6 files changed, 282 insertions, 108 deletions

diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 71291253114f..effef3713c5a 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -7,28 +7,36 @@
 #ifdef CONFIG_EFI
 extern void efi_init(void);
 extern void efi_idmap_init(void);
+extern void efi_virtmap_init(void);
 #else
 #define efi_init()
 #define efi_idmap_init()
+#define efi_virtmap_init()
 #endif
 
 #define efi_call_virt(f, ...)                                           \
 ({                                                                      \
-        efi_##f##_t *__f = efi.systab->runtime->f;                      \
+        efi_##f##_t *__f;                                               \
         efi_status_t __s;                                               \
                                                                         \
         kernel_neon_begin();                                            \
+        efi_virtmap_load();                                             \
+        __f = efi.systab->runtime->f;                                   \
         __s = __f(__VA_ARGS__);                                         \
+        efi_virtmap_unload();                                           \
         kernel_neon_end();                                              \
         __s;                                                            \
 })
 
 #define __efi_call_virt(f, ...)                                         \
 ({                                                                      \
-        efi_##f##_t *__f = efi.systab->runtime->f;                      \
+        efi_##f##_t *__f;                                               \
                                                                         \
         kernel_neon_begin();                                            \
+        efi_virtmap_load();                                             \
+        __f = efi.systab->runtime->f;                                   \
         __f(__VA_ARGS__);                                               \
+        efi_virtmap_unload();                                           \
         kernel_neon_end();                                              \
 })
 
@@ -46,4 +54,26 @@ extern void efi_idmap_init(void);
 
 #define EFI_ALLOC_ALIGN         SZ_64K
 
+/*
+ * On ARM systems, virtually remapped UEFI runtime services are set up in three
+ * distinct stages:
+ * - The stub retrieves the final version of the memory map from UEFI, populates
+ *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
+ *   service to communicate the new mapping to the firmware (Note that the new
+ *   mapping is not live at this time)
+ * - During early boot, the page tables are allocated and populated based on the
+ *   virt_addr fields in the memory map, but only if all descriptors with the
+ *   EFI_MEMORY_RUNTIME attribute have a non-zero value for virt_addr. If this
+ *   succeeds, the EFI_VIRTMAP flag is set to indicate that the virtual mappings
+ *   have been installed successfully.
+ * - During an early initcall(), the UEFI Runtime Services are enabled and the
+ *   EFI_RUNTIME_SERVICES bit set if some conditions are met, i.e., we need a
+ *   non-early mapping of the UEFI system table, and we need to have the virtmap
+ *   installed.
+ */
+#define EFI_VIRTMAP             EFI_ARCH_1
+
+void efi_virtmap_load(void);
+void efi_virtmap_unload(void);
+
 #endif /* _ASM_EFI_H */
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 2bb4347d0edf..755e545144ea 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -11,25 +11,31 @@
  *
  */
 
+#include <linux/atomic.h>
 #include <linux/dmi.h>
 #include <linux/efi.h>
 #include <linux/export.h>
 #include <linux/memblock.h>
+#include <linux/mm_types.h>
 #include <linux/bootmem.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/preempt.h>
+#include <linux/rbtree.h>
+#include <linux/rwsem.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/spinlock.h>
 
 #include <asm/cacheflush.h>
 #include <asm/efi.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
+#include <asm/mmu.h>
+#include <asm/pgtable.h>
 
 struct efi_memory_map memmap;
 
-static efi_runtime_services_t *runtime;
-
 static u64 efi_system_table;
 
 static int uefi_debug __initdata;
@@ -69,9 +75,33 @@ static void __init efi_setup_idmap(void)
         }
 }
 
+/*
+ * Translate a EFI virtual address into a physical address: this is necessary,
+ * as some data members of the EFI system table are virtually remapped after
+ * SetVirtualAddressMap() has been called.
+ */
+static phys_addr_t efi_to_phys(unsigned long addr)
+{
+        efi_memory_desc_t *md;
+
+        for_each_efi_memory_desc(&memmap, md) {
+                if (!(md->attribute & EFI_MEMORY_RUNTIME))
+                        continue;
+                if (md->virt_addr == 0)
+                        /* no virtual mapping has been installed by the stub */
+                        break;
+                if (md->virt_addr <= addr &&
+                    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
+                        return md->phys_addr + addr - md->virt_addr;
+        }
+        return addr;
+}
+
 static int __init uefi_init(void)
 {
         efi_char16_t *c16;
+        void *config_tables;
+        u64 table_size;
         char vendor[100] = "unknown";
         int i, retval;
 
@@ -99,7 +129,7 @@ static int __init uefi_init(void)
                         efi.systab->hdr.revision & 0xffff);
 
         /* Show what we know for posterity */
-        c16 = early_memremap(efi.systab->fw_vendor,
+        c16 = early_memremap(efi_to_phys(efi.systab->fw_vendor),
                              sizeof(vendor));
         if (c16) {
                 for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
@@ -112,8 +142,14 @@ static int __init uefi_init(void)
                 efi.systab->hdr.revision >> 16,
                 efi.systab->hdr.revision & 0xffff, vendor);
 
-        retval = efi_config_init(NULL);
+        table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
+        config_tables = early_memremap(efi_to_phys(efi.systab->tables),
+                                       table_size);
+
+        retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
+                                         sizeof(efi_config_table_64_t), NULL);