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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 3D8FAC43460 for ; Fri, 30 Apr 2021 05:58:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 25BD061490 for ; Fri, 30 Apr 2021 05:58:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230343AbhD3F7F (ORCPT ); Fri, 30 Apr 2021 01:59:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:52182 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230326AbhD3F7C (ORCPT ); Fri, 30 Apr 2021 01:59:02 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D0A1861459; Fri, 30 Apr 2021 05:58:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1619762294; bh=gw3wBljSCRXHRTHUZs4KMX9Q7f8d65AU/L1D7oBwq/g=; h=Date:From:To:Subject:In-Reply-To:From; b=qn/TT4BlE8VSRc1K4Ya71puzCP3PyxyKn8o+TI4ta54bT78Qqt1N2PZykqviYZ6OB I72wTJgdLqZjzpJOqzuo4hvEyu0BZAF1d2R2mdg3yidMnClSK5brMaDhnpP3GXBBbT yqJ3m7Pk6RDqcZeX4iYhr9LUjuyNrqtp15VGAL98= Date: Thu, 29 Apr 2021 22:58:13 -0700 From: Andrew Morton To: akpm@linux-foundation.org, bp@alien8.de, catalin.marinas@arm.com, davem@davemloft.net, dingtianhong@huawei.com, hch@lst.de, hpa@zytor.com, linmiaohe@huawei.com, linux-mm@kvack.org, linux@armlinux.org.uk, mingo@redhat.com, mm-commits@vger.kernel.org, mpe@ellerman.id.au, npiggin@gmail.com, sfr@canb.auug.org.au, tglx@linutronix.de, torvalds@linux-foundation.org, urezki@gmail.com, will@kernel.org Subject: [patch 098/178] mm/vmalloc: fix HUGE_VMAP regression by enabling huge pages in vmalloc_to_page Message-ID: <20210430055813.sm9dCohvJ%akpm@linux-foundation.org> In-Reply-To: <20210429225251.02b6386d21b69255b4f6c163@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Nicholas Piggin Subject: mm/vmalloc: fix HUGE_VMAP regression by enabling huge pages in vmalloc_to_page vmalloc_to_page returns NULL for addresses mapped by larger pages[*]. Whether or not a vmap is huge depends on the architecture details, alignments, boot options, etc., which the caller can not be expected to know. Therefore HUGE_VMAP is a regression for vmalloc_to_page. This change teaches vmalloc_to_page about larger pages, and returns the struct page that corresponds to the offset within the large page. This makes the API agnostic to mapping implementation details. [*] As explained by commit 029c54b095995 ("mm/vmalloc.c: huge-vmap: fail gracefully on unexpected huge vmap mappings") [npiggin@gmail.com: sparc32: add stub pud_page define for walking huge vmalloc page tables] Link: https://lkml.kernel.org/r/20210324232825.1157363-1-npiggin@gmail.com Link: https://lkml.kernel.org/r/20210317062402.533919-3-npiggin@gmail.com Signed-off-by: Nicholas Piggin Reviewed-by: Miaohe Lin Reviewed-by: Christoph Hellwig Cc: Borislav Petkov Cc: Catalin Marinas Cc: Ding Tianhong Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Michael Ellerman Cc: Russell King Cc: Thomas Gleixner Cc: Uladzislau Rezki (Sony) Cc: Will Deacon Cc: Stephen Rothwell Cc: David S. Miller Signed-off-by: Andrew Morton --- arch/sparc/include/asm/pgtable_32.h | 3 + mm/vmalloc.c | 41 ++++++++++++++++---------- 2 files changed, 29 insertions(+), 15 deletions(-) --- a/arch/sparc/include/asm/pgtable_32.h~mm-vmalloc-fix-huge_vmap-regression-by-enabling-huge-pages-in-vmalloc_to_page +++ a/arch/sparc/include/asm/pgtable_32.h @@ -321,6 +321,9 @@ static inline pte_t pte_modify(pte_t pte pgprot_val(newprot)); } +/* only used by the huge vmap code, should never be called */ +#define pud_page(pud) NULL + struct seq_file; void mmu_info(struct seq_file *m); --- a/mm/vmalloc.c~mm-vmalloc-fix-huge_vmap-regression-by-enabling-huge-pages-in-vmalloc_to_page +++ a/mm/vmalloc.c @@ -34,7 +34,7 @@ #include #include #include - +#include #include #include #include @@ -343,7 +343,9 @@ int is_vmalloc_or_module_addr(const void } /* - * Walk a vmap address to the struct page it maps. + * Walk a vmap address to the struct page it maps. Huge vmap mappings will + * return the tail page that corresponds to the base page address, which + * matches small vmap mappings. */ struct page *vmalloc_to_page(const void *vmalloc_addr) { @@ -363,25 +365,33 @@ struct page *vmalloc_to_page(const void if (pgd_none(*pgd)) return NULL; + if (WARN_ON_ONCE(pgd_leaf(*pgd))) + return NULL; /* XXX: no allowance for huge pgd */ + if (WARN_ON_ONCE(pgd_bad(*pgd))) + return NULL; + p4d = p4d_offset(pgd, addr); if (p4d_none(*p4d)) return NULL; - pud = pud_offset(p4d, addr); + if (p4d_leaf(*p4d)) + return p4d_page(*p4d) + ((addr & ~P4D_MASK) >> PAGE_SHIFT); + if (WARN_ON_ONCE(p4d_bad(*p4d))) + return NULL; - /* - * Don't dereference bad PUD or PMD (below) entries. This will also - * identify huge mappings, which we may encounter on architectures - * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be - * identified as vmalloc addresses by is_vmalloc_addr(), but are - * not [unambiguously] associated with a struct page, so there is - * no correct value to return for them. - */ - WARN_ON_ONCE(pud_bad(*pud)); - if (pud_none(*pud) || pud_bad(*pud)) + pud = pud_offset(p4d, addr); + if (pud_none(*pud)) + return NULL; + if (pud_leaf(*pud)) + return pud_page(*pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); + if (WARN_ON_ONCE(pud_bad(*pud))) return NULL; + pmd = pmd_offset(pud, addr); - WARN_ON_ONCE(pmd_bad(*pmd)); - if (pmd_none(*pmd) || pmd_bad(*pmd)) + if (pmd_none(*pmd)) + return NULL; + if (pmd_leaf(*pmd)) + return pmd_page(*pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); + if (WARN_ON_ONCE(pmd_bad(*pmd))) return NULL; ptep = pte_offset_map(pmd, addr); @@ -389,6 +399,7 @@ struct page *vmalloc_to_page(const void if (pte_present(pte)) page = pte_page(pte); pte_unmap(ptep); + return page; } EXPORT_SYMBOL(vmalloc_to_page); _