drivers/iommu/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 <[email protected]>
   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);