From ff3d0a12fb2dc123e2b46e9524ebf4e08de5c59c Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 27 Nov 2015 21:09:35 +0000 Subject: Documentation/x86: Update EFI memory region description Make it clear that the EFI page tables are only available during EFI runtime calls since that subject has come up a fair numbers of times in the past. Additionally, add the EFI region start and end addresses to the table so that it's possible to see at a glance where they fall in relation to other regions. Signed-off-by: Matt Fleming Reviewed-by: Borislav Petkov Acked-by: Borislav Petkov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Jones Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Sai Praneeth Prakhya Cc: Stephen Smalley Cc: Thomas Gleixner Cc: Toshi Kani Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1448658575-17029-7-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar --- Documentation/x86/x86_64/mm.txt | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'Documentation/x86') diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt index 05712ac83e38..c518dce7da4d 100644 --- a/Documentation/x86/x86_64/mm.txt +++ b/Documentation/x86/x86_64/mm.txt @@ -16,6 +16,8 @@ ffffec0000000000 - fffffc0000000000 (=44 bits) kasan shadow memory (16TB) ... unused hole ... ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks ... unused hole ... +ffffffef00000000 - ffffffff00000000 (=64 GB) EFI region mapping space +... unused hole ... ffffffff80000000 - ffffffffa0000000 (=512 MB) kernel text mapping, from phys 0 ffffffffa0000000 - ffffffffff5fffff (=1525 MB) module mapping space ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls @@ -32,11 +34,9 @@ reference. Current X86-64 implementations only support 40 bits of address space, but we support up to 46 bits. This expands into MBZ space in the page tables. -->trampoline_pgd: - -We map EFI runtime services in the aforementioned PGD in the virtual -range of 64Gb (arbitrarily set, can be raised if needed) - -0xffffffef00000000 - 0xffffffff00000000 +We map EFI runtime services in the 'efi_pgd' PGD in a 64Gb large virtual +memory window (this size is arbitrary, it can be raised later if needed). +The mappings are not part of any other kernel PGD and are only available +during EFI runtime calls. -Andi Kleen, Jul 2004 -- cgit v1.2.1