Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 EFI changes from Ingo Molnar:
 "Two fixes that should in principle increase robustness of our
  interaction with the EFI firmware, and a cleanup"

* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, efi: retry ExitBootServices() on failure
  efi: Convert runtime services function ptrs
  UEFI: Don't pass boot services regions to SetVirtualAddressMap()

1 files changed, 17 insertions, 3 deletions

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index c205035a6b96..d606463aa6d6 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -992,18 +992,20 @@ static efi_status_t exit_boot(struct boot_params *boot_params,
 	efi_memory_desc_t *mem_map;
 	efi_status_t status;
 	__u32 desc_version;
+	bool called_exit = false;
 	u8 nr_entries;
 	int i;
 
 	size = sizeof(*mem_map) * 32;
 
 again:
-	size += sizeof(*mem_map);
+	size += sizeof(*mem_map) * 2;
 	_size = size;
 	status = low_alloc(size, 1, (unsigned long *)&mem_map);
 	if (status != EFI_SUCCESS)
 		return status;
 
+get_map:
 	status = efi_call_phys5(sys_table->boottime->get_memory_map, &size,
 				mem_map, &key, &desc_size, &desc_version);
 	if (status == EFI_BUFFER_TOO_SMALL) {
@@ -1029,8 +1031,20 @@ again:
 	/* Might as well exit boot services now */
 	status = efi_call_phys2(sys_table->boottime->exit_boot_services,
 				handle, key);
-	if (status != EFI_SUCCESS)
-		goto free_mem_map;
+	if (status != EFI_SUCCESS) {
+		/*
+		 * ExitBootServices() will fail if any of the event
+		 * handlers change the memory map. In which case, we
+		 * must be prepared to retry, but only once so that
+		 * we're guaranteed to exit on repeated failures instead
+		 * of spinning forever.
+		 */
+		if (called_exit)
+			goto free_mem_map;
+
+		called_exit = true;
+		goto get_map;
+	}
 
 	/* Historic? */
 	boot_params->alt_mem_k = 32 * 1024;