Messages in this thread Patch in this message | | | From | Matt Fleming <> | Subject | [PATCH v3 6/6] Documentation/x86: Update EFI memory region description | Date | Mon, 23 Nov 2015 13:33:14 +0000 |
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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.
Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Denys Vlasenko <dvlasenk@redhat.com>, Cc: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> ---
Changes in v3: - Make it clear that we use a 64GB chunk of virtual address space, not the first 64Gb addresses.
Documentation/x86/x86_64/mm.txt | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
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 -- 2.6.2
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