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* arch/metag/mm/hugetlbpage.c
*
* METAG HugeTLB page support.
*
* Cloned from SuperH
*
* Cloned from sparc64 by Paul Mundt.
*
* Copyright (C) 2002, 2003 David S. Miller (davem@redhat.com)
*/
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/sysctl.h>
#include <asm/mman.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
/*
* If the arch doesn't supply something else, assume that hugepage
* size aligned regions are ok without further preparation.
*/
int prepare_hugepage_range(struct file *file, unsigned long addr,
unsigned long len)
{
struct mm_struct *mm = current->mm;
struct hstate *h = hstate_file(file);
struct vm_area_struct *vma;
if (len & ~huge_page_mask(h))
return -EINVAL;
if (addr & ~huge_page_mask(h))
return -EINVAL;
if (TASK_SIZE - len < addr)
return -EINVAL;
vma = find_vma(mm, ALIGN_HUGEPT(addr));
if (vma && !(vma->vm_flags & MAP_HUGETLB))
return -EINVAL;
vma = find_vma(mm, addr);
if (vma) {
if (addr + len > vma->vm_start)
return -EINVAL;
if (!(vma->vm_flags & MAP_HUGETLB) &&
(ALIGN_HUGEPT(addr + len) > vma->vm_start))
return -EINVAL;
}
return 0;
}
pte_t *huge_pte_alloc(struct mm_struct *mm,
unsigned long addr, unsigned long sz)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pgd = pgd_offset(mm, addr);
pud = pud_offset(pgd, addr);
pmd = pmd_offset(pud, addr);
pte = pte_alloc_map(mm, NULL, pmd, addr);
pgd->pgd &= ~_PAGE_SZ_MASK;
pgd->pgd |= _PAGE_SZHUGE;
return pte;
}
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte = NULL;
pgd = pgd_offset(mm, addr);
pud = pud_offset(pgd, addr);
pmd = pmd_offset(pud, addr);
pte = pte_offset_kernel(pmd, addr);
return pte;
}
int pmd_huge(pmd_t pmd)
{
return pmd_page_shift(pmd) > PAGE_SHIFT;
}
int pud_huge(pud_t pud)
{
return 0;
}
struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write)
{
return NULL;
}
#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
/*
* Look for an unmapped area starting after another hugetlb vma.
* There are guaranteed to be no huge pte's spare if all the huge pages are
* full size (4MB), so in that case compile out this search.
*/
#if HPAGE_SHIFT == HUGEPT_SHIFT
static inline unsigned long
hugetlb_get_unmapped_area_existing(unsigned long len)
{
return 0;
}
#else
static unsigned long
hugetlb_get_unmapped_area_existing(unsigned long len)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long start_addr, addr;
int after_huge;
if (mm->context.part_huge) {
start_addr = mm->context.part_huge;
after_huge = 1;
} else {
start_addr = TASK_UNMAPPED_BASE;
after_huge = 0;
}
new_search:
addr = start_addr;
for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
if ((!vma && !after_huge) || 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 new_search;
}
return 0;
}
/* skip ahead if we've aligned right over some vmas */
if (vma && vma->vm_end <= addr)
continue;
/* space before the next vma? */
if (after_huge && (!vma || ALIGN_HUGEPT(addr + len)
<= vma->vm_start)) {
unsigned long end = addr + len;
if (end & HUGEPT_MASK)
mm->context.part_huge = end;
else if (addr == mm->context.part_huge)
mm->context.part_huge = 0;
return addr;
}
if (vma->vm_flags & MAP_HUGETLB) {
/* space after a huge vma in 2nd level page table? */
if (vma->vm_end & HUGEPT_MASK) {
after_huge = 1;
/* no need to align to the next PT block */
addr = vma->vm_end;
continue;
}
}
after_huge = 0;
addr = ALIGN_HUGEPT(vma->vm_end);
}
}
#endif
/* Do a full search to find an area without any nearby normal pages. */
static unsigned long
hugetlb_get_unmapped_area_new_pmd(unsigned long len)
{
struct vm_unmapped_area_info info;
info.flags = 0;
info.length = len;
info.low_limit = TASK_UNMAPPED_BASE;
info.high_limit = TASK_SIZE;
info.align_mask = PAGE_MASK & HUGEPT_MASK;
info.align_offset = 0;
return vm_unmapped_area(&info);
}
unsigned long
hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct hstate *h = hstate_file(file);
if (len & ~huge_page_mask(h))
return -EINVAL;
if (len > TASK_SIZE)
return -ENOMEM;
if (flags & MAP_FIXED) {
if (prepare_hugepage_range(file, addr, len))
return -EINVAL;
return addr;
}
if (addr) {
addr = ALIGN(addr, huge_page_size(h));
if (!prepare_hugepage_range(file, addr, len))
return addr;
}
/*
* Look for an existing hugetlb vma with space after it (this is to to
* minimise fragmentation caused by huge pages.
*/
addr = hugetlb_get_unmapped_area_existing(len);
if (addr)
return addr;
/*
* Find an unmapped naturally aligned set of 4MB blocks that we can use
* for huge pages.
*/
return hugetlb_get_unmapped_area_new_pmd(len);
}
#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
/* necessary for boot time 4MB huge page allocation */
static __init int setup_hugepagesz(char *opt)
{
unsigned long ps = memparse(opt, &opt);
if (ps == (1 << HPAGE_SHIFT)) {
hugetlb_add_hstate(HPAGE_SHIFT - PAGE_SHIFT);
} else {
pr_err("hugepagesz: Unsupported page size %lu M\n",
ps >> 20);
return 0;
}
return 1;
}
__setup("hugepagesz=", setup_hugepagesz);
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