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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 DFA28ECE562 for ; Mon, 17 Sep 2018 08:49:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8DD79214C4 for ; Mon, 17 Sep 2018 08:49:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8DD79214C4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728250AbeIQOPy (ORCPT ); Mon, 17 Sep 2018 10:15:54 -0400 Received: from mx2.suse.de ([195.135.220.15]:44992 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727562AbeIQOPx (ORCPT ); Mon, 17 Sep 2018 10:15:53 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 9FE3FAF05; Mon, 17 Sep 2018 08:49:25 +0000 (UTC) Subject: Re: [PATCH v2] x86/mm: Expand static page table for fixmap space To: Feng Tang , Thomas Gleixner , Ingo Molnar , H Peter Anvin , Peter Zijlstra , Michal Hocko , x86@kernel.org, linux-kernel@vger.kernel.org, Yinghai Lu , Dave Hansen , Andi Kleen References: <20180917083952.27589-1-feng.tang@intel.com> From: Juergen Gross Openpgp: preference=signencrypt Autocrypt: addr=jgross@suse.com; prefer-encrypt=mutual; keydata= xsBNBFOMcBYBCACgGjqjoGvbEouQZw/ToiBg9W98AlM2QHV+iNHsEs7kxWhKMjrioyspZKOB ycWxw3ie3j9uvg9EOB3aN4xiTv4qbnGiTr3oJhkB1gsb6ToJQZ8uxGq2kaV2KL9650I1SJve dYm8Of8Zd621lSmoKOwlNClALZNew72NjJLEzTalU1OdT7/i1TXkH09XSSI8mEQ/ouNcMvIJ NwQpd369y9bfIhWUiVXEK7MlRgUG6MvIj6Y3Am/BBLUVbDa4+gmzDC9ezlZkTZG2t14zWPvx XP3FAp2pkW0xqG7/377qptDmrk42GlSKN4z76ELnLxussxc7I2hx18NUcbP8+uty4bMxABEB AAHNHkp1ZXJnZW4gR3Jvc3MgPGpncm9zc0BzdXNlLmRlPsLAeQQTAQIAIwUCU4xw6wIbAwcL CQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJELDendYovxMvi4UH/Ri+OXlObzqMANruTd4N zmVBAZgx1VW6jLc8JZjQuJPSsd/a+bNr3BZeLV6lu4Pf1Yl2Log129EX1KWYiFFvPbIiq5M5 kOXTO8Eas4CaScCvAZ9jCMQCgK3pFqYgirwTgfwnPtxFxO/F3ZcS8jovza5khkSKL9JGq8Nk czDTruQ/oy0WUHdUr9uwEfiD9yPFOGqp4S6cISuzBMvaAiC5YGdUGXuPZKXLpnGSjkZswUzY d9BVSitRL5ldsQCg6GhDoEAeIhUC4SQnT9SOWkoDOSFRXZ+7+WIBGLiWMd+yKDdRG5RyP/8f 3tgGiB6cyuYfPDRGsELGjUaTUq3H2xZgIPfOwE0EU4xwFgEIAMsx+gDjgzAY4H1hPVXgoLK8 B93sTQFN9oC6tsb46VpxyLPfJ3T1A6Z6MVkLoCejKTJ3K9MUsBZhxIJ0hIyvzwI6aYJsnOew cCiCN7FeKJ/oA1RSUemPGUcIJwQuZlTOiY0OcQ5PFkV5YxMUX1F/aTYXROXgTmSaw0aC1Jpo w7Ss1mg4SIP/tR88/d1+HwkJDVW1RSxC1PWzGizwRv8eauImGdpNnseneO2BNWRXTJumAWDD pYxpGSsGHXuZXTPZqOOZpsHtInFyi5KRHSFyk2Xigzvh3b9WqhbgHHHE4PUVw0I5sIQt8hJq 5nH5dPqz4ITtCL9zjiJsExHuHKN3NZsAEQEAAcLAXwQYAQIACQUCU4xwFgIbDAAKCRCw3p3W KL8TL0P4B/9YWver5uD/y/m0KScK2f3Z3mXJhME23vGBbMNlfwbr+meDMrJZ950CuWWnQ+d+ Ahe0w1X7e3wuLVODzjcReQ/v7b4JD3wwHxe+88tgB9byc0NXzlPJWBaWV01yB2/uefVKryAf AHYEd0gCRhx7eESgNBe3+YqWAQawunMlycsqKa09dBDL1PFRosF708ic9346GLHRc6Vj5SRA UTHnQqLetIOXZm3a2eQ1gpQK9MmruO86Vo93p39bS1mqnLLspVrL4rhoyhsOyh0Hd28QCzpJ wKeHTd0MAWAirmewHXWPco8p1Wg+V+5xfZzuQY0f4tQxvOpXpt4gQ1817GQ5/Ed/wsDtBBgB CAAgFiEEhRJncuj2BJSl0Jf3sN6d1ii/Ey8FAlrd8NACGwIAgQkQsN6d1ii/Ey92IAQZFggA HRYhBFMtsHpB9jjzHji4HoBcYbtP2GO+BQJa3fDQAAoJEIBcYbtP2GO+TYsA/30H/0V6cr/W V+J/FCayg6uNtm3MJLo4rE+o4sdpjjsGAQCooqffpgA+luTT13YZNV62hAnCLKXH9n3+ZAgJ RtAyDWk1B/0SMDVs1wxufMkKC3Q/1D3BYIvBlrTVKdBYXPxngcRoqV2J77lscEvkLNUGsu/z W2pf7+P3mWWlrPMJdlbax00vevyBeqtqNKjHstHatgMZ2W0CFC4hJ3YEetuRBURYPiGzuJXU pAd7a7BdsqWC4o+GTm5tnGrCyD+4gfDSpkOT53S/GNO07YkPkm/8J4OBoFfgSaCnQ1izwgJQ jIpcG2fPCI2/hxf2oqXPYbKr1v4Z1wthmoyUgGN0LPTIm+B5vdY82wI5qe9uN6UOGyTH2B3p hRQUWqCwu2sqkI3LLbTdrnyDZaixT2T0f4tyF5Lfs+Ha8xVMhIyzNb1byDI5FKCb Message-ID: <222318c7-7b12-66fd-4405-e19a2acb0cf8@suse.com> Date: Mon, 17 Sep 2018 10:49:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180917083952.27589-1-feng.tang@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/09/18 10:39, Feng Tang wrote: > We met a kernel panic when enabling earlycon, which is due to > the fixmap address of earlycon is not statically setup. > > Currently the static fixmap setup in head_64.S only covers 2M > virtual address space, while it acutually could be in 4M space > with different kernel configurations. > > So increase the static space to 4M for now by defining FIXMAP_PMD_NUM > to 2, and add a build time check for future possible overflow so that > the macro could be increased accordingly. > > Suggested-by: Thomas Gleixner > Signed-off-by: Feng Tang > --- > arch/x86/include/asm/fixmap.h | 3 +++ > arch/x86/include/asm/pgtable_64.h | 3 ++- > arch/x86/kernel/head_64.S | 16 ++++++++++++---- > arch/x86/mm/pgtable.c | 10 ++++++++++ > arch/x86/xen/mmu_pv.c | 7 +++++-- > 5 files changed, 32 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h > index e203169..ffaa0fa 100644 > --- a/arch/x86/include/asm/fixmap.h > +++ b/arch/x86/include/asm/fixmap.h > @@ -14,6 +14,9 @@ > #ifndef _ASM_X86_FIXMAP_H > #define _ASM_X86_FIXMAP_H > > +/* Put here to be accessble for assembly code like head_64.S */ > +#define FIXMAP_PMD_NUM 2 > + > #ifndef __ASSEMBLY__ > #include > #include > diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h > index ce2b590..9c85b54 100644 > --- a/arch/x86/include/asm/pgtable_64.h > +++ b/arch/x86/include/asm/pgtable_64.h > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > > extern p4d_t level4_kernel_pgt[512]; > extern p4d_t level4_ident_pgt[512]; > @@ -22,7 +23,7 @@ extern pud_t level3_ident_pgt[512]; > extern pmd_t level2_kernel_pgt[512]; > extern pmd_t level2_fixmap_pgt[512]; > extern pmd_t level2_ident_pgt[512]; > -extern pte_t level1_fixmap_pgt[512]; > +extern pte_t level1_fixmap_pgt[512 * FIXMAP_PMD_NUM]; > extern pgd_t init_top_pgt[]; > > #define swapper_pg_dir init_top_pgt > diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S > index 15ebc2f..a3618cf 100644 > --- a/arch/x86/kernel/head_64.S > +++ b/arch/x86/kernel/head_64.S > @@ -24,6 +24,7 @@ > #include "../entry/calling.h" > #include > #include > +#include > > #ifdef CONFIG_PARAVIRT > #include > @@ -445,13 +446,20 @@ NEXT_PAGE(level2_kernel_pgt) > KERNEL_IMAGE_SIZE/PMD_SIZE) > > NEXT_PAGE(level2_fixmap_pgt) > - .fill 506,8,0 > - .quad level1_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC > - /* 8MB reserved for vsyscalls + a 2MB hole = 4 + 1 entries */ > - .fill 5,8,0 > + .fill (512 - 4 - FIXMAP_PMD_NUM),8,0 > + pgtno = 0 > + .rept (FIXMAP_PMD_NUM) > + .quad level1_fixmap_pgt + (pgtno << PAGE_SHIFT) - __START_KERNEL_map \ > + + _PAGE_TABLE_NOENC; > + pgtno = pgtno + 1 > + .endr > + /* 6 MB reserved space + a 2MB hole */ > + .fill 4,8,0 > > NEXT_PAGE(level1_fixmap_pgt) > + .rept (FIXMAP_PMD_NUM) > .fill 512,8,0 > + .endr > > #undef PMDS > > diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c > index ae39455..a4052b1 100644 > --- a/arch/x86/mm/pgtable.c > +++ b/arch/x86/mm/pgtable.c > @@ -637,6 +637,16 @@ void __native_set_fixmap(enum fixed_addresses idx, pte_t pte) > { > unsigned long address = __fix_to_virt(idx); > > +#ifdef CONFIG_X86_64 > + /* > + * In arch/x86/kernel/head_64.S, the static page table has > + * been setup for fixmap. Add a sanity compiling check > + * whether fixmap space has exceeded the capacity. > + */ > + BUILD_BUG_ON(__end_of_permanent_fixed_addresses > + > (FIXMAP_PMD_NUM * PTRS_PER_PMD)); > +#endif > + > if (idx >= __end_of_fixed_addresses) { > BUG(); > return; > diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c > index 2fe5c9b..74c4e17 100644 > --- a/arch/x86/xen/mmu_pv.c > +++ b/arch/x86/xen/mmu_pv.c > @@ -1907,7 +1907,7 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) > /* L3_k[511] -> level2_fixmap_pgt */ > convert_pfn_mfn(level3_kernel_pgt); > > - /* L3_k[511][506] -> level1_fixmap_pgt */ > + /* L3_k[507, 508 - FIXMAP_PMD_NUM] -> level1_fixmap_pgt */ You messed up the comment. The [511] must not be dropped. I would swap the "508 - FIXMAP_PMD_NUM" and "507" in order to start with the lower index, and replace "," by "...": + /* L3_k[511][508-FIXMAP_PMD_NUM ... 507] -> level1_fixmap_pgt */ With that corrected you can have my: Reviewed-by: Juergen Gross (Xen parts) Juergen