/*
* 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/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/sysctl.h>
#include <asm/mman.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/machdep.h>
#include <asm/cputable.h>
#include <asm/spu.h>
#define PAGE_SHIFT_64K 16
#define PAGE_SHIFT_16M 24
#define PAGE_SHIFT_16G 34
#define NUM_LOW_AREAS (0x100000000UL >> SID_SHIFT)
#define NUM_HIGH_AREAS (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
#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;
/* Array of valid huge page sizes - non-zero value(hugepte_shift) is
* stored for the huge page sizes that are valid.
*/
unsigned int mmu_huge_psizes[MMU_PAGE_COUNT] = { }; /* initialize all to 0 */
#define hugepte_shift mmu_huge_psizes
#define PTRS_PER_HUGEPTE(psize) (1 << hugepte_shift[psize])
#define HUGEPTE_TABLE_SIZE(psize) (sizeof(pte_t) << hugepte_shift[psize])
#define HUGEPD_SHIFT(psize) (mmu_psize_to_shift(psize) \
+ hugepte_shift[psize])
#define HUGEPD_SIZE(psize) (1UL << HUGEPD_SHIFT(psize))
#define HUGEPD_MASK(psize) (~(HUGEPD_SIZE(psize)-1))
/* Subtract one from array size because we don't need a cache for 4K since
* is not a huge page size */
#define huge_pgtable_cache(psize) (pgtable_cache[HUGEPTE_CACHE_NUM \
+ psize-1])
#define HUGEPTE_CACHE_NAME(psize) (huge_pgtable_cache_name[psize])
static const char *huge_pgtable_cache_name[MMU_PAGE_COUNT] = {
"unused_4K", "hugepte_cache_64K", "unused_64K_AP",
"hugepte_cache_1M", "hugepte_cache_16M", "hugepte_cache_16G"
};
/* 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. */
#define HUGEPD_OK 0x1
typedef struct { unsigned long pd; } hugepd_t;
#define hugepd_none(hpd) ((hpd).pd == 0)
static inline int shift_to_mmu_psize(unsigned int shift)
{
switch (shift) {
#ifndef CONFIG_PPC_64K_PAGES
case PAGE_SHIFT_64K:
return MMU_PAGE_64K;
#endif
case PAGE_SHIFT_16M:
return MMU_PAGE_16M;
case PAGE_SHIFT_16G:
return MMU_PAGE_16G;
}
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();
}
static inline pte_t *hugepd_page(hugepd_t hpd)
{
BUG_ON(!(hpd.pd & HUGEPD_OK));
return (pte_t *)(hpd.pd & ~HUGEPD_OK);
}
static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr,
struct hstate *hstate)
{
unsigned int shift = huge_page_shift(hstate);
int psize = shift_to_mmu_psize(shift);
unsigned long idx = ((addr >> shift) & (PTRS_PER_HUGEPTE(psize)-1));
pte_t *dir = hugepd_page(*hpdp);
return dir + idx;
}
static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
unsigned long address, unsigned int psize)
{
pte_t *new = kmem_cache_zalloc(huge_pgtable_cache(psize),
GFP_KERNEL|__GFP_REPEAT);
if (! new)
return -ENOMEM;
spin_lock(&mm->page_table_lock);
if (!hugepd_none(*hpdp))
kmem_cache_free(huge_pgtable_cache(psize), new);
else
hpdp->pd = (unsigned long)new | HUGEPD_OK;
spin_unlock(&mm->page_table_lock);
return 0;
}
static pud_t *hpud_offset(pgd_t *pgd, unsigned long addr, struct hstate *hstate)
{
if (huge_page_shift(hstate) < PUD_SHIFT)
return pud_offset(pgd, addr);
else
return (pud_t *) pgd;
}
static pud_t *hpud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long addr,
struct hstate *hstate)
{
if (huge_page_shift(hstate) < PUD_SHIFT)
return pud_alloc(mm, pgd, addr);
else
return (pud_t *) pgd;
}
static pmd_t *hpmd_offset(pud_t *pud, unsigned long addr, struct hstate *hstate)
{
if (huge_page_shift(hstate) < PMD_SHIFT)
return pmd_offset(pud, addr);
else
return (pmd_t *) pud;
}
static pmd_t *hpmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr,
struct hstate *hstate)
{
if (huge_page_shift(hstate) < PMD_SHIFT)
return pmd_alloc(mm, pud, addr);
else
return (pmd_t *) pud;
}
/* 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;
}
/* Modelled after find_linux_pte() */
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pg;
pud_t *pu;
pmd_t *pm;
unsigned int psize;
unsigned int shift;
unsigned long sz;
struct hstate *hstate;
psize = get_slice_psize(mm, addr);
shift = mmu_psize_to_shift(psize);
sz = ((1UL) << shift);
hstate = size_to_hstate(sz);
addr &= hstate->mask;
pg = pgd_offset(mm, addr);
if (!pgd_none(*pg)) {
pu = hpud_offset(pg, addr, hstate);
if (!pud_none(*pu)) {
pm = hpmd_offset(pu, addr, hstate);
if (!pmd_none(*pm))
return hugepte_offset((hugepd_t *)pm, addr,
hstate);
}
}
return NULL;
}
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;
struct hstate *hstate;
unsigned int psize;
hstate = size_to_hstate(sz);
psize = get_slice_psize(mm, addr);
BUG_ON(!mmu_huge_psizes[psize]);
addr &= hstate->mask;
pg = pgd_offset(mm, addr);
pu = hpud_alloc(mm, pg, addr, hstate);
if (pu) {
pm = hpmd_alloc(mm, pu, addr, hstate);
if (pm)
hpdp = (hugepd_t *)pm;
}
if (! hpdp)
return NULL;
if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, psize))
return NULL;
return hugepte_offset(hpdp, addr, hstate);
}
int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
return 0;
}
static void free_hugepte_range(struct mmu_gather *tlb, hugepd_t *hpdp,
unsigned int psize)
{
pte_t *hugepte = hugepd_page(*hpdp);
hpdp->pd = 0;
tlb->need_flush = 1;
pgtable_free_tlb(tlb, pgtable_free_cache(hugepte,
HUGEPTE_CACHE_NUM+psize-1,
PGF_CACHENUM_MASK));
}
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,
unsigned int psize)
{
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_hugepte_range(tlb, (hugepd_t *)pmd, psize);
} 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);
}
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;
unsigned int shift;
unsigned int psize = get_slice_psize(tlb->mm, addr);
shift = mmu_psize_to_shift(psize);
start = addr;
pud = pud_offset(pgd, addr);
do {
next = pud_addr_end(addr, end);
if (shift < PMD_SHIFT) {
if (pud_none_or_clear_bad(pud))
continue;
hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
ceiling, psize);
} else {
if (pud_none(*pud))
continue;
free_hugepte_range(tlb, (hugepd_t *)pud, psize);
}
} 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);
}
/*
* 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;
unsigned long start;
/*
* Comments below take from the normal free_pgd_range(). They
* apply here too. The tests against HUGEPD_MASK below are
* essential, because we *don't* test for this at the bottom
* level. Without them we'll attempt to free a hugepte table
* when we unmap just part of it, even if there are other
* active mappings using it.
*
* The next few lines have given us lots of grief...
*
* Why are we testing HUGEPD* at this top level? Because
* often there will be no work to do at all, and we'd prefer
* not to go all the way down to the bottom just to discover
* that.
*
* Why all these "- 1"s? Because 0 represents both the bottom
* of the address space and the top of it (using -1 for the
* top wouldn't help much: the masks would do the wrong thing).
* The rule is that addr 0 and floor 0 refer to the bottom of
* the address space, but end 0 and ceiling 0 refer to the top
* Comparisons need to use "end - 1" and "ceiling - 1" (though
* that end 0 case should be mythical).
*
* Wherever addr is brought up or ceiling brought down, we
* must be careful to reject "the opposite 0" before it
* confuses the subsequent tests. But what about where end is
* brought down by HUGEPD_SIZE below? no, end can't go down to
* 0 there.
*
* Whereas we round start (addr) and ceiling down, by different
* masks at different levels, in order to test whether a table
* now has no other vmas using it, so can be freed, we don't
* bother to round floor or end up - the tests don't need that.
*/
unsigned int psize = get_slice_psize(tlb->mm, addr);
addr &= HUGEPD_MASK(psize);
if (addr < floor) {
addr += HUGEPD_SIZE(psize);
if (!addr)
return;
}
if (ceiling) {
ceiling &= HUGEPD_MASK(psize);
if (!ceiling)
return;
}
if (end - 1 > ceiling - 1)
end -= HUGEPD_SIZE(psize);
if (addr > end - 1)
return;
start = addr;
pgd = pgd_offset(tlb->mm, addr);
do {
psize = get_slice_psize(tlb->mm, addr);
BUG_ON(!mmu_huge_psizes[psize]);
next = pgd_addr_end(addr, end);
if (mmu_psize_to_shift(psize) < PUD_SHIFT) {
if (pgd_none_or_clear_bad(pgd))
continue;
hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
} else {
if (pgd_none(*pgd))
continue;
free_hugepte_range(tlb, (hugepd_t *)pgd, psize);
}
} while (pgd++, addr = next, addr != end);
}
void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
if (pte_present(*ptep)) {
/* We open-code pte_clear because we need to pass the right
* argument to hpte_need_flush (huge / !huge). Might not be
* necessary anymore if we make hpte_need_flush() get the
* page size from the slices
*/
unsigned int psize = get_slice_psize(mm, addr);
unsigned int shift = mmu_psize_to_shift(psize);
unsigned long sz = ((1UL) << shift);
struct hstate *hstate = size_to_hstate(sz);
pte_update(mm, addr & hstate->mask, ptep, ~0UL, 1);
}
*ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
}
pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
unsigned long old = pte_update(mm, addr, ptep, ~0UL, 1);
return __pte(old);
}
struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
pte_t *ptep;
struct page *page;
unsigned int mmu_psize = get_slice_psize(mm, address);
/* Verify it is a huge page else bail. */
if (!mmu_huge_psizes[mmu_psize])
return ERR_PTR(-EINVAL);
ptep = huge_pte_offset(mm, address);
page = pte_page(*ptep);
if (page) {
unsigned int shift = mmu_psize_to_shift(mmu_psize);
unsigned long sz = ((1UL) << shift);
page += (address % sz) / 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;
}
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);
}
/*
* Called by asm hashtable.S for doing lazy icache flush
*/
static unsigned int hash_huge_page_do_lazy_icache(unsigned long rflags,
pte_t pte, int trap, unsigned long sz)
{
struct page *page;
int i;
if (!pfn_valid(pte_pfn(pte)))
return rflags;
page = pte_page(pte);
/* page is dirty */
if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
if (trap == 0x400) {
for (i = 0; i < (sz / PAGE_SIZE); i++)
__flush_dcache_icache(page_address(page+i));
set_bit(PG_arch_1, &page->flags);
} else {
rflags |= HPTE_R_N;
}
}
return rflags;
}
int hash_huge_page(struct mm_struct *mm, unsigned long access,
unsigned long ea, unsigned long vsid, int local,
unsigned long trap)
{
pte_t *ptep;
unsigned long old_pte, new_pte;
unsigned long va, rflags, pa, sz;
long slot;
int err = 1;
int ssize = user_segment_size(ea);
unsigned int mmu_psize;
int shift;
mmu_psize = get_slice_psize(mm, ea);
if (!mmu_huge_psizes[mmu_psize])
goto out;
ptep = huge_pte_offset(mm, ea);
/* Search the Linux page table for a match with va */
va = hpt_va(ea, vsid, ssize);
/*
* If no pte found or not present, send the problem up to
* do_page_fault
*/
if (unlikely(!ptep || pte_none(*ptep)))
goto out;
/*
* Check the user's access rights to the page. If access should be
* prevented then send the problem up to do_page_fault.
*/
if (unlikely(access & ~pte_val(*ptep)))
goto out;
/*
* At this point, we have a pte (old_pte) which can be used to build
* or update an HPTE. There are 2 cases:
*
* 1. There is a valid (present) pte with no associated HPTE (this is
* the most common case)
* 2. There is a valid (present) pte with an associated HPTE. The
* current values of the pp bits in the HPTE prevent access
* because we are doing software DIRTY bit management and the
* page is currently not DIRTY.
*/
do {
old_pte = pte_val(*ptep);
if (old_pte & _PAGE_BUSY)
goto out;
new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
} while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
old_pte, new_pte));
rflags = 0x2 | (!(new_pte & _PAGE_RW));
/* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
shift = mmu_psize_to_shift(mmu_psize);
sz = ((1UL) << shift);
if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
/* No CPU has hugepages but lacks no execute, so we
* don't need to worry about that case */
rflags = hash_huge_page_do_lazy_icache(rflags, __pte(old_pte),
trap, sz);
/* Check if pte already has an hpte (case 2) */
if (unlikely(old_pte & _PAGE_HASHPTE)) {
/* There MIGHT be an HPTE for this pte */
unsigned long hash, slot;
hash = hpt_hash(va, shift, ssize);
if (old_pte & _PAGE_F_SECOND)
hash = ~hash;
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
slot += (old_pte & _PAGE_F_GIX) >> 12;
if (ppc_md.hpte_updatepp(slot, rflags, va, mmu_psize,
ssize, local) == -1)
old_pte &= ~_PAGE_HPTEFLAGS;
}
if (likely(!(old_pte & _PAGE_HASHPTE))) {
unsigned long hash = hpt_hash(va, shift, ssize);
unsigned long hpte_group;
pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
repeat:
hpte_group = ((hash & htab_hash_mask) *
HPTES_PER_GROUP) & ~0x7UL;
/* clear HPTE slot informations in new PTE */
#ifdef CONFIG_PPC_64K_PAGES
new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HPTE_SUB0;
#else
new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
#endif
/* Add in WIMG bits */
rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
_PAGE_COHERENT | _PAGE_GUARDED));
/* Insert into the hash table, primary slot */
slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags, 0,
mmu_psize, ssize);
/* Primary is full, try the secondary */
if (unlikely(slot == -1)) {
hpte_group = ((~hash & htab_hash_mask) *
HPTES_PER_GROUP) & ~0x7UL;
slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags,
HPTE_V_SECONDARY,
mmu_psize, ssize);
if (slot == -1) {
if (mftb() & 0x1)
hpte_group = ((hash & htab_hash_mask) *
HPTES_PER_GROUP)&~0x7UL;
ppc_md.hpte_remove(hpte_group);
goto repeat;
}
}
if (unlikely(slot == -2))
panic("hash_huge_page: pte_insert failed\n");
new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
}
/*
* No need to use ldarx/stdcx here
*/
*ptep = __pte(new_pte & ~_PAGE_BUSY);
err = 0;
out:
return err;
}
static void __init set_huge_psize(int psize)
{
/* Check that it is a page size supported by the hardware and
* that it fits within pagetable limits. */
if (mmu_psize_defs[psize].shift &&
mmu_psize_defs[psize].shift < SID_SHIFT_1T &&
(mmu_psize_defs[psize].shift > MIN_HUGEPTE_SHIFT ||
mmu_psize_defs[psize].shift == PAGE_SHIFT_64K ||
mmu_psize_defs[psize].shift == PAGE_SHIFT_16G)) {
/* Return if huge page size has already been setup or is the
* same as the base page size. */
if (mmu_huge_psizes[psize] ||
mmu_psize_defs[psize].shift == PAGE_SHIFT)
return;
hugetlb_add_hstate(mmu_psize_defs[psize].shift - PAGE_SHIFT);
switch (mmu_psize_defs[psize].shift) {
case PAGE_SHIFT_64K:
/* We only allow 64k hpages with 4k base page,
* which was checked above, and always put them
* at the PMD */
hugepte_shift[psize] = PMD_SHIFT;
break;
case PAGE_SHIFT_16M:
/* 16M pages can be at two different levels
* of pagestables based on base page size */
if (PAGE_SHIFT == PAGE_SHIFT_64K)
hugepte_shift[psize] = PMD_SHIFT;
else /* 4k base page */
hugepte_shift[psize] = PUD_SHIFT;
break;
case PAGE_SHIFT_16G:
/* 16G pages are always at PGD level */
hugepte_shift[psize] = PGDIR_SHIFT;
break;
}
hugepte_shift[psize] -= mmu_psize_defs[psize].shift;
} else
hugepte_shift[psize] = 0;
}
static int __init hugepage_setup_sz(char *str)
{
unsigned long long size;
int mmu_psize;
int shift;
size = memparse(str, &str);
shift = __ffs(size);
mmu_psize = shift_to_mmu_psize(shift);
if (mmu_psize >= 0 && mmu_psize_defs[mmu_psize].shift)
set_huge_psize(mmu_psize);
else
printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);
return 1;
}
__setup("hugepagesz=", hugepage_setup_sz);
static int __init hugetlbpage_init(void)
{
unsigned int psize;
if (!cpu_has_feature(CPU_FTR_16M_PAGE))
return -ENODEV;
/* Add supported huge page sizes. Need to change HUGE_MAX_HSTATE
* and adjust PTE_NONCACHE_NUM if the number of supported huge page
* sizes changes.
*/
set_huge_psize(MMU_PAGE_16M);
set_huge_psize(MMU_PAGE_16G);
/* Temporarily disable support for 64K huge pages when 64K SPU local
* store support is enabled as the current implementation conflicts.
*/
#ifndef CONFIG_SPU_FS_64K_LS
set_huge_psize(MMU_PAGE_64K);
#endif
for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
if (mmu_huge_psizes[psize]) {
huge_pgtable_cache(psize) = kmem_cache_create(
HUGEPTE_CACHE_NAME(psize),
HUGEPTE_TABLE_SIZE(psize),
HUGEPTE_TABLE_SIZE(psize),
0,
NULL);
if (!huge_pgtable_cache(psize))
panic("hugetlbpage_init(): could not create %s"\
"\n", HUGEPTE_CACHE_NAME(psize));
}
}
return 0;
}
module_init(hugetlbpage_init);
