[PATCH 4/9] x86/mm: Adjust vmalloc base and size at boot-time

From: Kirill A. Shutemov
Date: Wed Feb 14 2018 - 13:29:10 EST


vmalloc area has different placement and size depending on paging mode.
Let's adjust it during early boot accodring to machine capability.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/pgtable_64_types.h | 16 ++++++++++------
arch/x86/kernel/head64.c | 3 ++-
arch/x86/mm/kaslr.c | 3 ++-
3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 59d971c85de5..686329994ade 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -102,25 +102,29 @@ extern unsigned int ptrs_per_p4d;
#define LDT_PGD_ENTRY (pgtable_l5_enabled ? LDT_PGD_ENTRY_L5 : LDT_PGD_ENTRY_L4)
#define LDT_BASE_ADDR (LDT_PGD_ENTRY << PGDIR_SHIFT)

+#define __VMALLOC_BASE_L4 0xffffc90000000000
+#define __VMALLOC_BASE_L5 0xffa0000000000000
+
+#define VMALLOC_SIZE_TB_L4 32UL
+#define VMALLOC_SIZE_TB_L5 12800UL
+
#ifdef CONFIG_X86_5LEVEL
-# 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)
-# define __VMALLOC_BASE _AC(0xffffc90000000000, UL)
# define __VMEMMAP_BASE _AC(0xffffea0000000000, UL)
#endif

#ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
# define VMALLOC_START vmalloc_base
+# define VMALLOC_SIZE_TB (pgtable_l5_enabled ? VMALLOC_SIZE_TB_L5 : VMALLOC_SIZE_TB_L4)
# define VMEMMAP_START vmemmap_base
#else
-# define VMALLOC_START __VMALLOC_BASE
+# define VMALLOC_START __VMALLOC_BASE_L4
+# define VMALLOC_SIZE_TB VMALLOC_SIZE_TB_L4
# define VMEMMAP_START __VMEMMAP_BASE
#endif /* CONFIG_DYNAMIC_MEMORY_LAYOUT */

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

#define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE)
/* The module sections ends with the start of the fixmap */
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 876d3bf2b23a..22bf2015254c 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -51,7 +51,7 @@ EXPORT_SYMBOL(ptrs_per_p4d);
#ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4;
EXPORT_SYMBOL(page_offset_base);
-unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE;
+unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE_L4;
EXPORT_SYMBOL(vmalloc_base);
unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE;
EXPORT_SYMBOL(vmemmap_base);
@@ -87,6 +87,7 @@ static void __head check_la57_support(unsigned long physaddr)
*fixup_int(&pgdir_shift, physaddr) = 48;
*fixup_int(&ptrs_per_p4d, physaddr) = 512;
*fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5;
+ *fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5;
}
#else
static void __head check_la57_support(unsigned long physaddr) {}
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 7828a7ca3bba..641169d38184 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -50,7 +50,7 @@ static __initdata struct kaslr_memory_region {
unsigned long size_tb;
} kaslr_regions[] = {
{ &page_offset_base, 0 },
- { &vmalloc_base, VMALLOC_SIZE_TB },
+ { &vmalloc_base, 0 },
{ &vmemmap_base, 1 },
};

@@ -94,6 +94,7 @@ void __init kernel_randomize_memory(void)
return;

kaslr_regions[0].size_tb = 1 << (__PHYSICAL_MASK_SHIFT - TB_SHIFT);
+ kaslr_regions[1].size_tb = VMALLOC_SIZE_TB;

/*
* Update Physical memory mapping to available and
--
2.15.1