x86/mm/64: Make a full PGD-entry size hole in the memory map

amluto · Ingo Molnar · commit 9f449772a310 · 2017-12-23T21:13:00.000+01:00
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 &lt;luto@kernel.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Brian Gerst &lt;brgerst@gmail.com&gt;
Cc: Dave Hansen &lt;dave.hansen@intel.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: David Laight &lt;David.Laight@aculab.com&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Juergen Gross &lt;jgross@suse.com&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Kirill A. Shutemov &lt;kirill@shutemov.name&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
diff --git 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 tables:
 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 ...
diff --git 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)
