1 files changed, 530 insertions, 0 deletions

diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c
new file mode 100644
index 000000000000..28c23140c947
--- /dev/null
+++ b/arch/tile/mm/pgtable.c
@@ -0,0 +1,530 @@
+/*
+ * 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/smp.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/system.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(void)
+{
+        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),
+               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);
+        }
+}
+
+/*
+ * Associate a virtual page frame with a given physical page frame
+ * and protection flags for that frame.
+ */
+static void set_pte_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *pte;
+
+        pgd = swapper_pg_dir + pgd_index(vaddr);
+        if (pgd_none(*pgd)) {
+                BUG();
+                return;
+        }
+        pud = pud_offset(pgd, vaddr);
+        if (pud_none(*pud)) {
+                BUG();
+                return;
+        }
+        pmd = pmd_offset(pud, vaddr);
+        if (pmd_none(*pmd)) {
+                BUG();
+                return;
+        }
+        pte = pte_offset_kernel(pmd, vaddr);
+        /* <pfn,flags> stored as-is, to permit clearing entries */
+        set_pte(pte, pfn_pte(pfn, flags));
+
+        /*
+         * It's enough to flush this one mapping.
+         * This appears conservative since it is only called
+         * from __set_fixmap.
+         */
+        local_flush_tlb_page(NULL, vaddr, PAGE_SIZE);
+}
+
+void __set_fixmap(enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
+{
+        unsigned long address = __fix_to_virt(idx);
+
+        if (idx >= __end_of_fixed_addresses) {
+                BUG();
+                return;
+        }
+        set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
+}
+
+#if defined(CONFIG_HIGHPTE)
+pte_t *_pte_offset_map(pmd_t *dir, unsigned long address, enum km_type type)
+{
+        pte_t *pte = kmap_atomic(pmd_page(*dir), type) +
+                (pmd_ptfn(*dir) << HV_LOG2_PAGE_TABLE_ALIGN) & ~PAGE_MASK;
+        return &pte[pte_index(address)];
+}
+#endif
+
+/*
+ * 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 locking scheme was chosen on the basis of manfred's
+ * recommendations and having no core impact whatsoever.
+ * -- wli
+ */
+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
+
+        clone_pgd_range(pgd + KERNEL_PGD_INDEX_START,
+                        swapper_pg_dir + KERNEL_PGD_INDEX_START,
+                        KERNEL_PGD_PTRS);
+
+        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 *pte_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+        gfp_t flags = GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO|__GFP_COMP;
+        struct page *p;
+
+#ifdef CONFIG_HIGHPTE
+        flags |= __GFP_HIGHMEM;
+#endif
+
+        p = alloc_pages(flags, L2_USER_PGTABLE_ORDER);
+        if (p == NULL)
+                return NULL;
+
+        pgtable_page_ctor(p);
+        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 pte_free(struct mm_struct *mm, struct page *p)
+{
+        pgtable_page_dtor(p);
+        __free_pages(p, L2_USER_PGTABLE_ORDER);
+}
+
+void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte,
+                    unsigned long address)
+{
+        int i;
+
+        pgtable_page_dtor(pte);
+        tlb->need_flush = 1;
+        if (tlb_fast_mode(tlb)) {
+                struct page *pte_pages[L2_USER_PGTABLE_PAGES];
+                for (i = 0; i < L2_USER_PGTABLE_PAGES; ++i)
+                        pte_pages[i] = pte + i;
+                free_pages_and_swap_cache(pte_pages, L2_USER_PGTABLE_PAGES);
+                return;
+        }
+        for (i = 0; i < L2_USER_PGTABLE_PAGES; ++i) {
+                tlb->pages[tlb->nr++] = pte + i;
+                if (tlb->nr >= FREE_PTE_NR)
+                        tlb_flush_mmu(tlb, 0, 0);
+        }
+}
+
+#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
+
+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;
+        pmd = pmd_offset(pud, addr);
+        if (pmd_huge_page(*pmd))
+                return (pte_t *)pmd;
+        if (!pmd_present(*pmd))
+                return NULL;
+        return pte_offset_kernel(pmd, addr);
+}
+
+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;
+}
+
+void set_pte_order(pte_t *ptep, pte_t pte, int order)
+{
+        unsigned long pfn = pte_pfn(pte);
+        struct page *page = pfn_to_page(pfn);
+
+        /* Update the home of a PTE if necessary */
+        pte = pte_set_home(pte, page_home(page));
+
+#ifdef __tilegx__
+        *ptep = pte;
+#else
+        /*
+         * When setting a PTE, write the high bits first, then write
+         * the low bits.  This sets the "present" bit only after the
+         * other bits are in place.  If a particular PTE update
+         * involves transitioning from one valid PTE to another, it
+         * may be necessary to call set_pte_order() more than once,
+         * transitioning via a suitable intermediate state.
+         * Note that this sequence also means that if we are transitioning
+         * from any migrating PTE to a non-migrating one, we will not
+         * see a half-updated PTE with the migrating bit off.
+         */
+#if HV_PTE_INDEX_PRESENT >= 32 || HV_PTE_INDEX_MIGRATING >= 32
+# error Must write the present and migrating bits last
+#endif
+        ((u32 *)ptep)[1] = (u32)(pte_val(pte) >> 32);
+        barrier();
+        ((u32 *)ptep)[0] = (u32)(pte_val(pte));
+#endif
+}
+
+/* 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;
+}
+
+/*
+ * 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 = -1U;
+                hv_set_caching(-1U);
+        }
+}
+
+/*
+ * 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 int 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)) {
+                remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
+                return NULL;
+        }
+        return (__force void __iomem *) (offset + (char *)addr);
+}
+EXPORT_SYMBOL(ioremap_prot);
+
+/* Map a PCI MMIO bus address into VA space. */
+void __iomem *ioremap(resource_size_t phys_addr, unsigned long size)
+{
+        panic("ioremap for PCI MMIO is not supported");
+}
+EXPORT_SYMBOL(ioremap);
+
+/* 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. */
+        read_lock(&vmlist_lock);
+        for (p = vmlist; p; p = p->next) {
+                if (p->addr == addr)
+                        break;
+        }
+        read_unlock(&vmlist_lock);
+
+        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() */