1 files changed, 633 insertions, 0 deletions

diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
new file mode 100644
index 000000000000..f833dba2a028
--- /dev/null
+++ b/arch/powerpc/mm/slice.c
@@ -0,0 +1,633 @@
+/*
+ * address space "slices" (meta-segments) support
+ *
+ * Copyright (C) 2007 Benjamin Herrenschmidt, IBM Corporation.
+ *
+ * Based on hugetlb implementation
+ *
+ * Copyright (C) 2003 David Gibson, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <asm/mman.h>
+#include <asm/mmu.h>
+#include <asm/spu.h>
+
+static spinlock_t slice_convert_lock = SPIN_LOCK_UNLOCKED;
+
+
+#ifdef DEBUG
+int _slice_debug = 1;
+
+static void slice_print_mask(const char *label, struct slice_mask mask)
+{
+        char    *p, buf[16 + 3 + 16 + 1];
+        int     i;
+
+        if (!_slice_debug)
+                return;
+        p = buf;
+        for (i = 0; i < SLICE_NUM_LOW; i++)
+                *(p++) = (mask.low_slices & (1 << i)) ? '1' : '0';
+        *(p++) = ' ';
+        *(p++) = '-';
+        *(p++) = ' ';
+        for (i = 0; i < SLICE_NUM_HIGH; i++)
+                *(p++) = (mask.high_slices & (1 << i)) ? '1' : '0';
+        *(p++) = 0;
+
+        printk(KERN_DEBUG "%s:%s\n", label, buf);
+}
+
+#define slice_dbg(fmt...) do { if (_slice_debug) pr_debug(fmt); } while(0)
+
+#else
+
+static void slice_print_mask(const char *label, struct slice_mask mask) {}
+#define slice_dbg(fmt...)
+
+#endif
+
+static struct slice_mask slice_range_to_mask(unsigned long start,
+                                             unsigned long len)
+{
+        unsigned long end = start + len - 1;
+        struct slice_mask ret = { 0, 0 };
+
+        if (start < SLICE_LOW_TOP) {
+                unsigned long mend = min(end, SLICE_LOW_TOP);
+                unsigned long mstart = min(start, SLICE_LOW_TOP);
+
+                ret.low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
+                        - (1u << GET_LOW_SLICE_INDEX(mstart));
+        }
+
+        if ((start + len) > SLICE_LOW_TOP)
+                ret.high_slices = (1u << (GET_HIGH_SLICE_INDEX(end) + 1))
+                        - (1u << GET_HIGH_SLICE_INDEX(start));
+
+        return ret;
+}
+
+static int slice_area_is_free(struct mm_struct *mm, unsigned long addr,
+                              unsigned long len)
+{
+        struct vm_area_struct *vma;
+
+        if ((mm->task_size - len) < addr)
+                return 0;
+        vma = find_vma(mm, addr);
+        return (!vma || (addr + len) <= vma->vm_start);
+}
+
+static int slice_low_has_vma(struct mm_struct *mm, unsigned long slice)
+{
+        return !slice_area_is_free(mm, slice << SLICE_LOW_SHIFT,
+                                   1ul << SLICE_LOW_SHIFT);
+}
+
+static int slice_high_has_vma(struct mm_struct *mm, unsigned long slice)
+{
+        unsigned long start = slice << SLICE_HIGH_SHIFT;
+        unsigned long end = start + (1ul << SLICE_HIGH_SHIFT);
+
+        /* Hack, so that each addresses is controlled by exactly one
+         * of the high or low area bitmaps, the first high area starts
+         * at 4GB, not 0 */
+        if (start == 0)
+                start = SLICE_LOW_TOP;
+
+        return !slice_area_is_free(mm, start, end - start);
+}
+
+static struct slice_mask slice_mask_for_free(struct mm_struct *mm)
+{
+        struct slice_mask ret = { 0, 0 };
+        unsigned long i;
+
+        for (i = 0; i < SLICE_NUM_LOW; i++)
+                if (!slice_low_has_vma(mm, i))
+                        ret.low_slices |= 1u << i;
+
+        if (mm->task_size <= SLICE_LOW_TOP)
+                return ret;
+
+        for (i = 0; i < SLICE_NUM_HIGH; i++)
+                if (!slice_high_has_vma(mm, i))
+                        ret.high_slices |= 1u << i;
+
+        return ret;
+}
+
+static struct slice_mask slice_mask_for_size(struct mm_struct *mm, int psize)
+{
+        struct slice_mask ret = { 0, 0 };
+        unsigned long i;
+        u64 psizes;
+
+        psizes = mm->context.low_slices_psize;
+        for (i = 0; i < SLICE_NUM_LOW; i++)
+                if (((psizes >> (i * 4)) & 0xf) == psize)
+                        ret.low_slices |= 1u << i;
+
+        psizes = mm->context.high_slices_psize;
+        for (i = 0; i < SLICE_NUM_HIGH; i++)
+                if (((psizes >> (i * 4)) & 0xf) == psize)
+                        ret.high_slices |= 1u << i;
+
+        return ret;
+}
+
+static int slice_check_fit(struct slice_mask mask, struct slice_mask available)
+{
+        return (mask.low_slices & available.low_slices) == mask.low_slices &&
+                (mask.high_slices & available.high_slices) == mask.high_slices;
+}
+
+static void slice_flush_segments(void *parm)
+{
+        struct mm_struct *mm = parm;
+        unsigned long flags;
+
+        if (mm != current->active_mm)
+                return;
+
+        /* update the paca copy of the context struct */
+        get_paca()->context = current->active_mm->context;
+
+        local_irq_save(flags);
+        slb_flush_and_rebolt();
+        local_irq_restore(flags);
+}
+
+static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psize)
+{
+        /* Write the new slice psize bits */
+        u64 lpsizes, hpsizes;
+        unsigned long i, flags;
+
+        slice_dbg("slice_convert(mm=%p, psize=%d)\n", mm, psize);
+        slice_print_mask(" mask", mask);
+
+        /* We need to use a spinlock here to protect against
+         * concurrent 64k -> 4k demotion ...
+         */
+        spin_lock_irqsave(&slice_convert_lock, flags);
+
+        lpsizes = mm->context.low_slices_psize;
+        for (i = 0; i < SLICE_NUM_LOW; i++)
+                if (mask.low_slices & (1u << i))
+                        lpsizes = (lpsizes & ~(0xful << (i * 4))) |
+                                (((unsigned long)psize) << (i * 4));
+
+        hpsizes = mm->context.high_slices_psize;
+        for (i = 0; i < SLICE_NUM_HIGH; i++)
+                if (mask.high_slices & (1u << i))
+                        hpsizes = (hpsizes & ~(0xful << (i * 4))) |
+                                (((unsigned long)psize) << (i * 4));
+
+        mm->context.low_slices_psize = lpsizes;
+        mm->context.high_slices_psize = hpsizes;
+
+        slice_dbg(" lsps=%lx, hsps=%lx\n",
+                  mm->context.low_slices_psize,
+                  mm->context.high_slices_psize);
+
+        spin_unlock_irqrestore(&slice_convert_lock, flags);
+        mb();
+
+        /* XXX this is sub-optimal but will do for now */
+        on_each_cpu(slice_flush_segments, mm, 0, 1);
+#ifdef CONFIG_SPU_BASE
+        spu_flush_all_slbs(mm);
+#endif
+}
+
+static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
+                                              unsigned long len,
+                                              struct slice_mask available,
+                                              int psize, int use_cache)
+{
+        struct vm_area_struct *vma;
+        unsigned long start_addr, addr;
+        struct slice_mask mask;
+        int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
+
+        if (use_cache) {
+                if (len <= mm->cached_hole_size) {
+                        start_addr = addr = TASK_UNMAPPED_BASE;
+                        mm->cached_hole_size = 0;
+                } else
+                        start_addr = addr = mm->free_area_cache;
+        } else
+                start_addr = addr = TASK_UNMAPPED_BASE;
+
+full_search:
+        for (;;) {
+                addr = _ALIGN_UP(addr, 1ul << pshift);
+                if ((TASK_SIZE - len) < addr)
+                        break;
+                vma = find_vma(mm, addr);
+                BUG_ON(vma && (addr >= vma->vm_end));
+
+                mask = slice_range_to_mask(addr, len);
+                if (!slice_check_fit(mask, available)) {
+                        if (addr < SLICE_LOW_TOP)
+                                addr = _ALIGN_UP(addr + 1,  1ul << SLICE_LOW_SHIFT);
+                        else
+                                addr = _ALIGN_UP(addr + 1,  1ul << SLICE_HIGH_SHIFT);
+                        continue;
+                }
+                if (!vma || addr + len <= vma->vm_start) {
+                        /*
+                         * Remember the place where we stopped the search:
+                         */
+                        if (use_cache)
+                                mm->free_area_cache = addr + len;
+                        return addr;
+                }
+                if (use_cache && (addr + mm->cached_hole_size) < vma->vm_start)
+                        mm->cached_hole_size = vma->vm_start - addr;
+                addr = vma->vm_end;
+        }
+
+        /* Make sure we didn't miss any holes */
+        if (use_cache && start_addr != TASK_UNMAPPED_BASE) {
+                start_addr = addr = TASK_UNMAPPED_BASE;
+                mm->cached_hole_size = 0;
+                goto full_search;
+        }
+        return -ENOMEM;
+}
+
+static unsigned long slice_find_area_topdown(struct mm_struct *mm,
+                                             unsigned long len,
+                                             struct slice_mask available,
+                                             int psize, int use_cache)
+{
+        struct vm_area_struct *vma;
+        unsigned long addr;
+        struct slice_mask mask;
+        int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
+
+        /* check if free_area_cache is useful for us */
+        if (use_cache) {
+                if (len <= mm->cached_hole_size) {
+                        mm->cached_hole_size = 0;
+                        mm->free_area_cache = mm->mmap_base;
+                }
+
+                /* either no address requested or can't fit in requested
+                 * address hole
+                 */
+                addr = mm->free_area_cache;
+
+                /* make sure it can fit in the remaining address space */
+                if (addr > len) {
+                        addr = _ALIGN_DOWN(addr - len, 1ul << pshift);
+                        mask = slice_range_to_mask(addr, len);
+                        if (slice_check_fit(mask, available) &&
+                            slice_area_is_free(mm, addr, len))
+                                        /* remember the address as a hint for
+                                         * next time
+                                         */
+                                        return (mm->free_area_cache = addr);
+                }
+        }
+
+        addr = mm->mmap_base;
+        while (addr > len) {
+                /* Go down by chunk size */
+                addr = _ALIGN_DOWN(addr - len, 1ul << pshift);
+
+                /* Check for hit with different page size */
+                mask = slice_range_to_mask(addr, len);
+                if (!slice_check_fit(mask, available)) {
+                        if (addr < SLICE_LOW_TOP)
+                                addr = _ALIGN_DOWN(addr, 1ul << SLICE_LOW_SHIFT);
+                        else if (addr < (1ul << SLICE_HIGH_SHIFT))
+                                addr = SLICE_LOW_TOP;
+                        else
+                                addr = _ALIGN_DOWN(addr, 1ul << SLICE_HIGH_SHIFT);
+                        continue;
+                }
+
+                /*
+                 * Lookup failure means no vma is above this address,
+                 * else if new region fits below vma->vm_start,
+                 * return with success:
+                 */
+                vma = find_vma(mm, addr);
+                if (!vma || (addr + len) <= vma->vm_start) {
+                        /* remember the address as a hint for next time */
+                        if (use_cache)
+                                mm->free_area_cache = addr;
+                        return addr;
+                }
+
+                /* remember the largest hole we saw so far */
+                if (use_cache && (addr + mm->cached_hole_size) < vma->vm_start)
+                        mm->cached_hole_size = vma->vm_start - addr;
+
+                /* try just below the current vma->vm_start */
+                addr = vma->vm_start;
+        }
+
+        /*
+         * 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.
+         */
+        addr = slice_find_area_bottomup(mm, len, available, psize, 0);
+
+        /*
+         * Restore the topdown base:
+         */
+        if (use_cache) {
+                mm->free_area_cache = mm->mmap_base;
+                mm->cached_hole_size = ~0UL;
+        }
+
+        return addr;
+}
+
+
+static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
+                                     struct slice_mask mask, int psize,
+                                     int topdown, int use_cache)
+{
+        if (topdown)
+                return slice_find_area_topdown(mm, len, mask, psize, use_cache);
+        else
+                return slice_find_area_bottomup(mm, len, mask, psize, use_cache);
+}
+
+unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
+                                      unsigned long flags, unsigned int psize,
+                                      int topdown, int use_cache)
+{
+        struct slice_mask mask;
+        struct slice_mask good_mask;
+        struct slice_mask potential_mask = {0,0} /* silence stupid warning */;
+        int pmask_set = 0;
+        int fixed = (flags & MAP_FIXED);
+        int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
+        struct mm_struct *mm = current->mm;
+
+        /* Sanity checks */
+        BUG_ON(mm->task_size == 0);
+
+        slice_dbg("slice_get_unmapped_area(mm=%p, psize=%d...\n", mm, psize);
+        slice_dbg(" addr=%lx, len=%lx, flags=%lx, topdown=%d, use_cache=%d\n",
+                  addr, len, flags, topdown, use_cache);
+
+        if (len > mm->task_size)
+                return -ENOMEM;
+        if (fixed && (addr & ((1ul << pshift) - 1)))
+                return -EINVAL;
+        if (fixed && addr > (mm->task_size - len))
+                return -EINVAL;
+
+        /* If hint, make sure it matches our alignment restrictions */
+        if (!fixed && addr) {
+                addr = _ALIGN_UP(addr, 1ul << pshift);
+                slice_dbg(" aligned addr=%lx\n", addr);
+        }
+
+        /* First makeup a "good" mask of slices that have the right size
+         * already
+         */
+        good_mask = slice_mask_for_size(mm, psize);
+        slice_print_mask(" good_mask", good_mask);
+
+        /* First check hint if it's valid or if we have MAP_FIXED */
+        if ((addr != 0 || fixed) && (mm->task_size - len) >= addr) {
+
+                /* Don't bother with hint if it overlaps a VMA */
+                if (!fixed && !slice_area_is_free(mm, addr, len))
+                        goto search;
+
+                /* Build a mask for the requested range */
+                mask = slice_range_to_mask(addr, len);
+                slice_print_mask(" mask", mask);
+
+                /* Check if we fit in the good mask. If we do, we just return,
+                 * nothing else to do
+                 */
+                if (slice_check_fit(mask, good_mask)) {
+                        slice_dbg(" fits good !\n");
+                        return addr;
+                }
+
+                /* We don't fit in the good mask, check what other slices are
+                 * empty and thus can be converted
+                 */
+                potential_mask = slice_mask_for_free(mm);
+                potential_mask.low_slices |= good_mask.low_slices;
+                potential_mask.high_slices |= good_mask.high_slices;
+                pmask_set = 1;
+                slice_print_mask(" potential", potential_mask);
+                if (slice_check_fit(mask, potential_mask)) {
+                        slice_dbg(" fits potential !\n");
+                        goto convert;
+                }
+        }
+
+        /* If we have MAP_FIXED and failed the above step, then error out */
+        if (fixed)
+                return -EBUSY;
+
+ search:
+        slice_dbg(" search...\n");
+
+        /* Now let's see if we can find something in the existing slices
+         * for that size
+         */
+        addr = slice_find_area(mm, len, good_mask, psize, topdown, use_cache);
+        if (addr != -ENOMEM) {
+                /* Found within the good mask, we don't have to setup,
+                 * we thus return directly
+                 */
+                slice_dbg(" found area at 0x%lx\n", addr);
+                return addr;
+        }
+
+        /* Won't fit, check what can be converted */
+        if (!pmask_set) {
+                potential_mask = slice_mask_for_free(mm);
+                potential_mask.low_slices |= good_mask.low_slices;
+                potential_mask.high_slices |= good_mask.high_slices;
+                pmask_set = 1;
+                slice_print_mask(" potential", potential_mask);
+        }
+
+        /* Now let's see if we can find something in the existing slices
+         * for that size
+         */
+        addr = slice_find_area(mm, len, potential_mask, psize, topdown,
+                               use_cache);
+        if (addr == -ENOMEM)
+                return -ENOMEM;
+
+        mask = slice_range_to_mask(addr, len);
+        slice_dbg(" found potential area at 0x%lx\n", addr);
+        slice_print_mask(" mask", mask);
+
+ convert:
+        slice_convert(mm, mask, psize);
+        return addr;
+
+}
+EXPORT_SYMBOL_GPL(slice_get_unmapped_area);
+
+unsigned long arch_get_unmapped_area(struct file *filp,
+                                     unsigned long addr,
+                                     unsigned long len,
+                                     unsigned long pgoff,
+                                     unsigned long flags)
+{
+        return slice_get_unmapped_area(addr, len, flags,
+                                       current->mm->context.user_psize,
+                                       0, 1);
+}
+
+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)
+{
+        return slice_get_unmapped_area(addr0, len, flags,
+                                       current->mm->context.user_psize,
+                                       1, 1);
+}
+
+unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
+{
+        u64 psizes;
+        int index;
+
+        if (addr < SLICE_LOW_TOP) {
+                psizes = mm->context.low_slices_psize;
+                index = GET_LOW_SLICE_INDEX(addr);
+        } else {
+                psizes = mm->context.high_slices_psize;
+                index = GET_HIGH_SLICE_INDEX(addr);
+        }
+
+        return (psizes >> (index * 4)) & 0xf;
+}
+EXPORT_SYMBOL_GPL(get_slice_psize);
+
+/*
+ * This is called by hash_page when it needs to do a lazy conversion of
+ * an address space from real 64K pages to combo 4K pages (typically
+ * when hitting a non cacheable mapping on a processor or hypervisor
+ * that won't allow them for 64K pages).
+ *
+ * This is also called in init_new_context() to change back the user
+ * psize from whatever the parent context had it set to
+ *
+ * This function will only change the content of the {low,high)_slice_psize
+ * masks, it will not flush SLBs as this shall be handled lazily by the
+ * caller.
+ */
+void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
+{
+        unsigned long flags, lpsizes, hpsizes;
+        unsigned int old_psize;
+        int i;
+
+        slice_dbg("slice_set_user_psize(mm=%p, psize=%d)\n", mm, psize);
+
+        spin_lock_irqsave(&slice_convert_lock, flags);
+
+        old_psize = mm->context.user_psize;
+        slice_dbg(" old_psize=%d\n", old_psize);
+        if (old_psize == psize)
+                goto bail;
+
+        mm->context.user_psize = psize;
+        wmb();
+
+        lpsizes = mm->context.low_slices_psize;
+        for (i = 0; i < SLICE_NUM_LOW; i++)
+                if (((lpsizes >> (i * 4)) & 0xf) == old_psize)
+                        lpsizes = (lpsizes & ~(0xful << (i * 4))) |
+                                (((unsigned long)psize) << (i * 4));
+
+        hpsizes = mm->context.high_slices_psize;
+        for (i = 0; i < SLICE_NUM_HIGH; i++)
+                if (((hpsizes >> (i * 4)) & 0xf) == old_psize)
+                        hpsizes = (hpsizes & ~(0xful << (i * 4))) |
+                                (((unsigned long)psize) << (i * 4));
+
+        mm->context.low_slices_psize = lpsizes;
+        mm->context.high_slices_psize = hpsizes;
+
+        slice_dbg(" lsps=%lx, hsps=%lx\n",
+                  mm->context.low_slices_psize,
+                  mm->context.high_slices_psize);
+
+ bail:
+        spin_unlock_irqrestore(&slice_convert_lock, flags);
+}
+
+/*
+ * is_hugepage_only_range() is used by generic code to verify wether
+ * a normal mmap mapping (non hugetlbfs) is valid on a given area.
+ *
+ * until the generic code provides a more generic hook and/or starts
+ * calling arch get_unmapped_area for MAP_FIXED (which our implementation
+ * here knows how to deal with), we hijack it to keep standard mappings
+ * away from us.
+ *
+ * because of that generic code limitation, MAP_FIXED mapping cannot
+ * "convert" back a slice with no VMAs to the standard page size, only
+ * get_unmapped_area() can. It would be possible to fix it here but I
+ * prefer working on fixing the generic code instead.
+ *
+ * WARNING: This will not work if hugetlbfs isn't enabled since the
+ * generic code will redefine that function as 0 in that. This is ok
+ * for now as we only use slices with hugetlbfs enabled. This should
+ * be fixed as the generic code gets fixed.
+ */
+int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
+                           unsigned long len)
+{
+        struct slice_mask mask, available;
+
+        mask = slice_range_to_mask(addr, len);
+        available = slice_mask_for_size(mm, mm->context.user_psize);
+
+#if 0 /* too verbose */
+        slice_dbg("is_hugepage_only_range(mm=%p, addr=%lx, len=%lx)\n",
+                 mm, addr, len);
+        slice_print_mask(" mask", mask);
+        slice_print_mask(" available", available);
+#endif
+        return !slice_check_fit(mask, available);
+}
+