arch/tile: core support for Tilera 32-bit chips.

This change is the core kernel support for TILEPro and TILE64 chips.
No driver support (except the console driver) is included yet.

This includes the relevant Linux headers in asm/; the low-level
low-level "Tile architecture" headers in arch/, which are
shared with the hypervisor, etc., and are build-system agnostic;
and the relevant hypervisor headers in hv/.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reviewed-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 343 insertions, 0 deletions

diff --git a/arch/tile/mm/hugetlbpage.c b/arch/tile/mm/hugetlbpage.c
new file mode 100644
index 00000000000..c38570f8f0d
--- /dev/null
+++ b/arch/tile/mm/hugetlbpage.c
@@ -0,0 +1,343 @@
+/*
+ * 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/smp_lock.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>
+
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+		      unsigned long addr, unsigned long sz)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pte_t *pte = NULL;
+
+	/* We do not yet support multiple huge page sizes. */
+	BUG_ON(sz != PMD_SIZE);
+
+	pgd = pgd_offset(mm, addr);
+	pud = pud_alloc(mm, pgd, addr);
+	if (pud)
+		pte = (pte_t *) pmd_alloc(mm, pud, addr);
+	BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
+
+	return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd = NULL;
+
+	pgd = pgd_offset(mm, addr);
+	if (pgd_present(*pgd)) {
+		pud = pud_offset(pgd, addr);
+		if (pud_present(*pud))
+			pmd = pmd_offset(pud, addr);
+	}
+	return (pte_t *) pmd;
+}
+
+#ifdef HUGETLB_TEST
+struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
+			      int write)
+{
+	unsigned long start = address;
+	int length = 1;
+	int nr;
+	struct page *page;
+	struct vm_area_struct *vma;
+
+	vma = find_vma(mm, addr);
+	if (!vma || !is_vm_hugetlb_page(vma))
+		return ERR_PTR(-EINVAL);
+
+	pte = huge_pte_offset(mm, address);
+
+	/* hugetlb should be locked, and hence, prefaulted */
+	WARN_ON(!pte || pte_none(*pte));
+
+	page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
+
+	WARN_ON(!PageHead(page));
+
+	return page;
+}
+
+int pmd_huge(pmd_t pmd)
+{
+	return 0;
+}
+
+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;
+}
+
+#else
+
+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_val(pmd) & _PAGE_HUGE_PAGE);
+}
+
+int pud_huge(pud_t pud)
+{
+	return !!(pud_val(pud) & _PAGE_HUGE_PAGE);
+}
+
+struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+			     pmd_t *pmd, int write)
+{
+	struct page *page;
+
+	page = pte_page(*(pte_t *)pmd);
+	if (page)
+		page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
+	return page;
+}
+
+struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address,
+			     pud_t *pud, int write)
+{
+	struct page *page;
+
+	page = pte_page(*(pte_t *)pud);
+	if (page)
+		page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
+	return page;
+}
+
+int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
+{
+	return 0;
+}
+
+#endif
+
+#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 mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	unsigned long start_addr;
+
+	if (len > mm->cached_hole_size) {
+		start_addr = mm->free_area_cache;
+	} else {
+		start_addr = TASK_UNMAPPED_BASE;
+		mm->cached_hole_size = 0;
+	}
+
+full_search:
+	addr = ALIGN(start_addr, huge_page_size(h));
+
+	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
+		/* At this point:  (!vma || addr < vma->vm_end). */
+		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 full_search;
+			}
+			return -ENOMEM;
+		}
+		if (!vma || addr + len <= vma->vm_start) {
+			mm->free_area_cache = addr + len;
+			return addr;
+		}
+		if (addr + mm->cached_hole_size < vma->vm_start)
+			mm->cached_hole_size = vma->vm_start - addr;
+		addr = ALIGN(vma->vm_end, huge_page_size(h));
+	}
+}
+
+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 mm_struct *mm = current->mm;
+	struct vm_area_struct *vma, *prev_vma;
+	unsigned long base = mm->mmap_base, addr = addr0;
+	unsigned long largest_hole = mm->cached_hole_size;
+	int first_time = 1;
+
+	/* don't allow allocations above current base */
+	if (mm->free_area_cache > base)
+		mm->free_area_cache = base;
+
+	if (len <= largest_hole) {
+		largest_hole = 0;
+		mm->free_area_cache  = base;
+	}
+try_again:
+	/* make sure it can fit in the remaining address space */
+	if (mm->free_area_cache < len)
+		goto fail;
+
+	/* either no address requested or cant fit in requested address hole */
+	addr = (mm->free_area_cache - len) & huge_page_mask(h);
+	do {
+		/*
+		 * Lookup failure means no vma is above this address,
+		 * i.e. return with success:
+		 */
+		vma = find_vma_prev(mm, addr, &prev_vma);
+		if (!vma) {
+			return addr;
+			break;
+		}
+
+		/*
+		 * new region fits between prev_vma->vm_end and
+		 * vma->vm_start, use it:
+		 */
+		if (addr + len <= vma->vm_start &&
+			    (!prev_vma || (addr >= prev_vma->vm_end))) {
+			/* remember the address as a hint for next time */
+			mm->cached_hole_size = largest_hole;
+			mm->free_area_cache = addr;
+			return addr;
+		} else {
+			/* pull free_area_cache down to the first hole */
+			if (mm->free_area_cache == vma->vm_end) {
+				mm->free_area_cache = vma->vm_start;
+				mm->cached_hole_size = largest_hole;
+			}
+		}
+
+		/* remember the largest hole we saw so far */
+		if (addr + largest_hole < vma->vm_start)
+			largest_hole = vma->vm_start - addr;
+
+		/* try just below the current vma->vm_start */
+		addr = (vma->vm_start - len) & huge_page_mask(h);
+
+	} while (len <= vma->vm_start);
+
+fail:
+	/*
+	 * if hint left us with no space for the requested
+	 * mapping then try again:
+	 */
+	if (first_time) {
+		mm->free_area_cache = base;
+		largest_hole = 0;
+		first_time = 0;
+		goto try_again;
+	}
+	/*
+	 * 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.
+	 */
+	mm->free_area_cache = TASK_UNMAPPED_BASE;
+	mm->cached_hole_size = ~0UL;
+	addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
+			len, pgoff, flags);
+
+	/*
+	 * Restore the topdown base:
+	 */
+	mm->free_area_cache = base;
+	mm->cached_hole_size = ~0UL;
+
+	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);
+}
+
+static __init int setup_hugepagesz(char *opt)
+{
+	unsigned long ps = memparse(opt, &opt);
+	if (ps == PMD_SIZE) {
+		hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
+	} else if (ps == PUD_SIZE) {
+		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
+	} else {
+		printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
+			ps >> 20);
+		return 0;
+	}
+	return 1;
+}
+__setup("hugepagesz=", setup_hugepagesz);
+
+#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/