kernel-fxtec-pro1x/arch/tile/mm/hugetlbpage.c
Chris Metcalf 621b195515 arch/tile: support multiple huge page sizes dynamically
This change adds support for a new "super" bit in the PTE, using the new
arch_make_huge_pte() method.  The Tilera hypervisor sees the bit set at a
given level of the page table and gangs together 4, 16, or 64 consecutive
pages from that level of the hierarchy to create a larger TLB entry.

One extra "super" page size can be specified at each of the three levels
of the page table hierarchy on tilegx, using the "hugepagesz" argument
on the boot command line.  A new hypervisor API is added to allow Linux
to tell the hypervisor how many PTEs to gang together at each level of
the page table.

To allow pre-allocating huge pages larger than the buddy allocator can
handle, this change modifies the Tilera bootmem support to put all of
memory on tilegx platforms into bootmem.

As part of this change I eliminate the vestigial CONFIG_HIGHPTE support,
which never worked anyway, and eliminate the hv_page_size() API in favor
of the standard vma_kernel_pagesize() API.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-05-25 12:48:27 -04:00

497 lines
13 KiB
C

/*
* 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
};
/*
* This routine is a hybrid of pte_alloc_map() and pte_alloc_kernel().
* It assumes that L2 PTEs are never in HIGHMEM (we don't support that).
* It locks the user pagetable, and bumps up the mm->nr_ptes field,
* but otherwise allocate the page table using the kernel versions.
*/
static pte_t *pte_alloc_hugetlb(struct mm_struct *mm, pmd_t *pmd,
unsigned long address)
{
pte_t *new;
if (pmd_none(*pmd)) {
new = pte_alloc_one_kernel(mm, address);
if (!new)
return NULL;
smp_wmb(); /* See comment in __pte_alloc */
spin_lock(&mm->page_table_lock);
if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
mm->nr_ptes++;
pmd_populate_kernel(mm, pmd, new);
new = NULL;
} else
VM_BUG_ON(pmd_trans_splitting(*pmd));
spin_unlock(&mm->page_table_lock);
if (new)
pte_free_kernel(mm, new);
}
return pte_offset_kernel(pmd, address);
}
#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_hugetlb(mm, 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);
if (!pgd_present(*pgd))
return NULL;
/* We don't have four levels. */
pud = pud_offset(pgd, addr);
#ifndef __PAGETABLE_PUD_FOLDED
# error support fourth page table level
#endif
/* 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;
}
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;
}
#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 can't 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);
}
#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 */