blob: b649c288af9004bf38308059512b301f189e5b4a [file] [log] [blame]
/*
* PPC64 (POWER4) Huge TLB Page Support for Kernel.
*
* Copyright (C) 2003 David Gibson, IBM Corporation.
*
* Based on the IA-32 version:
* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
*/
#include <linux/mm.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/hugetlb.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#define PAGE_SHIFT_64K 16
#define PAGE_SHIFT_16M 24
#define PAGE_SHIFT_16G 34
#define MAX_NUMBER_GPAGES 1024
/* Tracks the 16G pages after the device tree is scanned and before the
* huge_boot_pages list is ready. */
static unsigned long gpage_freearray[MAX_NUMBER_GPAGES];
static unsigned nr_gpages;
/* Flag to mark huge PD pointers. This means pmd_bad() and pud_bad()
* will choke on pointers to hugepte tables, which is handy for
* catching screwups early. */
static inline int shift_to_mmu_psize(unsigned int shift)
{
int psize;
for (psize = 0; psize < MMU_PAGE_COUNT; ++psize)
if (mmu_psize_defs[psize].shift == shift)
return psize;
return -1;
}
static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
{
if (mmu_psize_defs[mmu_psize].shift)
return mmu_psize_defs[mmu_psize].shift;
BUG();
}
#define hugepd_none(hpd) ((hpd).pd == 0)
static inline pte_t *hugepd_page(hugepd_t hpd)
{
BUG_ON(!hugepd_ok(hpd));
return (pte_t *)((hpd.pd & ~HUGEPD_SHIFT_MASK) | 0xc000000000000000);
}
static inline unsigned int hugepd_shift(hugepd_t hpd)
{
return hpd.pd & HUGEPD_SHIFT_MASK;
}
static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr, unsigned pdshift)
{
unsigned long idx = (addr & ((1UL << pdshift) - 1)) >> hugepd_shift(*hpdp);
pte_t *dir = hugepd_page(*hpdp);
return dir + idx;
}
pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
{
pgd_t *pg;
pud_t *pu;
pmd_t *pm;
hugepd_t *hpdp = NULL;
unsigned pdshift = PGDIR_SHIFT;
if (shift)
*shift = 0;
pg = pgdir + pgd_index(ea);
if (is_hugepd(pg)) {
hpdp = (hugepd_t *)pg;
} else if (!pgd_none(*pg)) {
pdshift = PUD_SHIFT;
pu = pud_offset(pg, ea);
if (is_hugepd(pu))
hpdp = (hugepd_t *)pu;
else if (!pud_none(*pu)) {
pdshift = PMD_SHIFT;
pm = pmd_offset(pu, ea);
if (is_hugepd(pm))
hpdp = (hugepd_t *)pm;
else if (!pmd_none(*pm)) {
return pte_offset_map(pm, ea);
}
}
}
if (!hpdp)
return NULL;
if (shift)
*shift = hugepd_shift(*hpdp);
return hugepte_offset(hpdp, ea, pdshift);
}
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
}
static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
unsigned long address, unsigned pdshift, unsigned pshift)
{
pte_t *new = kmem_cache_zalloc(PGT_CACHE(pdshift - pshift),
GFP_KERNEL|__GFP_REPEAT);
BUG_ON(pshift > HUGEPD_SHIFT_MASK);
BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
if (! new)
return -ENOMEM;
spin_lock(&mm->page_table_lock);
if (!hugepd_none(*hpdp))
kmem_cache_free(PGT_CACHE(pdshift - pshift), new);
else
hpdp->pd = ((unsigned long)new & ~0x8000000000000000) | pshift;
spin_unlock(&mm->page_table_lock);
return 0;
}
pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
{
pgd_t *pg;
pud_t *pu;
pmd_t *pm;
hugepd_t *hpdp = NULL;
unsigned pshift = __ffs(sz);
unsigned pdshift = PGDIR_SHIFT;
addr &= ~(sz-1);
pg = pgd_offset(mm, addr);
if (pshift >= PUD_SHIFT) {
hpdp = (hugepd_t *)pg;
} else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
if (pshift >= PMD_SHIFT) {
hpdp = (hugepd_t *)pu;
} else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
hpdp = (hugepd_t *)pm;
}
}
if (!hpdp)
return NULL;
BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
return NULL;
return hugepte_offset(hpdp, addr, pdshift);
}
/* Build list of addresses of gigantic pages. This function is used in early
* boot before the buddy or bootmem allocator is setup.
*/
void add_gpage(unsigned long addr, unsigned long page_size,
unsigned long number_of_pages)
{
if (!addr)
return;
while (number_of_pages > 0) {
gpage_freearray[nr_gpages] = addr;
nr_gpages++;
number_of_pages--;
addr += page_size;
}
}
/* Moves the gigantic page addresses from the temporary list to the
* huge_boot_pages list.
*/
int alloc_bootmem_huge_page(struct hstate *hstate)
{
struct huge_bootmem_page *m;
if (nr_gpages == 0)
return 0;
m = phys_to_virt(gpage_freearray[--nr_gpages]);
gpage_freearray[nr_gpages] = 0;
list_add(&m->list, &huge_boot_pages);
m->hstate = hstate;
return 1;
}
int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
return 0;
}
static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
unsigned long start, unsigned long end,
unsigned long floor, unsigned long ceiling)
{
pte_t *hugepte = hugepd_page(*hpdp);
unsigned shift = hugepd_shift(*hpdp);
unsigned long pdmask = ~((1UL << pdshift) - 1);
start &= pdmask;
if (start < floor)
return;
if (ceiling) {
ceiling &= pdmask;
if (! ceiling)
return;
}
if (end - 1 > ceiling - 1)
return;
hpdp->pd = 0;
tlb->need_flush = 1;
pgtable_free_tlb(tlb, hugepte, pdshift - shift);
}
static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
unsigned long addr, unsigned long end,
unsigned long floor, unsigned long ceiling)
{
pmd_t *pmd;
unsigned long next;
unsigned long start;
start = addr;
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
if (pmd_none(*pmd))
continue;
free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
addr, next, floor, ceiling);
} while (pmd++, addr = next, addr != end);
start &= PUD_MASK;
if (start < floor)
return;
if (ceiling) {
ceiling &= PUD_MASK;
if (!ceiling)
return;
}
if (end - 1 > ceiling - 1)
return;
pmd = pmd_offset(pud, start);
pud_clear(pud);
pmd_free_tlb(tlb, pmd, start);
}
static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
unsigned long addr, unsigned long end,
unsigned long floor, unsigned long ceiling)
{
pud_t *pud;
unsigned long next;
unsigned long start;
start = addr;
pud = pud_offset(pgd, addr);
do {
next = pud_addr_end(addr, end);
if (!is_hugepd(pud)) {
if (pud_none_or_clear_bad(pud))
continue;
hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
ceiling);
} else {
free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
addr, next, floor, ceiling);
}
} while (pud++, addr = next, addr != end);
start &= PGDIR_MASK;
if (start < floor)
return;
if (ceiling) {
ceiling &= PGDIR_MASK;
if (!ceiling)
return;
}
if (end - 1 > ceiling - 1)
return;
pud = pud_offset(pgd, start);
pgd_clear(pgd);
pud_free_tlb(tlb, pud, start);
}
/*
* This function frees user-level page tables of a process.
*
* Must be called with pagetable lock held.
*/
void hugetlb_free_pgd_range(struct mmu_gather *tlb,
unsigned long addr, unsigned long end,
unsigned long floor, unsigned long ceiling)
{
pgd_t *pgd;
unsigned long next;
/*
* Because there are a number of different possible pagetable
* layouts for hugepage ranges, we limit knowledge of how
* things should be laid out to the allocation path
* (huge_pte_alloc(), above). Everything else works out the
* structure as it goes from information in the hugepd
* pointers. That means that we can't here use the
* optimization used in the normal page free_pgd_range(), of
* checking whether we're actually covering a large enough
* range to have to do anything at the top level of the walk
* instead of at the bottom.
*
* To make sense of this, you should probably go read the big
* block comment at the top of the normal free_pgd_range(),
* too.
*/
pgd = pgd_offset(tlb->mm, addr);
do {
next = pgd_addr_end(addr, end);
if (!is_hugepd(pgd)) {
if (pgd_none_or_clear_bad(pgd))
continue;
hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
} else {
free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
addr, next, floor, ceiling);
}
} while (pgd++, addr = next, addr != end);
}
struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
pte_t *ptep;
struct page *page;
unsigned shift;
unsigned long mask;
ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
/* Verify it is a huge page else bail. */
if (!ptep || !shift)
return ERR_PTR(-EINVAL);
mask = (1UL << shift) - 1;
page = pte_page(*ptep);
if (page)
page += (address & mask) / PAGE_SIZE;
return page;
}
int pmd_huge(pmd_t pmd)
{
return 0;
}
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)
{
BUG();
return NULL;
}
static noinline int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
unsigned long mask;
unsigned long pte_end;
struct page *head, *page;
pte_t pte;
int refs;
pte_end = (addr + sz) & ~(sz-1);
if (pte_end < end)
end = pte_end;
pte = *ptep;
mask = _PAGE_PRESENT | _PAGE_USER;
if (write)
mask |= _PAGE_RW;
if ((pte_val(pte) & mask) != mask)
return 0;
/* hugepages are never "special" */
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
refs = 0;
head = pte_page(pte);
page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
do {
VM_BUG_ON(compound_head(page) != head);
pages[*nr] = page;
(*nr)++;
page++;
refs++;
} while (addr += PAGE_SIZE, addr != end);
if (!page_cache_add_speculative(head, refs)) {
*nr -= refs;
return 0;
}
if (unlikely(pte_val(pte) != pte_val(*ptep))) {
/* Could be optimized better */
while (*nr) {
put_page(head);
(*nr)--;
}
}
return 1;
}
static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
unsigned long sz)
{
unsigned long __boundary = (addr + sz) & ~(sz-1);
return (__boundary - 1 < end - 1) ? __boundary : end;
}
int gup_hugepd(hugepd_t *hugepd, unsigned pdshift,
unsigned long addr, unsigned long end,
int write, struct page **pages, int *nr)
{
pte_t *ptep;
unsigned long sz = 1UL << hugepd_shift(*hugepd);
unsigned long next;
ptep = hugepte_offset(hugepd, addr, pdshift);
do {
next = hugepte_addr_end(addr, end, sz);
if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr))
return 0;
} while (ptep++, addr = next, addr != end);
return 1;
}
unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags)
{
struct hstate *hstate = hstate_file(file);
int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1, 0);
}
unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
{
unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
return 1UL << mmu_psize_to_shift(psize);
}
static int __init add_huge_page_size(unsigned long long size)
{
int shift = __ffs(size);
int mmu_psize;
/* Check that it is a page size supported by the hardware and
* that it fits within pagetable and slice limits. */
if (!is_power_of_2(size)
|| (shift > SLICE_HIGH_SHIFT) || (shift <= PAGE_SHIFT))
return -EINVAL;
if ((mmu_psize = shift_to_mmu_psize(shift)) < 0)
return -EINVAL;
#ifdef CONFIG_SPU_FS_64K_LS
/* Disable support for 64K huge pages when 64K SPU local store
* support is enabled as the current implementation conflicts.
*/
if (shift == PAGE_SHIFT_64K)
return -EINVAL;
#endif /* CONFIG_SPU_FS_64K_LS */
BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
/* Return if huge page size has already been setup */
if (size_to_hstate(size))
return 0;
hugetlb_add_hstate(shift - PAGE_SHIFT);
return 0;
}
static int __init hugepage_setup_sz(char *str)
{
unsigned long long size;
size = memparse(str, &str);
if (add_huge_page_size(size) != 0)
printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);
return 1;
}
__setup("hugepagesz=", hugepage_setup_sz);
static int __init hugetlbpage_init(void)
{
int psize;
if (!mmu_has_feature(MMU_FTR_16M_PAGE))
return -ENODEV;
for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
unsigned shift;
unsigned pdshift;
if (!mmu_psize_defs[psize].shift)
continue;
shift = mmu_psize_to_shift(psize);
if (add_huge_page_size(1ULL << shift) < 0)
continue;
if (shift < PMD_SHIFT)
pdshift = PMD_SHIFT;
else if (shift < PUD_SHIFT)
pdshift = PUD_SHIFT;
else
pdshift = PGDIR_SHIFT;
pgtable_cache_add(pdshift - shift, NULL);
if (!PGT_CACHE(pdshift - shift))
panic("hugetlbpage_init(): could not create "
"pgtable cache for %d bit pagesize\n", shift);
}
/* Set default large page size. Currently, we pick 16M or 1M
* depending on what is available
*/
if (mmu_psize_defs[MMU_PAGE_16M].shift)
HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift;
else if (mmu_psize_defs[MMU_PAGE_1M].shift)
HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift;
return 0;
}
module_init(hugetlbpage_init);
void flush_dcache_icache_hugepage(struct page *page)
{
int i;
BUG_ON(!PageCompound(page));
for (i = 0; i < (1UL << compound_order(page)); i++)
__flush_dcache_icache(page_address(page+i));
}