1 files changed, 745 insertions, 0 deletions

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
new file mode 100644
index 000000000000..0ea0994ed974
--- /dev/null
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -0,0 +1,745 @@
+/*
+ * PPC64 (POWER4) Huge TLB Page Support for Kernel.
+ *
+ * Copyright (C) 2003 David Gibson, IBM Corporation.
+ *
+ * Based on the IA-32 version:
+ * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
+ */
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/smp_lock.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/sysctl.h>
+#include <asm/mman.h>
+#include <asm/pgalloc.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
+#include <asm/machdep.h>
+#include <asm/cputable.h>
+#include <asm/tlb.h>
+
+#include <linux/sysctl.h>
+
+#define NUM_LOW_AREAS   (0x100000000UL >> SID_SHIFT)
+#define NUM_HIGH_AREAS  (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
+
+/* Modelled after find_linux_pte() */
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pg;
+        pud_t *pu;
+        pmd_t *pm;
+        pte_t *pt;
+
+        BUG_ON(! in_hugepage_area(mm->context, addr));
+
+        addr &= HPAGE_MASK;
+
+        pg = pgd_offset(mm, addr);
+        if (!pgd_none(*pg)) {
+                pu = pud_offset(pg, addr);
+                if (!pud_none(*pu)) {
+                        pm = pmd_offset(pu, addr);
+                        pt = (pte_t *)pm;
+                        BUG_ON(!pmd_none(*pm)
+                               && !(pte_present(*pt) && pte_huge(*pt)));
+                        return pt;
+                }
+        }
+
+        return NULL;
+}
+
+pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pg;
+        pud_t *pu;
+        pmd_t *pm;
+        pte_t *pt;
+
+        BUG_ON(! in_hugepage_area(mm->context, addr));
+
+        addr &= HPAGE_MASK;
+
+        pg = pgd_offset(mm, addr);
+        pu = pud_alloc(mm, pg, addr);
+
+        if (pu) {
+                pm = pmd_alloc(mm, pu, addr);
+                if (pm) {
+                        pt = (pte_t *)pm;
+                        BUG_ON(!pmd_none(*pm)
+                               && !(pte_present(*pt) && pte_huge(*pt)));
+                        return pt;
+                }
+        }
+
+        return NULL;
+}
+
+#define HUGEPTE_BATCH_SIZE      (HPAGE_SIZE / PMD_SIZE)
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+                     pte_t *ptep, pte_t pte)
+{
+        int i;
+
+        if (pte_present(*ptep)) {
+                pte_clear(mm, addr, ptep);
+                flush_tlb_pending();
+        }
+
+        for (i = 0; i < HUGEPTE_BATCH_SIZE; i++) {
+                *ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
+                ptep++;
+        }
+}
+
+pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
+                              pte_t *ptep)
+{
+        unsigned long old = pte_update(ptep, ~0UL);
+        int i;
+
+        if (old & _PAGE_HASHPTE)
+                hpte_update(mm, addr, old, 0);
+
+        for (i = 1; i < HUGEPTE_BATCH_SIZE; i++)
+                ptep[i] = __pte(0);
+
+        return __pte(old);
+}
+
+/*
+ * This function checks for proper alignment of input addr and len parameters.
+ */
+int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
+{
+        if (len & ~HPAGE_MASK)
+                return -EINVAL;
+        if (addr & ~HPAGE_MASK)
+                return -EINVAL;
+        if (! (within_hugepage_low_range(addr, len)
+               || within_hugepage_high_range(addr, len)) )
+                return -EINVAL;
+        return 0;
+}
+
+static void flush_low_segments(void *parm)
+{
+        u16 areas = (unsigned long) parm;
+        unsigned long i;
+
+        asm volatile("isync" : : : "memory");
+
+        BUILD_BUG_ON((sizeof(areas)*8) != NUM_LOW_AREAS);
+
+        for (i = 0; i < NUM_LOW_AREAS; i++) {
+                if (! (areas & (1U << i)))
+                        continue;
+                asm volatile("slbie %0"
+                             : : "r" ((i << SID_SHIFT) | SLBIE_C));
+        }
+
+        asm volatile("isync" : : : "memory");
+}
+
+static void flush_high_segments(void *parm)
+{
+        u16 areas = (unsigned long) parm;
+        unsigned long i, j;
+
+        asm volatile("isync" : : : "memory");
+
+        BUILD_BUG_ON((sizeof(areas)*8) != NUM_HIGH_AREAS);
+
+        for (i = 0; i < NUM_HIGH_AREAS; i++) {
+                if (! (areas & (1U << i)))
+                        continue;
+                for (j = 0; j < (1UL << (HTLB_AREA_SHIFT-SID_SHIFT)); j++)
+                        asm volatile("slbie %0"
+                                     :: "r" (((i << HTLB_AREA_SHIFT)
+                                             + (j << SID_SHIFT)) | SLBIE_C));
+        }
+
+        asm volatile("isync" : : : "memory");
+}
+
+static int prepare_low_area_for_htlb(struct mm_struct *mm, unsigned long area)
+{
+        unsigned long start = area << SID_SHIFT;
+        unsigned long end = (area+1) << SID_SHIFT;
+        struct vm_area_struct *vma;
+
+        BUG_ON(area >= NUM_LOW_AREAS);
+
+        /* Check no VMAs are in the region */
+        vma = find_vma(mm, start);
+        if (vma && (vma->vm_start < end))
+                return -EBUSY;
+
+        return 0;
+}
+
+static int prepare_high_area_for_htlb(struct mm_struct *mm, unsigned long area)
+{
+        unsigned long start = area << HTLB_AREA_SHIFT;
+        unsigned long end = (area+1) << HTLB_AREA_SHIFT;
+        struct vm_area_struct *vma;
+
+        BUG_ON(area >= NUM_HIGH_AREAS);
+
+        /* Check no VMAs are in the region */
+        vma = find_vma(mm, start);
+        if (vma && (vma->vm_start < end))
+                return -EBUSY;
+
+        return 0;
+}
+
+static int open_low_hpage_areas(struct mm_struct *mm, u16 newareas)
+{
+        unsigned long i;
+
+        BUILD_BUG_ON((sizeof(newareas)*8) != NUM_LOW_AREAS);
+        BUILD_BUG_ON((sizeof(mm->context.low_htlb_areas)*8) != NUM_LOW_AREAS);
+
+        newareas &= ~(mm->context.low_htlb_areas);
+        if (! newareas)
+                return 0; /* The segments we want are already open */
+
+        for (i = 0; i < NUM_LOW_AREAS; i++)
+                if ((1 << i) & newareas)
+                        if (prepare_low_area_for_htlb(mm, i) != 0)
+                                return -EBUSY;
+
+        mm->context.low_htlb_areas |= newareas;
+
+        /* update the paca copy of the context struct */
+        get_paca()->context = mm->context;
+
+        /* the context change must make it to memory before the flush,
+         * so that further SLB misses do the right thing. */
+        mb();
+        on_each_cpu(flush_low_segments, (void *)(unsigned long)newareas, 0, 1);
+
+        return 0;
+}
+
+static int open_high_hpage_areas(struct mm_struct *mm, u16 newareas)
+{
+        unsigned long i;
+
+        BUILD_BUG_ON((sizeof(newareas)*8) != NUM_HIGH_AREAS);
+        BUILD_BUG_ON((sizeof(mm->context.high_htlb_areas)*8)
+                     != NUM_HIGH_AREAS);
+
+        newareas &= ~(mm->context.high_htlb_areas);
+        if (! newareas)
+                return 0; /* The areas we want are already open */
+
+        for (i = 0; i < NUM_HIGH_AREAS; i++)
+                if ((1 << i) & newareas)
+                        if (prepare_high_area_for_htlb(mm, i) != 0)
+                                return -EBUSY;
+
+        mm->context.high_htlb_areas |= newareas;
+
+        /* update the paca copy of the context struct */
+        get_paca()->context = mm->context;
+
+        /* the context change must make it to memory before the flush,
+         * so that further SLB misses do the right thing. */
+        mb();
+        on_each_cpu(flush_high_segments, (void *)(unsigned long)newareas, 0, 1);
+
+        return 0;
+}
+
+int prepare_hugepage_range(unsigned long addr, unsigned long len)
+{
+        int err;
+
+        if ( (addr+len) < addr )
+                return -EINVAL;
+
+        if ((addr + len) < 0x100000000UL)
+                err = open_low_hpage_areas(current->mm,
+                                          LOW_ESID_MASK(addr, len));
+        else
+                err = open_high_hpage_areas(current->mm,
+                                            HTLB_AREA_MASK(addr, len));
+        if (err) {
+                printk(KERN_DEBUG "prepare_hugepage_range(%lx, %lx)"
+                       " failed (lowmask: 0x%04hx, highmask: 0x%04hx)\n",
+                       addr, len,
+                       LOW_ESID_MASK(addr, len), HTLB_AREA_MASK(addr, len));
+                return err;
+        }
+
+        return 0;
+}
+
+struct page *
+follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
+{
+        pte_t *ptep;
+        struct page *page;
+
+        if (! in_hugepage_area(mm->context, address))
+                return ERR_PTR(-EINVAL);
+
+        ptep = huge_pte_offset(mm, address);
+        page = pte_page(*ptep);
+        if (page)
+                page += (address % HPAGE_SIZE) / PAGE_SIZE;
+
+        return page;
+}
+
+int pmd_huge(pmd_t pmd)
+{
+        return 0;
+}
+
+struct page *
+follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+                pmd_t *pmd, int write)
+{
+        BUG();
+        return NULL;
+}
+
+/* Because we have an exclusive hugepage region which lies within the
+ * normal user address space, we have to take special measures to make
+ * non-huge mmap()s evade the hugepage reserved regions. */
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
+                                     unsigned long len, unsigned long pgoff,
+                                     unsigned long flags)
+{
+        struct mm_struct *mm = current->mm;
+        struct vm_area_struct *vma;
+        unsigned long start_addr;
+
+        if (len > TASK_SIZE)
+                return -ENOMEM;
+
+        if (addr) {
+                addr = PAGE_ALIGN(addr);
+                vma = find_vma(mm, addr);
+                if (((TASK_SIZE - len) >= addr)
+                    && (!vma || (addr+len) <= vma->vm_start)
+                    && !is_hugepage_only_range(mm, addr,len))
+                        return addr;
+        }
+        if (len > mm->cached_hole_size) {
+                start_addr = addr = mm->free_area_cache;
+        } else {
+                start_addr = addr = TASK_UNMAPPED_BASE;
+                mm->cached_hole_size = 0;
+        }
+
+full_search:
+        vma = find_vma(mm, addr);
+        while (TASK_SIZE - len >= addr) {
+                BUG_ON(vma && (addr >= vma->vm_end));
+
+                if (touches_hugepage_low_range(mm, addr, len)) {
+                        addr = ALIGN(addr+1, 1<<SID_SHIFT);
+                        vma = find_vma(mm, addr);
+                        continue;
+                }
+                if (touches_hugepage_high_range(mm, addr, len)) {
+                        addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT);
+                        vma = find_vma(mm, addr);
+                        continue;
+                }
+                if (!vma || addr + len <= vma->vm_start) {
+                        /*
+                         * Remember the place where we stopped the search:
+                         */
+                        mm->free_area_cache = addr + len;
+                        return addr;
+                }
+                if (addr + mm->cached_hole_size < vma->vm_start)
+                        mm->cached_hole_size = vma->vm_start - addr;
+                addr = vma->vm_end;
+                vma = vma->vm_next;
+        }
+
+        /* Make sure we didn't miss any holes */
+        if (start_addr != TASK_UNMAPPED_BASE) {
+                start_addr = addr = TASK_UNMAPPED_BASE;
+                mm->cached_hole_size = 0;
+                goto full_search;
+        }
+        return -ENOMEM;
+}
+
+/*
+ * This mmap-allocator allocates new areas top-down from below the
+ * stack's low limit (the base):
+ *
+ * Because we have an exclusive hugepage region which lies within the
+ * normal user address space, we have to take special measures to make
+ * non-huge mmap()s evade the hugepage reserved regions.
+ */
+unsigned long
+arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
+                          const unsigned long len, const unsigned long pgoff,
+                          const unsigned long flags)
+{
+        struct vm_area_struct *vma, *prev_vma;
+        struct mm_struct *mm = current->mm;
+        unsigned long base = mm->mmap_base, addr = addr0;
+        unsigned long largest_hole = mm->cached_hole_size;
+        int first_time = 1;
+
+        /* requested length too big for entire address space */
+        if (len > TASK_SIZE)
+                return -ENOMEM;
+
+        /* dont allow allocations above current base */
+        if (mm->free_area_cache > base)
+                mm->free_area_cache = base;
+
+        /* requesting a specific address */
+        if (addr) {
+                addr = PAGE_ALIGN(addr);
+                vma = find_vma(mm, addr);
+                if (TASK_SIZE - len >= addr &&
+                                (!vma || addr + len <= vma->vm_start)
+                                && !is_hugepage_only_range(mm, addr,len))
+                        return addr;
+        }
+
+        if (len <= largest_hole) {
+                largest_hole = 0;
+                mm->free_area_cache = base;
+        }
+try_again:
+        /* make sure it can fit in the remaining address space */
+        if (mm->free_area_cache < len)
+                goto fail;
+
+        /* either no address requested or cant fit in requested address hole */
+        addr = (mm->free_area_cache - len) & PAGE_MASK;
+        do {
+hugepage_recheck:
+                if (touches_hugepage_low_range(mm, addr, len)) {
+                        addr = (addr & ((~0) << SID_SHIFT)) - len;
+                        goto hugepage_recheck;
+                } else if (touches_hugepage_high_range(mm, addr, len)) {
+                        addr = (addr & ((~0UL) << HTLB_AREA_SHIFT)) - len;
+                        goto hugepage_recheck;
+                }
+
+                /*
+                 * Lookup failure means no vma is above this address,
+                 * i.e. return with success:
+                 */
+                if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
+                        return addr;
+
+                /*
+                 * new region fits between prev_vma->vm_end and
+                 * vma->vm_start, use it:
+                 */
+                if (addr+len <= vma->vm_start &&
+                          (!prev_vma || (addr >= prev_vma->vm_end))) {
+                        /* remember the address as a hint for next time */
+                        mm->cached_hole_size = largest_hole;
+                        return (mm->free_area_cache = addr);
+                } else {
+                        /* pull free_area_cache down to the first hole */
+                        if (mm->free_area_cache == vma->vm_end) {
+                                mm->free_area_cache = vma->vm_start;
+                                mm->cached_hole_size = largest_hole;
+                        }
+                }
+
+                /* remember the largest hole we saw so far */
+                if (addr + largest_hole < vma->vm_start)
+                        largest_hole = vma->vm_start - addr;
+
+                /* try just below the current vma->vm_start */
+                addr = vma->vm_start-len;
+        } while (len <= vma->vm_start);
+
+fail:
+        /*
+         * if hint left us with no space for the requested
+         * mapping then try again:
+         */
+        if (first_time) {
+                mm->free_area_cache = base;
+                largest_hole = 0;
+                first_time = 0;
+                goto try_again;
+        }
+        /*
+         * A failed mmap() very likely causes application failure,
+         * so fall back to the bottom-up function here. This scenario
+         * can happen with large stack limits and large mmap()
+         * allocations.
+         */
+        mm->free_area_cache = TASK_UNMAPPED_BASE;
+        mm->cached_hole_size = ~0UL;
+        addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
+        /*
+         * Restore the topdown base:
+         */
+        mm->free_area_cache = base;
+        mm->cached_hole_size = ~0UL;
+
+        return addr;
+}
+
+static unsigned long htlb_get_low_area(unsigned long len, u16 segmask)
+{
+        unsigned long addr = 0;
+        struct vm_area_struct *vma;
+
+        vma = find_vma(current->mm, addr);
+        while (addr + len <= 0x100000000UL) {
+                BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */
+
+                if (! __within_hugepage_low_range(addr, len, segmask)) {
+                        addr = ALIGN(addr+1, 1<<SID_SHIFT);
+                        vma = find_vma(current->mm, addr);
+                        continue;
+                }
+
+                if (!vma || (addr + len) <= vma->vm_start)
+                        return addr;
+                addr = ALIGN(vma->vm_end, HPAGE_SIZE);
+                /* Depending on segmask this might not be a confirmed
+                 * hugepage region, so the ALIGN could have skipped
+                 * some VMAs */
+                vma = find_vma(current->mm, addr);
+        }
+
+        return -ENOMEM;
+}
+
+static unsigned long htlb_get_high_area(unsigned long len, u16 areamask)
+{
+        unsigned long addr = 0x100000000UL;
+        struct vm_area_struct *vma;
+
+        vma = find_vma(current->mm, addr);
+        while (addr + len <= TASK_SIZE_USER64) {
+                BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */
+
+                if (! __within_hugepage_high_range(addr, len, areamask)) {
+                        addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT);
+                        vma = find_vma(current->mm, addr);
+                        continue;
+                }
+
+                if (!vma || (addr + len) <= vma->vm_start)
+                        return addr;
+                addr = ALIGN(vma->vm_end, HPAGE_SIZE);
+                /* Depending on segmask this might not be a confirmed
+                 * hugepage region, so the ALIGN could have skipped
+                 * some VMAs */
+                vma = find_vma(current->mm, addr);
+        }
+
+        return -ENOMEM;
+}
+
+unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
+                                        unsigned long len, unsigned long pgoff,
+                                        unsigned long flags)
+{
+        int lastshift;
+        u16 areamask, curareas;
+
+        if (len & ~HPAGE_MASK)
+                return -EINVAL;
+
+        if (!cpu_has_feature(CPU_FTR_16M_PAGE))
+                return -EINVAL;
+
+        if (test_thread_flag(TIF_32BIT)) {
+                curareas = current->mm->context.low_htlb_areas;
+
+                /* First see if we can do the mapping in the existing
+                 * low areas */
+                addr = htlb_get_low_area(len, curareas);
+                if (addr != -ENOMEM)
+                        return addr;
+
+                lastshift = 0;
+                for (areamask = LOW_ESID_MASK(0x100000000UL-len, len);
+                     ! lastshift; areamask >>=1) {
+                        if (areamask & 1)
+                                lastshift = 1;
+
+                        addr = htlb_get_low_area(len, curareas | areamask);
+                        if ((addr != -ENOMEM)
+                            && open_low_hpage_areas(current->mm, areamask) == 0)
+                                return addr;
+                }
+        } else {
+                curareas = current->mm->context.high_htlb_areas;
+
+                /* First see if we can do the mapping in the existing
+                 * high areas */
+                addr = htlb_get_high_area(len, curareas);
+                if (addr != -ENOMEM)
+                        return addr;
+
+                lastshift = 0;
+                for (areamask = HTLB_AREA_MASK(TASK_SIZE_USER64-len, len);
+                     ! lastshift; areamask >>=1) {
+                        if (areamask & 1)
+                                lastshift = 1;
+
+                        addr = htlb_get_high_area(len, curareas | areamask);
+                        if ((addr != -ENOMEM)
+                            && open_high_hpage_areas(current->mm, areamask) == 0)
+                                return addr;
+                }
+        }
+        printk(KERN_DEBUG "hugetlb_get_unmapped_area() unable to open"
+               " enough areas\n");
+        return -ENOMEM;
+}
+
+int hash_huge_page(struct mm_struct *mm, unsigned long access,
+                   unsigned long ea, unsigned long vsid, int local)
+{
+        pte_t *ptep;
+        unsigned long va, vpn;
+        pte_t old_pte, new_pte;
+        unsigned long rflags, prpn;
+        long slot;
+        int err = 1;
+
+        spin_lock(&mm->page_table_lock);
+
+        ptep = huge_pte_offset(mm, ea);
+
+        /* Search the Linux page table for a match with va */
+        va = (vsid << 28) | (ea & 0x0fffffff);
+        vpn = va >> HPAGE_SHIFT;
+
+        /*
+         * If no pte found or not present, send the problem up to
+         * do_page_fault
+         */
+        if (unlikely(!ptep || pte_none(*ptep)))
+                goto out;
+
+/*      BUG_ON(pte_bad(*ptep)); */
+
+        /* 
+         * 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. 
+         */
+
+
+        old_pte = *ptep;
+        new_pte = old_pte;
+
+        rflags = 0x2 | (! (pte_val(new_pte) & _PAGE_RW));
+        /* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
+        rflags |= ((pte_val(new_pte) & _PAGE_EXEC) ? 0 : HW_NO_EXEC);
+
+        /* Check if pte already has an hpte (case 2) */
+        if (unlikely(pte_val(old_pte) & _PAGE_HASHPTE)) {
+                /* There MIGHT be an HPTE for this pte */
+                unsigned long hash, slot;
+
+                hash = hpt_hash(vpn, 1);
+                if (pte_val(old_pte) & _PAGE_SECONDARY)
+                        hash = ~hash;
+                slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+                slot += (pte_val(old_pte) & _PAGE_GROUP_IX) >> 12;
+
+                if (ppc_md.hpte_updatepp(slot, rflags, va, 1, local) == -1)
+                        pte_val(old_pte) &= ~_PAGE_HPTEFLAGS;
+        }
+
+        if (likely(!(pte_val(old_pte) & _PAGE_HASHPTE))) {
+                unsigned long hash = hpt_hash(vpn, 1);
+                unsigned long hpte_group;
+
+                prpn = pte_pfn(old_pte);
+
+repeat:
+                hpte_group = ((hash & htab_hash_mask) *
+                              HPTES_PER_GROUP) & ~0x7UL;
+
+                /* Update the linux pte with the HPTE slot */
+                pte_val(new_pte) &= ~_PAGE_HPTEFLAGS;
+                pte_val(new_pte) |= _PAGE_HASHPTE;
+
+                /* Add in WIMG bits */
+                /* XXX We should store these in the pte */
+                rflags |= _PAGE_COHERENT;
+
+                slot = ppc_md.hpte_insert(hpte_group, va, prpn,
+                                          HPTE_V_LARGE, rflags);
+
+                /* Primary is full, try the secondary */
+                if (unlikely(slot == -1)) {
+                        pte_val(new_pte) |= _PAGE_SECONDARY;
+                        hpte_group = ((~hash & htab_hash_mask) *
+                                      HPTES_PER_GROUP) & ~0x7UL; 
+                        slot = ppc_md.hpte_insert(hpte_group, va, prpn,
+                                                  HPTE_V_LARGE |
+                                                  HPTE_V_SECONDARY,
+                                                  rflags);
+                        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");
+
+                pte_val(new_pte) |= (slot<<12) & _PAGE_GROUP_IX;
+
+                /* 
+                 * No need to use ldarx/stdcx here because all who
+                 * might be updating the pte will hold the
+                 * page_table_lock
+                 */
+                *ptep = new_pte;
+        }
+
+        err = 0;
+
+ out:
+        spin_unlock(&mm->page_table_lock);
+
+        return err;
+}