summaryrefslogtreecommitdiff
path: root/arch/powerpc/mm/book3s64/hash_4k.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/mm/book3s64/hash_4k.c')
-rw-r--r--arch/powerpc/mm/book3s64/hash_4k.c124
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_4k.c b/arch/powerpc/mm/book3s64/hash_4k.c
new file mode 100644
index 000000000000..22e787123cdf
--- /dev/null
+++ b/arch/powerpc/mm/book3s64/hash_4k.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright IBM Corporation, 2015
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include <linux/mm.h>
+#include <asm/machdep.h>
+#include <asm/mmu.h>
+
+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 long rflags, pa;
+ unsigned long old_pte, new_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;
+ if (access & _PAGE_WRITE)
+ new_pte |= _PAGE_DIRTY;
+ } while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
+
+ /*
+ * PP bits. _PAGE_USER is already PP bit 0x2, so we only
+ * need to add in 0x1 if it's a read-only user page
+ */
+ rflags = htab_convert_pte_flags(new_pte);
+ rpte = __real_pte(__pte(old_pte), ptep, PTRS_PER_PTE);
+
+ if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
+ !cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+ rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
+
+ vpn = hpt_vpn(ea, vsid, ssize);
+ if (unlikely(old_pte & H_PAGE_HASHPTE)) {
+ /*
+ * There MIGHT be an HPTE for this pte
+ */
+ unsigned long gslot = pte_get_hash_gslot(vpn, shift, ssize,
+ rpte, 0);
+
+ if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, MMU_PAGE_4K,
+ MMU_PAGE_4K, ssize, flags) == -1)
+ old_pte &= ~_PAGE_HPTEFLAGS;
+ }
+
+ if (likely(!(old_pte & H_PAGE_HASHPTE))) {
+
+ pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
+ hash = hpt_hash(vpn, shift, ssize);
+
+repeat:
+ hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+
+ /* 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;
+ 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;
+ 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 = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE;
+ new_pte |= pte_set_hidx(ptep, rpte, 0, slot, PTRS_PER_PTE);
+ }
+ *ptep = __pte(new_pte & ~H_PAGE_BUSY);
+ return 0;
+}