/* * 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 /* 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