1 files changed, 346 insertions, 0 deletions
diff --git a/arch/tile/mm/hugetlbpage.c b/arch/tile/mm/hugetlbpage.c
new file mode 100644
index 000000000..8416240c3
--- /dev/null
+++ b/arch/tile/mm/hugetlbpage.c
@@ -0,0 +1,346 @@
+/*
+ * 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.
+ *
+ * TILE Huge TLB Page Support for Kernel.
+ * Taken from i386 hugetlb implementation:
+ * 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/slab.h>
+#include <linux/err.h>
+#include <linux/sysctl.h>
+#include <linux/mman.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/setup.h>
+
+#ifdef CONFIG_HUGETLB_SUPER_PAGES
+
+/*
+ * Provide an additional huge page size (in addition to the regular default
+ * huge page size) if no "hugepagesz" arguments are specified.
+ * Note that it must be smaller than the default huge page size so
+ * that it's possible to allocate them on demand from the buddy allocator.
+ * You can change this to 64K (on a 16K build), 256K, 1M, or 4M,
+ * or not define it at all.
+ */
+#define ADDITIONAL_HUGE_SIZE (1024 * 1024UL)
+
+/* "Extra" page-size multipliers, one per level of the page table. */
+int huge_shift[HUGE_SHIFT_ENTRIES] = {
+#ifdef ADDITIONAL_HUGE_SIZE
+#define ADDITIONAL_HUGE_SHIFT __builtin_ctzl(ADDITIONAL_HUGE_SIZE / PAGE_SIZE)
+	[HUGE_SHIFT_PAGE] = ADDITIONAL_HUGE_SHIFT
+#endif
+};
+
+#endif
+
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+		      unsigned long addr, unsigned long sz)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+
+	addr &= -sz;   /* Mask off any low bits in the address. */
+
+	pgd = pgd_offset(mm, addr);
+	pud = pud_alloc(mm, pgd, addr);
+
+#ifdef CONFIG_HUGETLB_SUPER_PAGES
+	if (sz >= PGDIR_SIZE) {
+		BUG_ON(sz != PGDIR_SIZE &&
+		       sz != PGDIR_SIZE << huge_shift[HUGE_SHIFT_PGDIR]);
+		return (pte_t *)pud;
+	} else {
+		pmd_t *pmd = pmd_alloc(mm, pud, addr);
+		if (sz >= PMD_SIZE) {
+			BUG_ON(sz != PMD_SIZE &&
+			       sz != (PMD_SIZE << huge_shift[HUGE_SHIFT_PMD]));
+			return (pte_t *)pmd;
+		}
+		else {
+			if (sz != PAGE_SIZE << huge_shift[HUGE_SHIFT_PAGE])
+				panic("Unexpected page size %#lx\n", sz);
+			return pte_alloc_map(mm, NULL, pmd, addr);
+		}
+	}
+#else
+	BUG_ON(sz != PMD_SIZE);
+	return (pte_t *) pmd_alloc(mm, pud, addr);
+#endif
+}
+
+static pte_t *get_pte(pte_t *base, int index, int level)
+{
+	pte_t *ptep = base + index;
+#ifdef CONFIG_HUGETLB_SUPER_PAGES
+	if (!pte_present(*ptep) && huge_shift[level] != 0) {
+		unsigned long mask = -1UL << huge_shift[level];
+		pte_t *super_ptep = base + (index & mask);
+		pte_t pte = *super_ptep;
+		if (pte_present(pte) && pte_super(pte))
+			ptep = super_ptep;
+	}
+#endif
+	return ptep;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+#ifdef CONFIG_HUGETLB_SUPER_PAGES
+	pte_t *pte;
+#endif
+
+	/* Get the top-level page table entry. */
+	pgd = (pgd_t *)get_pte((pte_t *)mm->pgd, pgd_index(addr), 0);
+
+	/* We don't have four levels. */
+	pud = pud_offset(pgd, addr);
+#ifndef __PAGETABLE_PUD_FOLDED
+# error support fourth page table level
+#endif
+	if (!pud_present(*pud))
+		return NULL;
+
+	/* Check for an L0 huge PTE, if we have three levels. */
+#ifndef __PAGETABLE_PMD_FOLDED
+	if (pud_huge(*pud))
+		return (pte_t *)pud;
+
+	pmd = (pmd_t *)get_pte((pte_t *)pud_page_vaddr(*pud),
+			       pmd_index(addr), 1);
+	if (!pmd_present(*pmd))
+		return NULL;
+#else
+	pmd = pmd_offset(pud, addr);
+#endif
+
+	/* Check for an L1 huge PTE. */
+	if (pmd_huge(*pmd))
+		return (pte_t *)pmd;
+
+#ifdef CONFIG_HUGETLB_SUPER_PAGES
+	/* Check for an L2 huge PTE. */
+	pte = get_pte((pte_t *)pmd_page_vaddr(*pmd), pte_index(addr), 2);
+	if (!pte_present(*pte))
+		return NULL;
+	if (pte_super(*pte))
+		return pte;
+#endif
+
+	return NULL;
+}
+
+int pmd_huge(pmd_t pmd)
+{
+	return !!(pmd_val(pmd) & _PAGE_HUGE_PAGE);
+}
+
+int pud_huge(pud_t pud)
+{
+	return !!(pud_val(pud) & _PAGE_HUGE_PAGE);
+}
+
+int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
+{
+	return 0;
+}
+
+#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
+static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
+		unsigned long addr, unsigned long len,
+		unsigned long pgoff, unsigned long flags)
+{
+	struct hstate *h = hstate_file(file);
+	struct vm_unmapped_area_info info;
+
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = TASK_UNMAPPED_BASE;
+	info.high_limit = TASK_SIZE;
+	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
+	info.align_offset = 0;
+	return vm_unmapped_area(&info);
+}
+
+static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
+		unsigned long addr0, unsigned long len,
+		unsigned long pgoff, unsigned long flags)
+{
+	struct hstate *h = hstate_file(file);
+	struct vm_unmapped_area_info info;
+	unsigned long addr;
+
+	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+	info.length = len;
+	info.low_limit = PAGE_SIZE;
+	info.high_limit = current->mm->mmap_base;
+	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
+	info.align_offset = 0;
+	addr = vm_unmapped_area(&info);
+
+	/*
+	 * 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.
+	 */
+	if (addr & ~PAGE_MASK) {
+		VM_BUG_ON(addr != -ENOMEM);
+		info.flags = 0;
+		info.low_limit = TASK_UNMAPPED_BASE;
+		info.high_limit = TASK_SIZE;
+		addr = vm_unmapped_area(&info);
+	}
+
+	return addr;
+}
+
+unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
+		unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+	struct hstate *h = hstate_file(file);
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+
+	if (len & ~huge_page_mask(h))
+		return -EINVAL;
+	if (len > TASK_SIZE)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED) {
+		if (prepare_hugepage_range(file, addr, len))
+			return -EINVAL;
+		return addr;
+	}
+
+	if (addr) {
+		addr = ALIGN(addr, huge_page_size(h));
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr &&
+		    (!vma || addr + len <= vma->vm_start))
+			return addr;
+	}
+	if (current->mm->get_unmapped_area == arch_get_unmapped_area)
+		return hugetlb_get_unmapped_area_bottomup(file, addr, len,
+				pgoff, flags);
+	else
+		return hugetlb_get_unmapped_area_topdown(file, addr, len,
+				pgoff, flags);
+}
+#endif /* HAVE_ARCH_HUGETLB_UNMAPPED_AREA */
+
+#ifdef CONFIG_HUGETLB_SUPER_PAGES
+static __init int __setup_hugepagesz(unsigned long ps)
+{
+	int log_ps = __builtin_ctzl(ps);
+	int level, base_shift;
+
+	if ((1UL << log_ps) != ps || (log_ps & 1) != 0) {
+		pr_warn("Not enabling %ld byte huge pages; must be a power of four\n",
+			ps);
+		return -EINVAL;
+	}
+
+	if (ps > 64*1024*1024*1024UL) {
+		pr_warn("Not enabling %ld MB huge pages; largest legal value is 64 GB\n",
+			ps >> 20);
+		return -EINVAL;
+	} else if (ps >= PUD_SIZE) {
+		static long hv_jpage_size;
+		if (hv_jpage_size == 0)
+			hv_jpage_size = hv_sysconf(HV_SYSCONF_PAGE_SIZE_JUMBO);
+		if (hv_jpage_size != PUD_SIZE) {
+			pr_warn("Not enabling >= %ld MB huge pages: hypervisor reports size %ld\n",
+				PUD_SIZE >> 20, hv_jpage_size);
+			return -EINVAL;
+		}
+		level = 0;
+		base_shift = PUD_SHIFT;
+	} else if (ps >= PMD_SIZE) {
+		level = 1;
+		base_shift = PMD_SHIFT;
+	} else if (ps > PAGE_SIZE) {
+		level = 2;
+		base_shift = PAGE_SHIFT;
+	} else {
+		pr_err("hugepagesz: huge page size %ld too small\n", ps);
+		return -EINVAL;
+	}
+
+	if (log_ps != base_shift) {
+		int shift_val = log_ps - base_shift;
+		if (huge_shift[level] != 0) {
+			int old_shift = base_shift + huge_shift[level];
+			pr_warn("Not enabling %ld MB huge pages; already have size %ld MB\n",
+				ps >> 20, (1UL << old_shift) >> 20);
+			return -EINVAL;
+		}
+		if (hv_set_pte_super_shift(level, shift_val) != 0) {
+			pr_warn("Not enabling %ld MB huge pages; no hypervisor support\n",
+				ps >> 20);
+			return -EINVAL;
+		}
+		printk(KERN_DEBUG "Enabled %ld MB huge pages\n", ps >> 20);
+		huge_shift[level] = shift_val;
+	}
+
+	hugetlb_add_hstate(log_ps - PAGE_SHIFT);
+
+	return 0;
+}
+
+static bool saw_hugepagesz;
+
+static __init int setup_hugepagesz(char *opt)
+{
+	if (!saw_hugepagesz) {
+		saw_hugepagesz = true;
+		memset(huge_shift, 0, sizeof(huge_shift));
+	}
+	return __setup_hugepagesz(memparse(opt, NULL));
+}
+__setup("hugepagesz=", setup_hugepagesz);
+
+#ifdef ADDITIONAL_HUGE_SIZE
+/*
+ * Provide an additional huge page size if no "hugepagesz" args are given.
+ * In that case, all the cores have properly set up their hv super_shift
+ * already, but we need to notify the hugetlb code to enable the
+ * new huge page size from the Linux point of view.
+ */
+static __init int add_default_hugepagesz(void)
+{
+	if (!saw_hugepagesz) {
+		BUILD_BUG_ON(ADDITIONAL_HUGE_SIZE >= PMD_SIZE ||
+			     ADDITIONAL_HUGE_SIZE <= PAGE_SIZE);
+		BUILD_BUG_ON((PAGE_SIZE << ADDITIONAL_HUGE_SHIFT) !=
+			     ADDITIONAL_HUGE_SIZE);
+		BUILD_BUG_ON(ADDITIONAL_HUGE_SHIFT & 1);
+		hugetlb_add_hstate(ADDITIONAL_HUGE_SHIFT);
+	}
+	return 0;
+}
+arch_initcall(add_default_hugepagesz);
+#endif
+
+#endif /* CONFIG_HUGETLB_SUPER_PAGES */