int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
pte_t *ptep, unsigned long trap, unsigned long flags,
int ssize, int subpg_prot)
{
real_pte_t rpte;
unsigned long *hidxp;
unsigned long hpte_group;
unsigned int subpg_index;
unsigned long rflags, pa, hidx;
unsigned long old_pte, new_pte, subpg_pte;
unsigned long vpn, hash, slot;
unsigned long shift = mmu_psize_defs[MMU_PAGE_4K].shift;
/*
* atomically mark the linux large page PTE busy and dirty
*/
do {
pte_t pte = READ_ONCE(*ptep);
old_pte = pte_val(pte);
/* If PTE busy, retry the access */
if (unlikely(old_pte & H_PAGE_BUSY))
return 0;
/* If PTE permissions don't match, take page fault */
if (unlikely(!check_pte_access(access, old_pte)))
return 1;
/*
* Try to lock the PTE, add ACCESSED and DIRTY if it was
* a write access. Since this is 4K insert of 64K page size
* also add H_PAGE_COMBO
*/
new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED | H_PAGE_COMBO;
if (access & _PAGE_WRITE)
new_pte |= _PAGE_DIRTY;
} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
/*
* Handle the subpage protection bits
*/
subpg_pte = new_pte & ~subpg_prot;
rflags = htab_convert_pte_flags(subpg_pte);
if (!cpu_has_feature(CPU_FTR_NOEXECUTE) &&
!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
/*
* No CPU has hugepages but lacks no execute, so we
* don't need to worry about that case
*/
rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
}
subpg_index = (ea & (PAGE_SIZE - 1)) >> shift;
vpn = hpt_vpn(ea, vsid, ssize);
rpte = __real_pte(__pte(old_pte), ptep);
/*
*None of the sub 4k page is hashed
*/
if (!(old_pte & H_PAGE_HASHPTE))
goto htab_insert_hpte;
/*
* Check if the pte was already inserted into the hash table
* as a 64k HW page, and invalidate the 64k HPTE if so.
*/
if (!(old_pte & H_PAGE_COMBO)) {
flush_hash_page(vpn, rpte, MMU_PAGE_64K, ssize, flags);
/*
* clear the old slot details from the old and new pte.
* On hash insert failure we use old pte value and we don't
* want slot information there if we have a insert failure.
*/
old_pte &= ~(H_PAGE_HASHPTE | H_PAGE_F_GIX | H_PAGE_F_SECOND);
new_pte &= ~(H_PAGE_HASHPTE | H_PAGE_F_GIX | H_PAGE_F_SECOND);
goto htab_insert_hpte;
}
/*
* Check for sub page valid and update
*/
if (__rpte_sub_valid(rpte, subpg_index)) {
int ret;
hash = hpt_hash(vpn, shift, ssize);
hidx = __rpte_to_hidx(rpte, subpg_index);
if (hidx & _PTEIDX_SECONDARY)
hash = ~hash;
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
slot += hidx & _PTEIDX_GROUP_IX;
ret = mmu_hash_ops.hpte_updatepp(slot, rflags, vpn,
MMU_PAGE_4K, MMU_PAGE_4K,
ssize, flags);
/*
*if we failed because typically the HPTE wasn't really here
* we try an insertion.
*/
if (ret == -1)
goto htab_insert_hpte;
*ptep = __pte(new_pte & ~H_PAGE_BUSY);
return 0;
}
htab_insert_hpte:
/*
* handle H_PAGE_4K_PFN case
*/
if (old_pte & H_PAGE_4K_PFN) {
/*
* All the sub 4k page have the same
* physical address.
*/
pa = pte_pfn(__pte(old_pte)) << HW_PAGE_SHIFT;
} else {
pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
pa += (subpg_index << shift);
}
hash = hpt_hash(vpn, shift, ssize);
repeat:
hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
/* Insert into the hash table, primary slot */
slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, rflags, 0,
MMU_PAGE_4K, MMU_PAGE_4K, ssize);
/*
* Primary is full, try the secondary
*/
if (unlikely(slot == -1)) {
hpte_group = ((~hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa,
rflags, HPTE_V_SECONDARY,
MMU_PAGE_4K, MMU_PAGE_4K,
ssize);
if (slot == -1) {
if (mftb() & 0x1)
hpte_group = ((hash & htab_hash_mask) *
HPTES_PER_GROUP) & ~0x7UL;
mmu_hash_ops.hpte_remove(hpte_group);
/*
* FIXME!! Should be try the group from which we removed ?
*/
goto repeat;
}
}
/*
* Hypervisor failure. Restore old pte and return -1
* similar to __hash_page_*
*/
if (unlikely(slot == -2)) {
*ptep = __pte(old_pte);
hash_failure_debug(ea, access, vsid, trap, ssize,
MMU_PAGE_4K, MMU_PAGE_4K, old_pte);
return -1;
}
/*
* Insert slot number & secondary bit in PTE second half,
* clear H_PAGE_BUSY and set appropriate HPTE slot bit
* Since we have H_PAGE_BUSY set on ptep, we can be sure
* nobody is undating hidx.
*/
hidxp = (unsigned long *)(ptep + PTRS_PER_PTE);
rpte.hidx &= ~(0xfUL << (subpg_index << 2));
*hidxp = rpte.hidx | (slot << (subpg_index << 2));
new_pte = mark_subptegroup_valid(new_pte, subpg_index);
new_pte |= H_PAGE_HASHPTE;
/*
* check __real_pte for details on matching smp_rmb()
*/
smp_wmb();
*ptep = __pte(new_pte & ~H_PAGE_BUSY);
return 0;
}
int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
pte_t *ptep, unsigned long trap, unsigned long flags,
int ssize, int subpg_prot)
{
real_pte_t rpte;
unsigned long hpte_group;
unsigned int subpg_index;
unsigned long rflags, pa;
unsigned long old_pte, new_pte, subpg_pte;
unsigned long vpn, hash, slot, gslot;
unsigned long shift = mmu_psize_defs[MMU_PAGE_4K].shift;
/*
* atomically mark the linux large page PTE busy and dirty
*/
do {
pte_t pte = READ_ONCE(*ptep);
old_pte = pte_val(pte);
/* If PTE busy, retry the access */
if (unlikely(old_pte & H_PAGE_BUSY))
return 0;
/* If PTE permissions don't match, take page fault */
if (unlikely(!check_pte_access(access, old_pte)))
return 1;
/*
* Try to lock the PTE, add ACCESSED and DIRTY if it was
* a write access. Since this is 4K insert of 64K page size
* also add H_PAGE_COMBO
*/
new_pte = old_pte | H_PAGE_BUSY | _PAGE_ACCESSED | H_PAGE_COMBO;
if (access & _PAGE_WRITE)
new_pte |= _PAGE_DIRTY;
} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
/*
* Handle the subpage protection bits
*/
subpg_pte = new_pte & ~subpg_prot;
rflags = htab_convert_pte_flags(subpg_pte);
if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
/*
* No CPU has hugepages but lacks no execute, so we
* don't need to worry about that case
*/
rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
}
subpg_index = (ea & (PAGE_SIZE - 1)) >> shift;
vpn = hpt_vpn(ea, vsid, ssize);
rpte = __real_pte(__pte(old_pte), ptep);
/*
*None of the sub 4k page is hashed
*/
if (!(old_pte & H_PAGE_HASHPTE))
goto htab_insert_hpte;
/*
* Check if the pte was already inserted into the hash table
* as a 64k HW page, and invalidate the 64k HPTE if so.
*/
if (!(old_pte & H_PAGE_COMBO)) {
flush_hash_page(vpn, rpte, MMU_PAGE_64K, ssize, flags);
/*
* clear the old slot details from the old and new pte.
* On hash insert failure we use old pte value and we don't
* want slot information there if we have a insert failure.
*/
old_pte &= ~H_PAGE_HASHPTE;
new_pte &= ~H_PAGE_HASHPTE;
goto htab_insert_hpte;
}
/*
* Check for sub page valid and update
*/
if (__rpte_sub_valid(rpte, subpg_index)) {
int ret;
gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte,
subpg_index);
ret = mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn,
MMU_PAGE_4K, MMU_PAGE_4K,
ssize, flags);
/*
* If we failed because typically the HPTE wasn't really here
* we try an insertion.
*/
if (ret == -1)
goto htab_insert_hpte;
*ptep = __pte(new_pte & ~H_PAGE_BUSY);
return 0;
}
htab_insert_hpte:
/*
* Initialize all hidx entries to invalid value, the first time
* the PTE is about to allocate a 4K HPTE.
*/
if (!(old_pte & H_PAGE_COMBO))
rpte.hidx = INVALID_RPTE_HIDX;
/*
* handle H_PAGE_4K_PFN case
*/
if (old_pte & H_PAGE_4K_PFN) {
/*
* All the sub 4k page have the same
* physical address.
*/
pa = pte_pfn(__pte(old_pte)) << HW_PAGE_SHIFT;
} else {
pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
pa += (subpg_index << shift);
}
hash = hpt_hash(vpn, shift, ssize);
repeat:
hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
/* Insert into the hash table, primary slot */
slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa, rflags, 0,
MMU_PAGE_4K, MMU_PAGE_4K, ssize);
/*
* Primary is full, try the secondary
*/
if (unlikely(slot == -1)) {
bool soft_invalid;
hpte_group = ((~hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
slot = mmu_hash_ops.hpte_insert(hpte_group, vpn, pa,
rflags, HPTE_V_SECONDARY,
MMU_PAGE_4K, MMU_PAGE_4K,
ssize);
soft_invalid = hpte_soft_invalid(slot);
if (unlikely(soft_invalid)) {
/*
* We got a valid slot from a hardware point of view.
* but we cannot use it, because we use this special
* value; as defined by hpte_soft_invalid(), to track
* invalid slots. We cannot use it. So invalidate it.
*/
gslot = slot & _PTEIDX_GROUP_IX;
mmu_hash_ops.hpte_invalidate(hpte_group + gslot, vpn,
MMU_PAGE_4K, MMU_PAGE_4K,
ssize, 0);
}
if (unlikely(slot == -1 || soft_invalid)) {
/*
* For soft invalid slot, let's ensure that we release a
* slot from the primary, with the hope that we will
* acquire that slot next time we try. This will ensure
* that we do not get the same soft-invalid slot.
*/
if (soft_invalid || (mftb() & 0x1))
hpte_group = ((hash & htab_hash_mask) *
HPTES_PER_GROUP) & ~0x7UL;
mmu_hash_ops.hpte_remove(hpte_group);
/*
* FIXME!! Should be try the group from which we removed ?
*/
goto repeat;
}
}
/*
* Hypervisor failure. Restore old pte and return -1
* similar to __hash_page_*
*/
if (unlikely(slot == -2)) {
*ptep = __pte(old_pte);
hash_failure_debug(ea, access, vsid, trap, ssize,
MMU_PAGE_4K, MMU_PAGE_4K, old_pte);
return -1;
}
new_pte |= pte_set_hidx(ptep, rpte, subpg_index, slot);
new_pte |= H_PAGE_HASHPTE;
*ptep = __pte(new_pte & ~H_PAGE_BUSY);
return 0;
}