Patch "x86/efi: Only map RAM into EFI page tables if in mixed-mode" has been added to the 4.7-stable tree

Patch "x86/efi: Only map RAM into EFI page tables if in mixed-mode" has been added to the 4.7-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    x86/efi: Only map RAM into EFI page tables if in mixed-mode

to the 4.7-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-efi-only-map-ram-into-efi-page-tables-if-in-mixed-mode.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 1297667083d5442aafe3e337b9413bf02b114edb Mon Sep 17 00:00:00 2001
From: Matt Fleming <matt@codeblueprint.co.uk>
Date: Mon, 19 Sep 2016 13:09:09 +0100
Subject: x86/efi: Only map RAM into EFI page tables if in mixed-mode

From: Matt Fleming <matt@codeblueprint.co.uk>

commit 1297667083d5442aafe3e337b9413bf02b114edb upstream.

Waiman reported that booting with CONFIG_EFI_MIXED enabled on his
multi-terabyte HP machine results in boot crashes, because the EFI
region mapping functions loop forever while trying to map those
regions describing RAM.

While this patch doesn't fix the underlying hang, there's really no
reason to map EFI_CONVENTIONAL_MEMORY regions into the EFI page tables
when mixed-mode is not in use at runtime.

Reported-by: Waiman Long <waiman.long@hpe.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
CC: Theodore Ts'o <tytso@mit.edu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Scott J Norton <scott.norton@hpe.com>
Cc: Douglas Hatch <doug.hatch@hpe.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/platform/efi/efi_64.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -244,7 +244,7 @@ int __init efi_setup_page_tables(unsigne
 	 * text and allocate a new stack because we can't rely on the
 	 * stack pointer being < 4GB.
 	 */
-	if (!IS_ENABLED(CONFIG_EFI_MIXED))
+	if (!IS_ENABLED(CONFIG_EFI_MIXED) || efi_is_native())
 		return 0;
 
 	/*


Patches currently in stable-queue which might be from matt@codeblueprint.co.uk are

queue-4.7/x86-efi-only-map-ram-into-efi-page-tables-if-in-mixed-mode.patch