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1/*
2 * Copyright (C) 2001-2008 Silicon Graphics, Inc. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of version 2 of the GNU General Public License
6 * as published by the Free Software Foundation.
7 *
8 * A simple uncached page allocator using the generic allocator. This
9 * allocator first utilizes the spare (spill) pages found in the EFI
10 * memmap and will then start converting cached pages to uncached ones
11 * at a granule at a time. Node awareness is implemented by having a
12 * pool of pages per node.
13 */
14
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/init.h>
19#include <linux/errno.h>
20#include <linux/string.h>
21#include <linux/efi.h>
22#include <linux/genalloc.h>
23#include <linux/gfp.h>
24#include <asm/page.h>
25#include <asm/pal.h>
26#include <asm/system.h>
27#include <asm/pgtable.h>
28#include <linux/atomic.h>
29#include <asm/tlbflush.h>
30#include <asm/sn/arch.h>
31
32
33extern void __init efi_memmap_walk_uc(efi_freemem_callback_t, void *);
34
35struct uncached_pool {
36 struct gen_pool *pool;
37 struct mutex add_chunk_mutex; /* serialize adding a converted chunk */
38 int nchunks_added; /* #of converted chunks added to pool */
39 atomic_t status; /* smp called function's return status*/
40};
41
42#define MAX_CONVERTED_CHUNKS_PER_NODE 2
43
44struct uncached_pool uncached_pools[MAX_NUMNODES];
45
46
47static void uncached_ipi_visibility(void *data)
48{
49 int status;
50 struct uncached_pool *uc_pool = (struct uncached_pool *)data;
51
52 status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
53 if ((status != PAL_VISIBILITY_OK) &&
54 (status != PAL_VISIBILITY_OK_REMOTE_NEEDED))
55 atomic_inc(&uc_pool->status);
56}
57
58
59static void uncached_ipi_mc_drain(void *data)
60{
61 int status;
62 struct uncached_pool *uc_pool = (struct uncached_pool *)data;
63
64 status = ia64_pal_mc_drain();
65 if (status != PAL_STATUS_SUCCESS)
66 atomic_inc(&uc_pool->status);
67}
68
69
70/*
71 * Add a new chunk of uncached memory pages to the specified pool.
72 *
73 * @pool: pool to add new chunk of uncached memory to
74 * @nid: node id of node to allocate memory from, or -1
75 *
76 * This is accomplished by first allocating a granule of cached memory pages
77 * and then converting them to uncached memory pages.
78 */
79static int uncached_add_chunk(struct uncached_pool *uc_pool, int nid)
80{
81 struct page *page;
82 int status, i, nchunks_added = uc_pool->nchunks_added;
83 unsigned long c_addr, uc_addr;
84
85 if (mutex_lock_interruptible(&uc_pool->add_chunk_mutex) != 0)
86 return -1; /* interrupted by a signal */
87
88 if (uc_pool->nchunks_added > nchunks_added) {
89 /* someone added a new chunk while we were waiting */
90 mutex_unlock(&uc_pool->add_chunk_mutex);
91 return 0;
92 }
93
94 if (uc_pool->nchunks_added >= MAX_CONVERTED_CHUNKS_PER_NODE) {
95 mutex_unlock(&uc_pool->add_chunk_mutex);
96 return -1;
97 }
98
99 /* attempt to allocate a granule's worth of cached memory pages */
100
101 page = alloc_pages_exact_node(nid,
102 GFP_KERNEL | __GFP_ZERO | GFP_THISNODE,
103 IA64_GRANULE_SHIFT-PAGE_SHIFT);
104 if (!page) {
105 mutex_unlock(&uc_pool->add_chunk_mutex);
106 return -1;
107 }
108
109 /* convert the memory pages from cached to uncached */
110
111 c_addr = (unsigned long)page_address(page);
112 uc_addr = c_addr - PAGE_OFFSET + __IA64_UNCACHED_OFFSET;
113
114 /*
115 * There's a small race here where it's possible for someone to
116 * access the page through /dev/mem halfway through the conversion
117 * to uncached - not sure it's really worth bothering about
118 */
119 for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
120 SetPageUncached(&page[i]);
121
122 flush_tlb_kernel_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
123
124 status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
125 if (status == PAL_VISIBILITY_OK_REMOTE_NEEDED) {
126 atomic_set(&uc_pool->status, 0);
127 status = smp_call_function(uncached_ipi_visibility, uc_pool, 1);
128 if (status || atomic_read(&uc_pool->status))
129 goto failed;
130 } else if (status != PAL_VISIBILITY_OK)
131 goto failed;
132
133 preempt_disable();
134
135 if (ia64_platform_is("sn2"))
136 sn_flush_all_caches(uc_addr, IA64_GRANULE_SIZE);
137 else
138 flush_icache_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
139
140 /* flush the just introduced uncached translation from the TLB */
141 local_flush_tlb_all();
142
143 preempt_enable();
144
145 status = ia64_pal_mc_drain();
146 if (status != PAL_STATUS_SUCCESS)
147 goto failed;
148 atomic_set(&uc_pool->status, 0);
149 status = smp_call_function(uncached_ipi_mc_drain, uc_pool, 1);
150 if (status || atomic_read(&uc_pool->status))
151 goto failed;
152
153 /*
154 * The chunk of memory pages has been converted to uncached so now we
155 * can add it to the pool.
156 */
157 status = gen_pool_add(uc_pool->pool, uc_addr, IA64_GRANULE_SIZE, nid);
158 if (status)
159 goto failed;
160
161 uc_pool->nchunks_added++;
162 mutex_unlock(&uc_pool->add_chunk_mutex);
163 return 0;
164
165 /* failed to convert or add the chunk so give it back to the kernel */
166failed:
167 for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
168 ClearPageUncached(&page[i]);
169
170 free_pages(c_addr, IA64_GRANULE_SHIFT-PAGE_SHIFT);
171 mutex_unlock(&uc_pool->add_chunk_mutex);
172 return -1;
173}
174
175
176/*
177 * uncached_alloc_page
178 *
179 * @starting_nid: node id of node to start with, or -1
180 * @n_pages: number of contiguous pages to allocate
181 *
182 * Allocate the specified number of contiguous uncached pages on the
183 * the requested node. If not enough contiguous uncached pages are available
184 * on the requested node, roundrobin starting with the next higher node.
185 */
186unsigned long uncached_alloc_page(int starting_nid, int n_pages)
187{
188 unsigned long uc_addr;
189 struct uncached_pool *uc_pool;
190 int nid;
191
192 if (unlikely(starting_nid >= MAX_NUMNODES))
193 return 0;
194
195 if (starting_nid < 0)
196 starting_nid = numa_node_id();
197 nid = starting_nid;
198
199 do {
200 if (!node_state(nid, N_HIGH_MEMORY))
201 continue;
202 uc_pool = &uncached_pools[nid];
203 if (uc_pool->pool == NULL)
204 continue;
205 do {
206 uc_addr = gen_pool_alloc(uc_pool->pool,
207 n_pages * PAGE_SIZE);
208 if (uc_addr != 0)
209 return uc_addr;
210 } while (uncached_add_chunk(uc_pool, nid) == 0);
211
212 } while ((nid = (nid + 1) % MAX_NUMNODES) != starting_nid);
213
214 return 0;
215}
216EXPORT_SYMBOL(uncached_alloc_page);
217
218
219/*
220 * uncached_free_page
221 *
222 * @uc_addr: uncached address of first page to free
223 * @n_pages: number of contiguous pages to free
224 *
225 * Free the specified number of uncached pages.
226 */
227void uncached_free_page(unsigned long uc_addr, int n_pages)
228{
229 int nid = paddr_to_nid(uc_addr - __IA64_UNCACHED_OFFSET);
230 struct gen_pool *pool = uncached_pools[nid].pool;
231
232 if (unlikely(pool == NULL))
233 return;
234
235 if ((uc_addr & (0XFUL << 60)) != __IA64_UNCACHED_OFFSET)
236 panic("uncached_free_page invalid address %lx\n", uc_addr);
237
238 gen_pool_free(pool, uc_addr, n_pages * PAGE_SIZE);
239}
240EXPORT_SYMBOL(uncached_free_page);
241
242
243/*
244 * uncached_build_memmap,
245 *
246 * @uc_start: uncached starting address of a chunk of uncached memory
247 * @uc_end: uncached ending address of a chunk of uncached memory
248 * @arg: ignored, (NULL argument passed in on call to efi_memmap_walk_uc())
249 *
250 * Called at boot time to build a map of pages that can be used for
251 * memory special operations.
252 */
253static int __init uncached_build_memmap(u64 uc_start, u64 uc_end, void *arg)
254{
255 int nid = paddr_to_nid(uc_start - __IA64_UNCACHED_OFFSET);
256 struct gen_pool *pool = uncached_pools[nid].pool;
257 size_t size = uc_end - uc_start;
258
259 touch_softlockup_watchdog();
260
261 if (pool != NULL) {
262 memset((char *)uc_start, 0, size);
263 (void) gen_pool_add(pool, uc_start, size, nid);
264 }
265 return 0;
266}
267
268
269static int __init uncached_init(void)
270{
271 int nid;
272
273 for_each_node_state(nid, N_ONLINE) {
274 uncached_pools[nid].pool = gen_pool_create(PAGE_SHIFT, nid);
275 mutex_init(&uncached_pools[nid].add_chunk_mutex);
276 }
277
278 efi_memmap_walk_uc(uncached_build_memmap, NULL);
279 return 0;
280}
281
282__initcall(uncached_init);
1/*
2 * Copyright (C) 2001-2008 Silicon Graphics, Inc. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of version 2 of the GNU General Public License
6 * as published by the Free Software Foundation.
7 *
8 * A simple uncached page allocator using the generic allocator. This
9 * allocator first utilizes the spare (spill) pages found in the EFI
10 * memmap and will then start converting cached pages to uncached ones
11 * at a granule at a time. Node awareness is implemented by having a
12 * pool of pages per node.
13 */
14
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/init.h>
19#include <linux/errno.h>
20#include <linux/string.h>
21#include <linux/efi.h>
22#include <linux/genalloc.h>
23#include <linux/gfp.h>
24#include <asm/page.h>
25#include <asm/pal.h>
26#include <asm/pgtable.h>
27#include <linux/atomic.h>
28#include <asm/tlbflush.h>
29#include <asm/sn/arch.h>
30
31
32extern void __init efi_memmap_walk_uc(efi_freemem_callback_t, void *);
33
34struct uncached_pool {
35 struct gen_pool *pool;
36 struct mutex add_chunk_mutex; /* serialize adding a converted chunk */
37 int nchunks_added; /* #of converted chunks added to pool */
38 atomic_t status; /* smp called function's return status*/
39};
40
41#define MAX_CONVERTED_CHUNKS_PER_NODE 2
42
43struct uncached_pool uncached_pools[MAX_NUMNODES];
44
45
46static void uncached_ipi_visibility(void *data)
47{
48 int status;
49 struct uncached_pool *uc_pool = (struct uncached_pool *)data;
50
51 status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
52 if ((status != PAL_VISIBILITY_OK) &&
53 (status != PAL_VISIBILITY_OK_REMOTE_NEEDED))
54 atomic_inc(&uc_pool->status);
55}
56
57
58static void uncached_ipi_mc_drain(void *data)
59{
60 int status;
61 struct uncached_pool *uc_pool = (struct uncached_pool *)data;
62
63 status = ia64_pal_mc_drain();
64 if (status != PAL_STATUS_SUCCESS)
65 atomic_inc(&uc_pool->status);
66}
67
68
69/*
70 * Add a new chunk of uncached memory pages to the specified pool.
71 *
72 * @pool: pool to add new chunk of uncached memory to
73 * @nid: node id of node to allocate memory from, or -1
74 *
75 * This is accomplished by first allocating a granule of cached memory pages
76 * and then converting them to uncached memory pages.
77 */
78static int uncached_add_chunk(struct uncached_pool *uc_pool, int nid)
79{
80 struct page *page;
81 int status, i, nchunks_added = uc_pool->nchunks_added;
82 unsigned long c_addr, uc_addr;
83
84 if (mutex_lock_interruptible(&uc_pool->add_chunk_mutex) != 0)
85 return -1; /* interrupted by a signal */
86
87 if (uc_pool->nchunks_added > nchunks_added) {
88 /* someone added a new chunk while we were waiting */
89 mutex_unlock(&uc_pool->add_chunk_mutex);
90 return 0;
91 }
92
93 if (uc_pool->nchunks_added >= MAX_CONVERTED_CHUNKS_PER_NODE) {
94 mutex_unlock(&uc_pool->add_chunk_mutex);
95 return -1;
96 }
97
98 /* attempt to allocate a granule's worth of cached memory pages */
99
100 page = __alloc_pages_node(nid,
101 GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,
102 IA64_GRANULE_SHIFT-PAGE_SHIFT);
103 if (!page) {
104 mutex_unlock(&uc_pool->add_chunk_mutex);
105 return -1;
106 }
107
108 /* convert the memory pages from cached to uncached */
109
110 c_addr = (unsigned long)page_address(page);
111 uc_addr = c_addr - PAGE_OFFSET + __IA64_UNCACHED_OFFSET;
112
113 /*
114 * There's a small race here where it's possible for someone to
115 * access the page through /dev/mem halfway through the conversion
116 * to uncached - not sure it's really worth bothering about
117 */
118 for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
119 SetPageUncached(&page[i]);
120
121 flush_tlb_kernel_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
122
123 status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
124 if (status == PAL_VISIBILITY_OK_REMOTE_NEEDED) {
125 atomic_set(&uc_pool->status, 0);
126 status = smp_call_function(uncached_ipi_visibility, uc_pool, 1);
127 if (status || atomic_read(&uc_pool->status))
128 goto failed;
129 } else if (status != PAL_VISIBILITY_OK)
130 goto failed;
131
132 preempt_disable();
133
134 if (ia64_platform_is("sn2"))
135 sn_flush_all_caches(uc_addr, IA64_GRANULE_SIZE);
136 else
137 flush_icache_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
138
139 /* flush the just introduced uncached translation from the TLB */
140 local_flush_tlb_all();
141
142 preempt_enable();
143
144 status = ia64_pal_mc_drain();
145 if (status != PAL_STATUS_SUCCESS)
146 goto failed;
147 atomic_set(&uc_pool->status, 0);
148 status = smp_call_function(uncached_ipi_mc_drain, uc_pool, 1);
149 if (status || atomic_read(&uc_pool->status))
150 goto failed;
151
152 /*
153 * The chunk of memory pages has been converted to uncached so now we
154 * can add it to the pool.
155 */
156 status = gen_pool_add(uc_pool->pool, uc_addr, IA64_GRANULE_SIZE, nid);
157 if (status)
158 goto failed;
159
160 uc_pool->nchunks_added++;
161 mutex_unlock(&uc_pool->add_chunk_mutex);
162 return 0;
163
164 /* failed to convert or add the chunk so give it back to the kernel */
165failed:
166 for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
167 ClearPageUncached(&page[i]);
168
169 free_pages(c_addr, IA64_GRANULE_SHIFT-PAGE_SHIFT);
170 mutex_unlock(&uc_pool->add_chunk_mutex);
171 return -1;
172}
173
174
175/*
176 * uncached_alloc_page
177 *
178 * @starting_nid: node id of node to start with, or -1
179 * @n_pages: number of contiguous pages to allocate
180 *
181 * Allocate the specified number of contiguous uncached pages on the
182 * the requested node. If not enough contiguous uncached pages are available
183 * on the requested node, roundrobin starting with the next higher node.
184 */
185unsigned long uncached_alloc_page(int starting_nid, int n_pages)
186{
187 unsigned long uc_addr;
188 struct uncached_pool *uc_pool;
189 int nid;
190
191 if (unlikely(starting_nid >= MAX_NUMNODES))
192 return 0;
193
194 if (starting_nid < 0)
195 starting_nid = numa_node_id();
196 nid = starting_nid;
197
198 do {
199 if (!node_state(nid, N_HIGH_MEMORY))
200 continue;
201 uc_pool = &uncached_pools[nid];
202 if (uc_pool->pool == NULL)
203 continue;
204 do {
205 uc_addr = gen_pool_alloc(uc_pool->pool,
206 n_pages * PAGE_SIZE);
207 if (uc_addr != 0)
208 return uc_addr;
209 } while (uncached_add_chunk(uc_pool, nid) == 0);
210
211 } while ((nid = (nid + 1) % MAX_NUMNODES) != starting_nid);
212
213 return 0;
214}
215EXPORT_SYMBOL(uncached_alloc_page);
216
217
218/*
219 * uncached_free_page
220 *
221 * @uc_addr: uncached address of first page to free
222 * @n_pages: number of contiguous pages to free
223 *
224 * Free the specified number of uncached pages.
225 */
226void uncached_free_page(unsigned long uc_addr, int n_pages)
227{
228 int nid = paddr_to_nid(uc_addr - __IA64_UNCACHED_OFFSET);
229 struct gen_pool *pool = uncached_pools[nid].pool;
230
231 if (unlikely(pool == NULL))
232 return;
233
234 if ((uc_addr & (0XFUL << 60)) != __IA64_UNCACHED_OFFSET)
235 panic("uncached_free_page invalid address %lx\n", uc_addr);
236
237 gen_pool_free(pool, uc_addr, n_pages * PAGE_SIZE);
238}
239EXPORT_SYMBOL(uncached_free_page);
240
241
242/*
243 * uncached_build_memmap,
244 *
245 * @uc_start: uncached starting address of a chunk of uncached memory
246 * @uc_end: uncached ending address of a chunk of uncached memory
247 * @arg: ignored, (NULL argument passed in on call to efi_memmap_walk_uc())
248 *
249 * Called at boot time to build a map of pages that can be used for
250 * memory special operations.
251 */
252static int __init uncached_build_memmap(u64 uc_start, u64 uc_end, void *arg)
253{
254 int nid = paddr_to_nid(uc_start - __IA64_UNCACHED_OFFSET);
255 struct gen_pool *pool = uncached_pools[nid].pool;
256 size_t size = uc_end - uc_start;
257
258 touch_softlockup_watchdog();
259
260 if (pool != NULL) {
261 memset((char *)uc_start, 0, size);
262 (void) gen_pool_add(pool, uc_start, size, nid);
263 }
264 return 0;
265}
266
267
268static int __init uncached_init(void)
269{
270 int nid;
271
272 for_each_node_state(nid, N_ONLINE) {
273 uncached_pools[nid].pool = gen_pool_create(PAGE_SHIFT, nid);
274 mutex_init(&uncached_pools[nid].add_chunk_mutex);
275 }
276
277 efi_memmap_walk_uc(uncached_build_memmap, NULL);
278 return 0;
279}
280
281__initcall(uncached_init);