Commit 5fba4af4 authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
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asm-generic, x86: introduce generic pte_{alloc,free}_one[_kernel] 

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.

Link: http://lkml.kernel.org/r/1557296232-15361-2-git-send-email-rppt@linux.ibm.com


Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Guo Ren <ren_guo@c-sky.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Creasey <sammy@sammy.net>
Cc: Vincent Chen <deanbo422@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 790c7369

arch/x86/include/asm/pgalloc.h

+3 −16
Original line number Diff line number Diff line
@@ -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,

arch/x86/mm/pgtable.c

+9 −24
Original line number Diff line number Diff line
@@ -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;
@@ -399,14 +383,14 @@ 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)
@@ -424,7 +408,8 @@ void __init pgd_cache_init(void) 


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)

include/asm-generic/pgalloc.h

+103 −4
Original line number Diff line number Diff line 
/* 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 - 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 */

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