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([78.42.132.4]) by mrelayeu.kundenserver.de (mreue001) with ESMTPA (Nemesis) id 0Lcsbo-1a6Zhk1k3s-00iC2Z; Fri, 19 Feb 2016 17:20:04 +0100 From: Arnd Bergmann 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" 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> X-Mailer: git-send-email 2.7.0 X-Provags-ID: V03:K0:ce4LrQu+HIg1IHW5sj6DXmN31PSNmMi3fsGYyyI6U2obcHxvfXR TkrT8P179pXB3ZSZqbglw74j7OvdYgEPyZSi9a4b/MUp1HxR9q2wUurgFgJYIcFUqy+6NRR yM/yxUiVjrVQsHVCm002qrUWeFWdI2shuhGPnnEcKEAGi6CXIp5JQTYZ8E15qxH62T8Uelf 1d09Qt+VUwmy7eoymPofQ== X-UI-Out-Filterresults: notjunk:1; V01:K0:50qwXyiJjGg=:p9udZDoSw0GQxr+grYy4KL ouo1Savg5zP9Rajp7exwQWJgIs7DQcIrZYxcIvPSzNgs46xqGhNnzqCxAi50ktz2FQjH86dWx oJ9vHMbSN1ZDcGUIUAuiNem7sg17afTg3UzB0+HJtPZPC40OHUHaywi+nGDHonyxSo/u9NiQP zhSaL1MYu0kfz30Gt9TAeFLde2G0hBfKbaTGH4Rj9xin0dVwsoEnKjeLYodIs4R2WTXNTXEXs /mJWZ8Eg/DD69++LqcrGMf8Z6l8EPXlD5AiN1GPxN5J9MeAz6Ts4IXF4g4lfcmn+1YED7QOJr 4MU0wJT9zyV4BiY1FWRNqo5XJZ+842dIydGWT3JdwSwbtOM8BsEM8iw70zzLfhF2evzCseMV6 mX/9ViIW5MF93nTnvSDoFbsCRP7VqaqNHsZZaQn0j92FNM+X6b7OhIKRz95bFHRc/O3S3nPiY 6qXoc+DjAhJ6PtovWfGbPJURzWfknl7DlCs7F7nkAZd6ORuDZn2b+bmHZRBDmCR3DBwZUTyJA 9ZG4nfkwGocaHe/fHb40uQ+8qPXLBSklMIh+L0W2M+OSJD2IqUZgTpw0INqEeCiHFvjhgwWvz 1SaxhhF/6LfWKTj+ZNYOaHOGisVq4uumn/mfWWNx7UkmniVNJHTEBfvPdDRjRCq683yVuguPz /PVgKXA4XvkDMtwlKb/TZhuy5peZCc3AzWPsn/6NBL7cb58WE8z7t+MJOuP1XLnz0lBA= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(-) -- 2.7.0 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)