[GIT PULL] EFI fix

[Ingo Molnar]

Linus,

Please pull the latest efi-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 
efi-urgent-for-linus

   # HEAD: 976b489120cdab2b1b3a41ffa14661db43d58190 efi: Prevent GICv3 WARN() 
by mapping the memreserve table before first use

An arm64 warning fix.

 Thanks,

        Ingo

------------------>
Ard Biesheuvel (1):
      efi: Prevent GICv3 WARN() by mapping the memreserve table before first use


 drivers/firmware/efi/efi.c | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index fad7c62cfc0e..415849bab233 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -969,13 +969,33 @@ 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)
+{
+       if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR)
+               return -ENODEV;
+
+       efi_memreserve_root = memremap(efi.mem_reserve,
+                                      sizeof(*efi_memreserve_root),
+                                      MEMREMAP_WB);
+       if (WARN_ON_ONCE(!efi_memreserve_root))
+               return -ENOMEM;
+       return 0;
+}
+
+int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
 {
        struct linux_efi_memreserve *rsv;
+       int rc;
 
-       if (!efi_memreserve_root)
+       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;
@@ -993,14 +1013,10 @@ int efi_mem_reserve_persistent(phys_addr_t addr, u64 
size)
 
 static int __init efi_memreserve_root_init(void)
 {
-       if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR)
-               return -ENODEV;
-
-       efi_memreserve_root = memremap(efi.mem_reserve,
-                                      sizeof(*efi_memreserve_root),
-                                      MEMREMAP_WB);
-       if (!efi_memreserve_root)
-               return -ENOMEM;
+       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);