linux/arch/tile/mm/hugetlbpage.c

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/*
* 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);
}
#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 */