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linux/arch/s390/mm/pgtable.c
Niklas Schnelle b02002cc4c s390/pci: Implement ioremap_wc/prot() with MIO 
With our current support for the new MIO PCI instructions, write
combining/write back MMIO memory can be obtained via the pci_iomap_wc()
and pci_iomap_wc_range() functions.
This is achieved by using the write back address for a specific bar
as provided in clp_store_query_pci_fn()

These functions are however not widely used and instead drivers often
rely on ioremap_wc() and ioremap_prot(), which on other platforms enable
write combining using a PTE flag set through the pgrprot value.

While we do not have a write combining flag in the low order flag bits
of the PTE like x86_64 does, with MIO support, there is a write back bit
in the physical address (bit 1 on z15) and thus also the PTE.
Which bit is used to toggle write back and whether it is available at
all, is however not fixed in the architecture. Instead we get this
information from the CLP Store Logical Processor Characteristics for PCI
command. When the write back bit is not provided we fall back to the
existing behavior.

Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-09-14 10:30:07 +02:00

1132 lines
29 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0
/*
* 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/tlb.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/page-states.h>
pgprot_t pgprot_writecombine(pgprot_t prot)
{
/*
* mio_wb_bit_mask may be set on a different CPU, but it is only set
* once at init and only read afterwards.
*/
return __pgprot(pgprot_val(prot) | mio_wb_bit_mask);
}
EXPORT_SYMBOL_GPL(pgprot_writecombine);
pgprot_t pgprot_writethrough(pgprot_t prot)
{
/*
* mio_wb_bit_mask may be set on a different CPU, but it is only set
* once at init and only read afterwards.
*/
return __pgprot(pgprot_val(prot) & ~mio_wb_bit_mask);
}
EXPORT_SYMBOL_GPL(pgprot_writethrough);
static inline void ptep_ipte_local(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, int nodat)
{
unsigned long opt, asce;
if (MACHINE_HAS_TLB_GUEST) {
opt = 0;
asce = READ_ONCE(mm->context.gmap_asce);
if (asce == 0UL || nodat)
opt |= IPTE_NODAT;
if (asce != -1UL) {
asce = asce ? : mm->context.asce;
opt |= IPTE_GUEST_ASCE;
}
__ptep_ipte(addr, ptep, opt, asce, IPTE_LOCAL);
} else {
__ptep_ipte(addr, ptep, 0, 0, IPTE_LOCAL);
}
}
static inline void ptep_ipte_global(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, int nodat)
{
unsigned long opt, asce;
if (MACHINE_HAS_TLB_GUEST) {
opt = 0;
asce = READ_ONCE(mm->context.gmap_asce);
if (asce == 0UL || nodat)
opt |= IPTE_NODAT;
if (asce != -1UL) {
asce = asce ? : mm->context.asce;
opt |= IPTE_GUEST_ASCE;
}
__ptep_ipte(addr, ptep, opt, asce, IPTE_GLOBAL);
} else {
__ptep_ipte(addr, ptep, 0, 0, IPTE_GLOBAL);
}
}
static inline pte_t ptep_flush_direct(struct mm_struct *mm,
unsigned long addr, pte_t *ptep,
int nodat)
{
pte_t old;
old = *ptep;
if (unlikely(pte_val(old) & _PAGE_INVALID))
return old;
atomic_inc(&mm->context.flush_count);
if (MACHINE_HAS_TLB_LC &&
cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
ptep_ipte_local(mm, addr, ptep, nodat);
else
ptep_ipte_global(mm, addr, ptep, nodat);
atomic_dec(&mm->context.flush_count);
return old;
}
static inline pte_t ptep_flush_lazy(struct mm_struct *mm,
unsigned long addr, pte_t *ptep,
int nodat)
{
pte_t old;
old = *ptep;
if (unlikely(pte_val(old) & _PAGE_INVALID))
return old;
atomic_inc(&mm->context.flush_count);
if (cpumask_equal(&mm->context.cpu_attach_mask,
cpumask_of(smp_processor_id()))) {
pte_val(*ptep) |= _PAGE_INVALID;
mm->context.flush_mm = 1;
} else
ptep_ipte_global(mm, addr, ptep, nodat);
atomic_dec(&mm->context.flush_count);
return old;
}
static inline pgste_t pgste_get_lock(pte_t *ptep)
{
unsigned long new = 0;
#ifdef CONFIG_PGSTE
unsigned long old;
asm(
" lg %0,%2\n"
"0: lgr %1,%0\n"
" nihh %0,0xff7f\n" /* clear PCL bit in old */
" oihh %1,0x0080\n" /* set PCL bit in new */
" csg %0,%1,%2\n"
" jl 0b\n"
: "=&d" (old), "=&d" (new), "=Q" (ptep[PTRS_PER_PTE])
: "Q" (ptep[PTRS_PER_PTE]) : "cc", "memory");
#endif
return __pgste(new);
}
static inline void pgste_set_unlock(pte_t *ptep, pgste_t pgste)
{
#ifdef CONFIG_PGSTE
asm(
" nihh %1,0xff7f\n" /* clear PCL bit */
" stg %1,%0\n"
: "=Q" (ptep[PTRS_PER_PTE])
: "d" (pgste_val(pgste)), "Q" (ptep[PTRS_PER_PTE])
: "cc", "memory");
#endif
}
static inline pgste_t pgste_get(pte_t *ptep)
{
unsigned long pgste = 0;
#ifdef CONFIG_PGSTE
pgste = *(unsigned long *)(ptep + PTRS_PER_PTE);
#endif
return __pgste(pgste);
}
static inline void pgste_set(pte_t *ptep, pgste_t pgste)
{
#ifdef CONFIG_PGSTE
*(pgste_t *)(ptep + PTRS_PER_PTE) = pgste;
#endif
}
static inline pgste_t pgste_update_all(pte_t pte, pgste_t pgste,
struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
unsigned long address, bits, skey;
if (!mm_uses_skeys(mm) || pte_val(pte) & _PAGE_INVALID)
return pgste;
address = pte_val(pte) & PAGE_MASK;
skey = (unsigned long) page_get_storage_key(address);
bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
/* Transfer page changed & referenced bit to guest bits in pgste */
pgste_val(pgste) |= bits << 48; /* GR bit & GC bit */
/* Copy page access key and fetch protection bit to pgste */
pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
pgste_val(pgste) |= (skey & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
#endif
return pgste;
}
static inline void pgste_set_key(pte_t *ptep, pgste_t pgste, pte_t entry,
struct mm_struct *mm)
{
#ifdef CONFIG_PGSTE
unsigned long address;
unsigned long nkey;
if (!mm_uses_skeys(mm) || pte_val(entry) & _PAGE_INVALID)
return;
VM_BUG_ON(!(pte_val(*ptep) & _PAGE_INVALID));
address = pte_val(entry) & PAGE_MASK;
/*
* Set page access key and fetch protection bit from pgste.
* The guest C/R information is still in the PGSTE, set real
* key C/R to 0.
*/
nkey = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
nkey |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
page_set_storage_key(address, nkey, 0);
#endif
}
static inline pgste_t pgste_set_pte(pte_t *ptep, pgste_t pgste, pte_t entry)
{
#ifdef CONFIG_PGSTE
if ((pte_val(entry) & _PAGE_PRESENT) &&
(pte_val(entry) & _PAGE_WRITE) &&
!(pte_val(entry) & _PAGE_INVALID)) {
if (!MACHINE_HAS_ESOP) {
/*
* Without enhanced suppression-on-protection force
* the dirty bit on for all writable ptes.
*/
pte_val(entry) |= _PAGE_DIRTY;
pte_val(entry) &= ~_PAGE_PROTECT;
}
if (!(pte_val(entry) & _PAGE_PROTECT))
/* This pte allows write access, set user-dirty */
pgste_val(pgste) |= PGSTE_UC_BIT;
}
#endif
*ptep = entry;
return pgste;
}
static inline pgste_t pgste_pte_notify(struct mm_struct *mm,
unsigned long addr,
pte_t *ptep, pgste_t pgste)
{
#ifdef CONFIG_PGSTE
unsigned long bits;
bits = pgste_val(pgste) & (PGSTE_IN_BIT | PGSTE_VSIE_BIT);
if (bits) {
pgste_val(pgste) ^= bits;
ptep_notify(mm, addr, ptep, bits);
}
#endif
return pgste;
}
static inline pgste_t ptep_xchg_start(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
pgste_t pgste = __pgste(0);
if (mm_has_pgste(mm)) {
pgste = pgste_get_lock(ptep);
pgste = pgste_pte_notify(mm, addr, ptep, pgste);
}
return pgste;
}
static inline pte_t ptep_xchg_commit(struct mm_struct *mm,
unsigned long addr, pte_t *ptep,
pgste_t pgste, pte_t old, pte_t new)
{
if (mm_has_pgste(mm)) {
if (pte_val(old) & _PAGE_INVALID)
pgste_set_key(ptep, pgste, new, mm);
if (pte_val(new) & _PAGE_INVALID) {
pgste = pgste_update_all(old, pgste, mm);
if ((pgste_val(pgste) & _PGSTE_GPS_USAGE_MASK) ==
_PGSTE_GPS_USAGE_UNUSED)
pte_val(old) |= _PAGE_UNUSED;
}
pgste = pgste_set_pte(ptep, pgste, new);
pgste_set_unlock(ptep, pgste);
} else {
*ptep = new;
}
return old;
}
pte_t ptep_xchg_direct(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t new)
{
pgste_t pgste;
pte_t old;
int nodat;
preempt_disable();
pgste = ptep_xchg_start(mm, addr, ptep);
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
old = ptep_flush_direct(mm, addr, ptep, nodat);
old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
preempt_enable();
return old;
}
EXPORT_SYMBOL(ptep_xchg_direct);
pte_t ptep_xchg_lazy(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t new)
{
pgste_t pgste;
pte_t old;
int nodat;
preempt_disable();
pgste = ptep_xchg_start(mm, addr, ptep);
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
old = ptep_flush_lazy(mm, addr, ptep, nodat);
old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
preempt_enable();
return old;
}
EXPORT_SYMBOL(ptep_xchg_lazy);
pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr,
pte_t *ptep)
{
pgste_t pgste;
pte_t old;
int nodat;
struct mm_struct *mm = vma->vm_mm;
preempt_disable();
pgste = ptep_xchg_start(mm, addr, ptep);
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
old = ptep_flush_lazy(mm, addr, ptep, nodat);
if (mm_has_pgste(mm)) {
pgste = pgste_update_all(old, pgste, mm);
pgste_set(ptep, pgste);
}
return old;
}
void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
pte_t *ptep, pte_t old_pte, pte_t pte)
{
pgste_t pgste;
struct mm_struct *mm = vma->vm_mm;
if (!MACHINE_HAS_NX)
pte_val(pte) &= ~_PAGE_NOEXEC;
if (mm_has_pgste(mm)) {
pgste = pgste_get(ptep);
pgste_set_key(ptep, pgste, pte, mm);
pgste = pgste_set_pte(ptep, pgste, pte);
pgste_set_unlock(ptep, pgste);
} else {
*ptep = pte;
}
preempt_enable();
}
static inline void pmdp_idte_local(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
if (MACHINE_HAS_TLB_GUEST)
__pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
mm->context.asce, IDTE_LOCAL);
else
__pmdp_idte(addr, pmdp, 0, 0, IDTE_LOCAL);
if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
gmap_pmdp_idte_local(mm, addr);
}
static inline void pmdp_idte_global(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
if (MACHINE_HAS_TLB_GUEST) {
__pmdp_idte(addr, pmdp, IDTE_NODAT | IDTE_GUEST_ASCE,
mm->context.asce, IDTE_GLOBAL);
if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
gmap_pmdp_idte_global(mm, addr);
} else if (MACHINE_HAS_IDTE) {
__pmdp_idte(addr, pmdp, 0, 0, IDTE_GLOBAL);
if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
gmap_pmdp_idte_global(mm, addr);
} else {
__pmdp_csp(pmdp);
if (mm_has_pgste(mm) && mm->context.allow_gmap_hpage_1m)
gmap_pmdp_csp(mm, addr);
}
}
static inline pmd_t pmdp_flush_direct(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
pmd_t old;
old = *pmdp;
if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
return old;
atomic_inc(&mm->context.flush_count);
if (MACHINE_HAS_TLB_LC &&
cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
pmdp_idte_local(mm, addr, pmdp);
else
pmdp_idte_global(mm, addr, pmdp);
atomic_dec(&mm->context.flush_count);
return old;
}
static inline pmd_t pmdp_flush_lazy(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
pmd_t old;
old = *pmdp;
if (pmd_val(old) & _SEGMENT_ENTRY_INVALID)
return old;
atomic_inc(&mm->context.flush_count);
if (cpumask_equal(&mm->context.cpu_attach_mask,
cpumask_of(smp_processor_id()))) {
pmd_val(*pmdp) |= _SEGMENT_ENTRY_INVALID;
mm->context.flush_mm = 1;
if (mm_has_pgste(mm))
gmap_pmdp_invalidate(mm, addr);
} else {
pmdp_idte_global(mm, addr, pmdp);
}
atomic_dec(&mm->context.flush_count);
return old;
}
#ifdef CONFIG_PGSTE
static pmd_t *pmd_alloc_map(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pgd = pgd_offset(mm, addr);
p4d = p4d_alloc(mm, pgd, addr);
if (!p4d)
return NULL;
pud = pud_alloc(mm, p4d, addr);
if (!pud)
return NULL;
pmd = pmd_alloc(mm, pud, addr);
return pmd;
}
#endif
pmd_t pmdp_xchg_direct(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t new)
{
pmd_t old;
preempt_disable();
old = pmdp_flush_direct(mm, addr, pmdp);
*pmdp = new;
preempt_enable();
return old;
}
EXPORT_SYMBOL(pmdp_xchg_direct);
pmd_t pmdp_xchg_lazy(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t new)
{
pmd_t old;
preempt_disable();
old = pmdp_flush_lazy(mm, addr, pmdp);
*pmdp = new;
preempt_enable();
return old;
}
EXPORT_SYMBOL(pmdp_xchg_lazy);
static inline void pudp_idte_local(struct mm_struct *mm,
unsigned long addr, pud_t *pudp)
{
if (MACHINE_HAS_TLB_GUEST)
__pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
mm->context.asce, IDTE_LOCAL);
else
__pudp_idte(addr, pudp, 0, 0, IDTE_LOCAL);
}
static inline void pudp_idte_global(struct mm_struct *mm,
unsigned long addr, pud_t *pudp)
{
if (MACHINE_HAS_TLB_GUEST)
__pudp_idte(addr, pudp, IDTE_NODAT | IDTE_GUEST_ASCE,
mm->context.asce, IDTE_GLOBAL);
else if (MACHINE_HAS_IDTE)
__pudp_idte(addr, pudp, 0, 0, IDTE_GLOBAL);
else
/*
* Invalid bit position is the same for pmd and pud, so we can
* re-use _pmd_csp() here
*/
__pmdp_csp((pmd_t *) pudp);
}
static inline pud_t pudp_flush_direct(struct mm_struct *mm,
unsigned long addr, pud_t *pudp)
{
pud_t old;
old = *pudp;
if (pud_val(old) & _REGION_ENTRY_INVALID)
return old;
atomic_inc(&mm->context.flush_count);
if (MACHINE_HAS_TLB_LC &&
cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id())))
pudp_idte_local(mm, addr, pudp);
else
pudp_idte_global(mm, addr, pudp);
atomic_dec(&mm->context.flush_count);
return old;
}
pud_t pudp_xchg_direct(struct mm_struct *mm, unsigned long addr,
pud_t *pudp, pud_t new)
{
pud_t old;
preempt_disable();
old = pudp_flush_direct(mm, addr, pudp);
*pudp = new;
preempt_enable();
return old;
}
EXPORT_SYMBOL(pudp_xchg_direct);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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 */
#ifdef CONFIG_PGSTE
void ptep_set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t entry)
{
pgste_t pgste;
/* the mm_has_pgste() check is done in set_pte_at() */
preempt_disable();
pgste = pgste_get_lock(ptep);
pgste_val(pgste) &= ~_PGSTE_GPS_ZERO;
pgste_set_key(ptep, pgste, entry, mm);
pgste = pgste_set_pte(ptep, pgste, entry);
pgste_set_unlock(ptep, pgste);
preempt_enable();
}
void ptep_set_notify(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
pgste_t pgste;
preempt_disable();
pgste = pgste_get_lock(ptep);
pgste_val(pgste) |= PGSTE_IN_BIT;
pgste_set_unlock(ptep, pgste);
preempt_enable();
}
/**
* ptep_force_prot - change access rights of a locked pte
* @mm: pointer to the process mm_struct
* @addr: virtual address in the guest address space
* @ptep: pointer to the page table entry
* @prot: indicates guest access rights: PROT_NONE, PROT_READ or PROT_WRITE
* @bit: pgste bit to set (e.g. for notification)
*
* Returns 0 if the access rights were changed and -EAGAIN if the current
* and requested access rights are incompatible.
*/
int ptep_force_prot(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, int prot, unsigned long bit)
{
pte_t entry;
pgste_t pgste;
int pte_i, pte_p, nodat;
pgste = pgste_get_lock(ptep);
entry = *ptep;
/* Check pte entry after all locks have been acquired */
pte_i = pte_val(entry) & _PAGE_INVALID;
pte_p = pte_val(entry) & _PAGE_PROTECT;
if ((pte_i && (prot != PROT_NONE)) ||
(pte_p && (prot & PROT_WRITE))) {
pgste_set_unlock(ptep, pgste);
return -EAGAIN;
}
/* Change access rights and set pgste bit */
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
if (prot == PROT_NONE && !pte_i) {
ptep_flush_direct(mm, addr, ptep, nodat);
pgste = pgste_update_all(entry, pgste, mm);
pte_val(entry) |= _PAGE_INVALID;
}
if (prot == PROT_READ && !pte_p) {
ptep_flush_direct(mm, addr, ptep, nodat);
pte_val(entry) &= ~_PAGE_INVALID;
pte_val(entry) |= _PAGE_PROTECT;
}
pgste_val(pgste) |= bit;
pgste = pgste_set_pte(ptep, pgste, entry);
pgste_set_unlock(ptep, pgste);
return 0;
}
int ptep_shadow_pte(struct mm_struct *mm, unsigned long saddr,
pte_t *sptep, pte_t *tptep, pte_t pte)
{
pgste_t spgste, tpgste;
pte_t spte, tpte;
int rc = -EAGAIN;
if (!(pte_val(*tptep) & _PAGE_INVALID))
return 0; /* already shadowed */
spgste = pgste_get_lock(sptep);
spte = *sptep;
if (!(pte_val(spte) & _PAGE_INVALID) &&
!((pte_val(spte) & _PAGE_PROTECT) &&
!(pte_val(pte) & _PAGE_PROTECT))) {
pgste_val(spgste) |= PGSTE_VSIE_BIT;
tpgste = pgste_get_lock(tptep);
pte_val(tpte) = (pte_val(spte) & PAGE_MASK) |
(pte_val(pte) & _PAGE_PROTECT);
/* don't touch the storage key - it belongs to parent pgste */
tpgste = pgste_set_pte(tptep, tpgste, tpte);
pgste_set_unlock(tptep, tpgste);
rc = 1;
}
pgste_set_unlock(sptep, spgste);
return rc;
}
void ptep_unshadow_pte(struct mm_struct *mm, unsigned long saddr, pte_t *ptep)
{
pgste_t pgste;
int nodat;
pgste = pgste_get_lock(ptep);
/* notifier is called by the caller */
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
ptep_flush_direct(mm, saddr, ptep, nodat);
/* don't touch the storage key - it belongs to parent pgste */
pgste = pgste_set_pte(ptep, pgste, __pte(_PAGE_INVALID));
pgste_set_unlock(ptep, pgste);
}
static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry)
{
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);
dec_mm_counter(mm, mm_counter(page));
}
free_swap_and_cache(entry);
}
void ptep_zap_unused(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, int reset)
{
unsigned long pgstev;
pgste_t pgste;
pte_t pte;
/* Zap unused and logically-zero pages */
preempt_disable();
pgste = pgste_get_lock(ptep);
pgstev = pgste_val(pgste);
pte = *ptep;
if (!reset && pte_swap(pte) &&
((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED ||
(pgstev & _PGSTE_GPS_ZERO))) {
ptep_zap_swap_entry(mm, pte_to_swp_entry(pte));
pte_clear(mm, addr, ptep);
}
if (reset)
pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
pgste_set_unlock(ptep, pgste);
preempt_enable();
}
void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
unsigned long ptev;
pgste_t pgste;
/* Clear storage key ACC and F, but set R/C */
preempt_disable();
pgste = pgste_get_lock(ptep);
pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT);
pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT;
ptev = pte_val(*ptep);
if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
pgste_set_unlock(ptep, pgste);
preempt_enable();
}
/*
* Test and reset if a guest page is dirty
*/
bool ptep_test_and_clear_uc(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
pgste_t pgste;
pte_t pte;
bool dirty;
int nodat;
pgste = pgste_get_lock(ptep);
dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
pgste_val(pgste) &= ~PGSTE_UC_BIT;
pte = *ptep;
if (dirty && (pte_val(pte) & _PAGE_PRESENT)) {
pgste = pgste_pte_notify(mm, addr, ptep, pgste);
nodat = !!(pgste_val(pgste) & _PGSTE_GPS_NODAT);
ptep_ipte_global(mm, addr, ptep, nodat);
if (MACHINE_HAS_ESOP || !(pte_val(pte) & _PAGE_WRITE))
pte_val(pte) |= _PAGE_PROTECT;
else
pte_val(pte) |= _PAGE_INVALID;
*ptep = pte;
}
pgste_set_unlock(ptep, pgste);
return dirty;
}
EXPORT_SYMBOL_GPL(ptep_test_and_clear_uc);
int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned char key, bool nq)
{
unsigned long keyul, paddr;
spinlock_t *ptl;
pgste_t old, new;
pmd_t *pmdp;
pte_t *ptep;
pmdp = pmd_alloc_map(mm, addr);
if (unlikely(!pmdp))
return -EFAULT;
ptl = pmd_lock(mm, pmdp);
if (!pmd_present(*pmdp)) {
spin_unlock(ptl);
return -EFAULT;
}
if (pmd_large(*pmdp)) {
paddr = pmd_val(*pmdp) & HPAGE_MASK;
paddr |= addr & ~HPAGE_MASK;
/*
* Huge pmds need quiescing operations, they are
* always mapped.
*/
page_set_storage_key(paddr, key, 1);
spin_unlock(ptl);
return 0;
}
spin_unlock(ptl);
ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
if (unlikely(!ptep))
return -EFAULT;
new = old = pgste_get_lock(ptep);
pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
PGSTE_ACC_BITS | PGSTE_FP_BIT);
keyul = (unsigned long) key;
pgste_val(new) |= (keyul & (_PAGE_CHANGED | _PAGE_REFERENCED)) << 48;
pgste_val(new) |= (keyul & (_PAGE_ACC_BITS | _PAGE_FP_BIT)) << 56;
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
unsigned long bits, skey;
paddr = pte_val(*ptep) & PAGE_MASK;
skey = (unsigned long) page_get_storage_key(paddr);
bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
skey = key & (_PAGE_ACC_BITS | _PAGE_FP_BIT);
/* Set storage key ACC and FP */
page_set_storage_key(paddr, 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);
return 0;
}
EXPORT_SYMBOL(set_guest_storage_key);
/**
* Conditionally set a guest storage key (handling csske).
* oldkey will be updated when either mr or mc is set and a pointer is given.
*
* Returns 0 if a guests storage key update wasn't necessary, 1 if the guest
* storage key was updated and -EFAULT on access errors.
*/
int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned char key, unsigned char *oldkey,
bool nq, bool mr, bool mc)
{
unsigned char tmp, mask = _PAGE_ACC_BITS | _PAGE_FP_BIT;
int rc;
/* we can drop the pgste lock between getting and setting the key */
if (mr | mc) {
rc = get_guest_storage_key(current->mm, addr, &tmp);
if (rc)
return rc;
if (oldkey)
*oldkey = tmp;
if (!mr)
mask |= _PAGE_REFERENCED;
if (!mc)
mask |= _PAGE_CHANGED;
if (!((tmp ^ key) & mask))
return 0;
}
rc = set_guest_storage_key(current->mm, addr, key, nq);
return rc < 0 ? rc : 1;
}
EXPORT_SYMBOL(cond_set_guest_storage_key);
/**
* Reset a guest reference bit (rrbe), returning the reference and changed bit.
*
* Returns < 0 in case of error, otherwise the cc to be reported to the guest.
*/
int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr)
{
spinlock_t *ptl;
unsigned long paddr;
pgste_t old, new;
pmd_t *pmdp;
pte_t *ptep;
int cc = 0;
pmdp = pmd_alloc_map(mm, addr);
if (unlikely(!pmdp))
return -EFAULT;
ptl = pmd_lock(mm, pmdp);
if (!pmd_present(*pmdp)) {
spin_unlock(ptl);
return -EFAULT;
}
if (pmd_large(*pmdp)) {
paddr = pmd_val(*pmdp) & HPAGE_MASK;
paddr |= addr & ~HPAGE_MASK;
cc = page_reset_referenced(paddr);
spin_unlock(ptl);
return cc;
}
spin_unlock(ptl);
ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
if (unlikely(!ptep))
return -EFAULT;
new = old = pgste_get_lock(ptep);
/* Reset guest reference bit only */
pgste_val(new) &= ~PGSTE_GR_BIT;
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
paddr = pte_val(*ptep) & PAGE_MASK;
cc = page_reset_referenced(paddr);
/* Merge real referenced bit into host-set */
pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT;
}
/* Reflect guest's logical view, not physical */
cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49;
/* Changing the guest storage key is considered a change of the page */
if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT)
pgste_val(new) |= PGSTE_UC_BIT;
pgste_set_unlock(ptep, new);
pte_unmap_unlock(ptep, ptl);
return cc;
}
EXPORT_SYMBOL(reset_guest_reference_bit);
int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned char *key)
{
unsigned long paddr;
spinlock_t *ptl;
pgste_t pgste;
pmd_t *pmdp;
pte_t *ptep;
pmdp = pmd_alloc_map(mm, addr);
if (unlikely(!pmdp))
return -EFAULT;
ptl = pmd_lock(mm, pmdp);
if (!pmd_present(*pmdp)) {
/* Not yet mapped memory has a zero key */
spin_unlock(ptl);
*key = 0;
return 0;
}
if (pmd_large(*pmdp)) {
paddr = pmd_val(*pmdp) & HPAGE_MASK;
paddr |= addr & ~HPAGE_MASK;
*key = page_get_storage_key(paddr);
spin_unlock(ptl);
return 0;
}
spin_unlock(ptl);
ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl);
if (unlikely(!ptep))
return -EFAULT;
pgste = pgste_get_lock(ptep);
*key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56;
paddr = pte_val(*ptep) & PAGE_MASK;
if (!(pte_val(*ptep) & _PAGE_INVALID))
*key = page_get_storage_key(paddr);
/* Reflect guest's logical view, not physical */
*key |= (pgste_val(pgste) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 48;
pgste_set_unlock(ptep, pgste);
pte_unmap_unlock(ptep, ptl);
return 0;
}
EXPORT_SYMBOL(get_guest_storage_key);
/**
* pgste_perform_essa - perform ESSA actions on the PGSTE.
* @mm: the memory context. It must have PGSTEs, no check is performed here!
* @hva: the host virtual address of the page whose PGSTE is to be processed
* @orc: the specific action to perform, see the ESSA_SET_* macros.
* @oldpte: the PTE will be saved there if the pointer is not NULL.
* @oldpgste: the old PGSTE will be saved there if the pointer is not NULL.
*
* Return: 1 if the page is to be added to the CBRL, otherwise 0,
* or < 0 in case of error. -EINVAL is returned for invalid values
* of orc, -EFAULT for invalid addresses.
*/
int pgste_perform_essa(struct mm_struct *mm, unsigned long hva, int orc,
unsigned long *oldpte, unsigned long *oldpgste)
{
unsigned long pgstev;
spinlock_t *ptl;
pgste_t pgste;
pte_t *ptep;
int res = 0;
WARN_ON_ONCE(orc > ESSA_MAX);
if (unlikely(orc > ESSA_MAX))
return -EINVAL;
ptep = get_locked_pte(mm, hva, &ptl);
if (unlikely(!ptep))
return -EFAULT;
pgste = pgste_get_lock(ptep);
pgstev = pgste_val(pgste);
if (oldpte)
*oldpte = pte_val(*ptep);
if (oldpgste)
*oldpgste = pgstev;
switch (orc) {
case ESSA_GET_STATE:
break;
case ESSA_SET_STABLE:
pgstev &= ~(_PGSTE_GPS_USAGE_MASK | _PGSTE_GPS_NODAT);
pgstev |= _PGSTE_GPS_USAGE_STABLE;
break;
case ESSA_SET_UNUSED:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_UNUSED;
if (pte_val(*ptep) & _PAGE_INVALID)
res = 1;
break;
case ESSA_SET_VOLATILE:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
if (pte_val(*ptep) & _PAGE_INVALID)
res = 1;
break;
case ESSA_SET_POT_VOLATILE:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
pgstev |= _PGSTE_GPS_USAGE_POT_VOLATILE;
break;
}
if (pgstev & _PGSTE_GPS_ZERO) {
pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
break;
}
if (!(pgstev & PGSTE_GC_BIT)) {
pgstev |= _PGSTE_GPS_USAGE_VOLATILE;
res = 1;
break;
}
break;
case ESSA_SET_STABLE_RESIDENT:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_STABLE;
/*
* Since the resident state can go away any time after this
* call, we will not make this page resident. We can revisit
* this decision if a guest will ever start using this.
*/
break;
case ESSA_SET_STABLE_IF_RESIDENT:
if (!(pte_val(*ptep) & _PAGE_INVALID)) {
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_STABLE;
}
break;
case ESSA_SET_STABLE_NODAT:
pgstev &= ~_PGSTE_GPS_USAGE_MASK;
pgstev |= _PGSTE_GPS_USAGE_STABLE | _PGSTE_GPS_NODAT;
break;
default:
/* we should never get here! */
break;
}
/* If we are discarding a page, set it to logical zero */
if (res)
pgstev |= _PGSTE_GPS_ZERO;
pgste_val(pgste) = pgstev;
pgste_set_unlock(ptep, pgste);
pte_unmap_unlock(ptep, ptl);
return res;
}
EXPORT_SYMBOL(pgste_perform_essa);
/**
* set_pgste_bits - set specific PGSTE bits.
* @mm: the memory context. It must have PGSTEs, no check is performed here!
* @hva: the host virtual address of the page whose PGSTE is to be processed
* @bits: a bitmask representing the bits that will be touched
* @value: the values of the bits to be written. Only the bits in the mask
* will be written.
*
* Return: 0 on success, < 0 in case of error.
*/
int set_pgste_bits(struct mm_struct *mm, unsigned long hva,
unsigned long bits, unsigned long value)
{
spinlock_t *ptl;
pgste_t new;
pte_t *ptep;
ptep = get_locked_pte(mm, hva, &ptl);
if (unlikely(!ptep))
return -EFAULT;
new = pgste_get_lock(ptep);
pgste_val(new) &= ~bits;
pgste_val(new) |= value & bits;
pgste_set_unlock(ptep, new);
pte_unmap_unlock(ptep, ptl);
return 0;
}
EXPORT_SYMBOL(set_pgste_bits);
/**
* get_pgste - get the current PGSTE for the given address.
* @mm: the memory context. It must have PGSTEs, no check is performed here!
* @hva: the host virtual address of the page whose PGSTE is to be processed
* @pgstep: will be written with the current PGSTE for the given address.
*
* Return: 0 on success, < 0 in case of error.
*/
int get_pgste(struct mm_struct *mm, unsigned long hva, unsigned long *pgstep)
{
spinlock_t *ptl;
pte_t *ptep;
ptep = get_locked_pte(mm, hva, &ptl);
if (unlikely(!ptep))
return -EFAULT;
*pgstep = pgste_val(pgste_get(ptep));
pte_unmap_unlock(ptep, ptl);
return 0;
}
EXPORT_SYMBOL(get_pgste);
#endif
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