/*
* IA-32 Huge TLB Page Support for Kernel.
*
* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
*/
#include <linux/config.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/sysctl.h>
#include <asm/mman.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
static pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd = NULL;
pgd = pgd_offset(mm, addr);
pud = pud_alloc(mm, pgd, addr);
pmd = pmd_alloc(mm, pud, addr);
return (pte_t *) pmd;
}
static pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd = NULL;
pgd = pgd_offset(mm, addr);
pud = pud_offset(pgd, addr);
pmd = pmd_offset(pud, addr);
return (pte_t *) pmd;
}
static void set_huge_pte(struct mm_struct *mm, struct vm_area_struct *vma, struct page *page, pte_t * page_table, int write_access)
{
pte_t entry;
add_mm_counter(mm, rss, HPAGE_SIZE / PAGE_SIZE);
if (write_access) {
entry =
pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
} else
entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
entry = pte_mkyoung(entry);
mk_pte_huge(entry);
set_pte(page_table, entry);
}
/*
* This function checks for proper alignment of input addr and len parameters.
*/
int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
{
if (len & ~HPAGE_MASK)
return -EINVAL;
if (addr & ~HPAGE_MASK)
return -EINVAL;
return 0;
}
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
struct vm_area_struct *vma)
{
pte_t *src_pte, *dst_pte, entry;
struct page *ptepage;
unsigned long addr = vma->vm_start;
unsigned long end = vma->vm_end;
while (addr < end) {
dst_pte = huge_pte_alloc(dst, addr);
if (!dst_pte)
goto nomem;
src_pte = huge_pte_offset(src, addr);
entry = *src_pte;
ptepage = pte_page(entry);
get_page(ptepage);
set_pte(dst_pte, entry);
add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
addr += HPAGE_SIZE;
}
return 0;
nomem:
return -ENOMEM;
}
int
follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page **pages, struct vm_area_struct **vmas,
unsigned long *position, int *length, int i)
{
unsigned long vpfn, vaddr = *position;
int remainder = *length;
WARN_ON(!is_vm_hugetlb_page(vma));
vpfn = vaddr/PAGE_SIZE;
while (vaddr < vma->vm_end && remainder) {
if (pages) {
pte_t *pte;
struct page *page;
pte = huge_pte_offset(mm, vaddr);
/* hugetlb should be locked, and hence, prefaulted */
WARN_ON(!pte || pte_none(*pte));
page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
WARN_ON(!PageCompound(page));
get_page(page);
pages[i] = page;
}
if (vmas)
vmas[i] = vma;
vaddr += PAGE_SIZE;
++vpfn;
--remainder;
++i;
}
*length = remainder;
*position = vaddr;
return i;
}
#if 0 /* This is just for testing */
struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
unsigned long start = address;
int length = 1;
int nr;
struct page *page;
struct vm_area_struct *vma;
vma = find_vma(mm, addr);
if (!vma || !is_vm_hugetlb_page(vma))
return ERR_PTR(-EINVAL);
pte = huge_pte_offset(mm, address);
/* hugetlb should be locked, and hence, prefaulted */
WARN_ON(!pte || pte_none(*pte));
page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
WARN_ON(!PageCompound(page));
return page;
}
int pmd_huge(pmd_t pmd)
{
return 0;
}
struct page *
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write)
{
return NULL;
}
#else
struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
return ERR_PTR(-EINVAL);
}
int pmd_huge(pmd_t pmd)
{
return !!(pmd_val(pmd) & _PAGE_PSE);
}
struct page *
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write)
{
struct page *page;
page = pte_page(*(pte_t *)pmd);
if (page)
page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
return page;
}
#endif
void unmap_hugepage_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
pte_t pte, *ptep;
struct page *page;
BUG_ON(start & (HPAGE_SIZE - 1));
BUG_ON(end & (HPAGE_SIZE - 1));
for (address = start; address < end; address += HPAGE_SIZE) {
ptep = huge_pte_offset(mm, address);
if (!ptep)
continue;
pte = ptep_get_and_clear(mm, address, ptep);
if (pte_none(pte))
continue;
page = pte_page(pte);
put_page(page);
}
add_mm_counter(mm ,rss, -((end - start) >> PAGE_SHIFT));
flush_tlb_range(vma, start, end);
}
int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
{
struct mm_struct *mm = current->mm;
unsigned long addr;
int ret = 0;
BUG_ON(vma->vm_start & ~HPAGE_MASK);
BUG_ON(vma->vm_end & ~HPAGE_MASK);
spin_lock(&mm->page_table_lock);
for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
unsigned long idx;
pte_t *pte = huge_pte_alloc(mm, addr);
struct page *page;
if (!pte) {
ret = -ENOMEM;
goto out;
}
if (!pte_none(*pte)) {
pmd_t *pmd = (pmd_t *) pte;
page = pmd_page(*pmd);
pmd_clear(pmd);
mm->nr_ptes--;
dec_page_state(nr_page_table_pages);
page_cache_release(page);
}
idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
+ (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
page = find_get_page(mapping, idx);
if (!page) {
/* charge the fs quota first */
if (hugetlb_get_quota(mapping)) {
ret = -ENOMEM;
goto out;
}
page = alloc_huge_page();
if (!page) {
hugetlb_put_quota(mapping);
ret = -ENOMEM;
goto out;
}
ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
if (! ret) {
unlock_page(page);
} else {
hugetlb_put_quota(mapping);
free_huge_page(page);
goto out;
}
}
set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
}
out:
spin_unlock(&mm->page_table_lock);
return ret;
}
/* x86_64 also uses this file */
#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long start_addr;
start_addr = mm->free_area_cache;
full_search:
addr = ALIGN(start_addr, HPAGE_SIZE);
for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
/* At this point: (!vma || addr < vma->vm_end). */
if (TASK_SIZE - len < addr) {
/*
* Start a new search - just in case we missed
* some holes.
*/
if (start_addr != TASK_UNMAPPED_BASE) {
start_addr = TASK_UNMAPPED_BASE;
goto full_search;
}
return -ENOMEM;
}
if (!vma || addr + len <= vma->vm_start) {
mm->free_area_cache = addr + len;
return addr;
}
addr = ALIGN(vma->vm_end, HPAGE_SIZE);
}
}
static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
unsigned long addr0, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma, *prev_vma;
unsigned long base = mm->mmap_base, addr = addr0;
int first_time = 1;
/* don't allow allocations above current base */
if (mm->free_area_cache > base)
mm->free_area_cache = base;
try_again:
/* make sure it can fit in the remaining address space */
if (mm->free_area_cache < len)
goto fail;
/* either no address requested or cant fit in requested address hole */
addr = (mm->free_area_cache - len) & HPAGE_MASK;
do {
/*
* Lookup failure means no vma is above this address,
* i.e. return with success:
*/
if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
return addr;
/*
* new region fits between prev_vma->vm_end and
* vma->vm_start, use it:
*/
if (addr + len <= vma->vm_start &&
(!prev_vma || (addr >= prev_vma->vm_end)))
/* remember the address as a hint for next time */
return (mm->free_area_cache = addr);
else
/* pull free_area_cache down to the first hole */
if (mm->free_area_cache == vma->vm_end)
mm->free_area_cache = vma->vm_start;
/* try just below the current vma->vm_start */
addr = (vma->vm_start - len) & HPAGE_MASK;
} while (len <= vma->vm_start);
fail:
/*
* if hint left us with no space for the requested
* mapping then try again:
*/
if (first_time) {
mm->free_area_cache = base;
first_time = 0;
goto try_again;
}
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
mm->free_area_cache = TASK_UNMAPPED_BASE;
addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
len, pgoff, flags);
/*
* Restore the topdown base:
*/
mm->free_area_cache = base;
return addr;
}
unsigned long
hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
if (len & ~HPAGE_MASK)
return -EINVAL;
if (len > TASK_SIZE)
return -ENOMEM;
if (addr) {
addr = ALIGN(addr, HPAGE_SIZE);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr &&
(!vma || addr + len <= vma->vm_start))
return addr;
}
if (mm->get_unmapped_area == arch_get_unmapped_area)
return hugetlb_get_unmapped_area_bottomup(file, addr, len,
pgoff, flags);
else
return hugetlb_get_unmapped_area_topdown(file, addr, len,
pgoff, flags);
}
#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
