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-rw-r--r--arch/arm64/kernel/acpi.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index a7586a4db142..455966401102 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -261,6 +261,81 @@ pgprot_t __acpi_get_mem_attribute(phys_addr_t addr)
return __pgprot(PROT_DEVICE_nGnRnE);
}
+void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size)
+{
+ efi_memory_desc_t *md, *region = NULL;
+ pgprot_t prot;
+
+ if (WARN_ON_ONCE(!efi_enabled(EFI_MEMMAP)))
+ return NULL;
+
+ for_each_efi_memory_desc(md) {
+ u64 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
+
+ if (phys < md->phys_addr || phys >= end)
+ continue;
+
+ if (phys + size > end) {
+ pr_warn(FW_BUG "requested region covers multiple EFI memory regions\n");
+ return NULL;
+ }
+ region = md;
+ break;
+ }
+
+ /*
+ * It is fine for AML to remap regions that are not represented in the
+ * EFI memory map at all, as it only describes normal memory, and MMIO
+ * regions that require a virtual mapping to make them accessible to
+ * the EFI runtime services.
+ */
+ prot = __pgprot(PROT_DEVICE_nGnRnE);
+ if (region) {
+ switch (region->type) {
+ case EFI_LOADER_CODE:
+ case EFI_LOADER_DATA:
+ case EFI_BOOT_SERVICES_CODE:
+ case EFI_BOOT_SERVICES_DATA:
+ case EFI_CONVENTIONAL_MEMORY:
+ case EFI_PERSISTENT_MEMORY:
+ pr_warn(FW_BUG "requested region covers kernel memory @ %pa\n", &phys);
+ return NULL;
+
+ case EFI_RUNTIME_SERVICES_CODE:
+ /*
+ * This would be unusual, but not problematic per se,
+ * as long as we take care not to create a writable
+ * mapping for executable code.
+ */
+ prot = PAGE_KERNEL_RO;
+ break;
+
+ case EFI_ACPI_RECLAIM_MEMORY:
+ /*
+ * ACPI reclaim memory is used to pass firmware tables
+ * and other data that is intended for consumption by
+ * the OS only, which may decide it wants to reclaim
+ * that memory and use it for something else. We never
+ * do that, but we usually add it to the linear map
+ * anyway, in which case we should use the existing
+ * mapping.
+ */
+ if (memblock_is_map_memory(phys))
+ return (void __iomem *)__phys_to_virt(phys);
+ /* fall through */
+
+ default:
+ if (region->attribute & EFI_MEMORY_WB)
+ prot = PAGE_KERNEL;
+ else if (region->attribute & EFI_MEMORY_WT)
+ prot = __pgprot(PROT_NORMAL_WT);
+ else if (region->attribute & EFI_MEMORY_WC)
+ prot = __pgprot(PROT_NORMAL_NC);
+ }
+ }
+ return __ioremap(phys, size, prot);
+}
+
/*
* Claim Synchronous External Aborts as a firmware first notification.
*