x86/mm: Make LDT_BASE_ADDR dynamic

LDT_BASE_ADDR has different value in 4- and 5-level paging
configurations.

We need to make it dynamic in preparation for boot-time switching
between paging modes.

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/20180214111656.88514-6-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 5e2d724f8f472c4753404365cd90283610e7c4b7..903e4d054bcb22845a24ddb460b96391f5770f34 100644 (file)
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -92,18 +92,19 @@ extern unsigned int pgtable_l5_enabled;
  */
 #define MAXMEM                 _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)
 
+#define LDT_PGD_ENTRY_L4       -3UL
+#define LDT_PGD_ENTRY_L5       -112UL
+#define LDT_PGD_ENTRY          (pgtable_l5_enabled ? LDT_PGD_ENTRY_L5 : LDT_PGD_ENTRY_L4)
+#define LDT_BASE_ADDR          (LDT_PGD_ENTRY << PGDIR_SHIFT)
+
 #ifdef CONFIG_X86_5LEVEL
 # define VMALLOC_SIZE_TB       _AC(12800, UL)
 # define __VMALLOC_BASE                _AC(0xffa0000000000000, UL)
 # define __VMEMMAP_BASE                _AC(0xffd4000000000000, UL)
-# define LDT_PGD_ENTRY         _AC(-112, UL)
-# define LDT_BASE_ADDR         (LDT_PGD_ENTRY << PGDIR_SHIFT)
 #else
 # define VMALLOC_SIZE_TB       _AC(32, UL)
 # define __VMALLOC_BASE                _AC(0xffffc90000000000, UL)
 # define __VMEMMAP_BASE                _AC(0xffffea0000000000, UL)
-# define LDT_PGD_ENTRY         _AC(-3, UL)
-# define LDT_BASE_ADDR         (LDT_PGD_ENTRY << PGDIR_SHIFT)
 #endif
 
 #ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 2a4849e92831b0f9771a2742b01c5a6c9c806a42..a89f2dbc3531acbba3805e42bc1160430af960de 100644 (file)
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -89,7 +89,7 @@ static struct addr_marker address_markers[] = {
        [KASAN_SHADOW_END_NR]   = { KASAN_SHADOW_END,   "KASAN shadow end" },
 #endif
 #ifdef CONFIG_MODIFY_LDT_SYSCALL
-       [LDT_NR]                = { LDT_BASE_ADDR,      "LDT remap" },
+       [LDT_NR]                = { 0UL,                "LDT remap" },
 #endif
        [CPU_ENTRY_AREA_NR]     = { CPU_ENTRY_AREA_BASE,"CPU entry Area" },
 #ifdef CONFIG_X86_ESPFIX64
@@ -570,6 +570,9 @@ static int __init pt_dump_init(void)
        address_markers[LOW_KERNEL_NR].start_address = PAGE_OFFSET;
        address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
        address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START;
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
+       address_markers[LDT_NR].start_address = LDT_BASE_ADDR;
+#endif
 #endif
 #ifdef CONFIG_X86_32
        address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;