[GIT PULL] EFI fixes

[Ingo Molnar <mingo@xxxxxxxxxx>]

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: 88447c5b93d98be847f428c39ba589779a59eb83 efi: Allow the number of EFI configuration tables entries to be zero

Two EFI fixes: a quirk for weird systabs, plus add more robust error 
handling in the old 1:1 mapping code.

 Thanks,

	Ingo

------------------>
Gen Zhang (1):
      efi/x86/Add missing error handling to old_memmap 1:1 mapping code

Rob Bradford (1):
      efi: Allow the number of EFI configuration tables entries to be zero


 arch/x86/platform/efi/efi.c    | 2 ++
 arch/x86/platform/efi/efi_64.c | 9 ++++++---
 arch/x86/platform/efi/quirks.c | 3 +++
 drivers/firmware/efi/efi.c     | 3 +++
 4 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index e1cb01a22fa8..a7189a3b4d70 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -85,6 +85,8 @@ static efi_status_t __init phys_efi_set_virtual_address_map(
 	pgd_t *save_pgd;
 
 	save_pgd = efi_call_phys_prolog();
+	if (!save_pgd)
+		return EFI_ABORTED;
 
 	/* Disable interrupts around EFI calls: */
 	local_irq_save(flags);
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index cf0347f61b21..08ce8177c3af 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -84,13 +84,15 @@ pgd_t * __init efi_call_phys_prolog(void)
 
 	if (!efi_enabled(EFI_OLD_MEMMAP)) {
 		efi_switch_mm(&efi_mm);
-		return NULL;
+		return efi_mm.pgd;
 	}
 
 	early_code_mapping_set_exec(1);
 
 	n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
 	save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL);
+	if (!save_pgd)
+		return NULL;
 
 	/*
 	 * Build 1:1 identity mapping for efi=old_map usage. Note that
@@ -138,10 +140,11 @@ pgd_t * __init efi_call_phys_prolog(void)
 		pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX;
 	}
 
-out:
 	__flush_tlb_all();
-
 	return save_pgd;
+out:
+	efi_call_phys_epilog(save_pgd);
+	return NULL;
 }
 
 void __init efi_call_phys_epilog(pgd_t *save_pgd)
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index feb77777c8b8..632b83885867 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -513,6 +513,9 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
 	void *p, *tablep;
 	struct efi_setup_data *data;
 
+	if (nr_tables == 0)
+		return 0;
+
 	if (!efi_setup)
 		return 0;
 
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 55b77c576c42..521a541d02ad 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -636,6 +636,9 @@ int __init efi_config_init(efi_config_table_type_t *arch_tables)
 	void *config_tables;
 	int sz, ret;
 
+	if (efi.systab->nr_tables == 0)
+		return 0;
+
 	if (efi_enabled(EFI_64BIT))
 		sz = sizeof(efi_config_table_64_t);
 	else