diff options
Diffstat (limited to 'arch/powerpc/mm/hugetlbpage.c')
| -rw-r--r-- | arch/powerpc/mm/hugetlbpage.c | 745 |
1 files changed, 745 insertions, 0 deletions
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c new file mode 100644 index 000000000000..0ea0994ed974 --- /dev/null +++ b/arch/powerpc/mm/hugetlbpage.c @@ -0,0 +1,745 @@ +/* + * 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 <rohit.seth@intel.com> + */ + +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/hugetlb.h> +#include <linux/pagemap.h> +#include <linux/smp_lock.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/sysctl.h> +#include <asm/mman.h> +#include <asm/pgalloc.h> +#include <asm/tlb.h> +#include <asm/tlbflush.h> +#include <asm/mmu_context.h> +#include <asm/machdep.h> +#include <asm/cputable.h> +#include <asm/tlb.h> + +#include <linux/sysctl.h> + +#define NUM_LOW_AREAS (0x100000000UL >> SID_SHIFT) +#define NUM_HIGH_AREAS (PGTABLE_RANGE >> HTLB_AREA_SHIFT) + +/* Modelled after find_linux_pte() */ +pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) +{ + pgd_t *pg; + pud_t *pu; + pmd_t *pm; + pte_t *pt; + + BUG_ON(! in_hugepage_area(mm->context, addr)); + + addr &= HPAGE_MASK; + + pg = pgd_offset(mm, addr); + if (!pgd_none(*pg)) { + pu = pud_offset(pg, addr); + if (!pud_none(*pu)) { + pm = pmd_offset(pu, addr); + pt = (pte_t *)pm; + BUG_ON(!pmd_none(*pm) + && !(pte_present(*pt) && pte_huge(*pt))); + return pt; + } + } + + return NULL; +} + +pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr) +{ + pgd_t *pg; + pud_t *pu; + pmd_t *pm; + pte_t *pt; + + BUG_ON(! in_hugepage_area(mm->context, addr)); + + addr &= HPAGE_MASK; + + pg = pgd_offset(mm, addr); + pu = pud_alloc(mm, pg, addr); + + if (pu) { + pm = pmd_alloc(mm, pu, addr); + if (pm) { + pt = (pte_t *)pm; + BUG_ON(!pmd_none(*pm) + && !(pte_present(*pt) && pte_huge(*pt))); + return pt; + } + } + + return NULL; +} + +#define HUGEPTE_BATCH_SIZE (HPAGE_SIZE / PMD_SIZE) + +void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, pte_t pte) +{ + int i; + + if (pte_present(*ptep)) { + pte_clear(mm, addr, ptep); + flush_tlb_pending(); + } + + for (i = 0; i < HUGEPTE_BATCH_SIZE; i++) { + *ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS); + ptep++; + } +} + +pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, + pte_t *ptep) +{ + unsigned long old = pte_update(ptep, ~0UL); + int i; + + if (old & _PAGE_HASHPTE) + hpte_update(mm, addr, old, 0); + + for (i = 1; i < HUGEPTE_BATCH_SIZE; i++) + ptep[i] = __pte(0); + + return __pte(old); +} + +/* + * 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_low_segments(void *parm) +{ + u16 areas = (unsigned long) parm; + unsigned long i; + + asm volatile("isync" : : : "memory"); + + BUILD_BUG_ON((sizeof(areas)*8) != NUM_LOW_AREAS); + + for (i = 0; i < NUM_LOW_AREAS; i++) { + if (! (areas & (1U << i))) + continue; + asm volatile("slbie %0" + : : "r" ((i << SID_SHIFT) | SLBIE_C)); + } + + asm volatile("isync" : : : "memory"); +} + +static void flush_high_segments(void *parm) +{ + u16 areas = (unsigned long) parm; + unsigned long i, j; + + asm volatile("isync" : : : "memory"); + + BUILD_BUG_ON((sizeof(areas)*8) != NUM_HIGH_AREAS); + + for (i = 0; i < NUM_HIGH_AREAS; i++) { + if (! (areas & (1U << i))) + continue; + for (j = 0; j < (1UL << (HTLB_AREA_SHIFT-SID_SHIFT)); j++) + asm volatile("slbie %0" + :: "r" (((i << HTLB_AREA_SHIFT) + + (j << SID_SHIFT)) | SLBIE_C)); + } + + asm volatile("isync" : : : "memory"); +} + +static int prepare_low_area_for_htlb(struct mm_struct *mm, unsigned long area) +{ + unsigned long start = area << SID_SHIFT; + unsigned long end = (area+1) << SID_SHIFT; + struct vm_area_struct *vma; + + BUG_ON(area >= NUM_LOW_AREAS); + + /* Check no VMAs are in the region */ + vma = find_vma(mm, start); + if (vma && (vma->vm_start < end)) + return -EBUSY; + + return 0; +} + +static int prepare_high_area_for_htlb(struct mm_struct *mm, unsigned long area) +{ + unsigned long start = area << HTLB_AREA_SHIFT; + unsigned long end = (area+1) << HTLB_AREA_SHIFT; + struct vm_area_struct *vma; + + BUG_ON(area >= NUM_HIGH_AREAS); + + /* 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_areas(struct mm_struct *mm, u16 newareas) +{ + unsigned long i; + + BUILD_BUG_ON((sizeof(newareas)*8) != NUM_LOW_AREAS); + BUILD_BUG_ON((sizeof(mm->context.low_htlb_areas)*8) != NUM_LOW_AREAS); + + newareas &= ~(mm->context.low_htlb_areas); + if (! newareas) + return 0; /* The segments we want are already open */ + + for (i = 0; i < NUM_LOW_AREAS; i++) + if ((1 << i) & newareas) + if (prepare_low_area_for_htlb(mm, i) != 0) + return -EBUSY; + + mm->context.low_htlb_areas |= newareas; + + /* 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_low_segments, (void *)(unsigned long)newareas, 0, 1); + + return 0; +} + +static int open_high_hpage_areas(struct mm_struct *mm, u16 newareas) +{ + unsigned long i; + + BUILD_BUG_ON((sizeof(newareas)*8) != NUM_HIGH_AREAS); + BUILD_BUG_ON((sizeof(mm->context.high_htlb_areas)*8) + != NUM_HIGH_AREAS); + + newareas &= ~(mm->context.high_htlb_areas); + if (! newareas) + return 0; /* The areas we want are already open */ + + for (i = 0; i < NUM_HIGH_AREAS; i++) + if ((1 << i) & newareas) + if (prepare_high_area_for_htlb(mm, i) != 0) + return -EBUSY; + + mm->context.high_htlb_areas |= newareas; + + /* 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_high_segments, (void *)(unsigned long)newareas, 0, 1); + + return 0; +} + +int prepare_hugepage_range(unsigned long addr, unsigned long len) +{ + int err; + + if ( (addr+len) < addr ) + return -EINVAL; + + if ((addr + len) < 0x100000000UL) + err = open_low_hpage_areas(current->mm, + LOW_ESID_MASK(addr, len)); + else + err = open_high_hpage_areas(current->mm, + HTLB_AREA_MASK(addr, len)); + if (err) { + printk(KERN_DEBUG "prepare_hugepage_range(%lx, %lx)" + " failed (lowmask: 0x%04hx, highmask: 0x%04hx)\n", + addr, len, + LOW_ESID_MASK(addr, len), HTLB_AREA_MASK(addr, len)); + return err; + } + + return 0; +} + +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; + } + if (len > mm->cached_hole_size) { + start_addr = addr = mm->free_area_cache; + } else { + start_addr = addr = TASK_UNMAPPED_BASE; + mm->cached_hole_size = 0; + } + +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<<SID_SHIFT); + vma = find_vma(mm, addr); + continue; + } + if (touches_hugepage_high_range(mm, addr, len)) { + addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT); + vma = find_vma(mm, addr); + continue; + } + if (!vma || addr + len <= vma->vm_start) { + /* + * Remember the place where we stopped the search: + */ + mm->free_area_cache = addr + len; + return addr; + } + if (addr + mm->cached_hole_size < vma->vm_start) + mm->cached_hole_size = vma->vm_start - 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; + mm->cached_hole_size = 0; + 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; + unsigned long largest_hole = mm->cached_hole_size; + 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; + } + + if (len <= largest_hole) { + largest_hole = 0; + mm->free_area_cache = base; + } +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(mm, addr, len)) { + addr = (addr & ((~0UL) << HTLB_AREA_SHIFT)) - len; + goto hugepage_recheck; + } + + /* + * 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 */ + mm->cached_hole_size = largest_hole; + 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; + mm->cached_hole_size = largest_hole; + } + } + + /* remember the largest hole we saw so far */ + if (addr + largest_hole < vma->vm_start) + largest_hole = vma->vm_start - addr; + + /* 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; + largest_hole = 0; + 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; + mm->cached_hole_size = ~0UL; + addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); + /* + * Restore the topdown base: + */ + mm->free_area_cache = base; + mm->cached_hole_size = ~0UL; + + 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<<SID_SHIFT); + vma = find_vma(current->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, u16 areamask) +{ + unsigned long addr = 0x100000000UL; + struct vm_area_struct *vma; + + vma = find_vma(current->mm, addr); + while (addr + len <= TASK_SIZE_USER64) { + BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */ + + if (! __within_hugepage_high_range(addr, len, areamask)) { + addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT); + vma = find_vma(current->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; +} + +unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags) +{ + int lastshift; + u16 areamask, curareas; + + if (len & ~HPAGE_MASK) + return -EINVAL; + + if (!cpu_has_feature(CPU_FTR_16M_PAGE)) + return -EINVAL; + + if (test_thread_flag(TIF_32BIT)) { + curareas = current->mm->context.low_htlb_areas; + + /* First see if we can do the mapping in the existing + * low areas */ + addr = htlb_get_low_area(len, curareas); + if (addr != -ENOMEM) + return addr; + + lastshift = 0; + for (areamask = LOW_ESID_MASK(0x100000000UL-len, len); + ! lastshift; areamask >>=1) { + if (areamask & 1) + lastshift = 1; + + addr = htlb_get_low_area(len, curareas | areamask); + if ((addr != -ENOMEM) + && open_low_hpage_areas(current->mm, areamask) == 0) + return addr; + } + } else { + curareas = current->mm->context.high_htlb_areas; + + /* First see if we can do the mapping in the existing + * high areas */ + addr = htlb_get_high_area(len, curareas); + if (addr != -ENOMEM) + return addr; + + lastshift = 0; + for (areamask = HTLB_AREA_MASK(TASK_SIZE_USER64-len, len); + ! lastshift; areamask >>=1) { + if (areamask & 1) + lastshift = 1; + + addr = htlb_get_high_area(len, curareas | areamask); + if ((addr != -ENOMEM) + && open_high_hpage_areas(current->mm, areamask) == 0) + return addr; + } + } + printk(KERN_DEBUG "hugetlb_get_unmapped_area() unable to open" + " enough areas\n"); + return -ENOMEM; +} + +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 rflags, 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; + + rflags = 0x2 | (! (pte_val(new_pte) & _PAGE_RW)); + /* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */ + rflags |= ((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, rflags, 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 */ + rflags |= _PAGE_COHERENT; + + slot = ppc_md.hpte_insert(hpte_group, va, prpn, + HPTE_V_LARGE, rflags); + + /* 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, + HPTE_V_LARGE | + HPTE_V_SECONDARY, + rflags); + 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; +} |
