diff options
Diffstat (limited to 'kernel/arch/powerpc/mm/slice.c')
| -rw-r--r-- | kernel/arch/powerpc/mm/slice.c | 701 |
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 |