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linux/arch/s390/mm/pgtable.c
Martin Schwidefsky e5992f2e6c [S390] kvm guest address space mapping 
Add code that allows KVM to control the virtual memory layout that
is seen by a guest. The guest address space uses a second page table
that shares the last level pte-tables with the process page table.
If a page is unmapped from the process page table it is automatically
unmapped from the guest page table as well.

The guest address space mapping starts out empty, KVM can map any
individual 1MB segments from the process virtual memory to any 1MB
aligned location in the guest virtual memory. If a target segment in
the process virtual memory does not exist or is unmapped while a
guest mapping exists the desired target address is stored as an
invalid segment table entry in the guest page table.
The population of the guest page table is fault driven.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-07-24 10:48:21 +02:00

757 lines
20 KiB
C
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/*
* Copyright IBM Corp. 2007,2009
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/quicklist.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#ifndef CONFIG_64BIT
#define ALLOC_ORDER 1
#define FRAG_MASK 0x0f
#else
#define ALLOC_ORDER 2
#define FRAG_MASK 0x03
#endif
unsigned long VMALLOC_START = VMALLOC_END - VMALLOC_SIZE;
EXPORT_SYMBOL(VMALLOC_START);
static int __init parse_vmalloc(char *arg)
{
if (!arg)
return -EINVAL;
VMALLOC_START = (VMALLOC_END - memparse(arg, &arg)) & PAGE_MASK;
return 0;
}
early_param("vmalloc", parse_vmalloc);
unsigned long *crst_table_alloc(struct mm_struct *mm)
{
struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
if (!page)
return NULL;
return (unsigned long *) page_to_phys(page);
}
void crst_table_free(struct mm_struct *mm, unsigned long *table)
{
free_pages((unsigned long) table, ALLOC_ORDER);
}
#ifdef CONFIG_64BIT
int crst_table_upgrade(struct mm_struct *mm, unsigned long limit)
{
unsigned long *table, *pgd;
unsigned long entry;
BUG_ON(limit > (1UL << 53));
repeat:
table = crst_table_alloc(mm);
if (!table)
return -ENOMEM;
spin_lock_bh(&mm->page_table_lock);
if (mm->context.asce_limit < limit) {
pgd = (unsigned long *) mm->pgd;
if (mm->context.asce_limit <= (1UL << 31)) {
entry = _REGION3_ENTRY_EMPTY;
mm->context.asce_limit = 1UL << 42;
mm->context.asce_bits = _ASCE_TABLE_LENGTH |
_ASCE_USER_BITS |
_ASCE_TYPE_REGION3;
} else {
entry = _REGION2_ENTRY_EMPTY;
mm->context.asce_limit = 1UL << 53;
mm->context.asce_bits = _ASCE_TABLE_LENGTH |
_ASCE_USER_BITS |
_ASCE_TYPE_REGION2;
}
crst_table_init(table, entry);
pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd);
mm->pgd = (pgd_t *) table;
mm->task_size = mm->context.asce_limit;
table = NULL;
}
spin_unlock_bh(&mm->page_table_lock);
if (table)
crst_table_free(mm, table);
if (mm->context.asce_limit < limit)
goto repeat;
update_mm(mm, current);
return 0;
}
void crst_table_downgrade(struct mm_struct *mm, unsigned long limit)
{
pgd_t *pgd;
if (mm->context.asce_limit <= limit)
return;
__tlb_flush_mm(mm);
while (mm->context.asce_limit > limit) {
pgd = mm->pgd;
switch (pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) {
case _REGION_ENTRY_TYPE_R2:
mm->context.asce_limit = 1UL << 42;
mm->context.asce_bits = _ASCE_TABLE_LENGTH |
_ASCE_USER_BITS |
_ASCE_TYPE_REGION3;
break;
case _REGION_ENTRY_TYPE_R3:
mm->context.asce_limit = 1UL << 31;
mm->context.asce_bits = _ASCE_TABLE_LENGTH |
_ASCE_USER_BITS |
_ASCE_TYPE_SEGMENT;
break;
default:
BUG();
}
mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN);
mm->task_size = mm->context.asce_limit;
crst_table_free(mm, (unsigned long *) pgd);
}
update_mm(mm, current);
}
#endif
#ifdef CONFIG_PGSTE
/**
* gmap_alloc - allocate a guest address space
* @mm: pointer to the parent mm_struct
*
* Returns a guest address space structure.
*/
struct gmap *gmap_alloc(struct mm_struct *mm)
{
struct gmap *gmap;
struct page *page;
unsigned long *table;
gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL);
if (!gmap)
goto out;
INIT_LIST_HEAD(&gmap->crst_list);
gmap->mm = mm;
page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
if (!page)
goto out_free;
list_add(&page->lru, &gmap->crst_list);
table = (unsigned long *) page_to_phys(page);
crst_table_init(table, _REGION1_ENTRY_EMPTY);
gmap->table = table;
list_add(&gmap->list, &mm->context.gmap_list);
return gmap;
out_free:
kfree(gmap);
out:
return NULL;
}
EXPORT_SYMBOL_GPL(gmap_alloc);
static int gmap_unlink_segment(struct gmap *gmap, unsigned long *table)
{
struct gmap_pgtable *mp;
struct gmap_rmap *rmap;
struct page *page;
if (*table & _SEGMENT_ENTRY_INV)
return 0;
page = pfn_to_page(*table >> PAGE_SHIFT);
mp = (struct gmap_pgtable *) page->index;
list_for_each_entry(rmap, &mp->mapper, list) {
if (rmap->entry != table)
continue;
list_del(&rmap->list);
kfree(rmap);
break;
}
*table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
return 1;
}
static void gmap_flush_tlb(struct gmap *gmap)
{
if (MACHINE_HAS_IDTE)
__tlb_flush_idte((unsigned long) gmap->table |
_ASCE_TYPE_REGION1);
else
__tlb_flush_global();
}
/**
* gmap_free - free a guest address space
* @gmap: pointer to the guest address space structure
*/
void gmap_free(struct gmap *gmap)
{
struct page *page, *next;
unsigned long *table;
int i;
/* Flush tlb. */
if (MACHINE_HAS_IDTE)
__tlb_flush_idte((unsigned long) gmap->table |
_ASCE_TYPE_REGION1);
else
__tlb_flush_global();
/* Free all segment & region tables. */
down_read(&gmap->mm->mmap_sem);
list_for_each_entry_safe(page, next, &gmap->crst_list, lru) {
table = (unsigned long *) page_to_phys(page);
if ((*table & _REGION_ENTRY_TYPE_MASK) == 0)
/* Remove gmap rmap structures for segment table. */
for (i = 0; i < PTRS_PER_PMD; i++, table++)
gmap_unlink_segment(gmap, table);
__free_pages(page, ALLOC_ORDER);
}
up_read(&gmap->mm->mmap_sem);
list_del(&gmap->list);
kfree(gmap);
}
EXPORT_SYMBOL_GPL(gmap_free);
/**
* gmap_enable - switch primary space to the guest address space
* @gmap: pointer to the guest address space structure
*/
void gmap_enable(struct gmap *gmap)
{
/* Load primary space page table origin. */
S390_lowcore.user_asce = _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH |
_ASCE_USER_BITS | __pa(gmap->table);
asm volatile("lctlg 1,1,%0\n" : : "m" (S390_lowcore.user_asce) );
S390_lowcore.gmap = (unsigned long) gmap;
}
EXPORT_SYMBOL_GPL(gmap_enable);
/**
* gmap_disable - switch back to the standard primary address space
* @gmap: pointer to the guest address space structure
*/
void gmap_disable(struct gmap *gmap)
{
/* Load primary space page table origin. */
S390_lowcore.user_asce =
gmap->mm->context.asce_bits | __pa(gmap->mm->pgd);
asm volatile("lctlg 1,1,%0\n" : : "m" (S390_lowcore.user_asce) );
S390_lowcore.gmap = 0UL;
}
EXPORT_SYMBOL_GPL(gmap_disable);
static int gmap_alloc_table(struct gmap *gmap,
unsigned long *table, unsigned long init)
{
struct page *page;
unsigned long *new;
page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
if (!page)
return -ENOMEM;
new = (unsigned long *) page_to_phys(page);
crst_table_init(new, init);
down_read(&gmap->mm->mmap_sem);
if (*table & _REGION_ENTRY_INV) {
list_add(&page->lru, &gmap->crst_list);
*table = (unsigned long) new | _REGION_ENTRY_LENGTH |
(*table & _REGION_ENTRY_TYPE_MASK);
} else
__free_pages(page, ALLOC_ORDER);
up_read(&gmap->mm->mmap_sem);
return 0;
}
/**
* gmap_unmap_segment - unmap segment from the guest address space
* @gmap: pointer to the guest address space structure
* @addr: address in the guest address space
* @len: length of the memory area to unmap
*
* Returns 0 if the unmap succeded, -EINVAL if not.
*/
int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
{
unsigned long *table;
unsigned long off;
int flush;
if ((to | len) & (PMD_SIZE - 1))
return -EINVAL;
if (len == 0 || to + len < to)
return -EINVAL;
flush = 0;
down_read(&gmap->mm->mmap_sem);
for (off = 0; off < len; off += PMD_SIZE) {
/* Walk the guest addr space page table */
table = gmap->table + (((to + off) >> 53) & 0x7ff);
if (*table & _REGION_ENTRY_INV)
return 0;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
table = table + (((to + off) >> 42) & 0x7ff);
if (*table & _REGION_ENTRY_INV)
return 0;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
table = table + (((to + off) >> 31) & 0x7ff);
if (*table & _REGION_ENTRY_INV)
return 0;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
table = table + (((to + off) >> 20) & 0x7ff);
/* Clear segment table entry in guest address space. */
flush |= gmap_unlink_segment(gmap, table);
*table = _SEGMENT_ENTRY_INV;
}
up_read(&gmap->mm->mmap_sem);
if (flush)
gmap_flush_tlb(gmap);
return 0;
}
EXPORT_SYMBOL_GPL(gmap_unmap_segment);
/**
* gmap_mmap_segment - map a segment to the guest address space
* @gmap: pointer to the guest address space structure
* @from: source address in the parent address space
* @to: target address in the guest address space
*
* Returns 0 if the mmap succeded, -EINVAL or -ENOMEM if not.
*/
int gmap_map_segment(struct gmap *gmap, unsigned long from,
unsigned long to, unsigned long len)
{
unsigned long *table;
unsigned long off;
int flush;
if ((from | to | len) & (PMD_SIZE - 1))
return -EINVAL;
if (len == 0 || from + len > PGDIR_SIZE ||
from + len < from || to + len < to)
return -EINVAL;
flush = 0;
down_read(&gmap->mm->mmap_sem);
for (off = 0; off < len; off += PMD_SIZE) {
/* Walk the gmap address space page table */
table = gmap->table + (((to + off) >> 53) & 0x7ff);
if ((*table & _REGION_ENTRY_INV) &&
gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY))
goto out_unmap;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
table = table + (((to + off) >> 42) & 0x7ff);
if ((*table & _REGION_ENTRY_INV) &&
gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY))
goto out_unmap;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
table = table + (((to + off) >> 31) & 0x7ff);
if ((*table & _REGION_ENTRY_INV) &&
gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY))
goto out_unmap;
table = (unsigned long *) (*table & _REGION_ENTRY_ORIGIN);
table = table + (((to + off) >> 20) & 0x7ff);
/* Store 'from' address in an invalid segment table entry. */
flush |= gmap_unlink_segment(gmap, table);
*table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | (from + off);
}
up_read(&gmap->mm->mmap_sem);
if (flush)
gmap_flush_tlb(gmap);
return 0;
out_unmap:
up_read(&gmap->mm->mmap_sem);
gmap_unmap_segment(gmap, to, len);
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(gmap_map_segment);
unsigned long gmap_fault(unsigned long address, struct gmap *gmap)
{
unsigned long *table, vmaddr, segment;
struct mm_struct *mm;
struct gmap_pgtable *mp;
struct gmap_rmap *rmap;
struct vm_area_struct *vma;
struct page *page;
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
current->thread.gmap_addr = address;
mm = gmap->mm;
/* Walk the gmap address space page table */
table = gmap->table + ((address >> 53) & 0x7ff);
if (unlikely(*table & _REGION_ENTRY_INV))
return -EFAULT;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
table = table + ((address >> 42) & 0x7ff);
if (unlikely(*table & _REGION_ENTRY_INV))
return -EFAULT;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
table = table + ((address >> 31) & 0x7ff);
if (unlikely(*table & _REGION_ENTRY_INV))
return -EFAULT;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
table = table + ((address >> 20) & 0x7ff);
/* Convert the gmap address to an mm address. */
segment = *table;
if (likely(!(segment & _SEGMENT_ENTRY_INV))) {
page = pfn_to_page(segment >> PAGE_SHIFT);
mp = (struct gmap_pgtable *) page->index;
return mp->vmaddr | (address & ~PMD_MASK);
} else if (segment & _SEGMENT_ENTRY_RO) {
vmaddr = segment & _SEGMENT_ENTRY_ORIGIN;
vma = find_vma(mm, vmaddr);
if (!vma || vma->vm_start > vmaddr)
return -EFAULT;
/* Walk the parent mm page table */
pgd = pgd_offset(mm, vmaddr);
pud = pud_alloc(mm, pgd, vmaddr);
if (!pud)
return -ENOMEM;
pmd = pmd_alloc(mm, pud, vmaddr);
if (!pmd)
return -ENOMEM;
if (!pmd_present(*pmd) &&
__pte_alloc(mm, vma, pmd, vmaddr))
return -ENOMEM;
/* pmd now points to a valid segment table entry. */
rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT);
if (!rmap)
return -ENOMEM;
/* Link gmap segment table entry location to page table. */
page = pmd_page(*pmd);
mp = (struct gmap_pgtable *) page->index;
rmap->entry = table;
list_add(&rmap->list, &mp->mapper);
/* Set gmap segment table entry to page table. */
*table = pmd_val(*pmd) & PAGE_MASK;
return vmaddr | (address & ~PMD_MASK);
}
return -EFAULT;
}
EXPORT_SYMBOL_GPL(gmap_fault);
void gmap_unmap_notifier(struct mm_struct *mm, unsigned long *table)
{
struct gmap_rmap *rmap, *next;
struct gmap_pgtable *mp;
struct page *page;
int flush;
flush = 0;
spin_lock(&mm->page_table_lock);
page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
mp = (struct gmap_pgtable *) page->index;
list_for_each_entry_safe(rmap, next, &mp->mapper, list) {
*rmap->entry =
_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr;
list_del(&rmap->list);
kfree(rmap);
flush = 1;
}
spin_unlock(&mm->page_table_lock);
if (flush)
__tlb_flush_global();
}
static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
unsigned long vmaddr)
{
struct page *page;
unsigned long *table;
struct gmap_pgtable *mp;
page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
if (!page)
return NULL;
mp = kmalloc(sizeof(*mp), GFP_KERNEL|__GFP_REPEAT);
if (!mp) {
__free_page(page);
return NULL;
}
pgtable_page_ctor(page);
mp->vmaddr = vmaddr & PMD_MASK;
INIT_LIST_HEAD(&mp->mapper);
page->index = (unsigned long) mp;
atomic_set(&page->_mapcount, 3);
table = (unsigned long *) page_to_phys(page);
clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE/2);
clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
return table;
}
static inline void page_table_free_pgste(unsigned long *table)
{
struct page *page;
struct gmap_pgtable *mp;
page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
mp = (struct gmap_pgtable *) page->index;
BUG_ON(!list_empty(&mp->mapper));
pgtable_page_ctor(page);
atomic_set(&page->_mapcount, -1);
kfree(mp);
__free_page(page);
}
#else /* CONFIG_PGSTE */
static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
unsigned long vmaddr)
{
}
static inline void page_table_free_pgste(unsigned long *table)
{
}
static inline void gmap_unmap_notifier(struct mm_struct *mm,
unsigned long *table)
{
}
#endif /* CONFIG_PGSTE */
static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
{
unsigned int old, new;
do {
old = atomic_read(v);
new = old ^ bits;
} while (atomic_cmpxchg(v, old, new) != old);
return new;
}
/*
* page table entry allocation/free routines.
*/
unsigned long *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr)
{
struct page *page;
unsigned long *table;
unsigned int mask, bit;
if (mm_has_pgste(mm))
return page_table_alloc_pgste(mm, vmaddr);
/* Allocate fragments of a 4K page as 1K/2K page table */
spin_lock_bh(&mm->context.list_lock);
mask = FRAG_MASK;
if (!list_empty(&mm->context.pgtable_list)) {
page = list_first_entry(&mm->context.pgtable_list,
struct page, lru);
table = (unsigned long *) page_to_phys(page);
mask = atomic_read(&page->_mapcount);
mask = mask | (mask >> 4);
}
if ((mask & FRAG_MASK) == FRAG_MASK) {
spin_unlock_bh(&mm->context.list_lock);
page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
if (!page)
return NULL;
pgtable_page_ctor(page);
atomic_set(&page->_mapcount, 1);
table = (unsigned long *) page_to_phys(page);
clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE);
spin_lock_bh(&mm->context.list_lock);
list_add(&page->lru, &mm->context.pgtable_list);
} else {
for (bit = 1; mask & bit; bit <<= 1)
table += PTRS_PER_PTE;
mask = atomic_xor_bits(&page->_mapcount, bit);
if ((mask & FRAG_MASK) == FRAG_MASK)
list_del(&page->lru);
}
spin_unlock_bh(&mm->context.list_lock);
return table;
}
void page_table_free(struct mm_struct *mm, unsigned long *table)
{
struct page *page;
unsigned int bit, mask;
if (mm_has_pgste(mm)) {
gmap_unmap_notifier(mm, table);
return page_table_free_pgste(table);
}
/* Free 1K/2K page table fragment of a 4K page */
page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
bit = 1 << ((__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t)));
spin_lock_bh(&mm->context.list_lock);
if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
list_del(&page->lru);
mask = atomic_xor_bits(&page->_mapcount, bit);
if (mask & FRAG_MASK)
list_add(&page->lru, &mm->context.pgtable_list);
spin_unlock_bh(&mm->context.list_lock);
if (mask == 0) {
pgtable_page_dtor(page);
atomic_set(&page->_mapcount, -1);
__free_page(page);
}
}
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
static void __page_table_free_rcu(void *table, unsigned bit)
{
struct page *page;
if (bit == FRAG_MASK)
return page_table_free_pgste(table);
/* Free 1K/2K page table fragment of a 4K page */
page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
if (atomic_xor_bits(&page->_mapcount, bit) == 0) {
pgtable_page_dtor(page);
atomic_set(&page->_mapcount, -1);
__free_page(page);
}
}
void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table)
{
struct mm_struct *mm;
struct page *page;
unsigned int bit, mask;
mm = tlb->mm;
if (mm_has_pgste(mm)) {
gmap_unmap_notifier(mm, table);
table = (unsigned long *) (__pa(table) | FRAG_MASK);
tlb_remove_table(tlb, table);
return;
}
bit = 1 << ((__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t)));
page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
spin_lock_bh(&mm->context.list_lock);
if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK)
list_del(&page->lru);
mask = atomic_xor_bits(&page->_mapcount, bit | (bit << 4));
if (mask & FRAG_MASK)
list_add_tail(&page->lru, &mm->context.pgtable_list);
spin_unlock_bh(&mm->context.list_lock);
table = (unsigned long *) (__pa(table) | (bit << 4));
tlb_remove_table(tlb, table);
}
void __tlb_remove_table(void *_table)
{
void *table = (void *)((unsigned long) _table & PAGE_MASK);
unsigned type = (unsigned long) _table & ~PAGE_MASK;
if (type)
__page_table_free_rcu(table, type);
else
free_pages((unsigned long) table, ALLOC_ORDER);
}
#endif
/*
* switch on pgstes for its userspace process (for kvm)
*/
int s390_enable_sie(void)
{
struct task_struct *tsk = current;
struct mm_struct *mm, *old_mm;
/* Do we have switched amode? If no, we cannot do sie */
if (user_mode == HOME_SPACE_MODE)
return -EINVAL;
/* Do we have pgstes? if yes, we are done */
if (mm_has_pgste(tsk->mm))
return 0;
/* lets check if we are allowed to replace the mm */
task_lock(tsk);
if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
#ifdef CONFIG_AIO
!hlist_empty(&tsk->mm->ioctx_list) ||
#endif
tsk->mm != tsk->active_mm) {
task_unlock(tsk);
return -EINVAL;
}
task_unlock(tsk);
/* we copy the mm and let dup_mm create the page tables with_pgstes */
tsk->mm->context.alloc_pgste = 1;
mm = dup_mm(tsk);
tsk->mm->context.alloc_pgste = 0;
if (!mm)
return -ENOMEM;
/* Now lets check again if something happened */
task_lock(tsk);
if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||
#ifdef CONFIG_AIO
!hlist_empty(&tsk->mm->ioctx_list) ||
#endif
tsk->mm != tsk->active_mm) {
mmput(mm);
task_unlock(tsk);
return -EINVAL;
}
/* ok, we are alone. No ptrace, no threads, etc. */
old_mm = tsk->mm;
tsk->mm = tsk->active_mm = mm;
preempt_disable();
update_mm(mm, tsk);
atomic_inc(&mm->context.attach_count);
atomic_dec(&old_mm->context.attach_count);
cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
preempt_enable();
task_unlock(tsk);
mmput(old_mm);
return 0;
}
EXPORT_SYMBOL_GPL(s390_enable_sie);
#if defined(CONFIG_DEBUG_PAGEALLOC) && defined(CONFIG_HIBERNATION)
bool kernel_page_present(struct page *page)
{
unsigned long addr;
int cc;
addr = page_to_phys(page);
asm volatile(
" lra %1,0(%1)\n"
" ipm %0\n"
" srl %0,28"
: "=d" (cc), "+a" (addr) : : "cc");
return cc == 0;
}
#endif /* CONFIG_HIBERNATION && CONFIG_DEBUG_PAGEALLOC */
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