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

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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: Kirill 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kirill A. Shutemov 2018-02-14 14:16:50 +03:00 committed by Ingo Molnar
parent 02390b87a9
commit eedb92abb9
7 changed files with 25 additions and 16 deletions
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8
arch/x86/Kconfig
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@ -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

4
arch/x86/include/asm/kaslr.h
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@ -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) { }

4
arch/x86/include/asm/page_64.h
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@ -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;

4
arch/x86/include/asm/page_64_types.h
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@ -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)

4
arch/x86/include/asm/pgtable_64_types.h
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@ -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))

9
arch/x86/kernel/head64.c
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@ -39,6 +39,15 @@ extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
static unsigned int __initdata next_early_pgt;
pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
#ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE;
EXPORT_SYMBOL(page_offset_base);
unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE;
EXPORT_SYMBOL(vmalloc_base);
unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE;
EXPORT_SYMBOL(vmemmap_base);
#endif
#define __head __section(.head.text)
static void __head *fixup_pointer(void *ptr, unsigned long physaddr)

8
arch/x86/mm/kaslr.c
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@ -43,14 +43,6 @@
static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
static const unsigned long vaddr_end = CPU_ENTRY_AREA_BASE;
/* Default values */
unsigned long page_offset_base = __PAGE_OFFSET_BASE;
EXPORT_SYMBOL(page_offset_base);
unsigned long vmalloc_base = __VMALLOC_BASE;
EXPORT_SYMBOL(vmalloc_base);
unsigned long vmemmap_base = __VMEMMAP_BASE;
EXPORT_SYMBOL(vmemmap_base);
/*
* Memory regions randomized by KASLR (except modules that use a separate logic
* earlier during boot). The list is ordered based on virtual addresses. This