From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 2E83A6B02FA for ; Thu, 25 May 2017 16:34:28 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id a66so242847580pfl.6 for ; Thu, 25 May 2017 13:34:28 -0700 (PDT) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTPS id u195si29435729pgc.315.2017.05.25.13.34.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 25 May 2017 13:34:26 -0700 (PDT) From: "Kirill A. Shutemov" Subject: [PATCHv1, RFC 3/8] x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable Date: Thu, 25 May 2017 23:33:29 +0300 Message-Id: <20170525203334.867-4-kirill.shutemov@linux.intel.com> In-Reply-To: <20170525203334.867-1-kirill.shutemov@linux.intel.com> References: <20170525203334.867-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: Andi Kleen , Dave Hansen , Andy Lutomirski , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" For boot-time switching between 4- and 5-level paging we need to be able to fold p4d page table level at runtime. It requires variable PGDIR_SHIFT and PTRS_PER_P4D. Signed-off-by: Kirill A. Shutemov --- arch/x86/include/asm/pgtable_32.h | 2 ++ arch/x86/include/asm/pgtable_64_types.h | 7 +++++-- arch/x86/kernel/head64.c | 9 ++++++++- arch/x86/mm/dump_pagetables.c | 11 +++-------- arch/x86/mm/init_64.c | 2 +- arch/x86/platform/efi/efi_64.c | 4 ++-- 6 files changed, 21 insertions(+), 14 deletions(-) diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h index bfab55675c16..9c3c811347b0 100644 --- a/arch/x86/include/asm/pgtable_32.h +++ b/arch/x86/include/asm/pgtable_32.h @@ -32,6 +32,8 @@ static inline void pgtable_cache_init(void) { } static inline void check_pgt_cache(void) { } void paging_init(void); +static inline int pgd_large(pgd_t pgd) { return 0; } + /* * Define this if things work differently on an i386 and an i486: * it will (on an i486) warn about kernel memory accesses that are diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h index a9f77ead7088..a09f2fa91e09 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -19,6 +19,9 @@ typedef unsigned long pgprotval_t; typedef struct { pteval_t pte; } pte_t; +extern unsigned int pgdir_shift; +extern unsigned int ptrs_per_p4d; + #endif /* !__ASSEMBLY__ */ #define SHARED_KERNEL_PMD 0 @@ -28,14 +31,14 @@ typedef struct { pteval_t pte; } pte_t; /* * PGDIR_SHIFT determines what a top-level page table entry can map */ -#define PGDIR_SHIFT 48 +#define PGDIR_SHIFT pgdir_shift #define PTRS_PER_PGD 512 /* * 4th level page in 5-level paging case */ #define P4D_SHIFT 39 -#define PTRS_PER_P4D 512 +#define PTRS_PER_P4D ptrs_per_p4d #define P4D_SIZE (_AC(1, UL) << P4D_SHIFT) #define P4D_MASK (~(P4D_SIZE - 1)) diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 408ed402db1a..d4e8d4beeb62 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -38,6 +38,13 @@ extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD]; static unsigned int __initdata next_early_pgt; pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); +#ifdef CONFIG_X86_5LEVEL +unsigned int pgdir_shift = 48; +EXPORT_SYMBOL(pgdir_shift); +unsigned int ptrs_per_p4d = 512; +EXPORT_SYMBOL(ptrs_per_p4d); +#endif + #if defined(CONFIG_RANDOMIZE_MEMORY) || defined(CONFIG_X86_5LEVEL) unsigned long page_offset_base = __PAGE_OFFSET_BASE; EXPORT_SYMBOL(page_offset_base); @@ -273,7 +280,7 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0); BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0); BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); - BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == + MAYBE_BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == (__START_KERNEL & PGDIR_MASK))); BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END); diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 0470826d2bdc..d7b3cf2320fd 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -380,14 +380,15 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, p4d_t addr, #define p4d_none(a) pud_none(__pud(p4d_val(a))) #endif -#if PTRS_PER_P4D > 1 - static void walk_p4d_level(struct seq_file *m, struct pg_state *st, pgd_t addr, unsigned long P) { int i; p4d_t *start; pgprotval_t prot; + if (PTRS_PER_P4D > 1) + return walk_pud_level(m, st, __p4d(pgd_val(addr)), P); + start = (p4d_t *)pgd_page_vaddr(addr); for (i = 0; i < PTRS_PER_P4D; i++) { @@ -407,12 +408,6 @@ static void walk_p4d_level(struct seq_file *m, struct pg_state *st, pgd_t addr, } } -#else -#define walk_p4d_level(m,s,a,p) walk_pud_level(m,s,__p4d(pgd_val(a)),p) -#define pgd_large(a) p4d_large(__p4d(pgd_val(a))) -#define pgd_none(a) p4d_none(__p4d(pgd_val(a))) -#endif - static inline bool is_hypervisor_range(int idx) { #ifdef CONFIG_X86_64 diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 124f1a77c181..d135c613bf7b 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -143,7 +143,7 @@ void sync_global_pgds(unsigned long start, unsigned long end) * With folded p4d, pgd_none() is always false, we need to * handle synchonization on p4d level. */ - BUILD_BUG_ON(pgd_none(*pgd_ref)); + MAYBE_BUILD_BUG_ON(pgd_none(*pgd_ref)); p4d_ref = p4d_offset(pgd_ref, addr); if (p4d_none(*p4d_ref)) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index c488625c9712..d6cfba3e164f 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -186,8 +186,8 @@ void efi_sync_low_kernel_mappings(void) * only span a single PGD entry and that the entry also maps * other important kernel regions. */ - BUILD_BUG_ON(pgd_index(EFI_VA_END) != pgd_index(MODULES_END)); - BUILD_BUG_ON((EFI_VA_START & PGDIR_MASK) != + MAYBE_BUILD_BUG_ON(pgd_index(EFI_VA_END) != pgd_index(MODULES_END)); + MAYBE_BUILD_BUG_ON((EFI_VA_START & PGDIR_MASK) != (EFI_VA_END & PGDIR_MASK)); pgd_efi = efi_pgd + pgd_index(PAGE_OFFSET); -- 2.11.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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