Most architectures have identical or very similar implementation of pte_alloc_one_kernel(), pte_alloc_one(), pte_free_kernel() and pte_free().
Add a generic implementation that can be reused across architectures and enable its use on x86. The generic implementation uses GFP_KERNEL | __GFP_ZERO for the kernel page tables and GFP_KERNEL | __GFP_ZERO | __GFP_ACCOUNT for the user page tables. The "base" functions for PTE allocation, namely __pte_alloc_one_kernel() and __pte_alloc_one() are intended for the architectures that require additional actions after actual memory allocation or must use non-default GFP flags. x86 is switched to use generic pte_alloc_one_kernel(), pte_free_kernel() and pte_free(). x86 still implements pte_alloc_one() to allow run-time control of GFP flags required for "userpte" command line option. Signed-off-by: Mike Rapoport <r...@linux.ibm.com> --- arch/x86/include/asm/pgalloc.h | 19 ++------ arch/x86/mm/pgtable.c | 33 ++++--------- include/asm-generic/pgalloc.h | 107 +++++++++++++++++++++++++++++++++++++++-- 3 files changed, 115 insertions(+), 44 deletions(-) diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h index a281e61..29aa785 100644 --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -6,6 +6,9 @@ #include <linux/mm.h> /* for struct page */ #include <linux/pagemap.h> +#define __HAVE_ARCH_PTE_ALLOC_ONE +#include <asm-generic/pgalloc.h> /* for pte_{alloc,free}_one */ + static inline int __paravirt_pgd_alloc(struct mm_struct *mm) { return 0; } #ifdef CONFIG_PARAVIRT_XXL @@ -47,24 +50,8 @@ extern gfp_t __userpte_alloc_gfp; extern pgd_t *pgd_alloc(struct mm_struct *); extern void pgd_free(struct mm_struct *mm, pgd_t *pgd); -extern pte_t *pte_alloc_one_kernel(struct mm_struct *); extern pgtable_t pte_alloc_one(struct mm_struct *); -/* Should really implement gc for free page table pages. This could be - done with a reference count in struct page. */ - -static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) -{ - BUG_ON((unsigned long)pte & (PAGE_SIZE-1)); - free_page((unsigned long)pte); -} - -static inline void pte_free(struct mm_struct *mm, struct page *pte) -{ - pgtable_page_dtor(pte); - __free_page(pte); -} - extern void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte); static inline void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte, diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 7bd0170..aaca89b 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -13,33 +13,17 @@ phys_addr_t physical_mask __ro_after_init = (1ULL << __PHYSICAL_MASK_SHIFT) - 1; EXPORT_SYMBOL(physical_mask); #endif -#define PGALLOC_GFP (GFP_KERNEL_ACCOUNT | __GFP_ZERO) - #ifdef CONFIG_HIGHPTE -#define PGALLOC_USER_GFP __GFP_HIGHMEM +#define PGTABLE_HIGHMEM __GFP_HIGHMEM #else -#define PGALLOC_USER_GFP 0 +#define PGTABLE_HIGHMEM 0 #endif -gfp_t __userpte_alloc_gfp = PGALLOC_GFP | PGALLOC_USER_GFP; - -pte_t *pte_alloc_one_kernel(struct mm_struct *mm) -{ - return (pte_t *)__get_free_page(PGALLOC_GFP & ~__GFP_ACCOUNT); -} +gfp_t __userpte_alloc_gfp = GFP_PGTABLE_USER | PGTABLE_HIGHMEM; pgtable_t pte_alloc_one(struct mm_struct *mm) { - struct page *pte; - - pte = alloc_pages(__userpte_alloc_gfp, 0); - if (!pte) - return NULL; - if (!pgtable_page_ctor(pte)) { - __free_page(pte); - return NULL; - } - return pte; + return __pte_alloc_one(mm, __userpte_alloc_gfp); } static int __init setup_userpte(char *arg) @@ -235,7 +219,7 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count) { int i; bool failed = false; - gfp_t gfp = PGALLOC_GFP; + gfp_t gfp = GFP_PGTABLE_USER; if (mm == &init_mm) gfp &= ~__GFP_ACCOUNT; @@ -401,14 +385,14 @@ static inline pgd_t *_pgd_alloc(void) * We allocate one page for pgd. */ if (!SHARED_KERNEL_PMD) - return (pgd_t *)__get_free_pages(PGALLOC_GFP, + return (pgd_t *)__get_free_pages(GFP_PGTABLE_USER, PGD_ALLOCATION_ORDER); /* * Now PAE kernel is not running as a Xen domain. We can allocate * a 32-byte slab for pgd to save memory space. */ - return kmem_cache_alloc(pgd_cache, PGALLOC_GFP); + return kmem_cache_alloc(pgd_cache, GFP_PGTABLE_USER); } static inline void _pgd_free(pgd_t *pgd) @@ -422,7 +406,8 @@ static inline void _pgd_free(pgd_t *pgd) static inline pgd_t *_pgd_alloc(void) { - return (pgd_t *)__get_free_pages(PGALLOC_GFP, PGD_ALLOCATION_ORDER); + return (pgd_t *)__get_free_pages(GFP_PGTABLE_USER, + PGD_ALLOCATION_ORDER); } static inline void _pgd_free(pgd_t *pgd) diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h index 948714c..efecfb3 100644 --- a/include/asm-generic/pgalloc.h +++ b/include/asm-generic/pgalloc.h @@ -1,13 +1,112 @@ /* SPDX-License-Identifier: GPL-2.0 */ #ifndef __ASM_GENERIC_PGALLOC_H #define __ASM_GENERIC_PGALLOC_H -/* - * an empty file is enough for a nommu architecture - */ + #ifdef CONFIG_MMU -#error need to implement an architecture specific asm/pgalloc.h + +#define GFP_PGTABLE_KERNEL (GFP_KERNEL | __GFP_ZERO) +#define GFP_PGTABLE_USER (GFP_PGTABLE_KERNEL | __GFP_ACCOUNT) + +/** + * __pte_alloc_one_kernel - allocate a page for PTE-level kernel page table + * @mm: the mm_struct of the current context + * + * This function is intended for architectures that need + * anything beyond simple page allocation. + * + * Return: pointer to the allocated memory or %NULL on error + */ +static inline pte_t *__pte_alloc_one_kernel(struct mm_struct *mm) +{ + return (pte_t *)__get_free_page(GFP_PGTABLE_KERNEL); +} + +#ifndef __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL +/** + * pte_alloc_one_kernel - allocate a page for PTE-level kernel page table + * @mm: the mm_struct of the current context + * + * Return: pointer to the allocated memory or %NULL on error + */ +static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm) +{ + return __pte_alloc_one_kernel(mm); +} +#endif + +/** + * pte_free_kernel - free PTE-level kernel page table page + * @mm: the mm_struct of the current context + * @pte: pointer to the memory containing the page table + */ +static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) +{ + free_page((unsigned long)pte); +} + +/** + * __pte_alloc_one - allocate a page for PTE-level user page table + * @mm: the mm_struct of the current context + * @gfp: GFP flags to use for the allocation + * + * Allocates a page and runs the pgtable_page_ctor(). + * + * This function is intended for architectures that need + * anything beyond simple page allocation or must have custom GFP flags. + * + * Return: `struct page` initialized as page table or %NULL on error + */ +static inline pgtable_t __pte_alloc_one(struct mm_struct *mm, gfp_t gfp) +{ + struct page *pte; + + pte = alloc_page(gfp); + if (!pte) + return NULL; + if (!pgtable_page_ctor(pte)) { + __free_page(pte); + return NULL; + } + + return pte; +} + +#ifndef __HAVE_ARCH_PTE_ALLOC_ONE +/** + * pte_alloc_one - allocate a page for PTE-level user page table + * @mm: the mm_struct of the current context + * + * Allocates a page and runs the pgtable_page_ctor(). + * + * Return: `struct page` initialized as page table or %NULL on error + */ +static inline pgtable_t pte_alloc_one(struct mm_struct *mm) +{ + return __pte_alloc_one(mm, GFP_PGTABLE_USER); +} #endif +/* + * Should really implement gc for free page table pages. This could be + * done with a reference count in struct page. + */ + +/** + * pte_free_kernel - free PTE-level user page table page + * @mm: the mm_struct of the current context + * @pte_page: the `struct page` representing the page table + */ +static inline void pte_free(struct mm_struct *mm, struct page *pte_page) +{ + pgtable_page_dtor(pte_page); + __free_page(pte_page); +} + +#else /* CONFIG_MMU */ + +/* This is enough for a nommu architecture */ #define check_pgt_cache() do { } while (0) +#endif /* CONFIG_MMU */ + #endif /* __ASM_GENERIC_PGALLOC_H */ -- 2.7.4