metag: Huge TLB

Add huge TLB support to the metag architecture.

Signed-off-by: James Hogan <james.hogan@imgtec.com>

2 files changed, 377 insertions, 0 deletions

diff --git a/arch/metag/include/asm/hugetlb.h b/arch/metag/include/asm/hugetlb.h
new file mode 100644
index 000000000000..f545477e61f3
--- /dev/null
+++ b/arch/metag/include/asm/hugetlb.h
@@ -0,0 +1,86 @@
+#ifndef _ASM_METAG_HUGETLB_H
+#define _ASM_METAG_HUGETLB_H
+
+#include <asm/page.h>
+
+
+static inline int is_hugepage_only_range(struct mm_struct *mm,
+                                         unsigned long addr,
+                                         unsigned long len) {
+        return 0;
+}
+
+int prepare_hugepage_range(struct file *file, unsigned long addr,
+                                                unsigned long len);
+
+static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm)
+{
+}
+
+static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,
+                                          unsigned long addr, unsigned long end,
+                                          unsigned long floor,
+                                          unsigned long ceiling)
+{
+        free_pgd_range(tlb, addr, end, floor, ceiling);
+}
+
+static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+                                   pte_t *ptep, pte_t pte)
+{
+        set_pte_at(mm, addr, ptep, pte);
+}
+
+static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
+                                            unsigned long addr, pte_t *ptep)
+{
+        return ptep_get_and_clear(mm, addr, ptep);
+}
+
+static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
+                                         unsigned long addr, pte_t *ptep)
+{
+}
+
+static inline int huge_pte_none(pte_t pte)
+{
+        return pte_none(pte);
+}
+
+static inline pte_t huge_pte_wrprotect(pte_t pte)
+{
+        return pte_wrprotect(pte);
+}
+
+static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
+                                           unsigned long addr, pte_t *ptep)
+{
+        ptep_set_wrprotect(mm, addr, ptep);
+}
+
+static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
+                                             unsigned long addr, pte_t *ptep,
+                                             pte_t pte, int dirty)
+{
+        return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
+}
+
+static inline pte_t huge_ptep_get(pte_t *ptep)
+{
+        return *ptep;
+}
+
+static inline int arch_prepare_hugepage(struct page *page)
+{
+        return 0;
+}
+
+static inline void arch_release_hugepage(struct page *page)
+{
+}
+
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+}
+
+#endif /* _ASM_METAG_HUGETLB_H */
diff --git a/arch/metag/mm/hugetlbpage.c b/arch/metag/mm/hugetlbpage.c
new file mode 100644
index 000000000000..24ceed4f4eed
--- /dev/null
+++ b/arch/metag/mm/hugetlbpage.c
@@ -0,0 +1,291 @@
+/*
+ * arch/metag/mm/hugetlbpage.c
+ *
+ * METAG HugeTLB page support.
+ *
+ * Cloned from SuperH
+ *
+ * Cloned from sparc64 by Paul Mundt.
+ *
+ * Copyright (C) 2002, 2003 David S. Miller (davem@redhat.com)
+ */
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/sysctl.h>
+
+#include <asm/mman.h>
+#include <asm/pgalloc.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+
+/*
+ * If the arch doesn't supply something else, assume that hugepage
+ * size aligned regions are ok without further preparation.
+ */
+int prepare_hugepage_range(struct file *file, unsigned long addr,
+                                                unsigned long len)
+{
+        struct mm_struct *mm = current->mm;
+        struct hstate *h = hstate_file(file);
+        struct vm_area_struct *vma;
+
+        if (len & ~huge_page_mask(h))
+                return -EINVAL;
+        if (addr & ~huge_page_mask(h))
+                return -EINVAL;
+        if (TASK_SIZE - len < addr)
+                return -EINVAL;
+
+        vma = find_vma(mm, ALIGN_HUGEPT(addr));
+        if (vma && !(vma->vm_flags & MAP_HUGETLB))
+                return -EINVAL;
+
+        vma = find_vma(mm, addr);
+        if (vma) {
+                if (addr + len > vma->vm_start)
+                        return -EINVAL;
+                if (!(vma->vm_flags & MAP_HUGETLB) &&
+                    (ALIGN_HUGEPT(addr + len) > vma->vm_start))
+                        return -EINVAL;
+        }
+        return 0;
+}
+
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+                        unsigned long addr, unsigned long sz)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *pte;
+
+        pgd = pgd_offset(mm, addr);
+        pud = pud_offset(pgd, addr);
+        pmd = pmd_offset(pud, addr);
+        pte = pte_alloc_map(mm, NULL, pmd, addr);
+        pgd->pgd &= ~_PAGE_SZ_MASK;
+        pgd->pgd |= _PAGE_SZHUGE;
+
+        return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *pte = NULL;
+
+        pgd = pgd_offset(mm, addr);
+        pud = pud_offset(pgd, addr);
+        pmd = pmd_offset(pud, addr);
+        pte = pte_offset_kernel(pmd, addr);
+
+        return pte;
+}
+
+int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
+{
+        return 0;
+}
+
+struct page *follow_huge_addr(struct mm_struct *mm,
+                              unsigned long address, int write)
+{
+        return ERR_PTR(-EINVAL);
+}
+
+int pmd_huge(pmd_t pmd)
+{
+        return pmd_page_shift(pmd) > PAGE_SHIFT;
+}
+
+int pud_huge(pud_t pud)
+{
+        return 0;
+}
+
+struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+                             pmd_t *pmd, int write)
+{
+        return NULL;
+}
+
+#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
+
+/*
+ * Look for an unmapped area starting after another hugetlb vma.
+ * There are guaranteed to be no huge pte's spare if all the huge pages are
+ * full size (4MB), so in that case compile out this search.
+ */
+#if HPAGE_SHIFT == HUGEPT_SHIFT
+static inline unsigned long
+hugetlb_get_unmapped_area_existing(unsigned long len)
+{
+        return 0;
+}
+#else
+static unsigned long
+hugetlb_get_unmapped_area_existing(unsigned long len)
+{
+        struct mm_struct *mm = current->mm;
+        struct vm_area_struct *vma;
+        unsigned long start_addr, addr;
+        int after_huge;
+
+        if (mm->context.part_huge) {
+                start_addr = mm->context.part_huge;
+                after_huge = 1;
+        } else {
+                start_addr = TASK_UNMAPPED_BASE;
+                after_huge = 0;
+        }
+new_search:
+        addr = start_addr;
+
+        for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
+                if ((!vma && !after_huge) || TASK_SIZE - len < addr) {
+                        /*
+                         * Start a new search - just in case we missed
+                         * some holes.
+                         */
+                        if (start_addr != TASK_UNMAPPED_BASE) {
+                                start_addr = TASK_UNMAPPED_BASE;
+                                goto new_search;
+                        }
+                        return 0;
+                }
+                /* skip ahead if we've aligned right over some vmas */
+                if (vma && vma->vm_end <= addr)
+                        continue;
+                /* space before the next vma? */
+                if (after_huge && (!vma || ALIGN_HUGEPT(addr + len)
+                            <= vma->vm_start)) {
+                        unsigned long end = addr + len;
+                        if (end & HUGEPT_MASK)
+                                mm->context.part_huge = end;
+                        else if (addr == mm->context.part_huge)
+                                mm->context.part_huge = 0;
+                        return addr;
+                }
+                if (vma && (vma->vm_flags & MAP_HUGETLB)) {
+                        /* space after a huge vma in 2nd level page table? */
+                        if (vma->vm_end & HUGEPT_MASK) {
+                                after_huge = 1;
+                                /* no need to align to the next PT block */
+                                addr = vma->vm_end;
+                                continue;
+                        }
+                }
+                after_huge = 0;
+                addr = ALIGN_HUGEPT(vma->vm_end);
+        }
+}
+#endif
+
+/* Do a full search to find an area without any nearby normal pages. */
+static unsigned long
+hugetlb_get_unmapped_area_new_pmd(unsigned long len)
+{
+        struct mm_struct *mm = current->mm;
+        struct vm_area_struct *vma;
+        unsigned long start_addr, addr;
+
+        if (ALIGN_HUGEPT(len) > mm->cached_hole_size)
+                start_addr = mm->free_area_cache;
+        else
+                start_addr = TASK_UNMAPPED_BASE;
+
+new_search:
+        addr = ALIGN_HUGEPT(start_addr);
+
+        for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
+                if (TASK_SIZE - len < addr) {
+                        /*
+                         * Start a new search - just in case we missed
+                         * some holes.
+                         */
+                        if (start_addr != TASK_UNMAPPED_BASE) {
+                                start_addr = TASK_UNMAPPED_BASE;
+                                mm->cached_hole_size = 0;
+                                goto new_search;
+                        }
+                        return 0;
+                }
+                /* skip ahead if we've aligned right over some vmas */
+                if (vma && vma->vm_end <= addr)
+                        continue;
+                if (!vma || ALIGN_HUGEPT(addr + len) <= vma->vm_start) {
+#if HPAGE_SHIFT < HUGEPT_SHIFT
+                        if (len & HUGEPT_MASK)
+                                mm->context.part_huge = addr + len;
+#endif
+                        return addr;
+                }
+                addr = ALIGN_HUGEPT(vma->vm_end);
+        }
+}
+
+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);
+
+        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));
+                if (!prepare_hugepage_range(file, addr, len))
+                        return addr;
+        }
+
+        /*
+         * Look for an existing hugetlb vma with space after it (this is to to
+         * minimise fragmentation caused by huge pages.
+         */
+        addr = hugetlb_get_unmapped_area_existing(len);
+        if (addr)
+                return addr;
+
+        /*
+         * Find an unmapped naturally aligned set of 4MB blocks that we can use
+         * for huge pages.
+         */
+        addr = hugetlb_get_unmapped_area_new_pmd(len);
+        if (likely(addr))
+                return addr;
+
+        return -EINVAL;
+}
+
+#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
+
+/* necessary for boot time 4MB huge page allocation */
+static __init int setup_hugepagesz(char *opt)
+{
+        unsigned long ps = memparse(opt, &opt);
+        if (ps == (1 << HPAGE_SHIFT)) {
+                hugetlb_add_hstate(HPAGE_SHIFT - PAGE_SHIFT);
+        } else {
+                pr_err("hugepagesz: Unsupported page size %lu M\n",
+                       ps >> 20);
+                return 0;
+        }
+        return 1;
+}
+__setup("hugepagesz=", setup_hugepagesz);