xref: /linux/drivers/iommu/io-pgtable.c (revision 4b660dbd9ee2059850fd30e0df420ca7a38a1856)
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 
15 static const struct io_pgtable_init_fns *
16 io_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 #ifdef CONFIG_AMD_IOMMU
32 	[AMD_IOMMU_V1] = &io_pgtable_amd_iommu_v1_init_fns,
33 	[AMD_IOMMU_V2] = &io_pgtable_amd_iommu_v2_init_fns,
34 #endif
35 };
36 
37 static int check_custom_allocator(enum io_pgtable_fmt fmt,
38 				  struct io_pgtable_cfg *cfg)
39 {
40 	/* No custom allocator, no need to check the format. */
41 	if (!cfg->alloc && !cfg->free)
42 		return 0;
43 
44 	/* When passing a custom allocator, both the alloc and free
45 	 * functions should be provided.
46 	 */
47 	if (!cfg->alloc || !cfg->free)
48 		return -EINVAL;
49 
50 	/* Make sure the format supports custom allocators. */
51 	if (io_pgtable_init_table[fmt]->caps & IO_PGTABLE_CAP_CUSTOM_ALLOCATOR)
52 		return 0;
53 
54 	return -EINVAL;
55 }
56 
57 struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
58 					    struct io_pgtable_cfg *cfg,
59 					    void *cookie)
60 {
61 	struct io_pgtable *iop;
62 	const struct io_pgtable_init_fns *fns;
63 
64 	if (fmt >= IO_PGTABLE_NUM_FMTS)
65 		return NULL;
66 
67 	if (check_custom_allocator(fmt, cfg))
68 		return NULL;
69 
70 	fns = io_pgtable_init_table[fmt];
71 	if (!fns)
72 		return NULL;
73 
74 	iop = fns->alloc(cfg, cookie);
75 	if (!iop)
76 		return NULL;
77 
78 	iop->fmt	= fmt;
79 	iop->cookie	= cookie;
80 	iop->cfg	= *cfg;
81 
82 	return &iop->ops;
83 }
84 EXPORT_SYMBOL_GPL(alloc_io_pgtable_ops);
85 
86 /*
87  * It is the IOMMU driver's responsibility to ensure that the page table
88  * is no longer accessible to the walker by this point.
89  */
90 void free_io_pgtable_ops(struct io_pgtable_ops *ops)
91 {
92 	struct io_pgtable *iop;
93 
94 	if (!ops)
95 		return;
96 
97 	iop = io_pgtable_ops_to_pgtable(ops);
98 	io_pgtable_tlb_flush_all(iop);
99 	io_pgtable_init_table[iop->fmt]->free(iop);
100 }
101 EXPORT_SYMBOL_GPL(free_io_pgtable_ops);
102