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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: Mike 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Rapoport 2019-07-11 20:57:49 -07:00 committed by Linus Torvalds
parent 790c73690c
commit 5fba4af445
3 changed files with 115 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
arch/x86/include/asm/pgalloc.h
View File

@ -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,

33
arch/x86/mm/pgtable.c
View File

@ -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)

107
include/asm-generic/pgalloc.h
View File

@ -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 - 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 */