Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2001-2008 Silicon Graphics, Inc. All rights reserved.
4 *
5 * A simple uncached page allocator using the generic allocator. This
6 * allocator first utilizes the spare (spill) pages found in the EFI
7 * memmap and will then start converting cached pages to uncached ones
8 * at a granule at a time. Node awareness is implemented by having a
9 * pool of pages per node.
10 */
11
12#include <linux/types.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/errno.h>
17#include <linux/string.h>
18#include <linux/efi.h>
19#include <linux/nmi.h>
20#include <linux/genalloc.h>
21#include <linux/gfp.h>
22#include <linux/pgtable.h>
23#include <asm/page.h>
24#include <asm/pal.h>
25#include <linux/atomic.h>
26#include <asm/tlbflush.h>
27
28
29extern void __init efi_memmap_walk_uc(efi_freemem_callback_t, void *);
30
31struct uncached_pool {
32 struct gen_pool *pool;
33 struct mutex add_chunk_mutex; /* serialize adding a converted chunk */
34 int nchunks_added; /* #of converted chunks added to pool */
35 atomic_t status; /* smp called function's return status*/
36};
37
38#define MAX_CONVERTED_CHUNKS_PER_NODE 2
39
40struct uncached_pool uncached_pools[MAX_NUMNODES];
41
42
43static void uncached_ipi_visibility(void *data)
44{
45 int status;
46 struct uncached_pool *uc_pool = (struct uncached_pool *)data;
47
48 status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
49 if ((status != PAL_VISIBILITY_OK) &&
50 (status != PAL_VISIBILITY_OK_REMOTE_NEEDED))
51 atomic_inc(&uc_pool->status);
52}
53
54
55static void uncached_ipi_mc_drain(void *data)
56{
57 int status;
58 struct uncached_pool *uc_pool = (struct uncached_pool *)data;
59
60 status = ia64_pal_mc_drain();
61 if (status != PAL_STATUS_SUCCESS)
62 atomic_inc(&uc_pool->status);
63}
64
65
66/*
67 * Add a new chunk of uncached memory pages to the specified pool.
68 *
69 * @pool: pool to add new chunk of uncached memory to
70 * @nid: node id of node to allocate memory from, or -1
71 *
72 * This is accomplished by first allocating a granule of cached memory pages
73 * and then converting them to uncached memory pages.
74 */
75static int uncached_add_chunk(struct uncached_pool *uc_pool, int nid)
76{
77 struct page *page;
78 int status, i, nchunks_added = uc_pool->nchunks_added;
79 unsigned long c_addr, uc_addr;
80
81 if (mutex_lock_interruptible(&uc_pool->add_chunk_mutex) != 0)
82 return -1; /* interrupted by a signal */
83
84 if (uc_pool->nchunks_added > nchunks_added) {
85 /* someone added a new chunk while we were waiting */
86 mutex_unlock(&uc_pool->add_chunk_mutex);
87 return 0;
88 }
89
90 if (uc_pool->nchunks_added >= MAX_CONVERTED_CHUNKS_PER_NODE) {
91 mutex_unlock(&uc_pool->add_chunk_mutex);
92 return -1;
93 }
94
95 /* attempt to allocate a granule's worth of cached memory pages */
96
97 page = __alloc_pages_node(nid,
98 GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,
99 IA64_GRANULE_SHIFT-PAGE_SHIFT);
100 if (!page) {
101 mutex_unlock(&uc_pool->add_chunk_mutex);
102 return -1;
103 }
104
105 /* convert the memory pages from cached to uncached */
106
107 c_addr = (unsigned long)page_address(page);
108 uc_addr = c_addr - PAGE_OFFSET + __IA64_UNCACHED_OFFSET;
109
110 /*
111 * There's a small race here where it's possible for someone to
112 * access the page through /dev/mem halfway through the conversion
113 * to uncached - not sure it's really worth bothering about
114 */
115 for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
116 SetPageUncached(&page[i]);
117
118 flush_tlb_kernel_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
119
120 status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
121 if (status == PAL_VISIBILITY_OK_REMOTE_NEEDED) {
122 atomic_set(&uc_pool->status, 0);
123 smp_call_function(uncached_ipi_visibility, uc_pool, 1);
124 if (atomic_read(&uc_pool->status))
125 goto failed;
126 } else if (status != PAL_VISIBILITY_OK)
127 goto failed;
128
129 preempt_disable();
130
131 flush_icache_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
132
133 /* flush the just introduced uncached translation from the TLB */
134 local_flush_tlb_all();
135
136 preempt_enable();
137
138 status = ia64_pal_mc_drain();
139 if (status != PAL_STATUS_SUCCESS)
140 goto failed;
141 atomic_set(&uc_pool->status, 0);
142 smp_call_function(uncached_ipi_mc_drain, uc_pool, 1);
143 if (atomic_read(&uc_pool->status))
144 goto failed;
145
146 /*
147 * The chunk of memory pages has been converted to uncached so now we
148 * can add it to the pool.
149 */
150 status = gen_pool_add(uc_pool->pool, uc_addr, IA64_GRANULE_SIZE, nid);
151 if (status)
152 goto failed;
153
154 uc_pool->nchunks_added++;
155 mutex_unlock(&uc_pool->add_chunk_mutex);
156 return 0;
157
158 /* failed to convert or add the chunk so give it back to the kernel */
159failed:
160 for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
161 ClearPageUncached(&page[i]);
162
163 free_pages(c_addr, IA64_GRANULE_SHIFT-PAGE_SHIFT);
164 mutex_unlock(&uc_pool->add_chunk_mutex);
165 return -1;
166}
167
168
169/*
170 * uncached_alloc_page
171 *
172 * @starting_nid: node id of node to start with, or -1
173 * @n_pages: number of contiguous pages to allocate
174 *
175 * Allocate the specified number of contiguous uncached pages on the
176 * the requested node. If not enough contiguous uncached pages are available
177 * on the requested node, roundrobin starting with the next higher node.
178 */
179unsigned long uncached_alloc_page(int starting_nid, int n_pages)
180{
181 unsigned long uc_addr;
182 struct uncached_pool *uc_pool;
183 int nid;
184
185 if (unlikely(starting_nid >= MAX_NUMNODES))
186 return 0;
187
188 if (starting_nid < 0)
189 starting_nid = numa_node_id();
190 nid = starting_nid;
191
192 do {
193 if (!node_state(nid, N_HIGH_MEMORY))
194 continue;
195 uc_pool = &uncached_pools[nid];
196 if (uc_pool->pool == NULL)
197 continue;
198 do {
199 uc_addr = gen_pool_alloc(uc_pool->pool,
200 n_pages * PAGE_SIZE);
201 if (uc_addr != 0)
202 return uc_addr;
203 } while (uncached_add_chunk(uc_pool, nid) == 0);
204
205 } while ((nid = (nid + 1) % MAX_NUMNODES) != starting_nid);
206
207 return 0;
208}
209EXPORT_SYMBOL(uncached_alloc_page);
210
211
212/*
213 * uncached_free_page
214 *
215 * @uc_addr: uncached address of first page to free
216 * @n_pages: number of contiguous pages to free
217 *
218 * Free the specified number of uncached pages.
219 */
220void uncached_free_page(unsigned long uc_addr, int n_pages)
221{
222 int nid = paddr_to_nid(uc_addr - __IA64_UNCACHED_OFFSET);
223 struct gen_pool *pool = uncached_pools[nid].pool;
224
225 if (unlikely(pool == NULL))
226 return;
227
228 if ((uc_addr & (0XFUL << 60)) != __IA64_UNCACHED_OFFSET)
229 panic("uncached_free_page invalid address %lx\n", uc_addr);
230
231 gen_pool_free(pool, uc_addr, n_pages * PAGE_SIZE);
232}
233EXPORT_SYMBOL(uncached_free_page);
234
235
236/*
237 * uncached_build_memmap,
238 *
239 * @uc_start: uncached starting address of a chunk of uncached memory
240 * @uc_end: uncached ending address of a chunk of uncached memory
241 * @arg: ignored, (NULL argument passed in on call to efi_memmap_walk_uc())
242 *
243 * Called at boot time to build a map of pages that can be used for
244 * memory special operations.
245 */
246static int __init uncached_build_memmap(u64 uc_start, u64 uc_end, void *arg)
247{
248 int nid = paddr_to_nid(uc_start - __IA64_UNCACHED_OFFSET);
249 struct gen_pool *pool = uncached_pools[nid].pool;
250 size_t size = uc_end - uc_start;
251
252 touch_softlockup_watchdog();
253
254 if (pool != NULL) {
255 memset((char *)uc_start, 0, size);
256 (void) gen_pool_add(pool, uc_start, size, nid);
257 }
258 return 0;
259}
260
261
262static int __init uncached_init(void)
263{
264 int nid;
265
266 for_each_node_state(nid, N_ONLINE) {
267 uncached_pools[nid].pool = gen_pool_create(PAGE_SHIFT, nid);
268 mutex_init(&uncached_pools[nid].add_chunk_mutex);
269 }
270
271 efi_memmap_walk_uc(uncached_build_memmap, NULL);
272 return 0;
273}
274
275__initcall(uncached_init);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2001-2008 Silicon Graphics, Inc. All rights reserved.
4 *
5 * A simple uncached page allocator using the generic allocator. This
6 * allocator first utilizes the spare (spill) pages found in the EFI
7 * memmap and will then start converting cached pages to uncached ones
8 * at a granule at a time. Node awareness is implemented by having a
9 * pool of pages per node.
10 */
11
12#include <linux/types.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/errno.h>
17#include <linux/string.h>
18#include <linux/efi.h>
19#include <linux/nmi.h>
20#include <linux/genalloc.h>
21#include <linux/gfp.h>
22#include <linux/pgtable.h>
23#include <asm/efi.h>
24#include <asm/page.h>
25#include <asm/pal.h>
26#include <linux/atomic.h>
27#include <asm/tlbflush.h>
28
29struct uncached_pool {
30 struct gen_pool *pool;
31 struct mutex add_chunk_mutex; /* serialize adding a converted chunk */
32 int nchunks_added; /* #of converted chunks added to pool */
33 atomic_t status; /* smp called function's return status*/
34};
35
36#define MAX_CONVERTED_CHUNKS_PER_NODE 2
37
38struct uncached_pool uncached_pools[MAX_NUMNODES];
39
40
41static void uncached_ipi_visibility(void *data)
42{
43 int status;
44 struct uncached_pool *uc_pool = (struct uncached_pool *)data;
45
46 status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
47 if ((status != PAL_VISIBILITY_OK) &&
48 (status != PAL_VISIBILITY_OK_REMOTE_NEEDED))
49 atomic_inc(&uc_pool->status);
50}
51
52
53static void uncached_ipi_mc_drain(void *data)
54{
55 int status;
56 struct uncached_pool *uc_pool = (struct uncached_pool *)data;
57
58 status = ia64_pal_mc_drain();
59 if (status != PAL_STATUS_SUCCESS)
60 atomic_inc(&uc_pool->status);
61}
62
63
64/*
65 * Add a new chunk of uncached memory pages to the specified pool.
66 *
67 * @pool: pool to add new chunk of uncached memory to
68 * @nid: node id of node to allocate memory from, or -1
69 *
70 * This is accomplished by first allocating a granule of cached memory pages
71 * and then converting them to uncached memory pages.
72 */
73static int uncached_add_chunk(struct uncached_pool *uc_pool, int nid)
74{
75 struct page *page;
76 int status, i, nchunks_added = uc_pool->nchunks_added;
77 unsigned long c_addr, uc_addr;
78
79 if (mutex_lock_interruptible(&uc_pool->add_chunk_mutex) != 0)
80 return -1; /* interrupted by a signal */
81
82 if (uc_pool->nchunks_added > nchunks_added) {
83 /* someone added a new chunk while we were waiting */
84 mutex_unlock(&uc_pool->add_chunk_mutex);
85 return 0;
86 }
87
88 if (uc_pool->nchunks_added >= MAX_CONVERTED_CHUNKS_PER_NODE) {
89 mutex_unlock(&uc_pool->add_chunk_mutex);
90 return -1;
91 }
92
93 /* attempt to allocate a granule's worth of cached memory pages */
94
95 page = __alloc_pages_node(nid,
96 GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,
97 IA64_GRANULE_SHIFT-PAGE_SHIFT);
98 if (!page) {
99 mutex_unlock(&uc_pool->add_chunk_mutex);
100 return -1;
101 }
102
103 /* convert the memory pages from cached to uncached */
104
105 c_addr = (unsigned long)page_address(page);
106 uc_addr = c_addr - PAGE_OFFSET + __IA64_UNCACHED_OFFSET;
107
108 /*
109 * There's a small race here where it's possible for someone to
110 * access the page through /dev/mem halfway through the conversion
111 * to uncached - not sure it's really worth bothering about
112 */
113 for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
114 SetPageUncached(&page[i]);
115
116 flush_tlb_kernel_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
117
118 status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
119 if (status == PAL_VISIBILITY_OK_REMOTE_NEEDED) {
120 atomic_set(&uc_pool->status, 0);
121 smp_call_function(uncached_ipi_visibility, uc_pool, 1);
122 if (atomic_read(&uc_pool->status))
123 goto failed;
124 } else if (status != PAL_VISIBILITY_OK)
125 goto failed;
126
127 preempt_disable();
128
129 flush_icache_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
130
131 /* flush the just introduced uncached translation from the TLB */
132 local_flush_tlb_all();
133
134 preempt_enable();
135
136 status = ia64_pal_mc_drain();
137 if (status != PAL_STATUS_SUCCESS)
138 goto failed;
139 atomic_set(&uc_pool->status, 0);
140 smp_call_function(uncached_ipi_mc_drain, uc_pool, 1);
141 if (atomic_read(&uc_pool->status))
142 goto failed;
143
144 /*
145 * The chunk of memory pages has been converted to uncached so now we
146 * can add it to the pool.
147 */
148 status = gen_pool_add(uc_pool->pool, uc_addr, IA64_GRANULE_SIZE, nid);
149 if (status)
150 goto failed;
151
152 uc_pool->nchunks_added++;
153 mutex_unlock(&uc_pool->add_chunk_mutex);
154 return 0;
155
156 /* failed to convert or add the chunk so give it back to the kernel */
157failed:
158 for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
159 ClearPageUncached(&page[i]);
160
161 free_pages(c_addr, IA64_GRANULE_SHIFT-PAGE_SHIFT);
162 mutex_unlock(&uc_pool->add_chunk_mutex);
163 return -1;
164}
165
166
167/*
168 * uncached_alloc_page
169 *
170 * @starting_nid: node id of node to start with, or -1
171 * @n_pages: number of contiguous pages to allocate
172 *
173 * Allocate the specified number of contiguous uncached pages on the
174 * requested node. If not enough contiguous uncached pages are available
175 * on the requested node, roundrobin starting with the next higher node.
176 */
177unsigned long uncached_alloc_page(int starting_nid, int n_pages)
178{
179 unsigned long uc_addr;
180 struct uncached_pool *uc_pool;
181 int nid;
182
183 if (unlikely(starting_nid >= MAX_NUMNODES))
184 return 0;
185
186 if (starting_nid < 0)
187 starting_nid = numa_node_id();
188 nid = starting_nid;
189
190 do {
191 if (!node_state(nid, N_HIGH_MEMORY))
192 continue;
193 uc_pool = &uncached_pools[nid];
194 if (uc_pool->pool == NULL)
195 continue;
196 do {
197 uc_addr = gen_pool_alloc(uc_pool->pool,
198 n_pages * PAGE_SIZE);
199 if (uc_addr != 0)
200 return uc_addr;
201 } while (uncached_add_chunk(uc_pool, nid) == 0);
202
203 } while ((nid = (nid + 1) % MAX_NUMNODES) != starting_nid);
204
205 return 0;
206}
207EXPORT_SYMBOL(uncached_alloc_page);
208
209
210/*
211 * uncached_free_page
212 *
213 * @uc_addr: uncached address of first page to free
214 * @n_pages: number of contiguous pages to free
215 *
216 * Free the specified number of uncached pages.
217 */
218void uncached_free_page(unsigned long uc_addr, int n_pages)
219{
220 int nid = paddr_to_nid(uc_addr - __IA64_UNCACHED_OFFSET);
221 struct gen_pool *pool = uncached_pools[nid].pool;
222
223 if (unlikely(pool == NULL))
224 return;
225
226 if ((uc_addr & (0XFUL << 60)) != __IA64_UNCACHED_OFFSET)
227 panic("uncached_free_page invalid address %lx\n", uc_addr);
228
229 gen_pool_free(pool, uc_addr, n_pages * PAGE_SIZE);
230}
231EXPORT_SYMBOL(uncached_free_page);
232
233
234/*
235 * uncached_build_memmap,
236 *
237 * @uc_start: uncached starting address of a chunk of uncached memory
238 * @uc_end: uncached ending address of a chunk of uncached memory
239 * @arg: ignored, (NULL argument passed in on call to efi_memmap_walk_uc())
240 *
241 * Called at boot time to build a map of pages that can be used for
242 * memory special operations.
243 */
244static int __init uncached_build_memmap(u64 uc_start, u64 uc_end, void *arg)
245{
246 int nid = paddr_to_nid(uc_start - __IA64_UNCACHED_OFFSET);
247 struct gen_pool *pool = uncached_pools[nid].pool;
248 size_t size = uc_end - uc_start;
249
250 touch_softlockup_watchdog();
251
252 if (pool != NULL) {
253 memset((char *)uc_start, 0, size);
254 (void) gen_pool_add(pool, uc_start, size, nid);
255 }
256 return 0;
257}
258
259
260static int __init uncached_init(void)
261{
262 int nid;
263
264 for_each_online_node(nid) {
265 uncached_pools[nid].pool = gen_pool_create(PAGE_SHIFT, nid);
266 mutex_init(&uncached_pools[nid].add_chunk_mutex);
267 }
268
269 efi_memmap_walk_uc(uncached_build_memmap, NULL);
270 return 0;
271}
272
273__initcall(uncached_init);