } + } while (ptep++, addr += PAGE_SIZE, addr != end); } -static void walk_pmd(struct pg_state *st, pud_t *pudp, unsigned long start) +static void walk_pmd(struct pg_state *st, pud_t *pudp, unsigned long start, + unsigned long end) { - pmd_t *pmdp = pmd_offset(pudp, 0UL); - unsigned long addr; - unsigned i; + unsigned long next, addr = start; + pmd_t *pmdp = pmd_offset(pudp, start); - for (i = 0; i < PTRS_PER_PMD; i++, pmdp++) { + do { pmd_t pmd = READ_ONCE(*pmdp); + next = pmd_addr_end(addr, end); - addr = start + i * PMD_SIZE; if (pmd_none(pmd) || pmd_sect(pmd)) { note_page(st, addr, 3, pmd_val(pmd)); } else { BUG_ON(pmd_bad(pmd)); - walk_pte(st, pmdp, addr); + walk_pte(st, pmdp, addr, next); } - } + } while (pmdp++, addr = next, addr != end); } -static void walk_pud(struct pg_state *st, pgd_t *pgdp, unsigned long start) +static void walk_pud(struct pg_state *st, pgd_t *pgdp, unsigned long start, + unsigned long end) { - pud_t *pudp = pud_offset(pgdp, 0UL); - unsigned long addr; - unsigned i; + unsigned long next, addr = start; + pud_t *pudp = pud_offset(pgdp, start); - for (i = 0; i < PTRS_PER_PUD; i++, pudp++) { + do { pud_t pud = READ_ONCE(*pudp); + next = pud_addr_end(addr, end); - addr = start + i * PUD_SIZE; if (pud_none(pud) || pud_sect(pud)) { note_page(st, addr, 2, pud_val(pud)); } else { BUG_ON(pud_bad(pud)); - walk_pmd(st, pudp, addr); + walk_pmd(st, pudp, addr, next); } - } + } while (pudp++, addr = next, addr != end); } static void walk_pgd(struct pg_state *st, struct mm_struct *mm, unsigned long start) { - pgd_t *pgdp = pgd_offset(mm, 0UL); - unsigned i; - unsigned long addr; + unsigned long end = (start < TASK_SIZE_64) ? TASK_SIZE_64 : 0; + unsigned long next, addr = start; + pgd_t *pgdp = pgd_offset(mm, start); - for (i = 0; i < PTRS_PER_PGD; i++, pgdp++) { + do { pgd_t pgd = READ_ONCE(*pgdp); + next = pgd_addr_end(addr, end); - addr = start + i * PGDIR_SIZE; if (pgd_none(pgd)) { note_page(st, addr, 1, pgd_val(pgd)); } else { BUG_ON(pgd_bad(pgd)); - walk_pud(st, pgdp, addr); + walk_pud(st, pgdp, addr, next); } - } + } while (pgdp++, addr = next, addr != end); } void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info)