Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760128AbcDEVC4 (ORCPT ); Tue, 5 Apr 2016 17:02:56 -0400 Received: from mail-pa0-f54.google.com ([209.85.220.54]:34503 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752482AbcDEVCy (ORCPT ); Tue, 5 Apr 2016 17:02:54 -0400 Date: Tue, 5 Apr 2016 14:02:49 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Andrew Morton cc: "Kirill A. Shutemov" , Andrea Arcangeli , Andres Lagar-Cavilla , Yang Shi , Ning Qu , Arnd Bergman , Ralf Baechle , Vineet Gupta , Russell King , Will Deacon , Michael Ellerman , "Aneesh Kumar K.V" , Martin Schwidefsky , Gerald Schaefer , David Miller , Chris Metcalf , Ingo Molnar , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 10/10] arch: fix has_transparent_hugepage() In-Reply-To: Message-ID: References: User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6555 Lines: 189 I've just discovered that the useful-sounding has_transparent_hugepage() is actually an architecture-dependent minefield: on some arches it only builds if CONFIG_TRANSPARENT_HUGEPAGE=y, on others it's also there when not, but on some of those (arm and arm64) it then gives the wrong answer; and on mips alone it's marked __init, which would crash if called later (but so far it has not been called later). Straighten this out: make it available to all configs, with a sensible default in asm-generic/pgtable.h, removing its definitions from those arches (arc, arm, arm64, sparc, tile) which are served by the default, adding #define has_transparent_hugepage has_transparent_hugepage to those (mips, powerpc, s390, x86) which need to override the default at runtime, and removing the __init from mips (but maybe that kind of code should be avoided after init: set a static variable the first time it's called). Signed-off-by: Hugh Dickins --- arch/arc/include/asm/hugepage.h | 2 - arch/arm/include/asm/pgtable-3level.h | 5 ---- arch/arm64/include/asm/pgtable.h | 5 ---- arch/mips/include/asm/pgtable.h | 1 arch/mips/mm/tlb-r4k.c | 21 ++++++++--------- arch/powerpc/include/asm/book3s/64/pgtable.h | 1 arch/powerpc/include/asm/pgtable.h | 1 arch/s390/include/asm/pgtable.h | 1 arch/sparc/include/asm/pgtable_64.h | 2 - arch/tile/include/asm/pgtable.h | 1 arch/x86/include/asm/pgtable.h | 1 include/asm-generic/pgtable.h | 8 ++++++ 12 files changed, 23 insertions(+), 26 deletions(-) --- a/arch/arc/include/asm/hugepage.h +++ b/arch/arc/include/asm/hugepage.h @@ -61,8 +61,6 @@ static inline void set_pmd_at(struct mm_ extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd); -#define has_transparent_hugepage() 1 - /* Generic variants assume pgtable_t is struct page *, hence need for these */ #define __HAVE_ARCH_PGTABLE_DEPOSIT extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -281,11 +281,6 @@ static inline void set_pmd_at(struct mm_ flush_pmd_entry(pmdp); } -static inline int has_transparent_hugepage(void) -{ - return 1; -} - #endif /* __ASSEMBLY__ */ #endif /* _ASM_PGTABLE_3LEVEL_H */ --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -304,11 +304,6 @@ static inline pgprot_t mk_sect_prot(pgpr #define set_pmd_at(mm, addr, pmdp, pmd) set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd)) -static inline int has_transparent_hugepage(void) -{ - return 1; -} - #define __pgprot_modify(prot,mask,bits) \ __pgprot((pgprot_val(prot) & ~(mask)) | (bits)) --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -468,6 +468,7 @@ static inline int io_remap_pfn_range(str #ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define has_transparent_hugepage has_transparent_hugepage extern int has_transparent_hugepage(void); static inline int pmd_trans_huge(pmd_t pmd) --- a/arch/mips/mm/tlb-r4k.c +++ b/arch/mips/mm/tlb-r4k.c @@ -399,19 +399,20 @@ void add_wired_entry(unsigned long entry #ifdef CONFIG_TRANSPARENT_HUGEPAGE -int __init has_transparent_hugepage(void) +int has_transparent_hugepage(void) { - unsigned int mask; - unsigned long flags; + static unsigned int mask = -1; - local_irq_save(flags); - write_c0_pagemask(PM_HUGE_MASK); - back_to_back_c0_hazard(); - mask = read_c0_pagemask(); - write_c0_pagemask(PM_DEFAULT_MASK); - - local_irq_restore(flags); + if (mask == -1) { /* first call comes during __init */ + unsigned long flags; + local_irq_save(flags); + write_c0_pagemask(PM_HUGE_MASK); + back_to_back_c0_hazard(); + mask = read_c0_pagemask(); + write_c0_pagemask(PM_DEFAULT_MASK); + local_irq_restore(flags); + } return mask == PM_HUGE_MASK; } --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -219,6 +219,7 @@ extern void set_pmd_at(struct mm_struct pmd_t *pmdp, pmd_t pmd); extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd); +#define has_transparent_hugepage has_transparent_hugepage extern int has_transparent_hugepage(void); #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h @@ -65,7 +65,6 @@ extern int gup_hugepte(pte_t *ptep, unsi struct page **pages, int *nr); #ifndef CONFIG_TRANSPARENT_HUGEPAGE #define pmd_large(pmd) 0 -#define has_transparent_hugepage() 0 #endif pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, bool *is_thp, unsigned *shift); --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1223,6 +1223,7 @@ static inline int pmd_trans_huge(pmd_t p return pmd_val(pmd) & _SEGMENT_ENTRY_LARGE; } +#define has_transparent_hugepage has_transparent_hugepage static inline int has_transparent_hugepage(void) { return MACHINE_HAS_HPAGE ? 1 : 0; --- a/arch/sparc/include/asm/pgtable_64.h +++ b/arch/sparc/include/asm/pgtable_64.h @@ -681,8 +681,6 @@ static inline unsigned long pmd_trans_hu return pte_val(pte) & _PAGE_PMD_HUGE; } -#define has_transparent_hugepage() 1 - static inline pmd_t pmd_mkold(pmd_t pmd) { pte_t pte = __pte(pmd_val(pmd)); --- a/arch/tile/include/asm/pgtable.h +++ b/arch/tile/include/asm/pgtable.h @@ -487,7 +487,6 @@ static inline pmd_t pmd_modify(pmd_t pmd } #ifdef CONFIG_TRANSPARENT_HUGEPAGE -#define has_transparent_hugepage() 1 #define pmd_trans_huge pmd_huge_page #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -181,6 +181,7 @@ static inline int pmd_trans_huge(pmd_t p return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE; } +#define has_transparent_hugepage has_transparent_hugepage static inline int has_transparent_hugepage(void) { return cpu_has_pse; --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -806,4 +806,12 @@ static inline int pmd_clear_huge(pmd_t * #define io_remap_pfn_range remap_pfn_range #endif +#ifndef has_transparent_hugepage +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define has_transparent_hugepage() 1 +#else +#define has_transparent_hugepage() 0 +#endif +#endif + #endif /* _ASM_GENERIC_PGTABLE_H */