/* * 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 #include #include #include #include #include #include #include #include #include #include static DEFINE_SPINLOCK(slice_convert_lock); /* * One bit per slice. We have lower slices which cover 256MB segments * upto 4G range. That gets us 16 low slices. For the rest we track slices * in 1TB size. */ struct slice_mask { u64 low_slices; DECLARE_BITMAP(high_slices, SLICE_NUM_HIGH); }; #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 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 (start < SLICE_LOW_TOP) { 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 ((start + len) > SLICE_LOW_TOP) { 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->context.slb_addr_limit - 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); #ifdef CONFIG_PPC64 /* 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; #endif 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 (high_limit <= SLICE_LOW_TOP) 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 void slice_mask_for_size(struct mm_struct *mm, int psize, struct slice_mask *ret, unsigned long high_limit) { unsigned char *hpsizes, *lpsizes; int index, mask_index; unsigned long i; ret->low_slices = 0; if (SLICE_NUM_HIGH) bitmap_zero(ret->high_slices, SLICE_NUM_HIGH); lpsizes = mm->context.low_slices_psize; for (i = 0; i < SLICE_NUM_LOW; i++) { mask_index = i & 0x1; index = i >> 1; if (((lpsizes[index] >> (mask_index * 4)) & 0xf) == psize) ret->low_slices |= 1u << i; } if (high_limit <= SLICE_LOW_TOP) return; hpsizes = mm->context.high_slices_psize; for (i = 0; i < GET_HIGH_SLICE_INDEX(high_limit); i++) { mask_index = i & 0x1; index = i >> 1; if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize) __set_bit(i, ret->high_slices); } } static int slice_check_fit(struct mm_struct *mm, const struct slice_mask *mask, const struct slice_mask *available) { DECLARE_BITMAP(result, SLICE_NUM_HIGH); /* * Make sure we just do bit compare only to the max * addr limit and not the full bit map size. */ unsigned long slice_count = GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit); if (!SLICE_NUM_HIGH) return (mask->low_slices & available->low_slices) == mask->low_slices; bitmap_and(result, mask->high_slices, available->high_slices, slice_count); return (mask->low_slices & available->low_slices) == mask->low_slices && bitmap_equal(result, mask->high_slices, slice_count); } 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_rebolt(); 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; 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))) continue; mask_index = i & 0x1; index = i >> 1; lpsizes[index] = (lpsizes[index] & ~(0xf << (mask_index * 4))) | (((unsigned long)psize) << (mask_index * 4)); } hpsizes = mm->context.high_slices_psize; for (i = 0; i < GET_HIGH_SLICE_INDEX(mm->context.slb_addr_limit); i++) { if (!test_bit(i, mask->high_slices)) continue; mask_index = i & 0x1; index = i >> 1; hpsizes[index] = (hpsizes[index] & ~(0xf << (mask_index * 4))) | (((unsigned long)psize) << (mask_index * 4)); } slice_dbg(" lsps=%lx, hsps=%lx\n", (unsigned long)mm->context.low_slices_psize, (unsigned long)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, const 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 !!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; 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->context.slb_addr_limit - DEFAULT_MAP_WINDOW; 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, 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_or_mask(struct slice_mask *dst, const struct slice_mask *src) { dst->low_slices |= src->low_slices; if (!SLICE_NUM_HIGH) return; bitmap_or(dst->high_slices, dst->high_slices, src->high_slices, SLICE_NUM_HIGH); } static inline void slice_andnot_mask(struct slice_mask *dst, const struct slice_mask *src) { dst->low_slices &= ~src->low_slices; if (!SLICE_NUM_HIGH) return; bitmap_andnot(dst->high_slices, dst->high_slices, src->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 mask; struct slice_mask good_mask; struct slice_mask potential_mask; struct slice_mask compat_mask; 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->context.slb_addr_limit) { mm->context.slb_addr_limit = high_limit; on_each_cpu(slice_flush_segments, mm, 1); } /* * init different masks */ mask.low_slices = 0; /* silence stupid warning */; potential_mask.low_slices = 0; compat_mask.low_slices = 0; if (SLICE_NUM_HIGH) { bitmap_zero(mask.high_slices, SLICE_NUM_HIGH); bitmap_zero(potential_mask.high_slices, SLICE_NUM_HIGH); bitmap_zero(compat_mask.high_slices, SLICE_NUM_HIGH); } /* Sanity checks */ BUG_ON(mm->task_size == 0); BUG_ON(mm->context.slb_addr_limit == 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_UP(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 || !slice_area_is_free(mm, addr, len)) addr = 0; } /* First make up a "good" mask of slices that have the right size * already */ slice_mask_for_size(mm, psize, &good_mask, high_limit); 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) { slice_mask_for_size(mm, MMU_PAGE_4K, &compat_mask, high_limit); if (fixed) slice_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 */ slice_range_to_mask(addr, len, &mask); 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(mm, &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, 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); return newaddr; } } /* * 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, &good_mask); slice_print_mask(" potential", &potential_mask); if ((addr != 0 || fixed) && slice_check_fit(mm, &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, high_limit); 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, high_limit); #ifdef CONFIG_PPC_64K_PAGES if (addr == -ENOMEM && psize == MMU_PAGE_64K) { /* retry the search with 4k-page slices included */ slice_or_mask(&potential_mask, &compat_mask); addr = slice_find_area(mm, len, &potential_mask, psize, topdown, high_limit); } #endif if (addr == -ENOMEM) return -ENOMEM; slice_range_to_mask(addr, len, &mask); slice_dbg(" found potential area at 0x%lx\n", addr); slice_print_mask(" mask", &mask); convert: slice_andnot_mask(&mask, &good_mask); slice_andnot_mask(&mask, &compat_mask); if (mask.low_slices || (SLICE_NUM_HIGH && !bitmap_empty(mask.high_slices, SLICE_NUM_HIGH))) { 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 *psizes; int index, mask_index; /* * Radix doesn't use slice, but can get enabled along with MMU_SLICE */ if (radix_enabled()) { #ifdef CONFIG_PPC_64K_PAGES return MMU_PAGE_64K; #else return MMU_PAGE_4K; #endif } 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); } 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; 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. */ #ifdef CONFIG_PPC64 mm->context.slb_addr_limit = DEFAULT_MAP_WINDOW_USER64; #else mm->context.slb_addr_limit = DEFAULT_MAP_WINDOW; #endif mm->context.user_psize = psize; /* * Set all slice psizes to the default. */ lpsizes = mm->context.low_slices_psize; memset(lpsizes, (psize << 4) | psize, SLICE_NUM_LOW >> 1); hpsizes = mm->context.high_slices_psize; memset(hpsizes, (psize << 4) | psize, SLICE_NUM_HIGH >> 1); } 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 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; unsigned long high_limit = mm->context.slb_addr_limit; if (radix_enabled()) return 0; slice_range_to_mask(addr, len, &mask); slice_mask_for_size(mm, psize, &available, high_limit); #ifdef CONFIG_PPC_64K_PAGES /* We need to account for 4k slices too */ if (psize == MMU_PAGE_64K) { struct slice_mask compat_mask; slice_mask_for_size(mm, MMU_PAGE_4K, &compat_mask, high_limit); slice_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(mm, &mask, &available); } #endif