powerpc/mm: Split hash MMU specific hugepage code into a new file

This patch separates the parts of hugetlbpage.c which are inherently
specific to the hash MMU into a new hugelbpage-hash64.c file.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 167 insertions, 0 deletions

diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
new file mode 100644
index 000000000000..1508ffc1e1e1
--- /dev/null
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -0,0 +1,167 @@
+/*
+ * PPC64 Huge TLB Page Support for hash based MMUs (POWER4 and later)
+ *
+ * Copyright (C) 2003 David Gibson, IBM Corporation.
+ *
+ * Based on the IA-32 version:
+ * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/cacheflush.h>
+#include <asm/machdep.h>
+
+/*
+ * Called by asm hashtable.S for doing lazy icache flush
+ */
+static unsigned int hash_huge_page_do_lazy_icache(unsigned long rflags,
+                                        pte_t pte, int trap, unsigned long sz)
+{
+        struct page *page;
+        int i;
+
+        if (!pfn_valid(pte_pfn(pte)))
+                return rflags;
+
+        page = pte_page(pte);
+
+        /* page is dirty */
+        if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
+                if (trap == 0x400) {
+                        for (i = 0; i < (sz / PAGE_SIZE); i++)
+                                __flush_dcache_icache(page_address(page+i));
+                        set_bit(PG_arch_1, &page->flags);
+                } else {
+                        rflags |= HPTE_R_N;
+                }
+        }
+        return rflags;
+}
+
+int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
+                     pte_t *ptep, unsigned long trap, int local, int ssize,
+                     unsigned int shift, unsigned int mmu_psize)
+{
+        unsigned long old_pte, new_pte;
+        unsigned long va, rflags, pa, sz;
+        long slot;
+        int err = 1;
+
+        BUG_ON(shift != mmu_psize_defs[mmu_psize].shift);
+
+        /* Search the Linux page table for a match with va */
+        va = hpt_va(ea, vsid, ssize);
+
+        /*
+         * Check the user's access rights to the page.  If access should be
+         * prevented then send the problem up to do_page_fault.
+         */
+        if (unlikely(access & ~pte_val(*ptep)))
+                goto out;
+        /*
+         * At this point, we have a pte (old_pte) which can be used to build
+         * or update an HPTE. There are 2 cases:
+         *
+         * 1. There is a valid (present) pte with no associated HPTE (this is
+         *      the most common case)
+         * 2. There is a valid (present) pte with an associated HPTE. The
+         *      current values of the pp bits in the HPTE prevent access
+         *      because we are doing software DIRTY bit management and the
+         *      page is currently not DIRTY.
+         */
+
+
+        do {
+                old_pte = pte_val(*ptep);
+                if (old_pte & _PAGE_BUSY)
+                        goto out;
+                new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
+        } while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
+                                         old_pte, new_pte));
+
+        rflags = 0x2 | (!(new_pte & _PAGE_RW));
+        /* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
+        rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
+        sz = ((1UL) << shift);
+        if (!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_huge_page_do_lazy_icache(rflags, __pte(old_pte),
+                                                       trap, sz);
+
+        /* Check if pte already has an hpte (case 2) */
+        if (unlikely(old_pte & _PAGE_HASHPTE)) {
+                /* There MIGHT be an HPTE for this pte */
+                unsigned long hash, slot;
+
+                hash = hpt_hash(va, shift, ssize);
+                if (old_pte & _PAGE_F_SECOND)
+                        hash = ~hash;
+                slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+                slot += (old_pte & _PAGE_F_GIX) >> 12;
+
+                if (ppc_md.hpte_updatepp(slot, rflags, va, mmu_psize,
+                                         ssize, local) == -1)
+                        old_pte &= ~_PAGE_HPTEFLAGS;
+        }
+
+        if (likely(!(old_pte & _PAGE_HASHPTE))) {
+                unsigned long hash = hpt_hash(va, shift, ssize);
+                unsigned long hpte_group;
+
+                pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
+
+repeat:
+                hpte_group = ((hash & htab_hash_mask) *
+                              HPTES_PER_GROUP) & ~0x7UL;
+
+                /* clear HPTE slot informations in new PTE */
+#ifdef CONFIG_PPC_64K_PAGES
+                new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HPTE_SUB0;
+#else
+                new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
+#endif
+                /* Add in WIMG bits */
+                rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
+                                      _PAGE_COHERENT | _PAGE_GUARDED));
+
+                /* Insert into the hash table, primary slot */
+                slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags, 0,
+                                          mmu_psize, ssize);
+
+                /* Primary is full, try the secondary */
+                if (unlikely(slot == -1)) {
+                        hpte_group = ((~hash & htab_hash_mask) *
+                                      HPTES_PER_GROUP) & ~0x7UL;
+                        slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags,
+                                                  HPTE_V_SECONDARY,
+                                                  mmu_psize, ssize);
+                        if (slot == -1) {
+                                if (mftb() & 0x1)
+                                        hpte_group = ((hash & htab_hash_mask) *
+                                                      HPTES_PER_GROUP)&~0x7UL;
+
+                                ppc_md.hpte_remove(hpte_group);
+                                goto repeat;
+                        }
+                }
+
+                if (unlikely(slot == -2))
+                        panic("hash_huge_page: pte_insert failed\n");
+
+                new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
+        }
+
+        /*
+         * No need to use ldarx/stdcx here
+         */
+        *ptep = __pte(new_pte & ~_PAGE_BUSY);
+
+        err = 0;
+
+ out:
+        return err;
+}