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#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
 37static 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
 57struct 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}
 84EXPORT_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 */
 90void 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}
101EXPORT_SYMBOL_GPL(free_io_pgtable_ops);