/*
* linux/arch/i386/mm/pgtable.c
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/nmi.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/quicklist.h>
#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/fixmap.h>
#include <asm/e820.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
void show_mem(void)
{
int total = 0, reserved = 0;
int shared = 0, cached = 0;
int highmem = 0;
struct page *page;
pg_data_t *pgdat;
unsigned long i;
unsigned long flags;
printk(KERN_INFO "Mem-info:\n");
show_free_areas();
printk(KERN_INFO "Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
for_each_online_pgdat(pgdat) {
pgdat_resize_lock(pgdat, &flags);
for (i = 0; i < pgdat->node_spanned_pages; ++i) {
if (unlikely(i % MAX_ORDER_NR_PAGES == 0))
touch_nmi_watchdog();
page = pgdat_page_nr(pgdat, i);
total++;
if (PageHighMem(page))
highmem++;
if (PageReserved(page))
reserved++;
else if (PageSwapCache(page))
cached++;
else if (page_count(page))
shared += page_count(page) - 1;
}
pgdat_resize_unlock(pgdat, &flags);
}
printk(KERN_INFO "%d pages of RAM\n", total);
printk(KERN_INFO "%d pages of HIGHMEM\n", highmem);
printk(KERN_INFO "%d reserved pages\n", reserved);
printk(KERN_INFO "%d pages shared\n", shared);
printk(KERN_INFO "%d pages swap cached\n", cached);
printk(KERN_INFO "%lu pages dirty\n", global_page_state(NR_FILE_DIRTY));
printk(KERN_INFO "%lu pages writeback\n",
global_page_state(NR_WRITEBACK));
printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
printk(KERN_INFO "%lu pages slab\n",
global_page_state(NR_SLAB_RECLAIMABLE) +
global_page_state(NR_SLAB_UNRECLAIMABLE));
printk(KERN_INFO "%lu pages pagetables\n",
global_page_state(NR_PAGETABLE));
}
/*
* Associate a virtual page frame with a given physical page frame
* and protection flags for that frame.
*/
static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pgd = swapper_pg_dir + pgd_index(vaddr);
if (pgd_none(*pgd)) {
BUG();
return;
}
pud = pud_offset(pgd, vaddr);
if (pud_none(*pud)) {
BUG();
return;
}
pmd = pmd_offset(pud, vaddr);
if (pmd_none(*pmd)) {
BUG();
return;
}
pte = pte_offset_kernel(pmd, vaddr);
if (pgprot_val(flags))
set_pte_present(&init_mm, vaddr, pte, pfn_pte(pfn, flags));
else
pte_clear(&init_mm, vaddr, pte);
/*
* It's enough to flush this one mapping.
* (PGE mappings get flushed as well)
*/
__flush_tlb_one(vaddr);
}
/*
* Associate a large virtual page frame with a given physical page frame
* and protection flags for that frame. pfn is for the base of the page,
* vaddr is what the page gets mapped to - both must be properly aligned.
* The pmd must already be instantiated. Assumes PAE mode.
*/
void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
if (vaddr & (PMD_SIZE-1)) { /* vaddr is misaligned */
printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
return; /* BUG(); */
}
if (pfn & (PTRS_PER_PTE-1)) { /* pfn is misaligned */
printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
return; /* BUG(); */
}
pgd = swapper_pg_dir + pgd_index(vaddr);
if (pgd_none(*pgd)) {
printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
return; /* BUG(); */
}
pud = pud_offset(pgd, vaddr);
pmd = pmd_offset(pud, vaddr);
set_pmd(pmd, pfn_pmd(pfn, flags));
/*
* It's enough to flush this one mapping.
* (PGE mappings get flushed as well)
*/
__flush_tlb_one(vaddr);
}
static int fixmaps;
unsigned long __FIXADDR_TOP = 0xfffff000;
EXPORT_SYMBOL(__FIXADDR_TOP);
void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
{
unsigned long address = __fix_to_virt(idx);
if (idx >= __end_of_fixed_addresses) {
BUG();
return;
}
set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
fixmaps++;
}
/**
* reserve_top_address - reserves a hole in the top of kernel address space
* @reserve - size of hole to reserve
*
* Can be used to relocate the fixmap area and poke a hole in the top
* of kernel address space to make room for a hypervisor.
*/
void reserve_top_address(unsigned long reserve)
{
BUG_ON(fixmaps > 0);
printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
(int)-reserve);
__FIXADDR_TOP = -reserve - PAGE_SIZE;
__VMALLOC_RESERVE += reserve;
}
pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
}
pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
struct page *pte;
#ifdef CONFIG_HIGHPTE
pte = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT|__GFP_ZERO, 0);
#else
pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 0);
#endif
if (pte)
pgtable_page_ctor(pte);
return pte;
}
/*
* List of all pgd's needed for non-PAE so it can invalidate entries
* in both cached and uncached pgd's; not needed for PAE since the
* kernel pmd is shared. If PAE were not to share the pmd a similar
* tactic would be needed. This is essentially codepath-based locking
* against pageattr.c; it is the unique case in which a valid change
* of kernel pagetables can't be lazily synchronized by vmalloc faults.
* vmalloc faults work because attached pagetables are never freed.
* -- wli
*/
static inline void pgd_list_add(pgd_t *pgd)
{
struct page *page = virt_to_page(pgd);
list_add(&page->lru, &pgd_list);
}
static inline void pgd_list_del(pgd_t *pgd)
{
struct page *page = virt_to_page(pgd);
list_del(&page->lru);
}
#define UNSHARED_PTRS_PER_PGD \
(SHARED_KERNEL_PMD ? USER_PTRS_PER_PGD : PTRS_PER_PGD)
static void pgd_ctor(void *p)
{
pgd_t *pgd = p;
unsigned long flags;
/* Clear usermode parts of PGD */
memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
spin_lock_irqsave(&pgd_lock, flags);
/* If the pgd points to a shared pagetable level (either the
ptes in non-PAE, or shared PMD in PAE), then just copy the
references from swapper_pg_dir. */
if (PAGETABLE_LEVELS == 2 ||
(PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD)) {
clone_pgd_range(pgd + USER_PTRS_PER_PGD,
swapper_pg_dir + USER_PTRS_PER_PGD,
KERNEL_PGD_PTRS);
paravirt_alloc_pd_clone(__pa(pgd) >> PAGE_SHIFT,
__pa(swapper_pg_dir) >> PAGE_SHIFT,
USER_PTRS_PER_PGD,
KERNEL_PGD_PTRS);
}
/* list required to sync kernel mapping updates */
if (!SHARED_KERNEL_PMD)
pgd_list_add(pgd);
spin_unlock_irqrestore(&pgd_lock, flags);
}
static void pgd_dtor(void *pgd)
{
unsigned long flags; /* can be called from interrupt context */
if (SHARED_KERNEL_PMD)
return;
spin_lock_irqsave(&pgd_lock, flags);
pgd_list_del(pgd);
spin_unlock_irqrestore(&pgd_lock, flags);
}
#ifdef CONFIG_X86_PAE
/*
* Mop up any pmd pages which may still be attached to the pgd.
* Normally they will be freed by munmap/exit_mmap, but any pmd we
* preallocate which never got a corresponding vma will need to be
* freed manually.
*/
static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
{
int i;
for(i = 0; i < UNSHARED_PTRS_PER_PGD; i++) {
pgd_t pgd = pgdp[i];
if (pgd_val(pgd) != 0) {
pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
pgdp[i] = native_make_pgd(0);
paravirt_release_pd(pgd_val(pgd) >> PAGE_SHIFT);
pmd_free(mm, pmd);
}
}
}
/*
* In PAE mode, we need to do a cr3 reload (=tlb flush) when
* updating the top-level pagetable entries to guarantee the
* processor notices the update. Since this is expensive, and
* all 4 top-level entries are used almost immediately in a
* new process's life, we just pre-populate them here.
*
* Also, if we're in a paravirt environment where the kernel pmd is
* not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate
* and initialize the kernel pmds here.
*/
static int pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd)
{
pud_t *pud;
unsigned long addr;
int i;
pud = pud_offset(pgd, 0);
for (addr = i = 0; i < UNSHARED_PTRS_PER_PGD;
i++, pud++, addr += PUD_SIZE) {
pmd_t *pmd = pmd_alloc_one(mm, addr);
if (!pmd) {
pgd_mop_up_pmds(mm, pgd);
return 0;
}
if (i >= USER_PTRS_PER_PGD)
memcpy(pmd, (pmd_t *)pgd_page_vaddr(swapper_pg_dir[i]),
sizeof(pmd_t) * PTRS_PER_PMD);
pud_populate(mm, pud, pmd);
}
return 1;
}
#else /* !CONFIG_X86_PAE */
/* No need to prepopulate any pagetable entries in non-PAE modes. */
static int pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd)
{
return 1;
}
static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
{
}
#endif /* CONFIG_X86_PAE */
pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd = quicklist_alloc(0, GFP_KERNEL, pgd_ctor);
mm->pgd = pgd; /* so that alloc_pd can use it */
if (pgd && !pgd_prepopulate_pmd(mm, pgd)) {
quicklist_free(0, pgd_dtor, pgd);
pgd = NULL;
}
return pgd;
}
void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
pgd_mop_up_pmds(mm, pgd);
quicklist_free(0, pgd_dtor, pgd);
}
void check_pgt_cache(void)
{
quicklist_trim(0, pgd_dtor, 25, 16);
}
void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
{
pgtable_page_dtor(pte);
paravirt_release_pt(page_to_pfn(pte));
tlb_remove_page(tlb, pte);
}
#ifdef CONFIG_X86_PAE
void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
{
paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT);
tlb_remove_page(tlb, virt_to_page(pmd));
}
#endif
