[PATCH 4.14 021/146] x86/mm/64: Make a full PGD-entry size hole in the memory map

Greg Kroah-Hartman
2018-01-01T14:39:58Z

From: Andy Lutomirski <luto@kernel.org>

commit 9f449772a3106bcdd4eb8fdeb281147b0e99fb30 upstream.

Shrink vmalloc space from 16384TiB to 12800TiB to enlarge the hole starting
at 0xff90000000000000 to be a full PGD entry.

A subsequent patch will use this hole for the pagetable isolation LDT
alias.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
Documentation/x86/x86_64/mm.txt | 4 ++--
arch/x86/include/asm/pgtable_64_types.h | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -29,8 +29,8 @@ Virtual memory map with 5 level page tab
hole caused by [56:63] sign extension
ff00000000000000 - ff0fffffffffffff (=52 bits) guard hole, reserved for hypervisor
ff10000000000000 - ff8fffffffffffff (=55 bits) direct mapping of all phys. memory
-ff90000000000000 - ff91ffffffffffff (=49 bits) hole
-ff92000000000000 - ffd1ffffffffffff (=54 bits) vmalloc/ioremap space
+ff90000000000000 - ff9fffffffffffff (=52 bits) hole
+ffa0000000000000 - ffd1ffffffffffff (=54 bits) vmalloc/ioremap space (12800 TB)
ffd2000000000000 - ffd3ffffffffffff (=49 bits) hole
ffd4000000000000 - ffd5ffffffffffff (=49 bits) virtual memory map (512TB)
... unused hole ...
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -79,8 +79,8 @@ typedef struct { pteval_t pte; } pte_t;
#define MAXMEM _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)

#ifdef CONFIG_X86_5LEVEL
-# define VMALLOC_SIZE_TB _AC(16384, UL)
-# define __VMALLOC_BASE _AC(0xff92000000000000, UL)
+# define VMALLOC_SIZE_TB _AC(12800, UL)
+# define __VMALLOC_BASE _AC(0xffa0000000000000, UL)
# define __VMEMMAP_BASE _AC(0xffd4000000000000, UL)
#else
# define VMALLOC_SIZE_TB _AC(32, UL)