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path: root/drivers/firmware/efi/arm-runtime.c
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Diffstat (limited to 'drivers/firmware/efi/arm-runtime.c')
-rw-r--r--drivers/firmware/efi/arm-runtime.c135
1 files changed, 135 insertions, 0 deletions
diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
new file mode 100644
index 000000000..6ae21e41a
--- /dev/null
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -0,0 +1,135 @@
+/*
+ * Extensible Firmware Interface
+ *
+ * Based on Extensible Firmware Interface Specification version 2.4
+ *
+ * Copyright (C) 2013, 2014 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/efi.h>
+#include <linux/io.h>
+#include <linux/memblock.h>
+#include <linux/mm_types.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/mmu.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+
+extern u64 efi_system_table;
+
+static struct mm_struct efi_mm = {
+ .mm_rb = RB_ROOT,
+ .mm_users = ATOMIC_INIT(2),
+ .mm_count = ATOMIC_INIT(1),
+ .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
+ .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
+ .mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
+};
+
+static bool __init efi_virtmap_init(void)
+{
+ efi_memory_desc_t *md;
+
+ efi_mm.pgd = pgd_alloc(&efi_mm);
+ init_new_context(NULL, &efi_mm);
+
+ for_each_efi_memory_desc(&memmap, md) {
+ phys_addr_t phys = md->phys_addr;
+ int ret;
+
+ if (!(md->attribute & EFI_MEMORY_RUNTIME))
+ continue;
+ if (md->virt_addr == 0)
+ return false;
+
+ ret = efi_create_mapping(&efi_mm, md);
+ if (!ret) {
+ pr_info(" EFI remap %pa => %p\n",
+ &phys, (void *)(unsigned long)md->virt_addr);
+ } else {
+ pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",
+ &phys, ret);
+ return false;
+ }
+ }
+ return true;
+}
+
+/*
+ * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
+ * non-early mapping of the UEFI system table and virtual mappings for all
+ * EFI_MEMORY_RUNTIME regions.
+ */
+static int __init arm_enable_runtime_services(void)
+{
+ u64 mapsize;
+
+ if (!efi_enabled(EFI_BOOT)) {
+ pr_info("EFI services will not be available.\n");
+ return 0;
+ }
+
+ if (efi_runtime_disabled()) {
+ pr_info("EFI runtime services will be disabled.\n");
+ return 0;
+ }
+
+ pr_info("Remapping and enabling EFI services.\n");
+
+ mapsize = memmap.map_end - memmap.map;
+ memmap.map = (__force void *)ioremap_cache(memmap.phys_map,
+ mapsize);
+ if (!memmap.map) {
+ pr_err("Failed to remap EFI memory map\n");
+ return -ENOMEM;
+ }
+ memmap.map_end = memmap.map + mapsize;
+ efi.memmap = &memmap;
+
+ efi.systab = (__force void *)ioremap_cache(efi_system_table,
+ sizeof(efi_system_table_t));
+ if (!efi.systab) {
+ pr_err("Failed to remap EFI System Table\n");
+ return -ENOMEM;
+ }
+ set_bit(EFI_SYSTEM_TABLES, &efi.flags);
+
+ if (!efi_virtmap_init()) {
+ pr_err("No UEFI virtual mapping was installed -- runtime services will not be available\n");
+ return -ENOMEM;
+ }
+
+ /* Set up runtime services function pointers */
+ efi_native_runtime_setup();
+ set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+
+ efi.runtime_version = efi.systab->hdr.revision;
+
+ return 0;
+}
+early_initcall(arm_enable_runtime_services);
+
+void efi_virtmap_load(void)
+{
+ preempt_disable();
+ efi_set_pgd(&efi_mm);
+}
+
+void efi_virtmap_unload(void)
+{
+ efi_set_pgd(current->active_mm);
+ preempt_enable();
+}