From patchwork Wed Jun 15 17:35:45 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 9179017 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2B44560573 for ; Wed, 15 Jun 2016 17:39:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1D72E27CEA for ; Wed, 15 Jun 2016 17:39:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1220127F3E; Wed, 15 Jun 2016 17:39:03 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 823B027CEA for ; Wed, 15 Jun 2016 17:39:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753083AbcFORiz (ORCPT ); Wed, 15 Jun 2016 13:38:55 -0400 Received: from foss.arm.com ([217.140.101.70]:39180 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932529AbcFORiw (ORCPT ); Wed, 15 Jun 2016 13:38:52 -0400 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 6DE26950; Wed, 15 Jun 2016 10:39:33 -0700 (PDT) Received: from melchizedek.cambridge.arm.com (melchizedek.cambridge.arm.com [10.1.209.158]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id BABC53F246; Wed, 15 Jun 2016 10:38:50 -0700 (PDT) From: James Morse To: linux-arm-kernel@lists.infradead.org Cc: Will Deacon , Catalin Marinas , "Rafael J . Wysocki" , Pavel Machek , linux-pm@vger.kernel.org, Lorenzo Pieralisi , Mark Rutland , James Morse Subject: [PATCH v2 3/6] arm64: hibernate: Support DEBUG_PAGEALLOC Date: Wed, 15 Jun 2016 18:35:45 +0100 Message-Id: <1466012148-7674-4-git-send-email-james.morse@arm.com> X-Mailer: git-send-email 2.8.0.rc3 In-Reply-To: <1466012148-7674-1-git-send-email-james.morse@arm.com> References: <1466012148-7674-1-git-send-email-james.morse@arm.com> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP DEBUG_PAGEALLOC removes the valid bit of page table entries to prevent any access to unallocated memory. Hibernate uses this as a hint that those pages don't need to be saved/restored. This patch adds the kernel_page_present() function it uses. hibernate.c copies the resume kernel's linear map for use during restore. Add _copy_pte() to fill-in the holes made by DEBUG_PAGEALLOC in the resume kernel, so we can restore data the original kernel had at these addresses. Finally, DEBUG_PAGEALLOC means the linear-map alias of KERNEL_START to KERNEL_END may have holes in it, so we can't lazily clean this whole area to the PoC. Only clean the .mmuoff.text region, and the kernel/kvm idmaps. This reverts commit da24eb1f3f9e2c7b75c5f8c40d8e48e2c4789596. Reported-by: Will Deacon Signed-off-by: James Morse --- Change since v1: * Changed cleaning of text_text section to the new mmuoff section. arch/arm64/Kconfig | 1 - arch/arm64/kernel/hibernate.c | 45 ++++++++++++++++++++++++++++++++++--------- arch/arm64/mm/pageattr.c | 40 +++++++++++++++++++++++++++++++++++++- 3 files changed, 75 insertions(+), 11 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 5a0a691d4220..c7aa78b9f586 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -598,7 +598,6 @@ source kernel/Kconfig.preempt source kernel/Kconfig.hz config ARCH_SUPPORTS_DEBUG_PAGEALLOC - depends on !HIBERNATION def_bool y config ARCH_HAS_HOLES_MEMORYMODEL diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c index 56e548fe0386..75d45c4ceb84 100644 --- a/arch/arm64/kernel/hibernate.c +++ b/arch/arm64/kernel/hibernate.c @@ -235,8 +235,15 @@ int swsusp_arch_suspend(void) if (__cpu_suspend_enter(&state)) { ret = swsusp_save(); } else { - /* Clean kernel to PoC for secondary core startup */ - __flush_dcache_area(LMADDR(KERNEL_START), KERNEL_END - KERNEL_START); + /* Clean kernel core startup/idle code to PoC*/ + __flush_dcache_area(__mmuoff_text_start, + __mmuoff_text_end - __mmuoff_text_start); + __flush_dcache_area(__idmap_text_start, + __idmap_text_end - __idmap_text_start); + + /* Clean kvm setup code to PoC? */ + if (el2_reset_needed()) + __flush_dcache_area(__hyp_idmap_text_start, __hyp_idmap_text_end - __hyp_idmap_text_start); /* * Tell the hibernation core that we've just restored @@ -252,6 +259,32 @@ int swsusp_arch_suspend(void) return ret; } +static void _copy_pte(pte_t *dst_pte, pte_t *src_pte, unsigned long addr) +{ + unsigned long pfn = virt_to_pfn(addr); + + if (pte_valid(*src_pte)) { + /* + * Resume will overwrite areas that may be marked + * read only (code, rodata). Clear the RDONLY bit from + * the temporary mappings we use during restore. + */ + set_pte(dst_pte, __pte(pte_val(*src_pte) & ~PTE_RDONLY)); + } else if (debug_pagealloc_enabled()) { + /* + * debug_pagealloc may have removed the PTE_VALID bit if + * the page isn't in use by the resume kernel. It may have + * been in use by the original kernel, in which case we need + * to put it back in our copy to do the restore. + * + * Check for mappable memory that gives us a translation + * like part of the linear map. + */ + if (pfn_valid(pfn) && pte_pfn(*src_pte) == pfn) + set_pte(dst_pte, __pte((pte_val(*src_pte) & ~PTE_RDONLY) | PTE_VALID)); + } +} + static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start, unsigned long end) { @@ -267,13 +300,7 @@ static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start, src_pte = pte_offset_kernel(src_pmd, start); do { - if (!pte_none(*src_pte)) - /* - * Resume will overwrite areas that may be marked - * read only (code, rodata). Clear the RDONLY bit from - * the temporary mappings we use during restore. - */ - set_pte(dst_pte, __pte(pte_val(*src_pte) & ~PTE_RDONLY)); + _copy_pte(dst_pte, src_pte, addr); } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); return 0; diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index ca6d268e3313..b6c0da84258c 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -139,4 +139,42 @@ void __kernel_map_pages(struct page *page, int numpages, int enable) __pgprot(0), __pgprot(PTE_VALID)); } -#endif +#ifdef CONFIG_HIBERNATION +/* + * When built with CONFIG_DEBUG_PAGEALLOC and CONFIG_HIBERNATION, this function + * is used to determine if a linear map page has been marked as not-present by + * CONFIG_DEBUG_PAGEALLOC. Walk the page table and check the PTE_VALID bit. + * This is based on kern_addr_valid(), which almost does what we need. + */ +bool kernel_page_present(struct page *page) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + unsigned long addr = (unsigned long)page_address(page); + + pgd = pgd_offset_k(addr); + if (pgd_none(*pgd)) + return false; + + pud = pud_offset(pgd, addr); + if (pud_none(*pud)) + return false; + if (pud_sect(*pud)) + return true; + + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return false; + if (pmd_sect(*pmd)) + return true; + + pte = pte_offset_kernel(pmd, addr); + if (pte_none(*pte)) + return false; + + return pte_valid(*pte); +} +#endif /* CONFIG_HIBERNATION */ +#endif /* CONFIG_DEBUG_PAGEALLOC */