arch/arm64/mm/ioremap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 #include <linux/mm.h>
   4 #include <linux/io.h>
   5
   6 static ioremap_prot_hook_t ioremap_prot_hook;
   7
   8 int arm64_ioremap_prot_hook_register(ioremap_prot_hook_t hook)
   9 {
  10         if (WARN_ON(ioremap_prot_hook))
  11                 return -EBUSY;
  12
  13         ioremap_prot_hook = hook;
  14         return 0;
  15 }
  16
  17 void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
  18                            unsigned long prot)
  19 {
  20         unsigned long last_addr = phys_addr + size - 1;
  21         pgprot_t pgprot = __pgprot(prot);
  22
  23         /* Don't allow outside PHYS_MASK */
  24         if (last_addr & ~PHYS_MASK)
  25                 return NULL;
  26
  27         /* Don't allow RAM to be mapped. */
  28         if (WARN_ON(pfn_is_map_memory(__phys_to_pfn(phys_addr))))
  29                 return NULL;
  30
  31         /*
  32          * If a hook is registered (e.g. for confidential computing
  33          * purposes), call that now and barf if it fails.
  34          */
  35         if (unlikely(ioremap_prot_hook) &&
  36             WARN_ON(ioremap_prot_hook(phys_addr, size, &pgprot))) {
  37                 return NULL;
  38         }
  39
  40         return generic_ioremap_prot(phys_addr, size, pgprot);
  41 }
  42 EXPORT_SYMBOL(ioremap_prot);
  43
  44 /*
  45  * Must be called after early_fixmap_init
  46  */
  47 void __init early_ioremap_init(void)
  48 {
  49         early_ioremap_setup();
  50 }
  51
  52 bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
  53                                  unsigned long flags)
  54 {
  55         unsigned long pfn = PHYS_PFN(offset);
  56
  57         return pfn_is_map_memory(pfn);
  58 }