1 /*
2 * SPU local store allocation routines
3 *
4 * Copyright 2007 Benjamin Herrenschmidt, IBM Corp.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2, or (at your option)
9 * any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21 #undef DEBUG
22
23 #include <linux/kernel.h>
24 #include <linux/mm.h>
25 #include <linux/slab.h>
26 #include <linux/vmalloc.h>
27
28 #include <asm/spu.h>
29 #include <asm/spu_csa.h>
30 #include <asm/mmu.h>
31
32 #include "spufs.h"
33
spu_alloc_lscsa_std(struct spu_state * csa)34 static int spu_alloc_lscsa_std(struct spu_state *csa)
35 {
36 struct spu_lscsa *lscsa;
37 unsigned char *p;
38
39 lscsa = vzalloc(sizeof(struct spu_lscsa));
40 if (!lscsa)
41 return -ENOMEM;
42 csa->lscsa = lscsa;
43
44 /* Set LS pages reserved to allow for user-space mapping. */
45 for (p = lscsa->ls; p < lscsa->ls + LS_SIZE; p += PAGE_SIZE)
46 SetPageReserved(vmalloc_to_page(p));
47
48 return 0;
49 }
50
spu_free_lscsa_std(struct spu_state * csa)51 static void spu_free_lscsa_std(struct spu_state *csa)
52 {
53 /* Clear reserved bit before vfree. */
54 unsigned char *p;
55
56 if (csa->lscsa == NULL)
57 return;
58
59 for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
60 ClearPageReserved(vmalloc_to_page(p));
61
62 vfree(csa->lscsa);
63 }
64
65 #ifdef CONFIG_SPU_FS_64K_LS
66
67 #define SPU_64K_PAGE_SHIFT 16
68 #define SPU_64K_PAGE_ORDER (SPU_64K_PAGE_SHIFT - PAGE_SHIFT)
69 #define SPU_64K_PAGE_COUNT (1ul << SPU_64K_PAGE_ORDER)
70
spu_alloc_lscsa(struct spu_state * csa)71 int spu_alloc_lscsa(struct spu_state *csa)
72 {
73 struct page **pgarray;
74 unsigned char *p;
75 int i, j, n_4k;
76
77 /* Check availability of 64K pages */
78 if (!spu_64k_pages_available())
79 goto fail;
80
81 csa->use_big_pages = 1;
82
83 pr_debug("spu_alloc_lscsa(csa=0x%p), trying to allocate 64K pages\n",
84 csa);
85
86 /* First try to allocate our 64K pages. We need 5 of them
87 * with the current implementation. In the future, we should try
88 * to separate the lscsa with the actual local store image, thus
89 * allowing us to require only 4 64K pages per context
90 */
91 for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++) {
92 /* XXX This is likely to fail, we should use a special pool
93 * similar to what hugetlbfs does.
94 */
95 csa->lscsa_pages[i] = alloc_pages(GFP_KERNEL,
96 SPU_64K_PAGE_ORDER);
97 if (csa->lscsa_pages[i] == NULL)
98 goto fail;
99 }
100
101 pr_debug(" success ! creating vmap...\n");
102
103 /* Now we need to create a vmalloc mapping of these for the kernel
104 * and SPU context switch code to use. Currently, we stick to a
105 * normal kernel vmalloc mapping, which in our case will be 4K
106 */
107 n_4k = SPU_64K_PAGE_COUNT * SPU_LSCSA_NUM_BIG_PAGES;
108 pgarray = kmalloc(sizeof(struct page *) * n_4k, GFP_KERNEL);
109 if (pgarray == NULL)
110 goto fail;
111 for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++)
112 for (j = 0; j < SPU_64K_PAGE_COUNT; j++)
113 /* We assume all the struct page's are contiguous
114 * which should be hopefully the case for an order 4
115 * allocation..
116 */
117 pgarray[i * SPU_64K_PAGE_COUNT + j] =
118 csa->lscsa_pages[i] + j;
119 csa->lscsa = vmap(pgarray, n_4k, VM_USERMAP, PAGE_KERNEL);
120 kfree(pgarray);
121 if (csa->lscsa == NULL)
122 goto fail;
123
124 memset(csa->lscsa, 0, sizeof(struct spu_lscsa));
125
126 /* Set LS pages reserved to allow for user-space mapping.
127 *
128 * XXX isn't that a bit obsolete ? I think we should just
129 * make sure the page count is high enough. Anyway, won't harm
130 * for now
131 */
132 for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
133 SetPageReserved(vmalloc_to_page(p));
134
135 pr_debug(" all good !\n");
136
137 return 0;
138 fail:
139 pr_debug("spufs: failed to allocate lscsa 64K pages, falling back\n");
140 spu_free_lscsa(csa);
141 return spu_alloc_lscsa_std(csa);
142 }
143
spu_free_lscsa(struct spu_state * csa)144 void spu_free_lscsa(struct spu_state *csa)
145 {
146 unsigned char *p;
147 int i;
148
149 if (!csa->use_big_pages) {
150 spu_free_lscsa_std(csa);
151 return;
152 }
153 csa->use_big_pages = 0;
154
155 if (csa->lscsa == NULL)
156 goto free_pages;
157
158 for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
159 ClearPageReserved(vmalloc_to_page(p));
160
161 vunmap(csa->lscsa);
162 csa->lscsa = NULL;
163
164 free_pages:
165
166 for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++)
167 if (csa->lscsa_pages[i])
168 __free_pages(csa->lscsa_pages[i], SPU_64K_PAGE_ORDER);
169 }
170
171 #else /* CONFIG_SPU_FS_64K_LS */
172
spu_alloc_lscsa(struct spu_state * csa)173 int spu_alloc_lscsa(struct spu_state *csa)
174 {
175 return spu_alloc_lscsa_std(csa);
176 }
177
spu_free_lscsa(struct spu_state * csa)178 void spu_free_lscsa(struct spu_state *csa)
179 {
180 spu_free_lscsa_std(csa);
181 }
182
183 #endif /* !defined(CONFIG_SPU_FS_64K_LS) */
184