1 files changed, 39 insertions, 12 deletions

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 249eb70691b0..415849bab233 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -592,7 +592,11 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz,
 
 		early_memunmap(tbl, sizeof(*tbl));
 	}
+	return 0;
+}
 
+int __init efi_apply_persistent_mem_reservations(void)
+{
 	if (efi.mem_reserve != EFI_INVALID_TABLE_ADDR) {
 		unsigned long prsv = efi.mem_reserve;
 
@@ -963,36 +967,59 @@ bool efi_is_table_address(unsigned long phys_addr)
 }
 
 static DEFINE_SPINLOCK(efi_mem_reserve_persistent_lock);
+static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init;
 
-int efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
+static int __init efi_memreserve_map_root(void)
 {
-	struct linux_efi_memreserve *rsv, *parent;
-
 	if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR)
 		return -ENODEV;
 
-	rsv = kmalloc(sizeof(*rsv), GFP_KERNEL);
-	if (!rsv)
+	efi_memreserve_root = memremap(efi.mem_reserve,
+				       sizeof(*efi_memreserve_root),
+				       MEMREMAP_WB);
+	if (WARN_ON_ONCE(!efi_memreserve_root))
 		return -ENOMEM;
+	return 0;
+}
 
-	parent = memremap(efi.mem_reserve, sizeof(*rsv), MEMREMAP_WB);
-	if (!parent) {
-		kfree(rsv);
-		return -ENOMEM;
+int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
+{
+	struct linux_efi_memreserve *rsv;
+	int rc;
+
+	if (efi_memreserve_root == (void *)ULONG_MAX)
+		return -ENODEV;
+
+	if (!efi_memreserve_root) {
+		rc = efi_memreserve_map_root();
+		if (rc)
+			return rc;
 	}
 
+	rsv = kmalloc(sizeof(*rsv), GFP_ATOMIC);
+	if (!rsv)
+		return -ENOMEM;
+
 	rsv->base = addr;
 	rsv->size = size;
 
 	spin_lock(&efi_mem_reserve_persistent_lock);
-	rsv->next = parent->next;
-	parent->next = __pa(rsv);
+	rsv->next = efi_memreserve_root->next;
+	efi_memreserve_root->next = __pa(rsv);
 	spin_unlock(&efi_mem_reserve_persistent_lock);
 
-	memunmap(parent);
+	return 0;
+}
 
+static int __init efi_memreserve_root_init(void)
+{
+	if (efi_memreserve_root)
+		return 0;
+	if (efi_memreserve_map_root())
+		efi_memreserve_root = (void *)ULONG_MAX;
 	return 0;
 }
+early_initcall(efi_memreserve_root_init);
 
 #ifdef CONFIG_KEXEC
 static int update_efi_random_seed(struct notifier_block *nb,