Commit eedb92ab authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Ingo Molnar
Browse files

x86/mm: Make virtual memory layout dynamic for CONFIG_X86_5LEVEL=y 



We need to be able to adjust virtual memory layout at runtime to be able
to switch between 4- and 5-level paging at boot-time.

KASLR already has movable __VMALLOC_BASE, __VMEMMAP_BASE and __PAGE_OFFSET.
Let's re-use it.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180214111656.88514-4-kirill.shutemov@linux.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 02390b87

arch/x86/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -1430,6 +1430,7 @@ config X86_PAE 


config X86_5LEVEL

	bool "Enable 5-level page tables support"

	select DYNAMIC_MEMORY_LAYOUT

	depends on X86_64

	---help---

	  5-level paging enables access to larger address space:
@@ -2143,10 +2144,17 @@ config PHYSICAL_ALIGN 


	  Don't change this unless you know what you are doing.



config DYNAMIC_MEMORY_LAYOUT

	bool

	---help---

	  This option makes base addresses of vmalloc and vmemmap as well as

	  __PAGE_OFFSET movable during boot.



config RANDOMIZE_MEMORY

	bool "Randomize the kernel memory sections"

	depends on X86_64

	depends on RANDOMIZE_BASE

	select DYNAMIC_MEMORY_LAYOUT

	default RANDOMIZE_BASE

	---help---

	   Randomizes the base virtual address of kernel memory sections

arch/x86/include/asm/kaslr.h

+0 −4
Original line number Diff line number Diff line
@@ -5,10 +5,6 @@ 
unsigned long kaslr_get_random_long(const char *purpose);



#ifdef CONFIG_RANDOMIZE_MEMORY

extern unsigned long page_offset_base;

extern unsigned long vmalloc_base;

extern unsigned long vmemmap_base;



void kernel_randomize_memory(void);

#else

static inline void kernel_randomize_memory(void) { }

arch/x86/include/asm/page_64.h

+4 −0
Original line number Diff line number Diff line
@@ -11,6 +11,10 @@ 
extern unsigned long max_pfn;

extern unsigned long phys_base;



extern unsigned long page_offset_base;

extern unsigned long vmalloc_base;

extern unsigned long vmemmap_base;



static inline unsigned long __phys_addr_nodebug(unsigned long x)

{

	unsigned long y = x - __START_KERNEL_map;

arch/x86/include/asm/page_64_types.h

+2 −2
Original line number Diff line number Diff line
@@ -43,11 +43,11 @@ 
#define __PAGE_OFFSET_BASE      _AC(0xffff880000000000, UL)

#endif



#ifdef CONFIG_RANDOMIZE_MEMORY

#ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT

#define __PAGE_OFFSET           page_offset_base

#else

#define __PAGE_OFFSET           __PAGE_OFFSET_BASE

#endif /* CONFIG_RANDOMIZE_MEMORY */

#endif /* CONFIG_DYNAMIC_MEMORY_LAYOUT */



#define __START_KERNEL_map	_AC(0xffffffff80000000, UL)

arch/x86/include/asm/pgtable_64_types.h

+2 −2
Original line number Diff line number Diff line
@@ -100,13 +100,13 @@ typedef struct { pteval_t pte; } pte_t; 
# define LDT_BASE_ADDR		(LDT_PGD_ENTRY << PGDIR_SHIFT)

#endif



#ifdef CONFIG_RANDOMIZE_MEMORY

#ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT

# define VMALLOC_START		vmalloc_base

# define VMEMMAP_START		vmemmap_base

#else

# define VMALLOC_START		__VMALLOC_BASE

# define VMEMMAP_START		__VMEMMAP_BASE

#endif /* CONFIG_RANDOMIZE_MEMORY */

#endif /* CONFIG_DYNAMIC_MEMORY_LAYOUT */



#define VMALLOC_END		(VMALLOC_START + _AC((VMALLOC_SIZE_TB << 40) - 1, UL))

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