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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 10D95C3A5A0 for ; Mon, 19 Aug 2019 15:58:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C7CCE22CED for ; Mon, 19 Aug 2019 15:58:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C7CCE22CED Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 737B46B0272; Mon, 19 Aug 2019 11:58:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6E8A06B0275; Mon, 19 Aug 2019 11:58:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5D6FD6B0276; Mon, 19 Aug 2019 11:58:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0174.hostedemail.com [216.40.44.174]) by kanga.kvack.org (Postfix) with ESMTP id 3C2016B0272 for ; Mon, 19 Aug 2019 11:58:31 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id EAF26181AC9B4 for ; Mon, 19 Aug 2019 15:58:30 +0000 (UTC) X-FDA: 75839634780.27.story13_2d19a26978611 X-HE-Tag: story13_2d19a26978611 X-Filterd-Recvd-Size: 7018 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf20.hostedemail.com (Postfix) with ESMTP for ; Mon, 19 Aug 2019 15:58:29 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D4C5A344; Mon, 19 Aug 2019 08:58:28 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D1D7B3F718; Mon, 19 Aug 2019 08:58:26 -0700 (PDT) Date: Mon, 19 Aug 2019 16:58:24 +0100 From: Mark Rutland To: Pavel Tatashin Cc: jmorris@namei.org, sashal@kernel.org, ebiederm@xmission.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, corbet@lwn.net, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, marc.zyngier@arm.com, james.morse@arm.com, vladimir.murzin@arm.com, matthias.bgg@gmail.com, bhsharma@redhat.com, linux-mm@kvack.org Subject: Re: [PATCH v2 03/14] arm64, hibernate: add trans_table public functions Message-ID: <20190819155824.GE9927@lakrids.cambridge.arm.com> References: <20190817024629.26611-1-pasha.tatashin@soleen.com> <20190817024629.26611-4-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190817024629.26611-4-pasha.tatashin@soleen.com> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Aug 16, 2019 at 10:46:18PM -0400, Pavel Tatashin wrote: > trans_table_create_copy() and trans_table_map_page() are going to be > the basis for public interface of new subsystem that handles page > tables for cases which are between kernels: kexec, and hibernate. While the architecture uses the term 'translation table', in the kernel we generally use 'pgdir' or 'pgd' to refer to the tables, so please keep to that naming scheme. For example, in arch/arm64/mm/mmu.c we have a somewhat analagous function called create_pgd_mapping() -- could we use that here, to crate the mapping? Thanks, Mark. > > Signed-off-by: Pavel Tatashin > --- > arch/arm64/kernel/hibernate.c | 96 ++++++++++++++++++++++------------- > 1 file changed, 61 insertions(+), 35 deletions(-) > > diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c > index 96b6f8da7e49..449d69b5651c 100644 > --- a/arch/arm64/kernel/hibernate.c > +++ b/arch/arm64/kernel/hibernate.c > @@ -182,39 +182,15 @@ int arch_hibernation_header_restore(void *addr) > } > EXPORT_SYMBOL(arch_hibernation_header_restore); > > -/* > - * Copies length bytes, starting at src_start into an new page, > - * perform cache maintentance, then maps it at the specified address low > - * address as executable. > - * > - * This is used by hibernate to copy the code it needs to execute when > - * overwriting the kernel text. This function generates a new set of page > - * tables, which it loads into ttbr0. > - * > - * Length is provided as we probably only want 4K of data, even on a 64K > - * page system. > - */ > -static int create_safe_exec_page(void *src_start, size_t length, > - unsigned long dst_addr, > - phys_addr_t *phys_dst_addr) > +int trans_table_map_page(pgd_t *trans_table, void *page, > + unsigned long dst_addr, > + pgprot_t pgprot) > { > - void *page = (void *)get_safe_page(GFP_ATOMIC); > - pgd_t *trans_table; > pgd_t *pgdp; > pud_t *pudp; > pmd_t *pmdp; > pte_t *ptep; > > - if (!page) > - return -ENOMEM; > - > - memcpy((void *)page, src_start, length); > - __flush_icache_range((unsigned long)page, (unsigned long)page + length); > - > - trans_table = (void *)get_safe_page(GFP_ATOMIC); > - if (!trans_table) > - return -ENOMEM; > - > pgdp = pgd_offset_raw(trans_table, dst_addr); > if (pgd_none(READ_ONCE(*pgdp))) { > pudp = (void *)get_safe_page(GFP_ATOMIC); > @@ -242,6 +218,44 @@ static int create_safe_exec_page(void *src_start, size_t length, > ptep = pte_offset_kernel(pmdp, dst_addr); > set_pte(ptep, pfn_pte(virt_to_pfn(page), PAGE_KERNEL_EXEC)); > > + return 0; > +} > + > +/* > + * Copies length bytes, starting at src_start into an new page, > + * perform cache maintentance, then maps it at the specified address low > + * address as executable. > + * > + * This is used by hibernate to copy the code it needs to execute when > + * overwriting the kernel text. This function generates a new set of page > + * tables, which it loads into ttbr0. > + * > + * Length is provided as we probably only want 4K of data, even on a 64K > + * page system. > + */ > +static int create_safe_exec_page(void *src_start, size_t length, > + unsigned long dst_addr, > + phys_addr_t *phys_dst_addr) > +{ > + void *page = (void *)get_safe_page(GFP_ATOMIC); > + pgd_t *trans_table; > + int rc; > + > + if (!page) > + return -ENOMEM; > + > + memcpy(page, src_start, length); > + __flush_icache_range((unsigned long)page, (unsigned long)page + length); > + > + trans_table = (void *)get_safe_page(GFP_ATOMIC); > + if (!trans_table) > + return -ENOMEM; > + > + rc = trans_table_map_page(trans_table, page, dst_addr, > + PAGE_KERNEL_EXEC); > + if (rc) > + return rc; > + > /* > * Load our new page tables. A strict BBM approach requires that we > * ensure that TLBs are free of any entries that may overlap with the > @@ -259,7 +273,7 @@ static int create_safe_exec_page(void *src_start, size_t length, > write_sysreg(phys_to_ttbr(virt_to_phys(trans_table)), ttbr0_el1); > isb(); > > - *phys_dst_addr = virt_to_phys((void *)page); > + *phys_dst_addr = virt_to_phys(page); > > return 0; > } > @@ -462,6 +476,24 @@ static int copy_page_tables(pgd_t *dst_pgdp, unsigned long start, > return 0; > } > > +int trans_table_create_copy(pgd_t **dst_pgdp, unsigned long start, > + unsigned long end) > +{ > + int rc; > + pgd_t *trans_table = (pgd_t *)get_safe_page(GFP_ATOMIC); > + > + if (!trans_table) { > + pr_err("Failed to allocate memory for temporary page tables.\n"); > + return -ENOMEM; > + } > + > + rc = copy_page_tables(trans_table, start, end); > + if (!rc) > + *dst_pgdp = trans_table; > + > + return rc; > +} > + > /* > * Setup then Resume from the hibernate image using swsusp_arch_suspend_exit(). > * > @@ -483,13 +515,7 @@ int swsusp_arch_resume(void) > * Create a second copy of just the linear map, and use this when > * restoring. > */ > - tmp_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC); > - if (!tmp_pg_dir) { > - pr_err("Failed to allocate memory for temporary page tables.\n"); > - rc = -ENOMEM; > - goto out; > - } > - rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, 0); > + rc = trans_table_create_copy(&tmp_pg_dir, PAGE_OFFSET, 0); > if (rc) > goto out; > > -- > 2.22.1 >