diff options
Diffstat (limited to 'arch/powerpc/mm/book3s64/slice.c')
| -rw-r--r-- | arch/powerpc/mm/book3s64/slice.c | 807 |
1 files changed, 807 insertions, 0 deletions
diff --git a/arch/powerpc/mm/book3s64/slice.c b/arch/powerpc/mm/book3s64/slice.c new file mode 100644 index 000000000000..c0b58afb9a47 --- /dev/null +++ b/arch/powerpc/mm/book3s64/slice.c @@ -0,0 +1,807 @@ +// 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 addr, 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 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; + /* + * 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 addr, 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 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; + /* + * 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, TASK_UNMAPPED_BASE, 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, mm->mmap_base, len, mask, psize, high_limit); + else + return slice_find_area_bottomup(mm, mm->mmap_base, 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 long arch_get_unmapped_area(struct file *filp, + unsigned long addr, + unsigned long len, + unsigned long pgoff, + unsigned long flags) +{ + if (radix_enabled()) + return generic_get_unmapped_area(filp, addr, len, pgoff, flags); + + return slice_get_unmapped_area(addr, len, flags, + mm_ctx_user_psize(¤t->mm->context), 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) +{ + if (radix_enabled()) + return generic_get_unmapped_area_topdown(filp, addr0, len, pgoff, flags); + + return slice_get_unmapped_area(addr0, len, flags, + mm_ctx_user_psize(¤t->mm->context), 1); +} + +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); +} + +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); +} + +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); +} + +unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) +{ + /* With radix we don't use slice, so derive it from vma*/ + if (radix_enabled()) + return vma_kernel_pagesize(vma); + + return 1UL << mmu_psize_to_shift(get_slice_psize(vma->vm_mm, vma->vm_start)); +} + +static int file_to_psize(struct file *file) +{ + struct hstate *hstate = hstate_file(file); + return shift_to_mmu_psize(huge_page_shift(hstate)); +} + +unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags) +{ + if (radix_enabled()) + return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags); + + return slice_get_unmapped_area(addr, len, flags, file_to_psize(file), 1); +} +#endif |