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OpenCloudOS-Kernel/arch/ppc64/mm/hugetlbpage.c

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/*
* 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/smp_lock.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/tlb.h>
#include <linux/sysctl.h>
#define NUM_LOW_AREAS (0x100000000UL >> SID_SHIFT)
#define NUM_HIGH_AREAS (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
/* 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;
pte_t *pt;
BUG_ON(! in_hugepage_area(mm->context, addr));
addr &= HPAGE_MASK;
pg = pgd_offset(mm, addr);
if (!pgd_none(*pg)) {
pu = pud_offset(pg, addr);
if (!pud_none(*pu)) {
pm = pmd_offset(pu, addr);
pt = (pte_t *)pm;
BUG_ON(!pmd_none(*pm)
&& !(pte_present(*pt) && pte_huge(*pt)));
return pt;
}
}
return NULL;
}
pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pg;
pud_t *pu;
pmd_t *pm;
pte_t *pt;
BUG_ON(! in_hugepage_area(mm->context, addr));
addr &= HPAGE_MASK;
pg = pgd_offset(mm, addr);
pu = pud_alloc(mm, pg, addr);
if (pu) {
pm = pmd_alloc(mm, pu, addr);
if (pm) {
pt = (pte_t *)pm;
BUG_ON(!pmd_none(*pm)
&& !(pte_present(*pt) && pte_huge(*pt)));
return pt;
}
}
return NULL;
}
#define HUGEPTE_BATCH_SIZE (HPAGE_SIZE / PMD_SIZE)
void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
int i;
if (pte_present(*ptep)) {
pte_clear(mm, addr, ptep);
flush_tlb_pending();
}
for (i = 0; i < HUGEPTE_BATCH_SIZE; i++) {
*ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
ptep++;
}
}
pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
unsigned long old = pte_update(ptep, ~0UL);
int i;
if (old & _PAGE_HASHPTE)
hpte_update(mm, addr, old, 0);
for (i = 1; i < HUGEPTE_BATCH_SIZE; i++)
ptep[i] = __pte(0);
return __pte(old);
}
/*
* This function checks for proper alignment of input addr and len parameters.
*/
int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
{
if (len & ~HPAGE_MASK)
return -EINVAL;
if (addr & ~HPAGE_MASK)
return -EINVAL;
if (! (within_hugepage_low_range(addr, len)
|| within_hugepage_high_range(addr, len)) )
return -EINVAL;
return 0;
}
static void flush_low_segments(void *parm)
{
u16 areas = (unsigned long) parm;
unsigned long i;
asm volatile("isync" : : : "memory");
BUILD_BUG_ON((sizeof(areas)*8) != NUM_LOW_AREAS);
for (i = 0; i < NUM_LOW_AREAS; i++) {
if (! (areas & (1U << i)))
continue;
asm volatile("slbie %0"
: : "r" ((i << SID_SHIFT) | SLBIE_C));
}
asm volatile("isync" : : : "memory");
}
static void flush_high_segments(void *parm)
{
u16 areas = (unsigned long) parm;
unsigned long i, j;
asm volatile("isync" : : : "memory");
BUILD_BUG_ON((sizeof(areas)*8) != NUM_HIGH_AREAS);
for (i = 0; i < NUM_HIGH_AREAS; i++) {
if (! (areas & (1U << i)))
continue;
for (j = 0; j < (1UL << (HTLB_AREA_SHIFT-SID_SHIFT)); j++)
asm volatile("slbie %0"
:: "r" (((i << HTLB_AREA_SHIFT)
+ (j << SID_SHIFT)) | SLBIE_C));
}
asm volatile("isync" : : : "memory");
}
static int prepare_low_area_for_htlb(struct mm_struct *mm, unsigned long area)
{
unsigned long start = area << SID_SHIFT;
unsigned long end = (area+1) << SID_SHIFT;
struct vm_area_struct *vma;
BUG_ON(area >= NUM_LOW_AREAS);
/* Check no VMAs are in the region */
vma = find_vma(mm, start);
if (vma && (vma->vm_start < end))
return -EBUSY;
return 0;
}
static int prepare_high_area_for_htlb(struct mm_struct *mm, unsigned long area)
{
unsigned long start = area << HTLB_AREA_SHIFT;
unsigned long end = (area+1) << HTLB_AREA_SHIFT;
struct vm_area_struct *vma;
BUG_ON(area >= NUM_HIGH_AREAS);
/* Check no VMAs are in the region */
vma = find_vma(mm, start);
if (vma && (vma->vm_start < end))
return -EBUSY;
return 0;
}
static int open_low_hpage_areas(struct mm_struct *mm, u16 newareas)
{
unsigned long i;
BUILD_BUG_ON((sizeof(newareas)*8) != NUM_LOW_AREAS);
BUILD_BUG_ON((sizeof(mm->context.low_htlb_areas)*8) != NUM_LOW_AREAS);
newareas &= ~(mm->context.low_htlb_areas);
if (! newareas)
return 0; /* The segments we want are already open */
for (i = 0; i < NUM_LOW_AREAS; i++)
if ((1 << i) & newareas)
if (prepare_low_area_for_htlb(mm, i) != 0)
return -EBUSY;
mm->context.low_htlb_areas |= newareas;
/* update the paca copy of the context struct */
get_paca()->context = mm->context;
/* the context change must make it to memory before the flush,
* so that further SLB misses do the right thing. */
mb();
on_each_cpu(flush_low_segments, (void *)(unsigned long)newareas, 0, 1);
return 0;
}
static int open_high_hpage_areas(struct mm_struct *mm, u16 newareas)
{
unsigned long i;
BUILD_BUG_ON((sizeof(newareas)*8) != NUM_HIGH_AREAS);
BUILD_BUG_ON((sizeof(mm->context.high_htlb_areas)*8)
!= NUM_HIGH_AREAS);
newareas &= ~(mm->context.high_htlb_areas);
if (! newareas)
return 0; /* The areas we want are already open */
for (i = 0; i < NUM_HIGH_AREAS; i++)
if ((1 << i) & newareas)
if (prepare_high_area_for_htlb(mm, i) != 0)
return -EBUSY;
mm->context.high_htlb_areas |= newareas;
/* update the paca copy of the context struct */
get_paca()->context = mm->context;
/* the context change must make it to memory before the flush,
* so that further SLB misses do the right thing. */
mb();
on_each_cpu(flush_high_segments, (void *)(unsigned long)newareas, 0, 1);
return 0;
}
int prepare_hugepage_range(unsigned long addr, unsigned long len)
{
int err;
if ( (addr+len) < addr )
return -EINVAL;
if ((addr + len) < 0x100000000UL)
err = open_low_hpage_areas(current->mm,
LOW_ESID_MASK(addr, len));
else
err = open_high_hpage_areas(current->mm,
HTLB_AREA_MASK(addr, len));
if (err) {
printk(KERN_DEBUG "prepare_hugepage_range(%lx, %lx)"
" failed (lowmask: 0x%04hx, highmask: 0x%04hx)\n",
addr, len,
LOW_ESID_MASK(addr, len), HTLB_AREA_MASK(addr, len));
return err;
}
return 0;
}
struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
pte_t *ptep;
struct page *page;
if (! in_hugepage_area(mm->context, address))
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;
}
/* Because we have an exclusive hugepage region which lies within the
* normal user address space, we have to take special measures to make
* non-huge mmap()s evade the hugepage reserved regions. */
unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long start_addr;
if (len > TASK_SIZE)
return -ENOMEM;
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (((TASK_SIZE - len) >= addr)
&& (!vma || (addr+len) <= vma->vm_start)
&& !is_hugepage_only_range(mm, addr,len))
return addr;
}
if (len > mm->cached_hole_size) {
start_addr = addr = mm->free_area_cache;
} else {
start_addr = addr = TASK_UNMAPPED_BASE;
mm->cached_hole_size = 0;
}
full_search:
vma = find_vma(mm, addr);
while (TASK_SIZE - len >= addr) {
BUG_ON(vma && (addr >= vma->vm_end));
if (touches_hugepage_low_range(mm, addr, len)) {
addr = ALIGN(addr+1, 1<<SID_SHIFT);
vma = find_vma(mm, addr);
continue;
}
if (touches_hugepage_high_range(mm, addr, len)) {
addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT);
vma = find_vma(mm, addr);
continue;
}
if (!vma || addr + len <= vma->vm_start) {
/*
* Remember the place where we stopped the search:
*/
mm->free_area_cache = addr + len;
return addr;
}
if (addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
addr = vma->vm_end;
vma = vma->vm_next;
}
/* Make sure we didn't miss any holes */
if (start_addr != TASK_UNMAPPED_BASE) {
start_addr = addr = TASK_UNMAPPED_BASE;
mm->cached_hole_size = 0;
goto full_search;
}
return -ENOMEM;
}
/*
* This mmap-allocator allocates new areas top-down from below the
* stack's low limit (the base):
*
* Because we have an exclusive hugepage region which lies within the
* normal user address space, we have to take special measures to make
* non-huge mmap()s evade the hugepage reserved regions.
*/
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
struct vm_area_struct *vma, *prev_vma;
struct mm_struct *mm = current->mm;
unsigned long base = mm->mmap_base, addr = addr0;
unsigned long largest_hole = mm->cached_hole_size;
int first_time = 1;
/* requested length too big for entire address space */
if (len > TASK_SIZE)
return -ENOMEM;
/* dont allow allocations above current base */
if (mm->free_area_cache > base)
mm->free_area_cache = base;
/* requesting a specific address */
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr &&
(!vma || addr + len <= vma->vm_start)
&& !is_hugepage_only_range(mm, addr,len))
return addr;
}
if (len <= largest_hole) {
largest_hole = 0;
mm->free_area_cache = base;
}
try_again:
/* make sure it can fit in the remaining address space */
if (mm->free_area_cache < len)
goto fail;
/* either no address requested or cant fit in requested address hole */
addr = (mm->free_area_cache - len) & PAGE_MASK;
do {
hugepage_recheck:
if (touches_hugepage_low_range(mm, addr, len)) {
addr = (addr & ((~0) << SID_SHIFT)) - len;
goto hugepage_recheck;
} else if (touches_hugepage_high_range(mm, addr, len)) {
addr = (addr & ((~0UL) << HTLB_AREA_SHIFT)) - len;
goto hugepage_recheck;
}
/*
* Lookup failure means no vma is above this address,
* i.e. return with success:
*/
if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
return addr;
/*
* new region fits between prev_vma->vm_end and
* vma->vm_start, use it:
*/
if (addr+len <= vma->vm_start &&
(!prev_vma || (addr >= prev_vma->vm_end))) {
/* remember the address as a hint for next time */
mm->cached_hole_size = largest_hole;
return (mm->free_area_cache = addr);
} else {
/* pull free_area_cache down to the first hole */
if (mm->free_area_cache == vma->vm_end) {
mm->free_area_cache = vma->vm_start;
mm->cached_hole_size = largest_hole;
}
}
/* remember the largest hole we saw so far */
if (addr + largest_hole < vma->vm_start)
largest_hole = vma->vm_start - addr;
/* try just below the current vma->vm_start */
addr = vma->vm_start-len;
} while (len <= vma->vm_start);
fail:
/*
* if hint left us with no space for the requested
* mapping then try again:
*/
if (first_time) {
mm->free_area_cache = base;
largest_hole = 0;
first_time = 0;
goto try_again;
}
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
mm->free_area_cache = TASK_UNMAPPED_BASE;
mm->cached_hole_size = ~0UL;
addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
/*
* Restore the topdown base:
*/
mm->free_area_cache = base;
mm->cached_hole_size = ~0UL;
return addr;
}
static unsigned long htlb_get_low_area(unsigned long len, u16 segmask)
{
unsigned long addr = 0;
struct vm_area_struct *vma;
vma = find_vma(current->mm, addr);
while (addr + len <= 0x100000000UL) {
BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */
if (! __within_hugepage_low_range(addr, len, segmask)) {
addr = ALIGN(addr+1, 1<<SID_SHIFT);
vma = find_vma(current->mm, addr);
continue;
}
if (!vma || (addr + len) <= vma->vm_start)
return addr;
addr = ALIGN(vma->vm_end, HPAGE_SIZE);
/* Depending on segmask this might not be a confirmed
* hugepage region, so the ALIGN could have skipped
* some VMAs */
vma = find_vma(current->mm, addr);
}
return -ENOMEM;
}
static unsigned long htlb_get_high_area(unsigned long len, u16 areamask)
{
unsigned long addr = 0x100000000UL;
struct vm_area_struct *vma;
vma = find_vma(current->mm, addr);
while (addr + len <= TASK_SIZE_USER64) {
BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */
if (! __within_hugepage_high_range(addr, len, areamask)) {
addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT);
vma = find_vma(current->mm, addr);
continue;
}
if (!vma || (addr + len) <= vma->vm_start)
return addr;
addr = ALIGN(vma->vm_end, HPAGE_SIZE);
/* Depending on segmask this might not be a confirmed
* hugepage region, so the ALIGN could have skipped
* some VMAs */
vma = find_vma(current->mm, addr);
}
return -ENOMEM;
}
unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags)
{
int lastshift;
u16 areamask, curareas;
if (len & ~HPAGE_MASK)
return -EINVAL;
if (!cpu_has_feature(CPU_FTR_16M_PAGE))
return -EINVAL;
if (test_thread_flag(TIF_32BIT)) {
curareas = current->mm->context.low_htlb_areas;
/* First see if we can do the mapping in the existing
* low areas */
addr = htlb_get_low_area(len, curareas);
if (addr != -ENOMEM)
return addr;
lastshift = 0;
for (areamask = LOW_ESID_MASK(0x100000000UL-len, len);
! lastshift; areamask >>=1) {
if (areamask & 1)
lastshift = 1;
addr = htlb_get_low_area(len, curareas | areamask);
if ((addr != -ENOMEM)
&& open_low_hpage_areas(current->mm, areamask) == 0)
return addr;
}
} else {
curareas = current->mm->context.high_htlb_areas;
/* First see if we can do the mapping in the existing
* high areas */
addr = htlb_get_high_area(len, curareas);
if (addr != -ENOMEM)
return addr;
lastshift = 0;
for (areamask = HTLB_AREA_MASK(TASK_SIZE_USER64-len, len);
! lastshift; areamask >>=1) {
if (areamask & 1)
lastshift = 1;
addr = htlb_get_high_area(len, curareas | areamask);
if ((addr != -ENOMEM)
&& open_high_hpage_areas(current->mm, areamask) == 0)
return addr;
}
}
printk(KERN_DEBUG "hugetlb_get_unmapped_area() unable to open"
" enough areas\n");
return -ENOMEM;
}
int hash_huge_page(struct mm_struct *mm, unsigned long access,
unsigned long ea, unsigned long vsid, int local)
{
pte_t *ptep;
unsigned long va, vpn;
pte_t old_pte, new_pte;
unsigned long rflags, prpn;
long slot;
int err = 1;
spin_lock(&mm->page_table_lock);
ptep = huge_pte_offset(mm, ea);
/* Search the Linux page table for a match with va */
va = (vsid << 28) | (ea & 0x0fffffff);
vpn = va >> HPAGE_SHIFT;
/*
* If no pte found or not present, send the problem up to
* do_page_fault
*/
if (unlikely(!ptep || pte_none(*ptep)))
goto out;
/* BUG_ON(pte_bad(*ptep)); */
/*
* 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.
*/
old_pte = *ptep;
new_pte = old_pte;
rflags = 0x2 | (! (pte_val(new_pte) & _PAGE_RW));
/* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
rflags |= ((pte_val(new_pte) & _PAGE_EXEC) ? 0 : HW_NO_EXEC);
/* Check if pte already has an hpte (case 2) */
if (unlikely(pte_val(old_pte) & _PAGE_HASHPTE)) {
/* There MIGHT be an HPTE for this pte */
unsigned long hash, slot;
hash = hpt_hash(vpn, 1);
if (pte_val(old_pte) & _PAGE_SECONDARY)
hash = ~hash;
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
slot += (pte_val(old_pte) & _PAGE_GROUP_IX) >> 12;
if (ppc_md.hpte_updatepp(slot, rflags, va, 1, local) == -1)
pte_val(old_pte) &= ~_PAGE_HPTEFLAGS;
}
if (likely(!(pte_val(old_pte) & _PAGE_HASHPTE))) {
unsigned long hash = hpt_hash(vpn, 1);
unsigned long hpte_group;
prpn = pte_pfn(old_pte);
repeat:
hpte_group = ((hash & htab_hash_mask) *
HPTES_PER_GROUP) & ~0x7UL;
/* Update the linux pte with the HPTE slot */
pte_val(new_pte) &= ~_PAGE_HPTEFLAGS;
pte_val(new_pte) |= _PAGE_HASHPTE;
/* Add in WIMG bits */
/* XXX We should store these in the pte */
rflags |= _PAGE_COHERENT;
slot = ppc_md.hpte_insert(hpte_group, va, prpn,
HPTE_V_LARGE, rflags);
/* Primary is full, try the secondary */
if (unlikely(slot == -1)) {
pte_val(new_pte) |= _PAGE_SECONDARY;
hpte_group = ((~hash & htab_hash_mask) *
HPTES_PER_GROUP) & ~0x7UL;
slot = ppc_md.hpte_insert(hpte_group, va, prpn,
HPTE_V_LARGE |
HPTE_V_SECONDARY,
rflags);
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");
pte_val(new_pte) |= (slot<<12) & _PAGE_GROUP_IX;
/*
* No need to use ldarx/stdcx here because all who
* might be updating the pte will hold the
* page_table_lock
*/
*ptep = new_pte;
}
err = 0;
out:
spin_unlock(&mm->page_table_lock);
return err;
}
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