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Subject[PATCHv7 07/19] x86/mm: Make virtual memory layout movable for CONFIG_X86_5LEVEL
Date
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>
---
arch/x86/include/asm/kaslr.h | 4 ----
arch/x86/include/asm/page_64.h | 4 ++++
arch/x86/include/asm/page_64_types.h | 2 +-
arch/x86/include/asm/pgtable_64_types.h | 2 +-
arch/x86/kernel/head64.c | 9 +++++++++
arch/x86/mm/kaslr.c | 8 --------
6 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h
index 1052a797d71d..683c9d736314 100644
--- a/arch/x86/include/asm/kaslr.h
+++ b/arch/x86/include/asm/kaslr.h
@@ -4,10 +4,6 @@
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) { }
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index b50df06ad251..153496926ffe 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -10,6 +10,10 @@
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;
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 3f5f08b010d0..0126d6bc2eb1 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -42,7 +42,7 @@
#define __PAGE_OFFSET_BASE _AC(0xffff880000000000, UL)
#endif

-#ifdef CONFIG_RANDOMIZE_MEMORY
+#if defined(CONFIG_RANDOMIZE_MEMORY) || defined(CONFIG_X86_5LEVEL)
#define __PAGE_OFFSET page_offset_base
#else
#define __PAGE_OFFSET __PAGE_OFFSET_BASE
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 06470da156ba..a9f77ead7088 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -85,7 +85,7 @@ typedef struct { pteval_t pte; } pte_t;
#define __VMALLOC_BASE _AC(0xffffc90000000000, UL)
#define __VMEMMAP_BASE _AC(0xffffea0000000000, UL)
#endif
-#ifdef CONFIG_RANDOMIZE_MEMORY
+#if defined(CONFIG_RANDOMIZE_MEMORY) || defined(CONFIG_X86_5LEVEL)
#define VMALLOC_START vmalloc_base
#define VMEMMAP_START vmemmap_base
#else
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index bab4fa579450..d7b683cc0dd5 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -38,6 +38,15 @@ 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);

+#if defined(CONFIG_RANDOMIZE_MEMORY) || defined(CONFIG_X86_5LEVEL)
+unsigned long page_offset_base __read_mostly = __PAGE_OFFSET_BASE;
+EXPORT_SYMBOL(page_offset_base);
+unsigned long vmalloc_base __read_mostly = __VMALLOC_BASE;
+EXPORT_SYMBOL(vmalloc_base);
+unsigned long vmemmap_base __read_mostly = __VMEMMAP_BASE;
+EXPORT_SYMBOL(vmemmap_base);
+#endif
+
#define __head __section(.head.text)

static void __head *fixup_pointer(void *ptr, unsigned long physaddr)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index af599167fe3c..e6420b18f6e0 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -53,14 +53,6 @@ static const unsigned long vaddr_end = EFI_VA_END;
static const unsigned long vaddr_end = __START_KERNEL_map;
#endif

-/* 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
--
2.14.1
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