/* * PPC64 (POWER4) Huge TLB Page Support for Kernel. * * Copyright (C) 2003 David Gibson, IBM Corporation. * * Based on the IA-32 version: * Copyright (C) 2002, Rohit Seth */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define HUGEPGDIR_SHIFT (HPAGE_SHIFT + PAGE_SHIFT - 3) #define HUGEPGDIR_SIZE (1UL << HUGEPGDIR_SHIFT) #define HUGEPGDIR_MASK (~(HUGEPGDIR_SIZE-1)) #define HUGEPTE_INDEX_SIZE 9 #define HUGEPGD_INDEX_SIZE 10 #define PTRS_PER_HUGEPTE (1 << HUGEPTE_INDEX_SIZE) #define PTRS_PER_HUGEPGD (1 << HUGEPGD_INDEX_SIZE) static inline int hugepgd_index(unsigned long addr) { return (addr & ~REGION_MASK) >> HUGEPGDIR_SHIFT; } static pud_t *hugepgd_offset(struct mm_struct *mm, unsigned long addr) { int index; if (! mm->context.huge_pgdir) return NULL; index = hugepgd_index(addr); BUG_ON(index >= PTRS_PER_HUGEPGD); return (pud_t *)(mm->context.huge_pgdir + index); } static inline pte_t *hugepte_offset(pud_t *dir, unsigned long addr) { int index; if (pud_none(*dir)) return NULL; index = (addr >> HPAGE_SHIFT) % PTRS_PER_HUGEPTE; return (pte_t *)pud_page(*dir) + index; } static pud_t *hugepgd_alloc(struct mm_struct *mm, unsigned long addr) { BUG_ON(! in_hugepage_area(mm->context, addr)); if (! mm->context.huge_pgdir) { pgd_t *new; spin_unlock(&mm->page_table_lock); /* Don't use pgd_alloc(), because we want __GFP_REPEAT */ new = kmem_cache_alloc(zero_cache, GFP_KERNEL | __GFP_REPEAT); BUG_ON(memcmp(new, empty_zero_page, PAGE_SIZE)); spin_lock(&mm->page_table_lock); /* * Because we dropped the lock, we should re-check the * entry, as somebody else could have populated it.. */ if (mm->context.huge_pgdir) pgd_free(new); else mm->context.huge_pgdir = new; } return hugepgd_offset(mm, addr); } static pte_t *hugepte_alloc(struct mm_struct *mm, pud_t *dir, unsigned long addr) { if (! pud_present(*dir)) { pte_t *new; spin_unlock(&mm->page_table_lock); new = kmem_cache_alloc(zero_cache, GFP_KERNEL | __GFP_REPEAT); BUG_ON(memcmp(new, empty_zero_page, PAGE_SIZE)); spin_lock(&mm->page_table_lock); /* * Because we dropped the lock, we should re-check the * entry, as somebody else could have populated it.. */ if (pud_present(*dir)) { if (new) kmem_cache_free(zero_cache, new); } else { struct page *ptepage; if (! new) return NULL; ptepage = virt_to_page(new); ptepage->mapping = (void *) mm; ptepage->index = addr & HUGEPGDIR_MASK; pud_populate(mm, dir, new); } } return hugepte_offset(dir, addr); } pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) { pud_t *pud; BUG_ON(! in_hugepage_area(mm->context, addr)); pud = hugepgd_offset(mm, addr); if (! pud) return NULL; return hugepte_offset(pud, addr); } pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr) { pud_t *pud; BUG_ON(! in_hugepage_area(mm->context, addr)); pud = hugepgd_alloc(mm, addr); if (! pud) return NULL; return hugepte_alloc(mm, pud, addr); } /* * This function checks for proper alignment of input addr and len parameters. */ int is_aligned_hugepage_range(unsigned long addr, unsigned long len) { if (len & ~HPAGE_MASK) return -EINVAL; if (addr & ~HPAGE_MASK) return -EINVAL; if (! (within_hugepage_low_range(addr, len) || within_hugepage_high_range(addr, len)) ) return -EINVAL; return 0; } static void flush_segments(void *parm) { u16 segs = (unsigned long) parm; unsigned long i; asm volatile("isync" : : : "memory"); for (i = 0; i < 16; i++) { if (! (segs & (1U << i))) continue; asm volatile("slbie %0" : : "r" (i << SID_SHIFT)); } asm volatile("isync" : : : "memory"); } static int prepare_low_seg_for_htlb(struct mm_struct *mm, unsigned long seg) { unsigned long start = seg << SID_SHIFT; unsigned long end = (seg+1) << SID_SHIFT; struct vm_area_struct *vma; BUG_ON(seg >= 16); /* Check no VMAs are in the region */ vma = find_vma(mm, start); if (vma && (vma->vm_start < end)) return -EBUSY; return 0; } static int open_low_hpage_segs(struct mm_struct *mm, u16 newsegs) { unsigned long i; newsegs &= ~(mm->context.htlb_segs); if (! newsegs) return 0; /* The segments we want are already open */ for (i = 0; i < 16; i++) if ((1 << i) & newsegs) if (prepare_low_seg_for_htlb(mm, i) != 0) return -EBUSY; mm->context.htlb_segs |= newsegs; /* update the paca copy of the context struct */ get_paca()->context = mm->context; /* the context change must make it to memory before the flush, * so that further SLB misses do the right thing. */ mb(); on_each_cpu(flush_segments, (void *)(unsigned long)newsegs, 0, 1); return 0; } int prepare_hugepage_range(unsigned long addr, unsigned long len) { if (within_hugepage_high_range(addr, len)) return 0; else if ((addr < 0x100000000UL) && ((addr+len) < 0x100000000UL)) { int err; /* Yes, we need both tests, in case addr+len overflows * 64-bit arithmetic */ err = open_low_hpage_segs(current->mm, LOW_ESID_MASK(addr, len)); if (err) printk(KERN_DEBUG "prepare_hugepage_range(%lx, %lx)" " failed (segs: 0x%04hx)\n", addr, len, LOW_ESID_MASK(addr, len)); return err; } return -EINVAL; } struct page * follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) { pte_t *ptep; struct page *page; if (! in_hugepage_area(mm->context, address)) return ERR_PTR(-EINVAL); ptep = huge_pte_offset(mm, address); page = pte_page(*ptep); if (page) page += (address % HPAGE_SIZE) / PAGE_SIZE; return page; } int pmd_huge(pmd_t pmd) { return 0; } struct page * follow_huge_pmd(struct mm_struct *mm, unsigned long address, pmd_t *pmd, int write) { BUG(); return NULL; } /* Because we have an exclusive hugepage region which lies within the * normal user address space, we have to take special measures to make * non-huge mmap()s evade the hugepage reserved regions. */ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; unsigned long start_addr; if (len > TASK_SIZE) return -ENOMEM; if (addr) { addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (((TASK_SIZE - len) >= addr) && (!vma || (addr+len) <= vma->vm_start) && !is_hugepage_only_range(mm, addr,len)) return addr; } start_addr = addr = mm->free_area_cache; full_search: vma = find_vma(mm, addr); while (TASK_SIZE - len >= addr) { BUG_ON(vma && (addr >= vma->vm_end)); if (touches_hugepage_low_range(mm, addr, len)) { addr = ALIGN(addr+1, 1<vm_start) { /* * Remember the place where we stopped the search: */ mm->free_area_cache = addr + len; return addr; } addr = vma->vm_end; vma = vma->vm_next; } /* Make sure we didn't miss any holes */ if (start_addr != TASK_UNMAPPED_BASE) { start_addr = addr = TASK_UNMAPPED_BASE; goto full_search; } return -ENOMEM; } /* * This mmap-allocator allocates new areas top-down from below the * stack's low limit (the base): * * Because we have an exclusive hugepage region which lies within the * normal user address space, we have to take special measures to make * non-huge mmap()s evade the hugepage reserved regions. */ 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) { struct vm_area_struct *vma, *prev_vma; struct mm_struct *mm = current->mm; unsigned long base = mm->mmap_base, addr = addr0; int first_time = 1; /* requested length too big for entire address space */ if (len > TASK_SIZE) return -ENOMEM; /* dont allow allocations above current base */ if (mm->free_area_cache > base) mm->free_area_cache = base; /* requesting a specific address */ if (addr) { addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && (!vma || addr + len <= vma->vm_start) && !is_hugepage_only_range(mm, addr,len)) return addr; } try_again: /* make sure it can fit in the remaining address space */ if (mm->free_area_cache < len) goto fail; /* either no address requested or cant fit in requested address hole */ addr = (mm->free_area_cache - len) & PAGE_MASK; do { hugepage_recheck: if (touches_hugepage_low_range(mm, addr, len)) { addr = (addr & ((~0) << SID_SHIFT)) - len; goto hugepage_recheck; } else if (touches_hugepage_high_range(addr, len)) { addr = TASK_HPAGE_BASE - len; } /* * Lookup failure means no vma is above this address, * i.e. return with success: */ if (!(vma = find_vma_prev(mm, addr, &prev_vma))) return addr; /* * new region fits between prev_vma->vm_end and * vma->vm_start, use it: */ if (addr+len <= vma->vm_start && (!prev_vma || (addr >= prev_vma->vm_end))) /* remember the address as a hint for next time */ return (mm->free_area_cache = addr); else /* pull free_area_cache down to the first hole */ if (mm->free_area_cache == vma->vm_end) mm->free_area_cache = vma->vm_start; /* try just below the current vma->vm_start */ addr = vma->vm_start-len; } while (len <= vma->vm_start); fail: /* * if hint left us with no space for the requested * mapping then try again: */ if (first_time) { mm->free_area_cache = base; first_time = 0; goto try_again; } /* * 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. */ mm->free_area_cache = TASK_UNMAPPED_BASE; addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); /* * Restore the topdown base: */ mm->free_area_cache = base; return addr; } static unsigned long htlb_get_low_area(unsigned long len, u16 segmask) { unsigned long addr = 0; struct vm_area_struct *vma; vma = find_vma(current->mm, addr); while (addr + len <= 0x100000000UL) { BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */ if (! __within_hugepage_low_range(addr, len, segmask)) { addr = ALIGN(addr+1, 1<mm, addr); continue; } if (!vma || (addr + len) <= vma->vm_start) return addr; addr = ALIGN(vma->vm_end, HPAGE_SIZE); /* Depending on segmask this might not be a confirmed * hugepage region, so the ALIGN could have skipped * some VMAs */ vma = find_vma(current->mm, addr); } return -ENOMEM; } static unsigned long htlb_get_high_area(unsigned long len) { unsigned long addr = TASK_HPAGE_BASE; struct vm_area_struct *vma; vma = find_vma(current->mm, addr); for (vma = find_vma(current->mm, addr); addr + len <= TASK_HPAGE_END; vma = vma->vm_next) { BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */ BUG_ON(! within_hugepage_high_range(addr, len)); if (!vma || (addr + len) <= vma->vm_start) return addr; addr = ALIGN(vma->vm_end, HPAGE_SIZE); /* Because we're in a hugepage region, this alignment * should not skip us over any VMAs */ } return -ENOMEM; } unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { if (len & ~HPAGE_MASK) return -EINVAL; if (!cpu_has_feature(CPU_FTR_16M_PAGE)) return -EINVAL; if (test_thread_flag(TIF_32BIT)) { int lastshift = 0; u16 segmask, cursegs = current->mm->context.htlb_segs; /* First see if we can do the mapping in the existing * low hpage segments */ addr = htlb_get_low_area(len, cursegs); if (addr != -ENOMEM) return addr; for (segmask = LOW_ESID_MASK(0x100000000UL-len, len); ! lastshift; segmask >>=1) { if (segmask & 1) lastshift = 1; addr = htlb_get_low_area(len, cursegs | segmask); if ((addr != -ENOMEM) && open_low_hpage_segs(current->mm, segmask) == 0) return addr; } printk(KERN_DEBUG "hugetlb_get_unmapped_area() unable to open" " enough segments\n"); return -ENOMEM; } else { return htlb_get_high_area(len); } } void hugetlb_mm_free_pgd(struct mm_struct *mm) { int i; pgd_t *pgdir; spin_lock(&mm->page_table_lock); pgdir = mm->context.huge_pgdir; if (! pgdir) goto out; mm->context.huge_pgdir = NULL; /* cleanup any hugepte pages leftover */ for (i = 0; i < PTRS_PER_HUGEPGD; i++) { pud_t *pud = (pud_t *)(pgdir + i); if (! pud_none(*pud)) { pte_t *pte = (pte_t *)pud_page(*pud); struct page *ptepage = virt_to_page(pte); ptepage->mapping = NULL; BUG_ON(memcmp(pte, empty_zero_page, PAGE_SIZE)); kmem_cache_free(zero_cache, pte); } pud_clear(pud); } BUG_ON(memcmp(pgdir, empty_zero_page, PAGE_SIZE)); kmem_cache_free(zero_cache, pgdir); out: spin_unlock(&mm->page_table_lock); } int hash_huge_page(struct mm_struct *mm, unsigned long access, unsigned long ea, unsigned long vsid, int local) { pte_t *ptep; unsigned long va, vpn; pte_t old_pte, new_pte; unsigned long hpteflags, prpn; long slot; int err = 1; spin_lock(&mm->page_table_lock); ptep = huge_pte_offset(mm, ea); /* Search the Linux page table for a match with va */ va = (vsid << 28) | (ea & 0x0fffffff); vpn = va >> HPAGE_SHIFT; /* * If no pte found or not present, send the problem up to * do_page_fault */ if (unlikely(!ptep || pte_none(*ptep))) goto out; /* BUG_ON(pte_bad(*ptep)); */ /* * Check the user's access rights to the page. If access should be * prevented then send the problem up to do_page_fault. */ if (unlikely(access & ~pte_val(*ptep))) goto out; /* * At this point, we have a pte (old_pte) which can be used to build * or update an HPTE. There are 2 cases: * * 1. There is a valid (present) pte with no associated HPTE (this is * the most common case) * 2. There is a valid (present) pte with an associated HPTE. The * current values of the pp bits in the HPTE prevent access * because we are doing software DIRTY bit management and the * page is currently not DIRTY. */ old_pte = *ptep; new_pte = old_pte; hpteflags = 0x2 | (! (pte_val(new_pte) & _PAGE_RW)); /* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */ hpteflags |= ((pte_val(new_pte) & _PAGE_EXEC) ? 0 : HW_NO_EXEC); /* Check if pte already has an hpte (case 2) */ if (unlikely(pte_val(old_pte) & _PAGE_HASHPTE)) { /* There MIGHT be an HPTE for this pte */ unsigned long hash, slot; hash = hpt_hash(vpn, 1); if (pte_val(old_pte) & _PAGE_SECONDARY) hash = ~hash; slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; slot += (pte_val(old_pte) & _PAGE_GROUP_IX) >> 12; if (ppc_md.hpte_updatepp(slot, hpteflags, va, 1, local) == -1) pte_val(old_pte) &= ~_PAGE_HPTEFLAGS; } if (likely(!(pte_val(old_pte) & _PAGE_HASHPTE))) { unsigned long hash = hpt_hash(vpn, 1); unsigned long hpte_group; prpn = pte_pfn(old_pte); repeat: hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL; /* Update the linux pte with the HPTE slot */ pte_val(new_pte) &= ~_PAGE_HPTEFLAGS; pte_val(new_pte) |= _PAGE_HASHPTE; /* Add in WIMG bits */ /* XXX We should store these in the pte */ hpteflags |= _PAGE_COHERENT; slot = ppc_md.hpte_insert(hpte_group, va, prpn, 0, hpteflags, 0, 1); /* Primary is full, try the secondary */ if (unlikely(slot == -1)) { pte_val(new_pte) |= _PAGE_SECONDARY; hpte_group = ((~hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL; slot = ppc_md.hpte_insert(hpte_group, va, prpn, 1, hpteflags, 0, 1); if (slot == -1) { if (mftb() & 0x1) hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL; ppc_md.hpte_remove(hpte_group); goto repeat; } } if (unlikely(slot == -2)) panic("hash_huge_page: pte_insert failed\n"); pte_val(new_pte) |= (slot<<12) & _PAGE_GROUP_IX; /* * No need to use ldarx/stdcx here because all who * might be updating the pte will hold the * page_table_lock */ *ptep = new_pte; } err = 0; out: spin_unlock(&mm->page_table_lock); return err; }