LXR linux/arch/tile/include/asm/homecache.h

   1/*
   2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3 *
   4 *   This program is free software; you can redistribute it and/or
   5 *   modify it under the terms of the GNU General Public License
   6 *   as published by the Free Software Foundation, version 2.
   7 *
   8 *   This program is distributed in the hope that it will be useful, but
   9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11 *   NON INFRINGEMENT.  See the GNU General Public License for
  12 *   more details.
  13 *
  14 * Handle issues around the Tile "home cache" model of coherence.
  15 */
  16
  17#ifndef _ASM_TILE_HOMECACHE_H
  18#define _ASM_TILE_HOMECACHE_H
  19
  20#include <asm/page.h>
  21#include <linux/cpumask.h>
  22
  23struct page;
  24struct task_struct;
  25struct vm_area_struct;
  26struct zone;
  27
  28/*
  29 * Coherence point for the page is its memory controller.
  30 * It is not present in any cache (L1 or L2).
  31 */
  32#define PAGE_HOME_UNCACHED -1
  33
  34/*
  35 * Is this page immutable (unwritable) and thus able to be cached more
  36 * widely than would otherwise be possible?  This means we have "nc" set.
  37 */
  38#define PAGE_HOME_IMMUTABLE -2
  39
  40/*
  41 * Each cpu considers its own cache to be the home for the page,
  42 * which makes it incoherent.
  43 */
  44#define PAGE_HOME_INCOHERENT -3
  45
  46/* Home for the page is distributed via hash-for-home. */
  47#define PAGE_HOME_HASH -4
  48
  49/* Support wrapper to use instead of explicit hv_flush_remote(). */
  50extern void flush_remote(unsigned long cache_pfn, unsigned long cache_length,
  51                         const struct cpumask *cache_cpumask,
  52                         HV_VirtAddr tlb_va, unsigned long tlb_length,
  53                         unsigned long tlb_pgsize,
  54                         const struct cpumask *tlb_cpumask,
  55                         HV_Remote_ASID *asids, int asidcount);
  56
  57/* Set homing-related bits in a PTE (can also pass a pgprot_t). */
  58extern pte_t pte_set_home(pte_t pte, int home);
  59
  60/* Do a cache eviction on the specified cpus. */
  61extern void homecache_evict(const struct cpumask *mask);
  62
  63/*
  64 * Change a kernel page's homecache.  It must not be mapped in user space.
  65 * If !CONFIG_HOMECACHE, only usable on LOWMEM, and can only be called when
  66 * no other cpu can reference the page, and causes a full-chip cache/TLB flush.
  67 */
  68extern void homecache_change_page_home(struct page *, int order, int home);
  69
  70/*
  71 * Flush a page out of whatever cache(s) it is in.
  72 * This is more than just finv, since it properly handles waiting
  73 * for the data to reach memory, but it can be quite
  74 * heavyweight, particularly on incoherent or immutable memory.
  75 */
  76extern void homecache_finv_page(struct page *);
  77
  78/*
  79 * Flush a page out of the specified home cache.
  80 * Note that the specified home need not be the actual home of the page,
  81 * as for example might be the case when coordinating with I/O devices.
  82 */
  83extern void homecache_finv_map_page(struct page *, int home);
  84
  85/*
  86 * Allocate a page with the given GFP flags, home, and optionally
  87 * node.  These routines are actually just wrappers around the normal
  88 * alloc_pages() / alloc_pages_node() functions, which set and clear
  89 * a per-cpu variable to communicate with homecache_new_kernel_page().
  90 * If !CONFIG_HOMECACHE, uses homecache_change_page_home().
  91 */
  92extern struct page *homecache_alloc_pages(gfp_t gfp_mask,
  93                                          unsigned int order, int home);
  94extern struct page *homecache_alloc_pages_node(int nid, gfp_t gfp_mask,
  95                                               unsigned int order, int home);
  96#define homecache_alloc_page(gfp_mask, home) \
  97  homecache_alloc_pages(gfp_mask, 0, home)
  98
  99/*
 100 * These routines are just pass-throughs to free_pages() when
 101 * we support full homecaching.  If !CONFIG_HOMECACHE, then these
 102 * routines use homecache_change_page_home() to reset the home
 103 * back to the default before returning the page to the allocator.
 104 */
 105void __homecache_free_pages(struct page *, unsigned int order);
 106void homecache_free_pages(unsigned long addr, unsigned int order);
 107#define __homecache_free_page(page) __homecache_free_pages((page), 0)
 108#define homecache_free_page(page) homecache_free_pages((page), 0)
 109
 110
 111/*
 112 * Report the page home for LOWMEM pages by examining their kernel PTE,
 113 * or for highmem pages as the default home.
 114 */
 115extern int page_home(struct page *);
 116
 117#define homecache_migrate_kthread() do {} while (0)
 118
 119#define homecache_kpte_lock() 0
 120#define homecache_kpte_unlock(flags) do {} while (0)
 121
 122
 123#endif /* _ASM_TILE_HOMECACHE_H */
 124