pageattr.c

/*
 * Copyright 2002 Andi Kleen, SuSE Labs.
 * Thanks to Ben LaHaise for precious feedback.
 */
#include <linux/highmem.h>
#include <linux/bootmem.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/pfn.h>
#include <linux/percpu.h>
#include <linux/gfp.h>
#include <linux/pci.h>
#include <linux/vmalloc.h>

#include <asm/e820.h>
#include <asm/processor.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <linux/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/proto.h>
#include <asm/pat.h>

/*
 * The current flushing context - we pass it instead of 5 arguments:
 */
struct cpa_data {
	unsigned long	*vaddr;
	pgd_t		*pgd;
	pgprot_t	mask_set;
	pgprot_t	mask_clr;
	unsigned long	numpages;
	int		flags;
	unsigned long	pfn;
	unsigned	force_split : 1;
	int		curpage;
	struct page	**pages;
};

/*
 * Serialize cpa() (for !DEBUG_PAGEALLOC which uses large identity mappings)
 * using cpa_lock. So that we don't allow any other cpu, with stale large tlb
 * entries change the page attribute in parallel to some other cpu
 * splitting a large page entry along with changing the attribute.
 */
static DEFINE_SPINLOCK(cpa_lock);

#define CPA_FLUSHTLB 1
#define CPA_ARRAY 2
#define CPA_PAGES_ARRAY 4

#ifdef CONFIG_PROC_FS
static unsigned long direct_pages_count[PG_LEVEL_NUM];

void update_page_count(int level, unsigned long pages)
{
	/* Protect against CPA */
	spin_lock(&pgd_lock);
	direct_pages_count[level] += pages;
	spin_unlock(&pgd_lock);
}

static void split_page_count(int level)
{
	if (direct_pages_count[level] == 0)
		return;