blob: f42711f865f3f444308423a898340d211e049553 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* address space "slices" (meta-segments) support
*
* Copyright (C) 2007 Benjamin Herrenschmidt, IBM Corporation.
*
* Based on hugetlb implementation
*
* Copyright (C) 2003 David Gibson, IBM Corporation.
*/
#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 <linux/sched/mm.h>
#include <linux/security.h>
#include <asm/mman.h>
#include <asm/mmu.h>
#include <asm/copro.h>
#include <asm/hugetlb.h>
#include <asm/mmu_context.h>
static DEFINE_SPINLOCK(slice_convert_lock);
#ifdef DEBUG
int _slice_debug = 1;
static void slice_print_mask(const char *label, const struct slice_mask *mask)
{
if (!_slice_debug)
return;
pr_devel("%s low_slice: %*pbl\n", label,
(int)SLICE_NUM_LOW, &mask->low_slices);
pr_devel("%s high_slice: %*pbl\n", label,
(int)SLICE_NUM_HIGH, mask->high_slices);
}
#define slice_dbg(fmt...) do { if (_slice_debug) pr_devel(fmt); } while (0)
#else
static void slice_print_mask(const char *label, const struct slice_mask *mask) {}
#define slice_dbg(fmt...)
#endif
static inline notrace bool slice_addr_is_low(unsigned long addr)
{
u64 tmp = (u64)addr;
return tmp < SLICE_LOW_TOP;
}
static void slice_range_to_mask(unsigned long start, unsigned long len,
struct slice_mask *ret)
{
unsigned long end = start + len - 1;
ret->low_slices = 0;
if (SLICE_NUM_HIGH)
bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
if (slice_addr_is_low(start)) {
unsigned long mend = min(end,
(unsigned long)(SLICE_LOW_TOP - 1));
ret->low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
- (1u << GET_LOW_SLICE_INDEX(start));
}
if (SLICE_NUM_HIGH && !slice_addr_is_low(end)) {
unsigned long start_index = GET_HIGH_SLICE_INDEX(start);
unsigned long align_end = ALIGN(end, (1UL << SLICE_HIGH_SHIFT));
unsigned long count = GET_HIGH_SLICE_INDEX(align_end) - start_index;
bitmap_set(ret->high_slices, start_index, count);
}
}
static int slice_area_is_free(struct mm_struct *mm, unsigned long addr,
unsigned long len)
{
struct vm_area_struct *vma;
if ((mm_ctx_slb_addr_limit(&mm->context) - len) < addr)
return 0;
vma = find_vma(mm, addr);
return (!vma || (addr + len) <= vm_start_gap(vma));
}
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 = (unsigned long)SLICE_LOW_TOP;
return !slice_area_is_free(mm, start, end - start);
}
static void slice_mask_for_free(struct mm_struct *mm, struct slice_mask *ret,
unsigned long high_limit)
{
unsigned long i;
ret->low_slices = 0;
if (SLICE_NUM_HIGH)
bitmap_zero(ret->high_slices, SLICE_NUM_HIGH);
for (i = 0; i < SLICE_NUM_LOW; i++)
if (!slice_low_has_vma(mm, i))
ret->low_slices |= 1u << i;
if (slice_addr_is_low(high_limit - 1))
return;
for (i = 0; i < GET_HIGH_SLICE_INDEX(high_limit); i++)
if (!slice_high_has_vma(mm, i))
__set_bit(i, ret->high_slices);
}
static bool slice_check_range_fits(struct mm_struct *mm,
const struct slice_mask *available,
unsigned long start, unsigned long len)
{
unsigned long end = start + len - 1;
u64 low_slices = 0;
if (slice_addr_is_low(start)) {
unsigned long mend = min(end,
(unsigned long)(SLICE_LOW_TOP - 1));
low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
- (1u << GET_LOW_SLICE_INDEX(start));
}
if ((low_slices & available->low_slices) != low_slices)
return false;
if (SLICE_NUM_HIGH && !slice_addr_is_low(end)) {
unsigned long start_index = GET_HIGH_SLICE_INDEX(start);
unsigned long align_end = ALIGN(end, (1UL << SLICE_HIGH_SHIFT));
unsigned long count = GET_HIGH_SLICE_INDEX(align_end) - start_index;
unsigned long i;
for (i = start_index; i < start_index + count; i++) {
if (!test_bit(i, available->high_slices))
return false;
}
}
return true;
}
static void slice_flush_segments(void *parm)
{
#ifdef CONFIG_PPC64
struct mm_struct *mm = parm;
unsigned long flags;
if (mm != current->active_mm)
return;
copy_mm_to_paca(current->active_mm);
local_irq_save(flags);
slb_flush_and_restore_bolted();
local_irq_restore(flags);
#endif
}
static void slice_convert(struct mm_struct *mm,
const struct slice_mask *mask, int psize)
{
int index, mask_index;
/* Write the new slice psize bits */
unsigned char *hpsizes, *lpsizes;
struct slice_mask *psize_mask, *old_mask;
unsigned long i, flags;
int old_psize;
slice_dbg("slice_convert(mm=%p, psize=%d)\n", mm, psize);
slice_print_mask(" mask", mask);
psize_mask = slice_mask_for_size(&mm->context, psize);
/* We need to use a spinlock here to protect against
* concurrent 64k -> 4k demotion ...
*/
spin_lock_irqsave(&slice_convert_lock, flags);
lpsizes = mm_ctx_low_slices(&mm->context);
for (i = 0; i < SLICE_NUM_LOW; i++) {
if (!(mask->low_slices & (1u << i)))
continue;
mask_index = i & 0x1;
index = i >> 1;
/* Update the slice_mask */
old_psize = (lpsizes[index] >> (mask_index * 4)) & 0xf;
old_mask = slice_mask_for_size(&mm->context, old_psize);
old_mask->low_slices &= ~(1u << i);
psize_mask->low_slices |= 1u << i;
/* Update the sizes array */
lpsizes[index] = (lpsizes[index] & ~(0xf << (mask_index * 4))) |
(((unsigned long)psize) << (mask_index * 4));
}
hpsizes = mm_ctx_high_slices(&mm->context);
for (i = 0; i < GET_HIGH_SLICE_INDEX(mm_ctx_slb_addr_limit(&mm->context)); i++) {
if (!test_bit(i, mask->high_slices))
continue;
mask_index = i & 0x1;
index = i >> 1;
/* Update the slice_mask */
old_psize = (hpsizes[index] >> (mask_index * 4)) & 0xf;
old_mask = slice_mask_for_size(&mm->context, old_psize);
__clear_bit(i, old_mask->high_slices);
__set_bit(i, psize_mask->high_slices);
/* Update the sizes array */
hpsizes[index] = (hpsizes[index] & ~(0xf << (mask_index * 4))) |
(((unsigned long)psize) << (mask_index * 4));
}
slice_dbg(" lsps=%lx, hsps=%lx\n",
(unsigned long)mm_ctx_low_slices(&mm->context),
(unsigned long)mm_ctx_high_slices(&mm->context));
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,
const struct slice_mask *available,
int end, unsigned long *boundary_addr)
{
unsigned long slice;
if (slice_addr_is_low(addr)) {
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 !!test_bit(slice, available->high_slices);
}
}
static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
unsigned long len,
const struct slice_mask *available,
int psize, unsigned long high_limit)
{
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;
/*
* Check till the allow max value for this mmap request
*/
while (addr < high_limit) {
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 >= high_limit)
addr = high_limit;
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,
const struct slice_mask *available,
int psize, unsigned long high_limit)
{
int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
unsigned long addr, found, prev;
struct vm_unmapped_area_info info;
unsigned long min_addr = max(PAGE_SIZE, mmap_min_addr);
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;
/*
* If we are trying to allocate above DEFAULT_MAP_WINDOW
* Add the different to the mmap_base.
* Only for that request for which high_limit is above
* DEFAULT_MAP_WINDOW we should apply this.
*/
if (high_limit > DEFAULT_MAP_WINDOW)
addr += mm_ctx_slb_addr_limit(&mm->context) - DEFAULT_MAP_WINDOW;
while (addr > min_addr) {
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 < min_addr)
addr = min_addr;
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, high_limit);
}
static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
const struct slice_mask *mask, int psize,
int topdown, unsigned long high_limit)
{
if (topdown)
return slice_find_area_topdown(mm, len, mask, psize, high_limit);
else
return slice_find_area_bottomup(mm, len, mask, psize, high_limit);
}
static inline void slice_copy_mask(struct slice_mask *dst,
const struct slice_mask *src)
{
dst->low_slices = src->low_slices;
if (!SLICE_NUM_HIGH)
return;
bitmap_copy(dst->high_slices, src->high_slices, SLICE_NUM_HIGH);
}
static inline void slice_or_mask(struct slice_mask *dst,
const struct slice_mask *src1,
const struct slice_mask *src2)
{
dst->low_slices = src1->low_slices | src2->low_slices;
if (!SLICE_NUM_HIGH)
return;
bitmap_or(dst->high_slices, src1->high_slices, src2->high_slices, SLICE_NUM_HIGH);
}
static inline void slice_andnot_mask(struct slice_mask *dst,
const struct slice_mask *src1,
const struct slice_mask *src2)
{
dst->low_slices = src1->low_slices & ~src2->low_slices;
if (!SLICE_NUM_HIGH)
return;
bitmap_andnot(dst->high_slices, src1->high_slices, src2->high_slices, SLICE_NUM_HIGH);
}
#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 good_mask;
struct slice_mask potential_mask;
const struct slice_mask *maskp;
const struct slice_mask *compat_maskp = NULL;
int fixed = (flags & MAP_FIXED);
int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
unsigned long page_size = 1UL << pshift;
struct mm_struct *mm = current->mm;
unsigned long newaddr;
unsigned long high_limit;
high_limit = DEFAULT_MAP_WINDOW;
if (addr >= high_limit || (fixed && (addr + len > high_limit)))
high_limit = TASK_SIZE;
if (len > high_limit)
return -ENOMEM;
if (len & (page_size - 1))
return -EINVAL;
if (fixed) {
if (addr & (page_size - 1))
return -EINVAL;
if (addr > high_limit - len)
return -ENOMEM;
}
if (high_limit > mm_ctx_slb_addr_limit(&mm->context)) {
/*
* Increasing the slb_addr_limit does not require
* slice mask cache to be recalculated because it should
* be already initialised beyond the old address limit.
*/
mm_ctx_set_slb_addr_limit(&mm->context, high_limit);
on_each_cpu(slice_flush_segments, mm, 1);
}
/* Sanity checks */
BUG_ON(mm->task_size == 0);
BUG_ON(mm_ctx_slb_addr_limit(&mm->context) == 0);
VM_BUG_ON(radix_enabled());
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 hint, make sure it matches our alignment restrictions */
if (!fixed && addr) {
addr = ALIGN(addr, page_size);
slice_dbg(" aligned addr=%lx\n", addr);
/* Ignore hint if it's too large or overlaps a VMA */
if (addr > high_limit - len || addr < mmap_min_addr ||
!slice_area_is_free(mm, addr, len))
addr = 0;
}
/* First make up a "good" mask of slices that have the right size
* already
*/
maskp = slice_mask_for_size(&mm->context, psize);
/*
* 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.
*/
/*
* If we support combo pages, we can allow 64k pages in 4k slices
* The mask copies could be avoided in most cases here if we had
* a pointer to good mask for the next code to use.
*/
if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && psize == MMU_PAGE_64K) {
compat_maskp = slice_mask_for_size(&mm->context, MMU_PAGE_4K);
if (fixed)
slice_or_mask(&good_mask, maskp, compat_maskp);
else
slice_copy_mask(&good_mask, maskp);
} else {
slice_copy_mask(&good_mask, maskp);
}
slice_print_mask(" good_mask", &good_mask);
if (compat_maskp)
slice_print_mask(" compat_mask", compat_maskp);
/* First check hint if it's valid or if we have MAP_FIXED */
if (addr != 0 || fixed) {
/* Check if we fit in the good mask. If we do, we just return,
* nothing else to do
*/
if (slice_check_range_fits(mm, &good_mask, addr, len)) {
slice_dbg(" fits good !\n");
newaddr = addr;
goto 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, high_limit);
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);
goto return_addr;
}
}
/*
* We don't fit in the good mask, check what other slices are
* empty and thus can be converted
*/
slice_mask_for_free(mm, &potential_mask, high_limit);
slice_or_mask(&potential_mask, &potential_mask, &good_mask);
slice_print_mask(" potential", &potential_mask);
if (addr != 0 || fixed) {
if (slice_check_range_fits(mm, &potential_mask, addr, len)) {
slice_dbg(" fits potential !\n");
newaddr = addr;
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) {
newaddr = slice_find_area(mm, len, &good_mask,
psize, topdown, high_limit);
if (newaddr != -ENOMEM) {
slice_dbg(" found area at 0x%lx\n", newaddr);
goto return_addr;
}
}
/* Now let's see if we can find something in the existing slices
* for that size plus free slices
*/
newaddr = slice_find_area(mm, len, &potential_mask,
psize, topdown, high_limit);
if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && newaddr == -ENOMEM &&
psize == MMU_PAGE_64K) {
/* retry the search with 4k-page slices included */
slice_or_mask(&potential_mask, &potential_mask, compat_maskp);
newaddr = slice_find_area(mm, len, &potential_mask,
psize, topdown, high_limit);
}
if (newaddr == -ENOMEM)
return -ENOMEM;
slice_range_to_mask(newaddr, len, &potential_mask);
slice_dbg(" found potential area at 0x%lx\n", newaddr);
slice_print_mask(" mask", &potential_mask);
convert:
/*
* Try to allocate the context before we do slice convert
* so that we handle the context allocation failure gracefully.
*/
if (need_extra_context(mm, newaddr)) {
if (alloc_extended_context(mm, newaddr) < 0)
return -ENOMEM;
}
slice_andnot_mask(&potential_mask, &potential_mask, &good_mask);
if (compat_maskp && !fixed)
slice_andnot_mask(&potential_mask, &potential_mask, compat_maskp);
if (potential_mask.low_slices ||
(SLICE_NUM_HIGH &&
!bitmap_empty(potential_mask.high_slices, SLICE_NUM_HIGH))) {
slice_convert(mm, &potential_mask, psize);
if (psize > MMU_PAGE_BASE)
on_each_cpu(slice_flush_segments, mm, 1);
}
return newaddr;
return_addr:
if (need_extra_context(mm, newaddr)) {
if (alloc_extended_context(mm, newaddr) < 0)
return -ENOMEM;
}
return newaddr;
}
EXPORT_SYMBOL_GPL(slice_get_unmapped_area);
unsigned int notrace get_slice_psize(struct mm_struct *mm, unsigned long addr)
{
unsigned char *psizes;
int index, mask_index;
VM_BUG_ON(radix_enabled());
if (slice_addr_is_low(addr)) {
psizes = mm_ctx_low_slices(&mm->context);
index = GET_LOW_SLICE_INDEX(addr);
} else {
psizes = mm_ctx_high_slices(&mm->context);
index = GET_HIGH_SLICE_INDEX(addr);
}
mask_index = index & 0x1;
return (psizes[index >> 1] >> (mask_index * 4)) & 0xf;
}
EXPORT_SYMBOL_GPL(get_slice_psize);
void slice_init_new_context_exec(struct mm_struct *mm)
{
unsigned char *hpsizes, *lpsizes;
struct slice_mask *mask;
unsigned int psize = mmu_virtual_psize;
slice_dbg("slice_init_new_context_exec(mm=%p)\n", mm);
/*
* In the case of exec, use the default limit. In the
* case of fork it is just inherited from the mm being
* duplicated.
*/
mm_ctx_set_slb_addr_limit(&mm->context, SLB_ADDR_LIMIT_DEFAULT);
mm_ctx_set_user_psize(&mm->context, psize);
/*
* Set all slice psizes to the default.
*/
lpsizes = mm_ctx_low_slices(&mm->context);
memset(lpsizes, (psize << 4) | psize, SLICE_NUM_LOW >> 1);
hpsizes = mm_ctx_high_slices(&mm->context);
memset(hpsizes, (psize << 4) | psize, SLICE_NUM_HIGH >> 1);
/*
* Slice mask cache starts zeroed, fill the default size cache.
*/
mask = slice_mask_for_size(&mm->context, psize);
mask->low_slices = ~0UL;
if (SLICE_NUM_HIGH)
bitmap_fill(mask->high_slices, SLICE_NUM_HIGH);
}
#ifdef CONFIG_PPC_BOOK3S_64
void slice_setup_new_exec(void)
{
struct mm_struct *mm = current->mm;
slice_dbg("slice_setup_new_exec(mm=%p)\n", mm);
if (!is_32bit_task())
return;
mm_ctx_set_slb_addr_limit(&mm->context, DEFAULT_MAP_WINDOW);
}
#endif
void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
unsigned long len, unsigned int psize)
{
struct slice_mask mask;
VM_BUG_ON(radix_enabled());
slice_range_to_mask(start, len, &mask);
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 slice_is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
unsigned long len)
{
const struct slice_mask *maskp;
unsigned int psize = mm_ctx_user_psize(&mm->context);
VM_BUG_ON(radix_enabled());
maskp = slice_mask_for_size(&mm->context, psize);
/* We need to account for 4k slices too */
if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && psize == MMU_PAGE_64K) {
const struct slice_mask *compat_maskp;
struct slice_mask available;
compat_maskp = slice_mask_for_size(&mm->context, MMU_PAGE_4K);
slice_or_mask(&available, maskp, compat_maskp);
return !slice_check_range_fits(mm, &available, addr, len);
}
return !slice_check_range_fits(mm, maskp, addr, len);
}
#endif