blob: 1866b6a5171a4b9190d42418ee9425cb01fce1ed [file] [log] [blame]
/*
* Copyright IBM Corp. 2007, 2011
* 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/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#include <linux/swapops.h>
#include <linux/sysctl.h>
#include <linux/ksm.h>
#include <linux/mman.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
unsigned long *crst_table_alloc(struct mm_struct *mm)
{
struct page *page = alloc_pages(GFP_KERNEL, 2);
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, 2);
}
static void __crst_table_upgrade(void *arg)
{
struct mm_struct *mm = arg;
if (current->active_mm == mm) {
clear_user_asce();
set_user_asce(mm);
}
__tlb_flush_local();
}
int crst_table_upgrade(struct mm_struct *mm)
{
unsigned long *table, *pgd;
/* upgrade should only happen from 3 to 4 levels */
BUG_ON(mm->context.asce_limit != (1UL << 42));
table = crst_table_alloc(mm);
if (!table)
return -ENOMEM;
spin_lock_bh(&mm->page_table_lock);
pgd = (unsigned long *) mm->pgd;
crst_table_init(table, _REGION2_ENTRY_EMPTY);
pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd);
mm->pgd = (pgd_t *) table;
mm->context.asce_limit = 1UL << 53;
mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
_ASCE_USER_BITS | _ASCE_TYPE_REGION2;
mm->task_size = mm->context.asce_limit;
spin_unlock_bh(&mm->page_table_lock);
on_each_cpu(__crst_table_upgrade, mm, 0);
return 0;
}
void crst_table_downgrade(struct mm_struct *mm)
{
pgd_t *pgd;
/* downgrade should only happen from 3 to 2 levels (compat only) */
BUG_ON(mm->context.asce_limit != (1UL << 42));
if (current->active_mm == mm) {
clear_user_asce();
__tlb_flush_mm(mm);
}
pgd = mm->pgd;
mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN);
mm->context.asce_limit = 1UL << 31;
mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
_ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
mm->task_size = mm->context.asce_limit;
crst_table_free(mm, (unsigned long *) pgd);
if (current->active_mm == mm)
set_user_asce(mm);
}
#ifdef CONFIG_PGSTE
/**
* gmap_alloc - allocate a guest address space
* @mm: pointer to the parent mm_struct
* @limit: maximum size of the gmap address space
*
* Returns a guest address space structure.
*/
struct gmap *gmap_alloc(struct mm_struct *mm, unsigned long limit)
{
struct gmap *gmap;
struct page *page;
unsigned long *table;
unsigned long etype, atype;
if (limit < (1UL << 31)) {
limit = (1UL << 31) - 1;
atype = _ASCE_TYPE_SEGMENT;
etype = _SEGMENT_ENTRY_EMPTY;
} else if (limit < (1UL << 42)) {
limit = (1UL << 42) - 1;
atype = _ASCE_TYPE_REGION3;
etype = _REGION3_ENTRY_EMPTY;
} else if (limit < (1UL << 53)) {
limit = (1UL << 53) - 1;
atype = _ASCE_TYPE_REGION2;
etype = _REGION2_ENTRY_EMPTY;
} else {
limit = -1UL;
atype = _ASCE_TYPE_REGION1;
etype = _REGION1_ENTRY_EMPTY;
}
gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL);
if (!gmap)
goto out;
INIT_LIST_HEAD(&gmap->crst_list);
INIT_RADIX_TREE(&gmap->guest_to_host, GFP_KERNEL);
INIT_RADIX_TREE(&gmap->host_to_guest, GFP_ATOMIC);
spin_lock_init(&gmap->guest_table_lock);
gmap->mm = mm;
page = alloc_pages(GFP_KERNEL, 2);
if (!page)
goto out_free;
page->index = 0;
list_add(&page->lru, &gmap->crst_list);
table = (unsigned long *) page_to_phys(page);
crst_table_init(table, etype);
gmap->table = table;
gmap->asce = atype | _ASCE_TABLE_LENGTH |
_ASCE_USER_BITS | __pa(table);
gmap->asce_end = limit;
down_write(&mm->mmap_sem);
list_add(&gmap->list, &mm->context.gmap_list);
up_write(&mm->mmap_sem);
return gmap;
out_free:
kfree(gmap);
out:
return NULL;
}
EXPORT_SYMBOL_GPL(gmap_alloc);
static void gmap_flush_tlb(struct gmap *gmap)
{
if (MACHINE_HAS_IDTE)
__tlb_flush_idte(gmap->asce);
else
__tlb_flush_global();
}
static void gmap_radix_tree_free(struct radix_tree_root *root)
{
struct radix_tree_iter iter;
unsigned long indices[16];
unsigned long index;
void **slot;
int i, nr;
/* A radix tree is freed by deleting all of its entries */
index = 0;
do {
nr = 0;
radix_tree_for_each_slot(slot, root, &iter, index) {
indices[nr] = iter.index;
if (++nr == 16)
break;
}
for (i = 0; i < nr; i++) {
index = indices[i];
radix_tree_delete(root, index);
}
} while (nr > 0);
}
/**
* 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;
/* Flush tlb. */
if (MACHINE_HAS_IDTE)
__tlb_flush_idte(gmap->asce);
else
__tlb_flush_global();
/* Free all segment & region tables. */
list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
__free_pages(page, 2);
gmap_radix_tree_free(&gmap->guest_to_host);
gmap_radix_tree_free(&gmap->host_to_guest);
down_write(&gmap->mm->mmap_sem);
list_del(&gmap->list);
up_write(&gmap->mm->mmap_sem);
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)
{
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)
{
S390_lowcore.gmap = 0UL;
}
EXPORT_SYMBOL_GPL(gmap_disable);
/*
* gmap_alloc_table is assumed to be called with mmap_sem held
*/
static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
unsigned long init, unsigned long gaddr)
{
struct page *page;
unsigned long *new;
/* since we dont free the gmap table until gmap_free we can unlock */
page = alloc_pages(GFP_KERNEL, 2);
if (!page)
return -ENOMEM;
new = (unsigned long *) page_to_phys(page);
crst_table_init(new, init);
spin_lock(&gmap->mm->page_table_lock);
if (*table & _REGION_ENTRY_INVALID) {
list_add(&page->lru, &gmap->crst_list);
*table = (unsigned long) new | _REGION_ENTRY_LENGTH |
(*table & _REGION_ENTRY_TYPE_MASK);
page->index = gaddr;
page = NULL;
}
spin_unlock(&gmap->mm->page_table_lock);
if (page)
__free_pages(page, 2);
return 0;
}
/**
* __gmap_segment_gaddr - find virtual address from segment pointer
* @entry: pointer to a segment table entry in the guest address space
*
* Returns the virtual address in the guest address space for the segment
*/
static unsigned long __gmap_segment_gaddr(unsigned long *entry)
{
struct page *page;
unsigned long offset, mask;
offset = (unsigned long) entry / sizeof(unsigned long);
offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
page = virt_to_page((void *)((unsigned long) entry & mask));
return page->index + offset;
}
/**
* __gmap_unlink_by_vmaddr - unlink a single segment via a host address
* @gmap: pointer to the guest address space structure
* @vmaddr: address in the host process address space
*
* Returns 1 if a TLB flush is required
*/
static int __gmap_unlink_by_vmaddr(struct gmap *gmap, unsigned long vmaddr)
{
unsigned long *entry;
int flush = 0;
spin_lock(&gmap->guest_table_lock);
entry = radix_tree_delete(&gmap->host_to_guest, vmaddr >> PMD_SHIFT);
if (entry) {
flush = (*entry != _SEGMENT_ENTRY_INVALID);
*entry = _SEGMENT_ENTRY_INVALID;
}
spin_unlock(&gmap->guest_table_lock);
return flush;
}
/**
* __gmap_unmap_by_gaddr - unmap a single segment via a guest address
* @gmap: pointer to the guest address space structure
* @gaddr: address in the guest address space
*
* Returns 1 if a TLB flush is required
*/
static int __gmap_unmap_by_gaddr(struct gmap *gmap, unsigned long gaddr)
{
unsigned long vmaddr;
vmaddr = (unsigned long) radix_tree_delete(&gmap->guest_to_host,
gaddr >> PMD_SHIFT);
return vmaddr ? __gmap_unlink_by_vmaddr(gmap, vmaddr) : 0;
}
/**
* gmap_unmap_segment - unmap segment from the guest address space
* @gmap: pointer to the guest address space structure
* @to: address in the guest address space
* @len: length of the memory area to unmap
*
* Returns 0 if the unmap succeeded, -EINVAL if not.
*/
int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
{
unsigned long off;
int flush;
if ((to | len) & (PMD_SIZE - 1))
return -EINVAL;
if (len == 0 || to + len < to)
return -EINVAL;
flush = 0;
down_write(&gmap->mm->mmap_sem);
for (off = 0; off < len; off += PMD_SIZE)
flush |= __gmap_unmap_by_gaddr(gmap, to + off);
up_write(&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
* @len: length of the memory area to map
*
* Returns 0 if the mmap succeeded, -EINVAL or -ENOMEM if not.
*/
int gmap_map_segment(struct gmap *gmap, unsigned long from,
unsigned long to, unsigned long len)
{
unsigned long off;
int flush;
if ((from | to | len) & (PMD_SIZE - 1))
return -EINVAL;
if (len == 0 || from + len < from || to + len < to ||
from + len > TASK_MAX_SIZE || to + len > gmap->asce_end)
return -EINVAL;
flush = 0;
down_write(&gmap->mm->mmap_sem);
for (off = 0; off < len; off += PMD_SIZE) {
/* Remove old translation */
flush |= __gmap_unmap_by_gaddr(gmap, to + off);
/* Store new translation */
if (radix_tree_insert(&gmap->guest_to_host,
(to + off) >> PMD_SHIFT,
(void *) from + off))
break;
}
up_write(&gmap->mm->mmap_sem);
if (flush)
gmap_flush_tlb(gmap);
if (off >= len)
return 0;
gmap_unmap_segment(gmap, to, len);
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(gmap_map_segment);
/**
* __gmap_translate - translate a guest address to a user space address
* @gmap: pointer to guest mapping meta data structure
* @gaddr: guest address
*
* Returns user space address which corresponds to the guest address or
* -EFAULT if no such mapping exists.
* This function does not establish potentially missing page table entries.
* The mmap_sem of the mm that belongs to the address space must be held
* when this function gets called.
*/
unsigned long __gmap_translate(struct gmap *gmap, unsigned long gaddr)
{
unsigned long vmaddr;
vmaddr = (unsigned long)
radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT);
return vmaddr ? (vmaddr | (gaddr & ~PMD_MASK)) : -EFAULT;
}
EXPORT_SYMBOL_GPL(__gmap_translate);
/**
* gmap_translate - translate a guest address to a user space address
* @gmap: pointer to guest mapping meta data structure
* @gaddr: guest address
*
* Returns user space address which corresponds to the guest address or
* -EFAULT if no such mapping exists.
* This function does not establish potentially missing page table entries.
*/
unsigned long gmap_translate(struct gmap *gmap, unsigned long gaddr)
{
unsigned long rc;
down_read(&gmap->mm->mmap_sem);
rc = __gmap_translate(gmap, gaddr);
up_read(&gmap->mm->mmap_sem);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_translate);
/**
* gmap_unlink - disconnect a page table from the gmap shadow tables
* @gmap: pointer to guest mapping meta data structure
* @table: pointer to the host page table
* @vmaddr: vm address associated with the host page table
*/
static void gmap_unlink(struct mm_struct *mm, unsigned long *table,
unsigned long vmaddr)
{
struct gmap *gmap;
int flush;
list_for_each_entry(gmap, &mm->context.gmap_list, list) {
flush = __gmap_unlink_by_vmaddr(gmap, vmaddr);
if (flush)
gmap_flush_tlb(gmap);
}
}
/**
* gmap_link - set up shadow page tables to connect a host to a guest address
* @gmap: pointer to guest mapping meta data structure
* @gaddr: guest address
* @vmaddr: vm address
*
* Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
* if the vm address is already mapped to a different guest segment.
* The mmap_sem of the mm that belongs to the address space must be held
* when this function gets called.
*/
int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
{
struct mm_struct *mm;
unsigned long *table;
spinlock_t *ptl;
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
int rc;
/* Create higher level tables in the gmap page table */
table = gmap->table;
if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION1) {
table += (gaddr >> 53) & 0x7ff;
if ((*table & _REGION_ENTRY_INVALID) &&
gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY,
gaddr & 0xffe0000000000000UL))
return -ENOMEM;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
}
if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION2) {
table += (gaddr >> 42) & 0x7ff;
if ((*table & _REGION_ENTRY_INVALID) &&
gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY,
gaddr & 0xfffffc0000000000UL))
return -ENOMEM;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
}
if ((gmap->asce & _ASCE_TYPE_MASK) >= _ASCE_TYPE_REGION3) {
table += (gaddr >> 31) & 0x7ff;
if ((*table & _REGION_ENTRY_INVALID) &&
gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY,
gaddr & 0xffffffff80000000UL))
return -ENOMEM;
table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
}
table += (gaddr >> 20) & 0x7ff;
/* Walk the parent mm page table */
mm = gmap->mm;
pgd = pgd_offset(mm, vmaddr);
VM_BUG_ON(pgd_none(*pgd));
pud = pud_offset(pgd, vmaddr);
VM_BUG_ON(pud_none(*pud));
pmd = pmd_offset(pud, vmaddr);
VM_BUG_ON(pmd_none(*pmd));
/* large pmds cannot yet be handled */
if (pmd_large(*pmd))
return -EFAULT;
/* Link gmap segment table entry location to page table. */
rc = radix_tree_preload(GFP_KERNEL);
if (rc)
return rc;
ptl = pmd_lock(mm, pmd);
spin_lock(&gmap->guest_table_lock);
if (*table == _SEGMENT_ENTRY_INVALID) {
rc = radix_tree_insert(&gmap->host_to_guest,
vmaddr >> PMD_SHIFT, table);
if (!rc)
*table = pmd_val(*pmd);
} else
rc = 0;
spin_unlock(&gmap->guest_table_lock);
spin_unlock(ptl);
radix_tree_preload_end();
return rc;
}
/**
* gmap_fault - resolve a fault on a guest address
* @gmap: pointer to guest mapping meta data structure
* @gaddr: guest address
* @fault_flags: flags to pass down to handle_mm_fault()
*
* Returns 0 on success, -ENOMEM for out of memory conditions, and -EFAULT
* if the vm address is already mapped to a different guest segment.
*/
int gmap_fault(struct gmap *gmap, unsigned long gaddr,
unsigned int fault_flags)
{
unsigned long vmaddr;
int rc;
down_read(&gmap->mm->mmap_sem);
vmaddr = __gmap_translate(gmap, gaddr);
if (IS_ERR_VALUE(vmaddr)) {
rc = vmaddr;
goto out_up;
}
if (fixup_user_fault(current, gmap->mm, vmaddr, fault_flags)) {
rc = -EFAULT;
goto out_up;
}
rc = __gmap_link(gmap, gaddr, vmaddr);
out_up:
up_read(&gmap->mm->mmap_sem);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_fault);
static void gmap_zap_swap_entry(swp_entry_t entry, struct mm_struct *mm)
{
if (!non_swap_entry(entry))
dec_mm_counter(mm, MM_SWAPENTS);
else if (is_migration_entry(entry)) {
struct page *page = migration_entry_to_page(entry);
if (PageAnon(page))
dec_mm_counter(mm, MM_ANONPAGES);
else
dec_mm_counter(mm, MM_FILEPAGES);
}
free_swap_and_cache(entry);
}
/*
* this function is assumed to be called with mmap_sem held
*/
void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
{
unsigned long vmaddr, ptev, pgstev;
pte_t *ptep, pte;
spinlock_t *ptl;
pgste_t pgste;
/* Find the vm address for the guest address */
vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host,
gaddr >> PMD_SHIFT);
if (!vmaddr)
return;
vmaddr |= gaddr & ~PMD_MASK;
/* Get pointer to the page table entry */
ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
if (unlikely(!ptep))
return;
pte = *ptep;
if (!pte_swap(pte))
goto out_pte;
/* Zap unused and logically-zero pages */
pgste = pgste_get_lock(ptep);
pgstev = pgste_val(pgste);
ptev = pte_val(pte);
if (((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED) ||
((pgstev & _PGSTE_GPS_ZERO) && (ptev & _PAGE_INVALID))) {
gmap_zap_swap_entry(pte_to_swp_entry(pte), gmap->mm);
pte_clear(gmap->mm, vmaddr, ptep);
}
pgste_set_unlock(ptep, pgste);
out_pte:
pte_unmap_unlock(ptep, ptl);
}
EXPORT_SYMBOL_GPL(__gmap_zap);
void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to)
{
unsigned long gaddr, vmaddr, size;
struct vm_area_struct *vma;
down_read(&gmap->mm->mmap_sem);
for (gaddr = from; gaddr < to;
gaddr = (gaddr + PMD_SIZE) & PMD_MASK) {
/* Find the vm address for the guest address */
vmaddr = (unsigned long)
radix_tree_lookup(&gmap->guest_to_host,
gaddr >> PMD_SHIFT);
if (!vmaddr)
continue;
vmaddr |= gaddr & ~PMD_MASK;
/* Find vma in the parent mm */
vma = find_vma(gmap->mm, vmaddr);
if (!vma)
continue;
size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
zap_page_range(vma, vmaddr, size, NULL);
}
up_read(&gmap->mm->mmap_sem);
}
EXPORT_SYMBOL_GPL(gmap_discard);
static LIST_HEAD(gmap_notifier_list);
static DEFINE_SPINLOCK(gmap_notifier_lock);
/**
* gmap_register_ipte_notifier - register a pte invalidation callback
* @nb: pointer to the gmap notifier block
*/
void gmap_register_ipte_notifier(struct gmap_notifier *nb)
{
spin_lock(&gmap_notifier_lock);
list_add(&nb->list, &gmap_notifier_list);
spin_unlock(&gmap_notifier_lock);
}
EXPORT_SYMBOL_GPL(gmap_register_ipte_notifier);
/**
* gmap_unregister_ipte_notifier - remove a pte invalidation callback
* @nb: pointer to the gmap notifier block
*/
void gmap_unregister_ipte_notifier(struct gmap_notifier *nb)
{
spin_lock(&gmap_notifier_lock);
list_del_init(&nb->list);
spin_unlock(&gmap_notifier_lock);
}
EXPORT_SYMBOL_GPL(gmap_unregister_ipte_notifier);
/**
* gmap_ipte_notify - mark a range of ptes for invalidation notification
* @gmap: pointer to guest mapping meta data structure
* @gaddr: virtual address in the guest address space
* @len: size of area
*
* Returns 0 if for each page in the given range a gmap mapping exists and
* the invalidation notification could be set. If the gmap mapping is missing
* for one or more pages -EFAULT is returned. If no memory could be allocated
* -ENOMEM is returned. This function establishes missing page table entries.
*/
int gmap_ipte_notify(struct gmap *gmap, unsigned long gaddr, unsigned long len)
{
unsigned long addr;
spinlock_t *ptl;
pte_t *ptep, entry;
pgste_t pgste;
int rc = 0;
if ((gaddr & ~PAGE_MASK) || (len & ~PAGE_MASK))
return -EINVAL;
down_read(&gmap->mm->mmap_sem);
while (len) {
/* Convert gmap address and connect the page tables */
addr = __gmap_translate(gmap, gaddr);
if (IS_ERR_VALUE(addr)) {
rc = addr;
break;
}
/* Get the page mapped */
if (fixup_user_fault(current, gmap->mm, addr, FAULT_FLAG_WRITE)) {
rc = -EFAULT;
break;
}
rc = __gmap_link(gmap, gaddr, addr);
if (rc)
break;
/* Walk the process page table, lock and get pte pointer */
ptep = get_locked_pte(gmap->mm, addr, &ptl);
VM_BUG_ON(!ptep);
/* Set notification bit in the pgste of the pte */
entry = *ptep;
if ((pte_val(entry) & (_PAGE_INVALID | _PAGE_PROTECT)) == 0) {
pgste = pgste_get_lock(ptep);
pgste_val(pgste) |= PGSTE_IN_BIT;
pgste_set_unlock(ptep, pgste);
gaddr += PAGE_SIZE;
len -= PAGE_SIZE;
}
pte_unmap_unlock(ptep, ptl);
}
up_read(&gmap->mm->mmap_sem);
return rc;
}
EXPORT_SYMBOL_GPL(gmap_ipte_notify);
/**
* gmap_do_ipte_notify - call all invalidation callbacks for a specific pte.
* @mm: pointer to the process mm_struct
* @addr: virtual address in the process address space
* @pte: pointer to the page table entry
*
* This function is assumed to be called with the page table lock held
* for the pte to notify.
*/
void gmap_do_ipte_notify(struct mm_struct *mm, unsigned long vmaddr, pte_t *pte)
{
unsigned long offset, gaddr;
unsigned long *table;
struct gmap_notifier *nb;
struct gmap *gmap;
offset = ((unsigned long) pte) & (255 * sizeof(pte_t));
offset = offset * (4096 / sizeof(pte_t));
spin_lock(&gmap_notifier_lock);
list_for_each_entry(gmap, &mm->context.gmap_list, list) {
table = radix_tree_lookup(&gmap->host_to_guest,
vmaddr >> PMD_SHIFT);
if (!table)
continue;
gaddr = __gmap_segment_gaddr(table) + offset;
list_for_each_entry(nb, &gmap_notifier_list, list)
nb->notifier_call(gmap, gaddr);
}
spin_unlock(&gmap_notifier_lock);
}
EXPORT_SYMBOL_GPL(gmap_do_ipte_notify);
int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned long key, bool nq)
{
spinlock_t *ptl;
pgste_t old, new;
pte_t *ptep;
down_read(&mm->mmap_sem);
retry:
ptep = get_locked_pte(mm, addr, &ptl);
if (unlikely(!ptep)) {
up_read(&mm->mmap_sem);
return -EFAULT;
}
if (!(pte_val(*ptep) & _PAGE_INVALID) &&
(pte_val(*ptep) & _PAGE_PROTECT)) {
pte_unmap_unlock(ptep, ptl);
if (fixup_user_fault(current, mm, addr, FAULT_FLAG_WRITE)) {
up_read(&mm->mmap_sem);
return -EFAULT;
}
goto retry;
}
new = old = pgste_get_lock(ptep);
pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
PGSTE_ACC_BITS | PGSTE_FP_BIT);
pgste_val(new) |= (key & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
pgste_val(new) |= (key & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
unsigned long address, bits, skey;
address = pte_val(*ptep) & PAGE_MASK;
skey = (unsigned long) page_get_storage_key(address);
bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
/* Set storage key ACC and FP */
page_set_storage_key(address, skey, !nq);
/* Merge host changed & referenced into pgste */
pgste_val(new) |= bits << 52;
}
/* changing the guest storage key is considered a change of the page */
if ((pgste_val(new) ^ pgste_val(old)) &
(PGSTE_ACC_BITS | PGSTE_FP_BIT | PGSTE_GR_BIT | PGSTE_GC_BIT))
pgste_val(new) |= PGSTE_UC_BIT;
pgste_set_unlock(ptep, new);
pte_unmap_unlock(ptep, ptl);
up_read(&mm->mmap_sem);
return 0;
}
EXPORT_SYMBOL(set_guest_storage_key);
unsigned long get_guest_storage_key(struct mm_struct *mm, unsigned long addr)
{
spinlock_t *ptl;
pgste_t pgste;
pte_t *ptep;
uint64_t physaddr;
unsigned long key = 0;
down_read(&mm->mmap_sem);
ptep = get_locked_pte(mm, addr, &ptl);
if (unlikely(!ptep)) {
up_read(&mm->mmap_sem);
return -EFAULT;
}
pgste = pgste_get_lock(ptep);
if (pte_val(*ptep) & _PAGE_INVALID) {
key |= (pgste_val(pgste) & PGSTE_ACC_BITS) >> 56;
key |= (pgste_val(pgste) & PGSTE_FP_BIT) >> 56;
key |= (pgste_val(pgste) & PGSTE_GR_BIT) >> 48;
key |= (pgste_val(pgste) & PGSTE_GC_BIT) >> 48;
} else {
physaddr = pte_val(*ptep) & PAGE_MASK;
key = page_get_storage_key(physaddr);
/* Reflect guest's logical view, not physical */
if (pgste_val(pgste) & PGSTE_GR_BIT)
key |= _PAGE_REFERENCED;
if (pgste_val(pgste) & PGSTE_GC_BIT)
key |= _PAGE_CHANGED;
}
pgste_set_unlock(ptep, pgste);
pte_unmap_unlock(ptep, ptl);
up_read(&mm->mmap_sem);
return key;
}
EXPORT_SYMBOL(get_guest_storage_key);
static int page_table_allocate_pgste_min = 0;
static int page_table_allocate_pgste_max = 1;
int page_table_allocate_pgste = 0;
EXPORT_SYMBOL(page_table_allocate_pgste);
static struct ctl_table page_table_sysctl[] = {
{
.procname = "allocate_pgste",
.data = &page_table_allocate_pgste,
.maxlen = sizeof(int),
.mode = S_IRUGO | S_IWUSR,
.proc_handler = proc_dointvec,
.extra1 = &page_table_allocate_pgste_min,
.extra2 = &page_table_allocate_pgste_max,
},
{ }
};
static struct ctl_table page_table_sysctl_dir[] = {
{
.procname = "vm",
.maxlen = 0,
.mode = 0555,
.child = page_table_sysctl,
},
{ }
};
static int __init page_table_register_sysctl(void)
{
return register_sysctl_table(page_table_sysctl_dir) ? 0 : -ENOMEM;
}
__initcall(page_table_register_sysctl);
#else /* CONFIG_PGSTE */
static inline void gmap_unlink(struct mm_struct *mm, unsigned long *table,
unsigned long vmaddr)
{
}
#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 *table;
struct page *page;
unsigned int mask, bit;
/* Try to get a fragment of a 4K page as a 2K page table */
if (!mm_alloc_pgste(mm)) {
table = NULL;
spin_lock_bh(&mm->context.list_lock);
if (!list_empty(&mm->context.pgtable_list)) {
page = list_first_entry(&mm->context.pgtable_list,
struct page, lru);
mask = atomic_read(&page->_mapcount);
mask = (mask | (mask >> 4)) & 3;
if (mask != 3) {
table = (unsigned long *) page_to_phys(page);
bit = mask & 1; /* =1 -> second 2K */
if (bit)
table += PTRS_PER_PTE;
atomic_xor_bits(&page->_mapcount, 1U << bit);
list_del(&page->lru);
}
}
spin_unlock_bh(&mm->context.list_lock);
if (table)
return table;
}
/* Allocate a fresh page */
page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
if (!page)
return NULL;
if (!pgtable_page_ctor(page)) {
__free_page(page);
return NULL;
}
/* Initialize page table */
table = (unsigned long *) page_to_phys(page);
if (mm_alloc_pgste(mm)) {
/* Return 4K page table with PGSTEs */
atomic_set(&page->_mapcount, 3);
clear_table(table, _PAGE_INVALID, PAGE_SIZE/2);
clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2);
} else {
/* Return the first 2K fragment of the page */
atomic_set(&page->_mapcount, 1);
clear_table(table, _PAGE_INVALID, PAGE_SIZE);
spin_lock_bh(&mm->context.list_lock);
list_add(&page->lru, &mm->context.pgtable_list);
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;
page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
if (!mm_alloc_pgste(mm)) {
/* Free 2K page table fragment of a 4K page */
bit = (__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
spin_lock_bh(&mm->context.list_lock);
mask = atomic_xor_bits(&page->_mapcount, 1U << bit);
if (mask & 3)
list_add(&page->lru, &mm->context.pgtable_list);
else
list_del(&page->lru);
spin_unlock_bh(&mm->context.list_lock);
if (mask != 0)
return;
}
pgtable_page_dtor(page);
atomic_set(&page->_mapcount, -1);
__free_page(page);
}
void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
unsigned long vmaddr)
{
struct mm_struct *mm;
struct page *page;
unsigned int bit, mask;
mm = tlb->mm;
page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
if (mm_alloc_pgste(mm)) {
gmap_unlink(mm, table, vmaddr);
table = (unsigned long *) (__pa(table) | 3);
tlb_remove_table(tlb, table);
return;
}
bit = (__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t));
spin_lock_bh(&mm->context.list_lock);
mask = atomic_xor_bits(&page->_mapcount, 0x11U << bit);
if (mask & 3)
list_add_tail(&page->lru, &mm->context.pgtable_list);
else
list_del(&page->lru);
spin_unlock_bh(&mm->context.list_lock);
table = (unsigned long *) (__pa(table) | (1U << bit));
tlb_remove_table(tlb, table);
}
static void __tlb_remove_table(void *_table)
{
unsigned int mask = (unsigned long) _table & 3;
void *table = (void *)((unsigned long) _table ^ mask);
struct page *page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
switch (mask) {
case 0: /* pmd or pud */
free_pages((unsigned long) table, 2);
break;
case 1: /* lower 2K of a 4K page table */
case 2: /* higher 2K of a 4K page table */
if (atomic_xor_bits(&page->_mapcount, mask << 4) != 0)
break;
/* fallthrough */
case 3: /* 4K page table with pgstes */
pgtable_page_dtor(page);
atomic_set(&page->_mapcount, -1);
__free_page(page);
break;
}
}
static void tlb_remove_table_smp_sync(void *arg)
{
/* Simply deliver the interrupt */
}
static void tlb_remove_table_one(void *table)
{
/*
* This isn't an RCU grace period and hence the page-tables cannot be
* assumed to be actually RCU-freed.
*
* It is however sufficient for software page-table walkers that rely
* on IRQ disabling. See the comment near struct mmu_table_batch.
*/
smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
__tlb_remove_table(table);
}
static void tlb_remove_table_rcu(struct rcu_head *head)
{
struct mmu_table_batch *batch;
int i;
batch = container_of(head, struct mmu_table_batch, rcu);
for (i = 0; i < batch->nr; i++)
__tlb_remove_table(batch->tables[i]);
free_page((unsigned long)batch);
}
void tlb_table_flush(struct mmu_gather *tlb)
{
struct mmu_table_batch **batch = &tlb->batch;
if (*batch) {
call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
*batch = NULL;
}
}
void tlb_remove_table(struct mmu_gather *tlb, void *table)
{
struct mmu_table_batch **batch = &tlb->batch;
tlb->mm->context.flush_mm = 1;
if (*batch == NULL) {
*batch = (struct mmu_table_batch *)
__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
if (*batch == NULL) {
__tlb_flush_mm_lazy(tlb->mm);
tlb_remove_table_one(table);
return;
}
(*batch)->nr = 0;
}
(*batch)->tables[(*batch)->nr++] = table;
if ((*batch)->nr == MAX_TABLE_BATCH)
tlb_flush_mmu(tlb);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline void thp_split_vma(struct vm_area_struct *vma)
{
unsigned long addr;
for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE)
follow_page(vma, addr, FOLL_SPLIT);
}
static inline void thp_split_mm(struct mm_struct *mm)
{
struct vm_area_struct *vma;
for (vma = mm->mmap; vma != NULL; vma = vma->vm_next) {
thp_split_vma(vma);
vma->vm_flags &= ~VM_HUGEPAGE;
vma->vm_flags |= VM_NOHUGEPAGE;
}
mm->def_flags |= VM_NOHUGEPAGE;
}
#else
static inline void thp_split_mm(struct mm_struct *mm)
{
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
/*
* switch on pgstes for its userspace process (for kvm)
*/
int s390_enable_sie(void)
{
struct mm_struct *mm = current->mm;
/* Do we have pgstes? if yes, we are done */
if (mm_has_pgste(mm))
return 0;
/* Fail if the page tables are 2K */
if (!mm_alloc_pgste(mm))
return -EINVAL;
down_write(&mm->mmap_sem);
mm->context.has_pgste = 1;
/* split thp mappings and disable thp for future mappings */
thp_split_mm(mm);
up_write(&mm->mmap_sem);
return 0;
}
EXPORT_SYMBOL_GPL(s390_enable_sie);
/*
* Enable storage key handling from now on and initialize the storage
* keys with the default key.
*/
static int __s390_enable_skey(pte_t *pte, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
unsigned long ptev;
pgste_t pgste;
pgste = pgste_get_lock(pte);
/*
* Remove all zero page mappings,
* after establishing a policy to forbid zero page mappings
* following faults for that page will get fresh anonymous pages
*/
if (is_zero_pfn(pte_pfn(*pte))) {
ptep_flush_direct(walk->mm, addr, pte);
pte_val(*pte) = _PAGE_INVALID;
}
/* Clear storage key */
pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT |
PGSTE_GR_BIT | PGSTE_GC_BIT);
ptev = pte_val(*pte);
if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
pgste_set_unlock(pte, pgste);
return 0;
}
int s390_enable_skey(void)
{
struct mm_walk walk = { .pte_entry = __s390_enable_skey };
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
int rc = 0;
down_write(&mm->mmap_sem);
if (mm_use_skey(mm))
goto out_up;
mm->context.use_skey = 1;
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
MADV_UNMERGEABLE, &vma->vm_flags)) {
mm->context.use_skey = 0;
rc = -ENOMEM;
goto out_up;
}
}
mm->def_flags &= ~VM_MERGEABLE;
walk.mm = mm;
walk_page_range(0, TASK_SIZE, &walk);
out_up:
up_write(&mm->mmap_sem);
return rc;
}
EXPORT_SYMBOL_GPL(s390_enable_skey);
/*
* Reset CMMA state, make all pages stable again.
*/
static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pgste_t pgste;
pgste = pgste_get_lock(pte);
pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
pgste_set_unlock(pte, pgste);
return 0;
}
void s390_reset_cmma(struct mm_struct *mm)
{
struct mm_walk walk = { .pte_entry = __s390_reset_cmma };
down_write(&mm->mmap_sem);
walk.mm = mm;
walk_page_range(0, TASK_SIZE, &walk);
up_write(&mm->mmap_sem);
}
EXPORT_SYMBOL_GPL(s390_reset_cmma);
/*
* Test and reset if a guest page is dirty
*/
bool gmap_test_and_clear_dirty(unsigned long address, struct gmap *gmap)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
spinlock_t *ptl;
bool dirty = false;
pgd = pgd_offset(gmap->mm, address);
pud = pud_alloc(gmap->mm, pgd, address);
if (!pud)
return false;
pmd = pmd_alloc(gmap->mm, pud, address);
if (!pmd)
return false;
/* We can't run guests backed by huge pages, but userspace can
* still set them up and then try to migrate them without any
* migration support.
*/
if (pmd_large(*pmd))
return true;
pte = pte_alloc_map_lock(gmap->mm, pmd, address, &ptl);
if (unlikely(!pte))
return false;
if (ptep_test_and_clear_user_dirty(gmap->mm, address, pte))
dirty = true;
spin_unlock(ptl);
return dirty;
}
EXPORT_SYMBOL_GPL(gmap_test_and_clear_dirty);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
int pmdp_clear_flush_young(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
/* No need to flush TLB
* On s390 reference bits are in storage key and never in TLB */
return pmdp_test_and_clear_young(vma, address, pmdp);
}
int pmdp_set_access_flags(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp,
pmd_t entry, int dirty)
{
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
entry = pmd_mkyoung(entry);
if (dirty)
entry = pmd_mkdirty(entry);
if (pmd_same(*pmdp, entry))
return 0;
pmdp_invalidate(vma, address, pmdp);
set_pmd_at(vma->vm_mm, address, pmdp, entry);
return 1;
}
static void pmdp_splitting_flush_sync(void *arg)
{
/* Simply deliver the interrupt */
}
void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
if (!test_and_set_bit(_SEGMENT_ENTRY_SPLIT_BIT,
(unsigned long *) pmdp)) {
/* need to serialize against gup-fast (IRQ disabled) */
smp_call_function(pmdp_splitting_flush_sync, NULL, 1);
}
}
void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pgtable)
{
struct list_head *lh = (struct list_head *) pgtable;
assert_spin_locked(pmd_lockptr(mm, pmdp));
/* FIFO */
if (!pmd_huge_pte(mm, pmdp))
INIT_LIST_HEAD(lh);
else
list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
pmd_huge_pte(mm, pmdp) = pgtable;
}
pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
{
struct list_head *lh;
pgtable_t pgtable;
pte_t *ptep;
assert_spin_locked(pmd_lockptr(mm, pmdp));
/* FIFO */
pgtable = pmd_huge_pte(mm, pmdp);
lh = (struct list_head *) pgtable;
if (list_empty(lh))
pmd_huge_pte(mm, pmdp) = NULL;
else {
pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
list_del(lh);
}
ptep = (pte_t *) pgtable;
pte_val(*ptep) = _PAGE_INVALID;
ptep++;
pte_val(*ptep) = _PAGE_INVALID;
return pgtable;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */