/*
* 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 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 + 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 (len & ((1ul << pshift) - 1))
return -EINVAL;
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
* 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)
{
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);
}
