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 */