diff options
Diffstat (limited to 'kernel/arch/tile/mm/pgtable.c')
| -rw-r--r-- | kernel/arch/tile/mm/pgtable.c | 584 |
1 files changed, 584 insertions, 0 deletions
diff --git a/kernel/arch/tile/mm/pgtable.c b/kernel/arch/tile/mm/pgtable.c new file mode 100644 index 000000000..7bf2491a9 --- /dev/null +++ b/kernel/arch/tile/mm/pgtable.c @@ -0,0 +1,584 @@ +/* + * Copyright 2010 Tilera Corporation. All Rights Reserved. + * + * 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, version 2. + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + */ + +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/mm.h> +#include <linux/swap.h> +#include <linux/highmem.h> +#include <linux/slab.h> +#include <linux/pagemap.h> +#include <linux/spinlock.h> +#include <linux/cpumask.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/vmalloc.h> +#include <linux/smp.h> + +#include <asm/pgtable.h> +#include <asm/pgalloc.h> +#include <asm/fixmap.h> +#include <asm/tlb.h> +#include <asm/tlbflush.h> +#include <asm/homecache.h> + +#define K(x) ((x) << (PAGE_SHIFT-10)) + +/* + * The normal show_free_areas() is too verbose on Tile, with dozens + * of processors and often four NUMA zones each with high and lowmem. + */ +void show_mem(unsigned int filter) +{ + struct zone *zone; + + pr_err("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu free:%lu\n slab:%lu mapped:%lu pagetables:%lu bounce:%lu pagecache:%lu swap:%lu\n", + (global_page_state(NR_ACTIVE_ANON) + + global_page_state(NR_ACTIVE_FILE)), + (global_page_state(NR_INACTIVE_ANON) + + global_page_state(NR_INACTIVE_FILE)), + global_page_state(NR_FILE_DIRTY), + global_page_state(NR_WRITEBACK), + global_page_state(NR_UNSTABLE_NFS), + global_page_state(NR_FREE_PAGES), + (global_page_state(NR_SLAB_RECLAIMABLE) + + global_page_state(NR_SLAB_UNRECLAIMABLE)), + global_page_state(NR_FILE_MAPPED), + global_page_state(NR_PAGETABLE), + global_page_state(NR_BOUNCE), + global_page_state(NR_FILE_PAGES), + get_nr_swap_pages()); + + for_each_zone(zone) { + unsigned long flags, order, total = 0, largest_order = -1; + + if (!populated_zone(zone)) + continue; + + spin_lock_irqsave(&zone->lock, flags); + for (order = 0; order < MAX_ORDER; order++) { + int nr = zone->free_area[order].nr_free; + total += nr << order; + if (nr) + largest_order = order; + } + spin_unlock_irqrestore(&zone->lock, flags); + pr_err("Node %d %7s: %lukB (largest %luKb)\n", + zone_to_nid(zone), zone->name, + K(total), largest_order ? K(1UL) << largest_order : 0); + } +} + +/** + * shatter_huge_page() - ensure a given address is mapped by a small page. + * + * This function converts a huge PTE mapping kernel LOWMEM into a bunch + * of small PTEs with the same caching. No cache flush required, but we + * must do a global TLB flush. + * + * Any caller that wishes to modify a kernel mapping that might + * have been made with a huge page should call this function, + * since doing so properly avoids race conditions with installing the + * newly-shattered page and then flushing all the TLB entries. + * + * @addr: Address at which to shatter any existing huge page. + */ +void shatter_huge_page(unsigned long addr) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + unsigned long flags = 0; /* happy compiler */ +#ifdef __PAGETABLE_PMD_FOLDED + struct list_head *pos; +#endif + + /* Get a pointer to the pmd entry that we need to change. */ + addr &= HPAGE_MASK; + BUG_ON(pgd_addr_invalid(addr)); + BUG_ON(addr < PAGE_OFFSET); /* only for kernel LOWMEM */ + pgd = swapper_pg_dir + pgd_index(addr); + pud = pud_offset(pgd, addr); + BUG_ON(!pud_present(*pud)); + pmd = pmd_offset(pud, addr); + BUG_ON(!pmd_present(*pmd)); + if (!pmd_huge_page(*pmd)) + return; + + spin_lock_irqsave(&init_mm.page_table_lock, flags); + if (!pmd_huge_page(*pmd)) { + /* Lost the race to convert the huge page. */ + spin_unlock_irqrestore(&init_mm.page_table_lock, flags); + return; + } + + /* Shatter the huge page into the preallocated L2 page table. */ + pmd_populate_kernel(&init_mm, pmd, get_prealloc_pte(pmd_pfn(*pmd))); + +#ifdef __PAGETABLE_PMD_FOLDED + /* Walk every pgd on the system and update the pmd there. */ + spin_lock(&pgd_lock); + list_for_each(pos, &pgd_list) { + pmd_t *copy_pmd; + pgd = list_to_pgd(pos) + pgd_index(addr); + pud = pud_offset(pgd, addr); + copy_pmd = pmd_offset(pud, addr); + __set_pmd(copy_pmd, *pmd); + } + spin_unlock(&pgd_lock); +#endif + + /* Tell every cpu to notice the change. */ + flush_remote(0, 0, NULL, addr, HPAGE_SIZE, HPAGE_SIZE, + cpu_possible_mask, NULL, 0); + + /* Hold the lock until the TLB flush is finished to avoid races. */ + spin_unlock_irqrestore(&init_mm.page_table_lock, flags); +} + +/* + * List of all pgd's needed so it can invalidate entries in both cached + * and uncached pgd's. This is essentially codepath-based locking + * against pageattr.c; it is the unique case in which a valid change + * of kernel pagetables can't be lazily synchronized by vmalloc faults. + * vmalloc faults work because attached pagetables are never freed. + * + * The lock is always taken with interrupts disabled, unlike on x86 + * and other platforms, because we need to take the lock in + * shatter_huge_page(), which may be called from an interrupt context. + * We are not at risk from the tlbflush IPI deadlock that was seen on + * x86, since we use the flush_remote() API to have the hypervisor do + * the TLB flushes regardless of irq disabling. + */ +DEFINE_SPINLOCK(pgd_lock); +LIST_HEAD(pgd_list); + +static inline void pgd_list_add(pgd_t *pgd) +{ + list_add(pgd_to_list(pgd), &pgd_list); +} + +static inline void pgd_list_del(pgd_t *pgd) +{ + list_del(pgd_to_list(pgd)); +} + +#define KERNEL_PGD_INDEX_START pgd_index(PAGE_OFFSET) +#define KERNEL_PGD_PTRS (PTRS_PER_PGD - KERNEL_PGD_INDEX_START) + +static void pgd_ctor(pgd_t *pgd) +{ + unsigned long flags; + + memset(pgd, 0, KERNEL_PGD_INDEX_START*sizeof(pgd_t)); + spin_lock_irqsave(&pgd_lock, flags); + +#ifndef __tilegx__ + /* + * Check that the user interrupt vector has no L2. + * It never should for the swapper, and new page tables + * should always start with an empty user interrupt vector. + */ + BUG_ON(((u64 *)swapper_pg_dir)[pgd_index(MEM_USER_INTRPT)] != 0); +#endif + + memcpy(pgd + KERNEL_PGD_INDEX_START, + swapper_pg_dir + KERNEL_PGD_INDEX_START, + KERNEL_PGD_PTRS * sizeof(pgd_t)); + + pgd_list_add(pgd); + spin_unlock_irqrestore(&pgd_lock, flags); +} + +static void pgd_dtor(pgd_t *pgd) +{ + unsigned long flags; /* can be called from interrupt context */ + + spin_lock_irqsave(&pgd_lock, flags); + pgd_list_del(pgd); + spin_unlock_irqrestore(&pgd_lock, flags); +} + +pgd_t *pgd_alloc(struct mm_struct *mm) +{ + pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL); + if (pgd) + pgd_ctor(pgd); + return pgd; +} + +void pgd_free(struct mm_struct *mm, pgd_t *pgd) +{ + pgd_dtor(pgd); + kmem_cache_free(pgd_cache, pgd); +} + + +#define L2_USER_PGTABLE_PAGES (1 << L2_USER_PGTABLE_ORDER) + +struct page *pgtable_alloc_one(struct mm_struct *mm, unsigned long address, + int order) +{ + gfp_t flags = GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO; + struct page *p; + int i; + + p = alloc_pages(flags, L2_USER_PGTABLE_ORDER); + if (p == NULL) + return NULL; + + if (!pgtable_page_ctor(p)) { + __free_pages(p, L2_USER_PGTABLE_ORDER); + return NULL; + } + + /* + * Make every page have a page_count() of one, not just the first. + * We don't use __GFP_COMP since it doesn't look like it works + * correctly with tlb_remove_page(). + */ + for (i = 1; i < order; ++i) { + init_page_count(p+i); + inc_zone_page_state(p+i, NR_PAGETABLE); + } + + return p; +} + +/* + * Free page immediately (used in __pte_alloc if we raced with another + * process). We have to correct whatever pte_alloc_one() did before + * returning the pages to the allocator. + */ +void pgtable_free(struct mm_struct *mm, struct page *p, int order) +{ + int i; + + pgtable_page_dtor(p); + __free_page(p); + + for (i = 1; i < order; ++i) { + __free_page(p+i); + dec_zone_page_state(p+i, NR_PAGETABLE); + } +} + +void __pgtable_free_tlb(struct mmu_gather *tlb, struct page *pte, + unsigned long address, int order) +{ + int i; + + pgtable_page_dtor(pte); + tlb_remove_page(tlb, pte); + + for (i = 1; i < order; ++i) { + tlb_remove_page(tlb, pte + i); + dec_zone_page_state(pte + i, NR_PAGETABLE); + } +} + +#ifndef __tilegx__ + +/* + * FIXME: needs to be atomic vs hypervisor writes. For now we make the + * window of vulnerability a bit smaller by doing an unlocked 8-bit update. + */ +int ptep_test_and_clear_young(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ +#if HV_PTE_INDEX_ACCESSED < 8 || HV_PTE_INDEX_ACCESSED >= 16 +# error Code assumes HV_PTE "accessed" bit in second byte +#endif + u8 *tmp = (u8 *)ptep; + u8 second_byte = tmp[1]; + if (!(second_byte & (1 << (HV_PTE_INDEX_ACCESSED - 8)))) + return 0; + tmp[1] = second_byte & ~(1 << (HV_PTE_INDEX_ACCESSED - 8)); + return 1; +} + +/* + * This implementation is atomic vs hypervisor writes, since the hypervisor + * always writes the low word (where "accessed" and "dirty" are) and this + * routine only writes the high word. + */ +void ptep_set_wrprotect(struct mm_struct *mm, + unsigned long addr, pte_t *ptep) +{ +#if HV_PTE_INDEX_WRITABLE < 32 +# error Code assumes HV_PTE "writable" bit in high word +#endif + u32 *tmp = (u32 *)ptep; + tmp[1] = tmp[1] & ~(1 << (HV_PTE_INDEX_WRITABLE - 32)); +} + +#endif + +/* + * Return a pointer to the PTE that corresponds to the given + * address in the given page table. A NULL page table just uses + * the standard kernel page table; the preferred API in this case + * is virt_to_kpte(). + * + * The returned pointer can point to a huge page in other levels + * of the page table than the bottom, if the huge page is present + * in the page table. For bottom-level PTEs, the returned pointer + * can point to a PTE that is either present or not. + */ +pte_t *virt_to_pte(struct mm_struct* mm, unsigned long addr) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + + if (pgd_addr_invalid(addr)) + return NULL; + + pgd = mm ? pgd_offset(mm, addr) : swapper_pg_dir + pgd_index(addr); + pud = pud_offset(pgd, addr); + if (!pud_present(*pud)) + return NULL; + if (pud_huge_page(*pud)) + return (pte_t *)pud; + pmd = pmd_offset(pud, addr); + if (!pmd_present(*pmd)) + return NULL; + if (pmd_huge_page(*pmd)) + return (pte_t *)pmd; + return pte_offset_kernel(pmd, addr); +} +EXPORT_SYMBOL(virt_to_pte); + +pte_t *virt_to_kpte(unsigned long kaddr) +{ + BUG_ON(kaddr < PAGE_OFFSET); + return virt_to_pte(NULL, kaddr); +} +EXPORT_SYMBOL(virt_to_kpte); + +pgprot_t set_remote_cache_cpu(pgprot_t prot, int cpu) +{ + unsigned int width = smp_width; + int x = cpu % width; + int y = cpu / width; + BUG_ON(y >= smp_height); + BUG_ON(hv_pte_get_mode(prot) != HV_PTE_MODE_CACHE_TILE_L3); + BUG_ON(cpu < 0 || cpu >= NR_CPUS); + BUG_ON(!cpu_is_valid_lotar(cpu)); + return hv_pte_set_lotar(prot, HV_XY_TO_LOTAR(x, y)); +} + +int get_remote_cache_cpu(pgprot_t prot) +{ + HV_LOTAR lotar = hv_pte_get_lotar(prot); + int x = HV_LOTAR_X(lotar); + int y = HV_LOTAR_Y(lotar); + BUG_ON(hv_pte_get_mode(prot) != HV_PTE_MODE_CACHE_TILE_L3); + return x + y * smp_width; +} + +/* + * Convert a kernel VA to a PA and homing information. + */ +int va_to_cpa_and_pte(void *va, unsigned long long *cpa, pte_t *pte) +{ + struct page *page = virt_to_page(va); + pte_t null_pte = { 0 }; + + *cpa = __pa(va); + + /* Note that this is not writing a page table, just returning a pte. */ + *pte = pte_set_home(null_pte, page_home(page)); + + return 0; /* return non-zero if not hfh? */ +} +EXPORT_SYMBOL(va_to_cpa_and_pte); + +void __set_pte(pte_t *ptep, pte_t pte) +{ +#ifdef __tilegx__ + *ptep = pte; +#else +# if HV_PTE_INDEX_PRESENT >= 32 || HV_PTE_INDEX_MIGRATING >= 32 +# error Must write the present and migrating bits last +# endif + if (pte_present(pte)) { + ((u32 *)ptep)[1] = (u32)(pte_val(pte) >> 32); + barrier(); + ((u32 *)ptep)[0] = (u32)(pte_val(pte)); + } else { + ((u32 *)ptep)[0] = (u32)(pte_val(pte)); + barrier(); + ((u32 *)ptep)[1] = (u32)(pte_val(pte) >> 32); + } +#endif /* __tilegx__ */ +} + +void set_pte(pte_t *ptep, pte_t pte) +{ + if (pte_present(pte) && + (!CHIP_HAS_MMIO() || hv_pte_get_mode(pte) != HV_PTE_MODE_MMIO)) { + /* The PTE actually references physical memory. */ + unsigned long pfn = pte_pfn(pte); + if (pfn_valid(pfn)) { + /* Update the home of the PTE from the struct page. */ + pte = pte_set_home(pte, page_home(pfn_to_page(pfn))); + } else if (hv_pte_get_mode(pte) == 0) { + /* remap_pfn_range(), etc, must supply PTE mode. */ + panic("set_pte(): out-of-range PFN and mode 0\n"); + } + } + + __set_pte(ptep, pte); +} + +/* Can this mm load a PTE with cached_priority set? */ +static inline int mm_is_priority_cached(struct mm_struct *mm) +{ + return mm->context.priority_cached != 0; +} + +/* + * Add a priority mapping to an mm_context and + * notify the hypervisor if this is the first one. + */ +void start_mm_caching(struct mm_struct *mm) +{ + if (!mm_is_priority_cached(mm)) { + mm->context.priority_cached = -1UL; + hv_set_caching(-1UL); + } +} + +/* + * Validate and return the priority_cached flag. We know if it's zero + * that we don't need to scan, since we immediately set it non-zero + * when we first consider a MAP_CACHE_PRIORITY mapping. + * + * We only _try_ to acquire the mmap_sem semaphore; if we can't acquire it, + * since we're in an interrupt context (servicing switch_mm) we don't + * worry about it and don't unset the "priority_cached" field. + * Presumably we'll come back later and have more luck and clear + * the value then; for now we'll just keep the cache marked for priority. + */ +static unsigned long update_priority_cached(struct mm_struct *mm) +{ + if (mm->context.priority_cached && down_write_trylock(&mm->mmap_sem)) { + struct vm_area_struct *vm; + for (vm = mm->mmap; vm; vm = vm->vm_next) { + if (hv_pte_get_cached_priority(vm->vm_page_prot)) + break; + } + if (vm == NULL) + mm->context.priority_cached = 0; + up_write(&mm->mmap_sem); + } + return mm->context.priority_cached; +} + +/* Set caching correctly for an mm that we are switching to. */ +void check_mm_caching(struct mm_struct *prev, struct mm_struct *next) +{ + if (!mm_is_priority_cached(next)) { + /* + * If the new mm doesn't use priority caching, just see if we + * need the hv_set_caching(), or can assume it's already zero. + */ + if (mm_is_priority_cached(prev)) + hv_set_caching(0); + } else { + hv_set_caching(update_priority_cached(next)); + } +} + +#if CHIP_HAS_MMIO() + +/* Map an arbitrary MMIO address, homed according to pgprot, into VA space. */ +void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size, + pgprot_t home) +{ + void *addr; + struct vm_struct *area; + unsigned long offset, last_addr; + pgprot_t pgprot; + + /* Don't allow wraparound or zero size */ + last_addr = phys_addr + size - 1; + if (!size || last_addr < phys_addr) + return NULL; + + /* Create a read/write, MMIO VA mapping homed at the requested shim. */ + pgprot = PAGE_KERNEL; + pgprot = hv_pte_set_mode(pgprot, HV_PTE_MODE_MMIO); + pgprot = hv_pte_set_lotar(pgprot, hv_pte_get_lotar(home)); + + /* + * Mappings have to be page-aligned + */ + offset = phys_addr & ~PAGE_MASK; + phys_addr &= PAGE_MASK; + size = PAGE_ALIGN(last_addr+1) - phys_addr; + + /* + * Ok, go for it.. + */ + area = get_vm_area(size, VM_IOREMAP /* | other flags? */); + if (!area) + return NULL; + area->phys_addr = phys_addr; + addr = area->addr; + if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size, + phys_addr, pgprot)) { + free_vm_area(area); + return NULL; + } + return (__force void __iomem *) (offset + (char *)addr); +} +EXPORT_SYMBOL(ioremap_prot); + +/* Unmap an MMIO VA mapping. */ +void iounmap(volatile void __iomem *addr_in) +{ + volatile void __iomem *addr = (volatile void __iomem *) + (PAGE_MASK & (unsigned long __force)addr_in); +#if 1 + vunmap((void * __force)addr); +#else + /* x86 uses this complicated flow instead of vunmap(). Is + * there any particular reason we should do the same? */ + struct vm_struct *p, *o; + + /* Use the vm area unlocked, assuming the caller + ensures there isn't another iounmap for the same address + in parallel. Reuse of the virtual address is prevented by + leaving it in the global lists until we're done with it. + cpa takes care of the direct mappings. */ + p = find_vm_area((void *)addr); + + if (!p) { + pr_err("iounmap: bad address %p\n", addr); + dump_stack(); + return; + } + + /* Finally remove it */ + o = remove_vm_area((void *)addr); + BUG_ON(p != o || o == NULL); + kfree(p); +#endif +} +EXPORT_SYMBOL(iounmap); + +#endif /* CHIP_HAS_MMIO() */ |