kernel-ark/arch/powerpc/mm/hugetlbpage.c
Jon Tollefson 4ec161cf73 [POWERPC] Add hugepagesz boot-time parameter
This adds the hugepagesz boot-time parameter for ppc64.  It lets one
pick the size for huge pages.  The choices available are 64K and 16M
when the base page size is 4k.  It defaults to 16M (previously the
only only choice) if nothing or an invalid choice is specified.

Tested 64K huge pages successfully with the libhugetlbfs 1.2.

Signed-off-by: Jon Tollefson <kniht@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-01-17 14:57:36 +11:00

620 lines
15 KiB
C

/*
* 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 HPAGE_SHIFT_64K 16
#define HPAGE_SHIFT_16M 24
#define NUM_LOW_AREAS (0x100000000UL >> SID_SHIFT)
#define NUM_HIGH_AREAS (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
unsigned int hugepte_shift;
#define PTRS_PER_HUGEPTE (1 << hugepte_shift)
#define HUGEPTE_TABLE_SIZE (sizeof(pte_t) << hugepte_shift)
#define HUGEPD_SHIFT (HPAGE_SHIFT + hugepte_shift)
#define HUGEPD_SIZE (1UL << HUGEPD_SHIFT)
#define HUGEPD_MASK (~(HUGEPD_SIZE-1))
#define huge_pgtable_cache (pgtable_cache[HUGEPTE_CACHE_NUM])
/* 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 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)
{
unsigned long idx = ((addr >> HPAGE_SHIFT) & (PTRS_PER_HUGEPTE-1));
pte_t *dir = hugepd_page(*hpdp);
return dir + idx;
}
static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
unsigned long address)
{
pte_t *new = kmem_cache_alloc(huge_pgtable_cache,
GFP_KERNEL|__GFP_REPEAT);
if (! new)
return -ENOMEM;
spin_lock(&mm->page_table_lock);
if (!hugepd_none(*hpdp))
kmem_cache_free(huge_pgtable_cache, new);
else
hpdp->pd = (unsigned long)new | HUGEPD_OK;
spin_unlock(&mm->page_table_lock);
return 0;
}
/* Base page size affects how we walk hugetlb page tables */
#ifdef CONFIG_PPC_64K_PAGES
#define hpmd_offset(pud, addr) pmd_offset(pud, addr)
#define hpmd_alloc(mm, pud, addr) pmd_alloc(mm, pud, addr)
#else
static inline
pmd_t *hpmd_offset(pud_t *pud, unsigned long addr)
{
if (HPAGE_SHIFT == HPAGE_SHIFT_64K)
return pmd_offset(pud, addr);
else
return (pmd_t *) pud;
}
static inline
pmd_t *hpmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr)
{
if (HPAGE_SHIFT == HPAGE_SHIFT_64K)
return pmd_alloc(mm, pud, addr);
else
return (pmd_t *) pud;
}
#endif
/* 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;
BUG_ON(get_slice_psize(mm, addr) != mmu_huge_psize);
addr &= HPAGE_MASK;
pg = pgd_offset(mm, addr);
if (!pgd_none(*pg)) {
pu = pud_offset(pg, addr);
if (!pud_none(*pu)) {
pm = hpmd_offset(pu, addr);
if (!pmd_none(*pm))
return hugepte_offset((hugepd_t *)pm, addr);
}
}
return NULL;
}
pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pg;
pud_t *pu;
pmd_t *pm;
hugepd_t *hpdp = NULL;
BUG_ON(get_slice_psize(mm, addr) != mmu_huge_psize);
addr &= HPAGE_MASK;
pg = pgd_offset(mm, addr);
pu = pud_alloc(mm, pg, addr);
if (pu) {
pm = hpmd_alloc(mm, pu, addr);
if (pm)
hpdp = (hugepd_t *)pm;
}
if (! hpdp)
return NULL;
if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr))
return NULL;
return hugepte_offset(hpdp, addr);
}
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)
{
pte_t *hugepte = hugepd_page(*hpdp);
hpdp->pd = 0;
tlb->need_flush = 1;
pgtable_free_tlb(tlb, pgtable_free_cache(hugepte, HUGEPTE_CACHE_NUM,
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)
{
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);
} 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;
start = addr;
pud = pud_offset(pgd, addr);
do {
next = pud_addr_end(addr, end);
#ifdef CONFIG_PPC_64K_PAGES
if (pud_none_or_clear_bad(pud))
continue;
hugetlb_free_pmd_range(tlb, pud, addr, next, floor, ceiling);
#else
if (HPAGE_SHIFT == HPAGE_SHIFT_64K) {
if (pud_none_or_clear_bad(pud))
continue;
hugetlb_free_pmd_range(tlb, pud, addr, next, floor, ceiling);
} else {
if (pud_none(*pud))
continue;
free_hugepte_range(tlb, (hugepd_t *)pud);
}
#endif
} 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.
*/
addr &= HUGEPD_MASK;
if (addr < floor) {
addr += HUGEPD_SIZE;
if (!addr)
return;
}
if (ceiling) {
ceiling &= HUGEPD_MASK;
if (!ceiling)
return;
}
if (end - 1 > ceiling - 1)
end -= HUGEPD_SIZE;
if (addr > end - 1)
return;
start = addr;
pgd = pgd_offset((*tlb)->mm, addr);
do {
BUG_ON(get_slice_psize((*tlb)->mm, addr) != mmu_huge_psize);
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(pgd))
continue;
hugetlb_free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
} 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
*/
pte_update(mm, addr & HPAGE_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;
if (get_slice_psize(mm, address) != mmu_huge_psize)
return ERR_PTR(-EINVAL);
ptep = huge_pte_offset(mm, address);
page = pte_page(*ptep);
if (page)
page += (address % HPAGE_SIZE) / PAGE_SIZE;
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)
{
BUG();
return NULL;
}
unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags)
{
return slice_get_unmapped_area(addr, len, flags,
mmu_huge_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)
{
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 < (HPAGE_SIZE / 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;
long slot;
int err = 1;
int ssize = user_segment_size(ea);
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 | _PAGE_HASHPTE;
} 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);
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);
/* 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, HPAGE_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_huge_psize,
ssize, local) == -1)
old_pte &= ~_PAGE_HPTEFLAGS;
}
if (likely(!(old_pte & _PAGE_HASHPTE))) {
unsigned long hash = hpt_hash(va, HPAGE_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 */
new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
/* Add in WIMG bits */
/* XXX We should store these in the pte */
/* --BenH: I think they are ... */
rflags |= _PAGE_COHERENT;
/* Insert into the hash table, primary slot */
slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags, 0,
mmu_huge_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_huge_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;
}
void 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 &&
(mmu_psize_defs[psize].shift > MIN_HUGEPTE_SHIFT ||
mmu_psize_defs[psize].shift == HPAGE_SHIFT_64K)) {
HPAGE_SHIFT = mmu_psize_defs[psize].shift;
mmu_huge_psize = psize;
#ifdef CONFIG_PPC_64K_PAGES
hugepte_shift = (PMD_SHIFT-HPAGE_SHIFT);
#else
if (HPAGE_SHIFT == HPAGE_SHIFT_64K)
hugepte_shift = (PMD_SHIFT-HPAGE_SHIFT);
else
hugepte_shift = (PUD_SHIFT-HPAGE_SHIFT);
#endif
} else
HPAGE_SHIFT = 0;
}
static int __init hugepage_setup_sz(char *str)
{
unsigned long long size;
int mmu_psize = -1;
int shift;
size = memparse(str, &str);
shift = __ffs(size);
switch (shift) {
#ifndef CONFIG_PPC_64K_PAGES
case HPAGE_SHIFT_64K:
mmu_psize = MMU_PAGE_64K;
break;
#endif
case HPAGE_SHIFT_16M:
mmu_psize = MMU_PAGE_16M;
break;
}
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 void zero_ctor(struct kmem_cache *cache, void *addr)
{
memset(addr, 0, kmem_cache_size(cache));
}
static int __init hugetlbpage_init(void)
{
if (!cpu_has_feature(CPU_FTR_16M_PAGE))
return -ENODEV;
huge_pgtable_cache = kmem_cache_create("hugepte_cache",
HUGEPTE_TABLE_SIZE,
HUGEPTE_TABLE_SIZE,
0,
zero_ctor);
if (! huge_pgtable_cache)
panic("hugetlbpage_init(): could not create hugepte cache\n");
return 0;
}
module_init(hugetlbpage_init);