Initial import

1 files changed, 584 insertions, 0 deletions

diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c
new file mode 100644
index 000000000..7bf2491a9
--- /dev/null
+++ b/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() */