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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/powerpc/mm/slice.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/powerpc/mm/slice.c')
-rw-r--r--kernel/arch/powerpc/mm/slice.c701
1 files changed, 701 insertions, 0 deletions
diff --git a/kernel/arch/powerpc/mm/slice.c b/kernel/arch/powerpc/mm/slice.c
new file mode 100644
index 000000000..0f432a702
--- /dev/null
+++ b/kernel/arch/powerpc/mm/slice.c
@@ -0,0 +1,701 @@
+/*
+ * 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/export.h>
+#include <linux/hugetlb.h>
+#include <asm/mman.h>
+#include <asm/mmu.h>
+#include <asm/copro.h>
+#include <asm/hugetlb.h>
+
+/* some sanity checks */
+#if (PGTABLE_RANGE >> 43) > SLICE_MASK_SIZE
+#error PGTABLE_RANGE exceeds slice_mask high_slices size
+#endif
+
+static DEFINE_SPINLOCK(slice_convert_lock);
+
+
+#ifdef DEBUG
+int _slice_debug = 1;
+
+static void slice_print_mask(const char *label, struct slice_mask mask)
+{
+ char *p, buf[16 + 3 + 64 + 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 & (1ul << 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 = (1ul << (GET_HIGH_SLICE_INDEX(end) + 1))
+ - (1ul << 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 |= 1ul << i;
+
+ return ret;
+}
+
+static struct slice_mask slice_mask_for_size(struct mm_struct *mm, int psize)
+{
+ unsigned char *hpsizes;
+ int index, mask_index;
+ struct slice_mask ret = { 0, 0 };
+ unsigned long i;
+ u64 lpsizes;
+
+ lpsizes = mm->context.low_slices_psize;
+ for (i = 0; i < SLICE_NUM_LOW; i++)
+ if (((lpsizes >> (i * 4)) & 0xf) == psize)
+ ret.low_slices |= 1u << i;
+
+ hpsizes = mm->context.high_slices_psize;
+ for (i = 0; i < SLICE_NUM_HIGH; i++) {
+ mask_index = i & 0x1;
+ index = i >> 1;
+ if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
+ ret.high_slices |= 1ul << 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)
+{
+ int index, mask_index;
+ /* Write the new slice psize bits */
+ unsigned char *hpsizes;
+ u64 lpsizes;
+ 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));
+
+ /* Assign the value back */
+ mm->context.low_slices_psize = lpsizes;
+
+ hpsizes = mm->context.high_slices_psize;
+ for (i = 0; i < SLICE_NUM_HIGH; i++) {
+ mask_index = i & 0x1;
+ index = i >> 1;
+ if (mask.high_slices & (1ul << i))
+ hpsizes[index] = (hpsizes[index] &
+ ~(0xf << (mask_index * 4))) |
+ (((unsigned long)psize) << (mask_index * 4));
+ }
+
+ slice_dbg(" lsps=%lx, hsps=%lx\n",
+ mm->context.low_slices_psize,
+ mm->context.high_slices_psize);
+
+ spin_unlock_irqrestore(&slice_convert_lock, flags);
+
+ copro_flush_all_slbs(mm);
+}
+
+/*
+ * Compute which slice addr is part of;
+ * set *boundary_addr to the start or end boundary of that slice
+ * (depending on 'end' parameter);
+ * return boolean indicating if the slice is marked as available in the
+ * 'available' slice_mark.
+ */
+static bool slice_scan_available(unsigned long addr,
+ struct slice_mask available,
+ int end,
+ unsigned long *boundary_addr)
+{
+ unsigned long slice;
+ if (addr < SLICE_LOW_TOP) {
+ slice = GET_LOW_SLICE_INDEX(addr);
+ *boundary_addr = (slice + end) << SLICE_LOW_SHIFT;
+ return !!(available.low_slices & (1u << slice));
+ } else {
+ slice = GET_HIGH_SLICE_INDEX(addr);
+ *boundary_addr = (slice + end) ?
+ ((slice + end) << SLICE_HIGH_SHIFT) : SLICE_LOW_TOP;
+ return !!(available.high_slices & (1ul << slice));
+ }
+}
+
+static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
+ unsigned long len,
+ struct slice_mask available,
+ int psize)
+{
+ int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
+ unsigned long addr, found, next_end;
+ struct vm_unmapped_area_info info;
+
+ info.flags = 0;
+ info.length = len;
+ info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
+ info.align_offset = 0;
+
+ addr = TASK_UNMAPPED_BASE;
+ while (addr < TASK_SIZE) {
+ info.low_limit = addr;
+ if (!slice_scan_available(addr, available, 1, &addr))
+ continue;
+
+ next_slice:
+ /*
+ * At this point [info.low_limit; addr) covers
+ * available slices only and ends at a slice boundary.
+ * Check if we need to reduce the range, or if we can
+ * extend it to cover the next available slice.
+ */
+ if (addr >= TASK_SIZE)
+ addr = TASK_SIZE;
+ else if (slice_scan_available(addr, available, 1, &next_end)) {
+ addr = next_end;
+ goto next_slice;
+ }
+ info.high_limit = addr;
+
+ found = vm_unmapped_area(&info);
+ if (!(found & ~PAGE_MASK))
+ return found;
+ }
+
+ return -ENOMEM;
+}
+
+static unsigned long slice_find_area_topdown(struct mm_struct *mm,
+ unsigned long len,
+ struct slice_mask available,
+ int psize)
+{
+ int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
+ unsigned long addr, found, prev;
+ struct vm_unmapped_area_info info;
+
+ info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+ info.length = len;
+ info.align_mask = PAGE_MASK & ((1ul << pshift) - 1);
+ info.align_offset = 0;
+
+ addr = mm->mmap_base;
+ while (addr > PAGE_SIZE) {
+ info.high_limit = addr;
+ if (!slice_scan_available(addr - 1, available, 0, &addr))
+ continue;
+
+ prev_slice:
+ /*
+ * At this point [addr; info.high_limit) covers
+ * available slices only and starts at a slice boundary.
+ * Check if we need to reduce the range, or if we can
+ * extend it to cover the previous available slice.
+ */
+ if (addr < PAGE_SIZE)
+ addr = PAGE_SIZE;
+ else if (slice_scan_available(addr - 1, available, 0, &prev)) {
+ addr = prev;
+ goto prev_slice;
+ }
+ info.low_limit = addr;
+
+ found = vm_unmapped_area(&info);
+ if (!(found & ~PAGE_MASK))
+ return found;
+ }
+
+ /*
+ * 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.
+ */
+ return slice_find_area_bottomup(mm, len, available, psize);
+}
+
+
+static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
+ struct slice_mask mask, int psize,
+ int topdown)
+{
+ if (topdown)
+ return slice_find_area_topdown(mm, len, mask, psize);
+ else
+ return slice_find_area_bottomup(mm, len, mask, psize);
+}
+
+#define or_mask(dst, src) do { \
+ (dst).low_slices |= (src).low_slices; \
+ (dst).high_slices |= (src).high_slices; \
+} while (0)
+
+#define andnot_mask(dst, src) do { \
+ (dst).low_slices &= ~(src).low_slices; \
+ (dst).high_slices &= ~(src).high_slices; \
+} while (0)
+
+#ifdef CONFIG_PPC_64K_PAGES
+#define MMU_PAGE_BASE MMU_PAGE_64K
+#else
+#define MMU_PAGE_BASE MMU_PAGE_4K
+#endif
+
+unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
+ unsigned long flags, unsigned int psize,
+ int topdown)
+{
+ struct slice_mask mask = {0, 0};
+ struct slice_mask good_mask;
+ struct slice_mask potential_mask = {0,0} /* silence stupid warning */;
+ struct slice_mask compat_mask = {0, 0};
+ int fixed = (flags & MAP_FIXED);
+ int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
+ struct mm_struct *mm = current->mm;
+ unsigned long newaddr;
+
+ /* 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\n",
+ addr, len, flags, topdown);
+
+ if (len > mm->task_size)
+ return -ENOMEM;
+ if (len & ((1ul << pshift) - 1))
+ return -EINVAL;
+ if (fixed && (addr & ((1ul << pshift) - 1)))
+ return -EINVAL;
+ if (fixed && addr > (mm->task_size - len))
+ return -ENOMEM;
+
+ /* 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);
+ /* Ignore hint if it's too large or overlaps a VMA */
+ if (addr > mm->task_size - len ||
+ !slice_area_is_free(mm, addr, len))
+ addr = 0;
+ }
+
+ /* First make up 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);
+
+ /*
+ * Here "good" means slices that are already the right page size,
+ * "compat" means slices that have a compatible page size (i.e.
+ * 4k in a 64k pagesize kernel), and "free" means slices without
+ * any VMAs.
+ *
+ * If MAP_FIXED:
+ * check if fits in good | compat => OK
+ * check if fits in good | compat | free => convert free
+ * else bad
+ * If have hint:
+ * check if hint fits in good => OK
+ * check if hint fits in good | free => convert free
+ * Otherwise:
+ * search in good, found => OK
+ * search in good | free, found => convert free
+ * search in good | compat | free, found => convert free.
+ */
+
+#ifdef CONFIG_PPC_64K_PAGES
+ /* If we support combo pages, we can allow 64k pages in 4k slices */
+ if (psize == MMU_PAGE_64K) {
+ compat_mask = slice_mask_for_size(mm, MMU_PAGE_4K);
+ if (fixed)
+ or_mask(good_mask, compat_mask);
+ }
+#endif
+
+ /* First check hint if it's valid or if we have MAP_FIXED */
+ if (addr != 0 || fixed) {
+ /* 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;
+ }
+ } else {
+ /* Now let's see if we can find something in the existing
+ * slices for that size
+ */
+ newaddr = slice_find_area(mm, len, good_mask, psize, topdown);
+ if (newaddr != -ENOMEM) {
+ /* Found within the good mask, we don't have to setup,
+ * we thus return directly
+ */
+ slice_dbg(" found area at 0x%lx\n", newaddr);
+ return newaddr;
+ }
+ }
+
+ /* 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);
+ or_mask(potential_mask, good_mask);
+ slice_print_mask(" potential", potential_mask);
+
+ if ((addr != 0 || fixed) && slice_check_fit(mask, potential_mask)) {
+ slice_dbg(" fits potential !\n");
+ goto convert;
+ }
+
+ /* If we have MAP_FIXED and failed the above steps, then error out */
+ if (fixed)
+ return -EBUSY;
+
+ slice_dbg(" search...\n");
+
+ /* If we had a hint that didn't work out, see if we can fit
+ * anywhere in the good area.
+ */
+ if (addr) {
+ addr = slice_find_area(mm, len, good_mask, psize, topdown);
+ if (addr != -ENOMEM) {
+ slice_dbg(" found area at 0x%lx\n", addr);
+ return addr;
+ }
+ }
+
+ /* Now let's see if we can find something in the existing slices
+ * for that size plus free slices
+ */
+ addr = slice_find_area(mm, len, potential_mask, psize, topdown);
+
+#ifdef CONFIG_PPC_64K_PAGES
+ if (addr == -ENOMEM && psize == MMU_PAGE_64K) {
+ /* retry the search with 4k-page slices included */
+ or_mask(potential_mask, compat_mask);
+ addr = slice_find_area(mm, len, potential_mask, psize,
+ topdown);
+ }
+#endif
+
+ 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:
+ andnot_mask(mask, good_mask);
+ andnot_mask(mask, compat_mask);
+ if (mask.low_slices || mask.high_slices) {
+ slice_convert(mm, mask, psize);
+ if (psize > MMU_PAGE_BASE)
+ on_each_cpu(slice_flush_segments, mm, 1);
+ }
+ 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);
+}
+
+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);
+}
+
+unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
+{
+ unsigned char *hpsizes;
+ int index, mask_index;
+
+ if (addr < SLICE_LOW_TOP) {
+ u64 lpsizes;
+ lpsizes = mm->context.low_slices_psize;
+ index = GET_LOW_SLICE_INDEX(addr);
+ return (lpsizes >> (index * 4)) & 0xf;
+ }
+ hpsizes = mm->context.high_slices_psize;
+ index = GET_HIGH_SLICE_INDEX(addr);
+ mask_index = index & 0x1;
+ return (hpsizes[index >> 1] >> (mask_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
+ * N.B. This may be called before mm->context.id has been set.
+ *
+ * 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)
+{
+ int index, mask_index;
+ unsigned char *hpsizes;
+ unsigned long flags, lpsizes;
+ 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));
+ /* Assign the value back */
+ mm->context.low_slices_psize = lpsizes;
+
+ hpsizes = mm->context.high_slices_psize;
+ for (i = 0; i < SLICE_NUM_HIGH; i++) {
+ mask_index = i & 0x1;
+ index = i >> 1;
+ if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == old_psize)
+ hpsizes[index] = (hpsizes[index] &
+ ~(0xf << (mask_index * 4))) |
+ (((unsigned long)psize) << (mask_index * 4));
+ }
+
+
+
+
+ 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);
+}
+
+void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
+ unsigned long len, unsigned int psize)
+{
+ struct slice_mask mask = slice_range_to_mask(start, len);
+
+ slice_convert(mm, mask, psize);
+}
+
+#ifdef CONFIG_HUGETLB_PAGE
+/*
+ * is_hugepage_only_range() is used by generic code to verify whether
+ * 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;
+ unsigned int psize = mm->context.user_psize;
+
+ mask = slice_range_to_mask(addr, len);
+ available = slice_mask_for_size(mm, psize);
+#ifdef CONFIG_PPC_64K_PAGES
+ /* We need to account for 4k slices too */
+ if (psize == MMU_PAGE_64K) {
+ struct slice_mask compat_mask;
+ compat_mask = slice_mask_for_size(mm, MMU_PAGE_4K);
+ or_mask(available, compat_mask);
+ }
+#endif
+
+#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);
+}
+#endif