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
34static 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
51static 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
71int 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;
138fail:
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
144void 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
173int spu_alloc_lscsa(struct spu_state *csa)
174{
175	return spu_alloc_lscsa_std(csa);
176}
177
178void 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