From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f50.google.com (mail-lf0-f50.google.com [209.85.215.50]) by kanga.kvack.org (Postfix) with ESMTP id D0EB36B0005 for ; Fri, 19 Feb 2016 11:20:13 -0500 (EST) Received: by mail-lf0-f50.google.com with SMTP id 78so57084890lfy.3 for ; Fri, 19 Feb 2016 08:20:13 -0800 (PST) Received: from mout.kundenserver.de (mout.kundenserver.de. [212.227.126.134]) by mx.google.com with ESMTPS id 76si7086998lfy.115.2016.02.19.08.20.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 Feb 2016 08:20:12 -0800 (PST) From: Arnd Bergmann Subject: [PATCH v2] [RFC] ARM: modify pgd_t definition for TRANSPARENT_HUGEPAGE_PUD Date: Fri, 19 Feb 2016 17:19:35 +0100 Message-Id: <1455898786-2720743-1-git-send-email-arnd@arndb.de> Sender: owner-linux-mm@kvack.org List-ID: To: Russell King Cc: linux-arm-kernel@lists.infradead.org, Arnd Bergmann , Sam Ravnborg , Andrew Morton , Matthew Wilcox , Jan Kara , "Kirill A. Shutemov" , Ross Zwisler , Dan Williams , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, "David S. Miller" I ran into build errors on ARM after Willy's newly added generic TRANSPARENT_HUGEPAGE_PUD support. We don't support this feature on ARM at all, but the patch causes a build error anyway: In file included from ../kernel/memremap.c:17:0: ../include/linux/pfn_t.h:108:7: error: 'pud_mkdevmap' declared as function returning an array pud_t pud_mkdevmap(pud_t pud); We don't use a PUD on ARM, so pud_t is defined as pmd_t, which in turn is defined as typedef unsigned long pgd_t[2]; on NOMMU and on 2-level MMU configurations. There is an (unused) other definition using a struct around the array, which happens to work fine here. There is a comment in the file about the fact the other version is "easier on the compiler", and I've traced that version back to linux-2.1.80 when ARM support was first merged back in 1998. It's probably a safe assumption that this is no longer necessary: The same logic existed in asm-i386 at the time but was removed a year later in 2.3.23pre3. The STRICT_MM_TYPECHECKS logic also ended up getting copied into other architectures, which use them in various ways: * both defined, but using strict: arch/alpha/include/asm/page.h:#define STRICT_MM_TYPECHECKS arch/sparc/include/asm/page_64.h:#define STRICT_MM_TYPECHECKS arch/ia64/include/asm/page.h:# define STRICT_MM_TYPECHECKS arch/parisc/include/asm/page.h:#define STRICT_MM_TYPECHECKS * both defined, but using non-strict: arch/arc/include/asm/page.h:#undef STRICT_MM_TYPECHECKS arch/arm/include/asm/pgtable-2level-types.h:#undef STRICT_MM_TYPECHECKS arch/arm/include/asm/pgtable-3level-types.h:#undef STRICT_MM_TYPECHECKS arch/arm64/include/asm/pgtable-types.h:#undef STRICT_MM_TYPECHECKS arch/sparc/include/asm/page_32.h:/* #define STRICT_MM_TYPECHECKS */ arch/unicore32/include/asm/page.h:#undef STRICT_MM_TYPECHECKS * Kconfig option: arch/powerpc/Kconfig.debug:config STRICT_MM_TYPECHECKS default n Everthing else uses only the strict definitions. For the moment, this only does the minimal change to fix things on ARM in linux-next. At least in case of sparc32, passing structs to functions is traditionally inefficient and the non-strict version should be kept, whether we change any of the other architectures depends on further testing. Signed-off-by: Arnd Bergmann Fixes: a27da20ed50e ("mm: add support for PUD-sized transparent hugepages") Link: http://www.spinics.net/lists/linux-mm/msg101404.html --- arch/arm/include/asm/page-nommu.h | 4 ++-- arch/arm/include/asm/pgtable-2level-types.h | 7 +++---- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/arm/include/asm/page-nommu.h b/arch/arm/include/asm/page-nommu.h index d1b162a18dcb..3db1ca22fecb 100644 --- a/arch/arm/include/asm/page-nommu.h +++ b/arch/arm/include/asm/page-nommu.h @@ -31,12 +31,12 @@ */ typedef unsigned long pte_t; typedef unsigned long pmd_t; -typedef unsigned long pgd_t[2]; +typedef struct { unsigned long pgd[2]; } pgd_t; typedef unsigned long pgprot_t; #define pte_val(x) (x) #define pmd_val(x) (x) -#define pgd_val(x) ((x)[0]) +#define pgd_val(x) ((x).pgd[0]) #define pgprot_val(x) (x) #define __pte(x) (x) diff --git a/arch/arm/include/asm/pgtable-2level-types.h b/arch/arm/include/asm/pgtable-2level-types.h index 66cb5b0e89c5..9b9815d5ebd6 100644 --- a/arch/arm/include/asm/pgtable-2level-types.h +++ b/arch/arm/include/asm/pgtable-2level-types.h @@ -24,6 +24,9 @@ typedef u32 pteval_t; typedef u32 pmdval_t; +typedef struct { pmdval_t pgd[2]; } pgd_t; +#define pgd_val(x) ((x).pgd[0]) + #undef STRICT_MM_TYPECHECKS #ifdef STRICT_MM_TYPECHECKS @@ -32,12 +35,10 @@ typedef u32 pmdval_t; */ typedef struct { pteval_t pte; } pte_t; typedef struct { pmdval_t pmd; } pmd_t; -typedef struct { pmdval_t pgd[2]; } pgd_t; typedef struct { pteval_t pgprot; } pgprot_t; #define pte_val(x) ((x).pte) #define pmd_val(x) ((x).pmd) -#define pgd_val(x) ((x).pgd[0]) #define pgprot_val(x) ((x).pgprot) #define __pte(x) ((pte_t) { (x) } ) @@ -50,12 +51,10 @@ typedef struct { pteval_t pgprot; } pgprot_t; */ typedef pteval_t pte_t; typedef pmdval_t pmd_t; -typedef pmdval_t pgd_t[2]; typedef pteval_t pgprot_t; #define pte_val(x) (x) #define pmd_val(x) (x) -#define pgd_val(x) ((x)[0]) #define pgprot_val(x) (x) #define __pte(x) (x) -- 2.7.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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