Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934353AbcCNO1m (ORCPT ); Mon, 14 Mar 2016 10:27:42 -0400 Received: from mail-wm0-f54.google.com ([74.125.82.54]:32905 "EHLO mail-wm0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932102AbcCNO1i (ORCPT ); Mon, 14 Mar 2016 10:27:38 -0400 Date: Mon, 14 Mar 2016 14:27:34 +0000 From: Matt Fleming To: Ingo Molnar Cc: Scott Ashcroft , "H . Peter Anvin" , Thomas Gleixner , Ard Biesheuvel , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, Maarten Lankhorst , Matthew Garrett , Borislav Petkov , Ben Hutchings , Raphael Hertzog , Roger Shimizu , Alexis Murzeau , Julia Lawall Subject: Re: [PATCH] x86/efi: Always map boot service regions into new EFI page tables Message-ID: <20160314142734.GE2619@codeblueprint.co.uk> References: <1457695163-29632-1-git-send-email-matt@codeblueprint.co.uk> <1457695163-29632-2-git-send-email-matt@codeblueprint.co.uk> <1457888975.3884.9.camel@talk21.com> <20160313215847.GA2619@codeblueprint.co.uk> <20160313230736.GB2619@codeblueprint.co.uk> <20160314103019.GA32573@gmail.com> <20160314113502.GC2619@codeblueprint.co.uk> <20160314120502.GA17388@gmail.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="tKW2IUtsqtDRztdT" Content-Disposition: inline In-Reply-To: <20160314120502.GA17388@gmail.com> User-Agent: Mutt/1.5.24+41 (02bc14ed1569) (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6455 Lines: 123 --tKW2IUtsqtDRztdT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, 14 Mar, at 01:05:02PM, Ingo Molnar wrote: > > There's a number of such occurences that look suspicious: > > triton:~/tip> git grep 'cpa->pfn.*<<.*PAGE_SHIFT' arch/x86/ > arch/x86/mm/pageattr.c: set_pmd(pmd, __pmd(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | > arch/x86/mm/pageattr.c: set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | > arch/x86/mm/pageattr.c: unsigned long laddr = (unsigned long)__va(cpa->pfn << PAGE_SHIFT); > arch/x86/mm/pageattr.c: unsigned long temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) + > > are you sure none of the code runs on 32-bit? The following occurrences do not run on 32-bit, > arch/x86/mm/pageattr.c: set_pmd(pmd, __pmd(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | > arch/x86/mm/pageattr.c: set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | but these might, > arch/x86/mm/pageattr.c: unsigned long laddr = (unsigned long)__va(cpa->pfn << PAGE_SHIFT); > arch/x86/mm/pageattr.c: unsigned long temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) + > All this got introduced with: > > | commit edc3b9129cecd0f0857112136f5b8b1bc1d45918 > | Author: Matt Fleming > | Date: Fri Nov 27 21:09:31 2015 +0000 > | > | x86/mm/pat: Ensure cpa->pfn only contains page frame numbers > > AFAICS. Kinda. The bugs that do not run on 32-bit were introduced with this commit. The ones that will run on 32-bit existed before this. Running the attached semantic patch across arch/x86/mm yields a few more places where we get the data type wrong for PAE, * file: arch/x86/mm/mmap.c:43 shifting int '( ( - 1UL ) & STACK_RND_MASK )' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/pageattr-test.c:57 shifting long 'i' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr-test.c:138 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/gup.c:422 shifting int 'nr' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/gup.c:303 shifting unsigned long '( unsigned long ) nr_pages' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/gup.c:370 shifting unsigned long '( unsigned long ) nr_pages' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pat.c:751 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr-test.c:57 shifting long 'i' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:947 shifting unsigned 'num_pages' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/pageattr.c:1995 shifting unsigned 'numpages' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/pageattr-test.c:138 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1117 shifting unsigned long 'cpa -> numpages' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1017 shifting unsigned long 'cpa -> numpages' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1277 shifting unsigned long 'cpa -> pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1318 shifting unsigned long 'cpa -> pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:986 shifting unsigned long 'cpa -> pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/pageattr.c:1059 shifting unsigned long 'cpa -> pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:197 shifting unsigned long 'end_pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:100 shifting unsigned long 'min_pfn_mapped' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:641 shifting unsigned long 'pagenr' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:111 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:121 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:111 shifting unsigned long __initdata 'pgt_buf_end' by PAGE_SHIFT is truncated to 32-bits * file: arch/x86/mm/init.c:196 shifting unsigned long 'start_pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:91 shifting unsigned long '( unsigned long ) num' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init.c:117 shifting unsigned long '( pfn + i )' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:293 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:301 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:344 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:361 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE * file: arch/x86/mm/init_32.c:471 shifting unsigned long 'pfn' by PAGE_SHIFT is truncated to 32-bits for PAE The coccinelle script isn't perfect, and there are a number of false positives. For example, the first hit is bogus and looks like a coccinelle bug, but the results do show some things that need to be investigated. Running it over arch/x86/ turns up 66 potential issues. --tKW2IUtsqtDRztdT Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="page-shift.cocci" // A variable declared as a 32-bit data type should not be shifted by // PAGE_SHIFT because the result may not fit in sizeof(T) for large // numbers of pages, or high page frame numbers, e.g. both of these // are potentially bogus: // // unsigned long pfn; // unsigned int numpages; // ... // unsigned long pa = pfn << PAGE_SHIFT; // unsigned long size = numpages << PAGE_SHIFT; // // Options: --no-includes --include-headers virtual context virtual report virtual org @inttrunc@ {int, unsigned int, size_t, signed int, long, unsigned long, signed long} i; position p; type tt; tt i1; @@ \(i@p\&i1\) << PAGE_SHIFT @script:python@ p << inttrunc.p; i << inttrunc.i; tt << inttrunc.tt; @@ pae_types = ["unsigned long", "signed long", "long"] print "* file: %s:%s shifting %s '%s' by PAGE_SHIFT is truncated to 32-bits%s" % \ (p[0].file, p[0].line, tt, i, \ " for PAE" if tt in pae_types else "") --tKW2IUtsqtDRztdT--