/*
* PPC Huge TLB Page Support for Kernel.
*
* Copyright (C) 2003 David Gibson, IBM Corporation.
* Copyright (C) 2011 Becky Bruce, Freescale Semiconductor
*
* 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 <linux/export.h>
#include <linux/of_fdt.h>
#include <linux/memblock.h>
#include <linux/moduleparam.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/kmemleak.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/setup.h>
#include <asm/hugetlb.h>
#include <asm/pte-walk.h>
bool hugetlb_disabled = false;
#define hugepd_none(hpd) (hpd_val(hpd) == 0)
#define PTE_T_ORDER (__builtin_ffs(sizeof(pte_t)) - __builtin_ffs(sizeof(void *)))
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz)
{
/*
* Only called for hugetlbfs pages, hence can ignore THP and the
* irq disabled walk.
*/
return __find_linux_pte(mm->pgd, addr, NULL, NULL);
}
static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
unsigned long address, unsigned int pdshift,
unsigned int pshift, spinlock_t *ptl)
{
struct kmem_cache *cachep;
pte_t *new;
int i;
int num_hugepd;
if (pshift >= pdshift) {
cachep = PGT_CACHE(PTE_T_ORDER);
num_hugepd = 1 << (pshift - pdshift);
} else if (IS_ENABLED(CONFIG_PPC_8xx)) {
cachep = PGT_CACHE(PTE_INDEX_SIZE);
num_hugepd = 1;
} else {
cachep = PGT_CACHE(pdshift - pshift);
num_hugepd = 1;
}
if (!cachep) {
WARN_ONCE(1, "No page table cache created for hugetlb tables");
return -ENOMEM;
}
new = kmem_cache_alloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL));
BUG_ON(pshift > HUGEPD_SHIFT_MASK);
BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
if (!new)
return -ENOMEM;
/*
* Make sure other cpus find the hugepd set only after a
* properly initialized page table is visible to them.
* For more details look for comment in __pte_alloc().
*/
smp_wmb();
spin_lock(ptl);
/*
* We have multiple higher-level entries that point to the same
* actual pte location. Fill in each as we go and backtrack on error.
* We need all of these so the DTLB pgtable walk code can find the
* right higher-level entry without knowing if it's a hugepage or not.
*/
for (i = 0; i < num_hugepd; i++, hpdp++) {
if (unlikely(!hugepd_none(*hpdp)))
break;
hugepd_populate(hpdp, new, pshift);
}
/* If we bailed from the for loop early, an error occurred, clean up */
if (i < num_hugepd) {
for (i = i - 1 ; i >= 0; i--, hpdp--)
*hpdp = __hugepd(0);
kmem_cache_free(cachep, new);
} else {
kmemleak_ignore(new);
}
spin_unlock(ptl);
return 0;
}
/*
* At this point we do the placement change only for BOOK3S 64. This would
* possibly work on other subarchs.
*/
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;
spinlock_t *ptl;
addr &= ~(sz-1);
pg = pgd_offset(mm, addr);
#ifdef CONFIG_PPC_BOOK3S_64
if (pshift == PGDIR_SHIFT)
/* 16GB huge page */
return (pte_t *) pg;
else if (pshift > PUD_SHIFT) {
/*
* We need to use hugepd table
*/
ptl = &mm->page_table_lock;
hpdp = (hugepd_t *)pg;
} else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
if (!pu)
return NULL;
if (pshift == PUD_SHIFT)
return (pte_t *)pu;
else if (pshift > PMD_SHIFT) {
ptl = pud_lockptr(mm, pu);
hpdp = (hugepd_t *)pu;
} else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
if (!pm)
return NULL;
if (pshift == PMD_SHIFT)
/* 16MB hugepage */
return (pte_t *)pm;
else {
ptl = pmd_lockptr(mm, pm);
hpdp = (hugepd_t *)pm;
}
}
}
#else
if (pshift >= PGDIR_SHIFT) {
ptl = &mm->page_table_lock;
hpdp = (hugepd_t *)pg;
} else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
if (!pu)
return NULL;
if (pshift >= PUD_SHIFT) {
ptl = pud_lockptr(mm, pu);
hpdp = (hugepd_t *)pu;
} else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
if (!pm)
return NULL;
ptl = pmd_lockptr(mm, pm);
hpdp = (hugepd_t *)pm;
}
}
#endif
if (!hpdp)
return NULL;
BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr,
pdshift, pshift, ptl))
return NULL;
return hugepte_offset(*hpdp, addr, pdshift);
}
#ifdef CONFIG_PPC_BOOK3S_64
/*
* Tracks gpages after the device tree is scanned and before the
* huge_boot_pages list is ready on pseries.
*/
#define MAX_NUMBER_GPAGES 1024
__initdata static u64 gpage_freearray[MAX_NUMBER_GPAGES];
__initdata static unsigned nr_gpages;
/*
* Build list of addresses of gigantic pages. This function is used in early
* boot before the buddy allocator is setup.
*/
void __init pseries_add_gpage(u64 addr, u64 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;
}
}
int __init pseries_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;
}
#endif
int __init alloc_bootmem_huge_page(struct hstate *h)
{
#ifdef CONFIG_PPC_BOOK3S_64
if (firmware_has_feature(FW_FEATURE_LPAR) && !radix_enabled())
return pseries_alloc_bootmem_huge_page(h);
#endif
return __alloc_bootmem_huge_page(h);
}
#ifndef CONFIG_PPC_BOOK3S_64
#define HUGEPD_FREELIST_SIZE \
((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
struct hugepd_freelist {
struct rcu_head rcu;
unsigned int index;
void *ptes[0];
};
static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
static void hugepd_free_rcu_callback(struct rcu_head *head)
{
struct hugepd_freelist *batch =
container_of(head, struct hugepd_freelist, rcu);
unsigned int i;
for (i = 0; i < batch->index; i++)
kmem_cache_free(PGT_CACHE(PTE_T_ORDER), batch->ptes[i]);
free_page((unsigned long)batch);
}
static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
{
struct hugepd_freelist **batchp;
batchp = &get_cpu_var(hugepd_freelist_cur);
if (atomic_read(&tlb->mm->mm_users) < 2 ||
mm_is_thread_local(tlb->mm)) {
kmem_cache_free(PGT_CACHE(PTE_T_ORDER), hugepte);
put_cpu_var(hugepd_freelist_cur);
return;
}
if (*batchp == NULL) {
*batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
(*batchp)->index = 0;
}
(*batchp)->ptes[(*batchp)->index++] = hugepte;
if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
call_rcu(&(*batchp)->rcu, hugepd_free_rcu_callback);
*batchp = NULL;
}
put_cpu_var(hugepd_freelist_cur);
}
#else
static inline void hugepd_free(struct mmu_gather *tlb, void *hugepte) {}
#endif
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);
int i;
unsigned long pdmask = ~((1UL << pdshift) - 1);
unsigned int num_hugepd = 1;
unsigned int shift = hugepd_shift(*hpdp);
/* Note: On fsl the hpdp may be the first of several */
if (shift > pdshift)
num_hugepd = 1 << (shift - pdshift);
start &= pdmask;
if (start < floor)
return;
if (ceiling) {
ceiling &= pdmask;
if (! ceiling)
return;
}
if (end - 1 > ceiling - 1)
return;
for (i = 0; i < num_hugepd; i++, hpdp++)
*hpdp = __hugepd(0);
if (shift >= pdshift)
hugepd_free(tlb, hugepte);
else if (IS_ENABLED(CONFIG_PPC_8xx))
pgtable_free_tlb(tlb, hugepte,
get_hugepd_cache_index(PTE_INDEX_SIZE));
else
pgtable_free_tlb(tlb, hugepte,
get_hugepd_cache_index(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;
do {
unsigned long more;
pmd = pmd_offset(pud, addr);
next = pmd_addr_end(addr, end);
if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
/*
* if it is not hugepd pointer, we should already find
* it cleared.
*/
WARN_ON(!pmd_none_or_clear_bad(pmd));
continue;
}
/*
* Increment next by the size of the huge mapping since
* there may be more than one entry at this level for a
* single hugepage, but all of them point to
* the same kmem cache that holds the hugepte.
*/
more = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
if (more > next)
next = more;
free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
addr, next, floor, ceiling);
} while (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);
mm_dec_nr_pmds(tlb->mm);
}
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;
do {
pud = pud_offset(pgd, addr);
next = pud_addr_end(addr, end);
if (!is_hugepd(__hugepd(pud_val(*pud)))) {
if (pud_none_or_clear_bad(pud))
continue;
hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
ceiling);
} else {
unsigned long more;
/*
* Increment next by the size of the huge mapping since
* there may be more than one entry at this level for a
* single hugepage, but all of them point to
* the same kmem cache that holds the hugepte.
*/
more = addr + (1 << hugepd_shift(*(hugepd_t *)pud));
if (more > next)
next = more;
free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
addr, next, floor, ceiling);
}
} while (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);
mm_dec_nr_puds(tlb->mm);
}
/*
* This function frees user-level page tables of a process.
*/
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.
*/
do {
next = pgd_addr_end(addr, end);
pgd = pgd_offset(tlb->mm, addr);
if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
if (pgd_none_or_clear_bad(pgd))
continue;
hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
} else {
unsigned long more;
/*
* Increment next by the size of the huge mapping since
* there may be more than one entry at the pgd level
* for a single hugepage, but all of them point to the
* same kmem cache that holds the hugepte.
*/
more = addr + (1 << hugepd_shift(*(hugepd_t *)pgd));
if (more > next)
next = more;
free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
addr, next, floor, ceiling);
}
} while (addr = next, addr != end);
}
struct page *follow_huge_pd(struct vm_area_struct *vma,
unsigned long address, hugepd_t hpd,
int flags, int pdshift)
{
pte_t *ptep;
spinlock_t *ptl;
struct page *page = NULL;
unsigned long mask;
int shift = hugepd_shift(hpd);
struct mm_struct *mm = vma->vm_mm;
retry:
/*
* hugepage directory entries are protected by mm->page_table_lock
* Use this instead of huge_pte_lockptr
*/
ptl = &mm->page_table_lock;
spin_lock(ptl);
ptep = hugepte_offset(hpd, address, pdshift);
if (pte_present(*ptep)) {
mask = (1UL << shift) - 1;
page = pte_page(*ptep);
page += ((address & mask) >> PAGE_SHIFT);
if (flags & FOLL_GET)
get_page(page);
} else {
if (is_hugetlb_entry_migration(*ptep)) {
spin_unlock(ptl);
__migration_entry_wait(mm, ptep, ptl);
goto retry;
}
}
spin_unlock(ptl);
return page;
}
#ifdef CONFIG_PPC_MM_SLICES
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));
#ifdef CONFIG_PPC_RADIX_MMU
if (radix_enabled())
return radix__hugetlb_get_unmapped_area(file, addr, len,
pgoff, flags);
#endif
return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
}
#endif
unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
{
/* With radix we don't use slice, so derive it from vma*/
if (IS_ENABLED(CONFIG_PPC_MM_SLICES) && !radix_enabled()) {
unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
return 1UL << mmu_psize_to_shift(psize);
}
return vma_kernel_pagesize(vma);
}
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 (size <= PAGE_SIZE || !is_power_of_2(size))
return -EINVAL;
mmu_psize = check_and_get_huge_psize(shift);
if (mmu_psize < 0)
return -EINVAL;
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) {
hugetlb_bad_size();
pr_err("Invalid huge page size specified(%llu)\n", size);
}
return 1;
}
__setup("hugepagesz=", hugepage_setup_sz);
static int __init hugetlbpage_init(void)
{
bool configured = false;
int psize;
if (hugetlb_disabled) {
pr_info("HugeTLB support is disabled!\n");
return 0;
}
if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled() &&
!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);
#ifdef CONFIG_PPC_BOOK3S_64
if (shift > PGDIR_SHIFT)
continue;
else if (shift > PUD_SHIFT)
pdshift = PGDIR_SHIFT;
else if (shift > PMD_SHIFT)
pdshift = PUD_SHIFT;
else
pdshift = PMD_SHIFT;
#else
if (shift < PUD_SHIFT)
pdshift = PMD_SHIFT;
else if (shift < PGDIR_SHIFT)
pdshift = PUD_SHIFT;
else
pdshift = PGDIR_SHIFT;
#endif
if (add_huge_page_size(1ULL << shift) < 0)
continue;
/*
* if we have pdshift and shift value same, we don't
* use pgt cache for hugepd.
*/
if (pdshift > shift && IS_ENABLED(CONFIG_PPC_8xx))
pgtable_cache_add(PTE_INDEX_SIZE);
else if (pdshift > shift)
pgtable_cache_add(pdshift - shift);
else if (IS_ENABLED(CONFIG_PPC_FSL_BOOK3E) || IS_ENABLED(CONFIG_PPC_8xx))
pgtable_cache_add(PTE_T_ORDER);
configured = true;
}
if (configured) {
if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE))
hugetlbpage_init_default();
} else
pr_info("Failed to initialize. Disabling HugeTLB");
return 0;
}
arch_initcall(hugetlbpage_init);
void flush_dcache_icache_hugepage(struct page *page)
{
int i;
void *start;
BUG_ON(!PageCompound(page));
for (i = 0; i < (1UL << compound_order(page)); i++) {
if (!PageHighMem(page)) {
__flush_dcache_icache(page_address(page+i));
} else {
start = kmap_atomic(page+i);
__flush_dcache_icache(start);
kunmap_atomic(start);
}
}
}
