diff options
Diffstat (limited to 'arch/powerpc/mm/slice.c')
| -rw-r--r-- | arch/powerpc/mm/slice.c | 633 |
1 files changed, 633 insertions, 0 deletions
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c new file mode 100644 index 00000000000..f833dba2a02 --- /dev/null +++ b/arch/powerpc/mm/slice.c @@ -0,0 +1,633 @@ +/* + * 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 spinlock_t slice_convert_lock = SPIN_LOCK_UNLOCKED; + + +#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 (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 + * + * 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); +} + |