io-pgtable.c

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Generic page table allocator for IOMMUs.
 4 *
 5 * Copyright (C) 2014 ARM Limited
 6 *
 7 * Author: Will Deacon <will.deacon@arm.com>
 8 */
 9
10#include <linux/bug.h>
11#include <linux/io-pgtable.h>
12#include <linux/kernel.h>
13#include <linux/types.h>
14
15static const struct io_pgtable_init_fns *
16io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] = {
17#ifdef CONFIG_IOMMU_IO_PGTABLE_LPAE
18	[ARM_32_LPAE_S1] = &io_pgtable_arm_32_lpae_s1_init_fns,
19	[ARM_32_LPAE_S2] = &io_pgtable_arm_32_lpae_s2_init_fns,
20	[ARM_64_LPAE_S1] = &io_pgtable_arm_64_lpae_s1_init_fns,
21	[ARM_64_LPAE_S2] = &io_pgtable_arm_64_lpae_s2_init_fns,
22	[ARM_MALI_LPAE] = &io_pgtable_arm_mali_lpae_init_fns,
23#endif
24#ifdef CONFIG_IOMMU_IO_PGTABLE_DART
25	[APPLE_DART] = &io_pgtable_apple_dart_init_fns,
26	[APPLE_DART2] = &io_pgtable_apple_dart_init_fns,
27#endif
28#ifdef CONFIG_IOMMU_IO_PGTABLE_ARMV7S
29	[ARM_V7S] = &io_pgtable_arm_v7s_init_fns,
30#endif
31};
32
33static int check_custom_allocator(enum io_pgtable_fmt fmt,
34				  struct io_pgtable_cfg *cfg)
35{
36	/* No custom allocator, no need to check the format. */
37	if (!cfg->alloc && !cfg->free)
38		return 0;
39
40	/* When passing a custom allocator, both the alloc and free
41	 * functions should be provided.
42	 */
43	if (!cfg->alloc || !cfg->free)
44		return -EINVAL;
45
46	/* Make sure the format supports custom allocators. */
47	if (io_pgtable_init_table[fmt]->caps & IO_PGTABLE_CAP_CUSTOM_ALLOCATOR)
48		return 0;
49
50	return -EINVAL;
51}
52
53struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
54					    struct io_pgtable_cfg *cfg,
55					    void *cookie)
56{
57	struct io_pgtable *iop;
58	const struct io_pgtable_init_fns *fns;
59
60	if (fmt >= IO_PGTABLE_NUM_FMTS)
61		return NULL;
62
63	if (check_custom_allocator(fmt, cfg))
64		return NULL;
65
66	fns = io_pgtable_init_table[fmt];
67	if (!fns)
68		return NULL;
69
70	iop = fns->alloc(cfg, cookie);
71	if (!iop)
72		return NULL;
73
74	iop->fmt	= fmt;
75	iop->cookie	= cookie;
76	iop->cfg	= *cfg;
77
78	return &iop->ops;
79}
80EXPORT_SYMBOL_GPL(alloc_io_pgtable_ops);
81
82/*
83 * It is the IOMMU driver's responsibility to ensure that the page table
84 * is no longer accessible to the walker by this point.
85 */
86void free_io_pgtable_ops(struct io_pgtable_ops *ops)
87{
88	struct io_pgtable *iop;
89
90	if (!ops)
91		return;
92
93	iop = io_pgtable_ops_to_pgtable(ops);
94	io_pgtable_tlb_flush_all(iop);
95	io_pgtable_init_table[iop->fmt]->free(iop);
96}
97EXPORT_SYMBOL_GPL(free_io_pgtable_ops);