x86/mm/64: Always use dynamic memory layout

Dynamic memory layout is used by KASLR and 5-level paging.

CONFIG_X86_5LEVEL is going to be removed, making 5-level paging support
unconditional which requires unconditional support of dynamic memory
layout.

Remove CONFIG_DYNAMIC_MEMORY_LAYOUT.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250516123306.3812286-2-kirill.shutemov@linux.intel.com

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 90570e3582ccfbc7df8b849bea2c265ef423c4fd..22c60be0eb372fce204455ff576f9bbd1c7f754b 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1467,7 +1467,6 @@ config X86_PAE
 config X86_5LEVEL
        bool "Enable 5-level page tables support"
        default y
-       select DYNAMIC_MEMORY_LAYOUT
        select SPARSEMEM_VMEMMAP
        depends on X86_64
        help
@@ -2168,17 +2167,10 @@ 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

diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 1faa8f88850ab5ab7f445d05b32290ec2984f47f..6b8c8169c71d662c3df63aea3d9bd83abb642019 100644 (file)
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -41,11 +41,7 @@
 #define __PAGE_OFFSET_BASE_L5  _AC(0xff11000000000000, UL)
 #define __PAGE_OFFSET_BASE_L4  _AC(0xffff888000000000, UL)
 
-#ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
 #define __PAGE_OFFSET           page_offset_base
-#else
-#define __PAGE_OFFSET           __PAGE_OFFSET_BASE_L4
-#endif /* CONFIG_DYNAMIC_MEMORY_LAYOUT */
 
 #define __START_KERNEL_map     _AC(0xffffffff80000000, UL)
 

diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index e83721db18c9200b5d53b88ee4158a347f422229..eee06f77b2456639e79e01a93a0719512f8e9df7 100644 (file)
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -128,15 +128,9 @@ extern unsigned int ptrs_per_p4d;
 #define __VMEMMAP_BASE_L4      0xffffea0000000000UL
 #define __VMEMMAP_BASE_L5      0xffd4000000000000UL
 
-#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_L4
-# define VMALLOC_SIZE_TB       VMALLOC_SIZE_TB_L4
-# define VMEMMAP_START         __VMEMMAP_BASE_L4
-#endif /* CONFIG_DYNAMIC_MEMORY_LAYOUT */
 
 #ifdef CONFIG_RANDOMIZE_MEMORY
 # define DIRECT_MAP_PHYSMEM_END        direct_map_physmem_end

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 14f7dda20954b6719af54ce5d7174e196478a0f5..9f617be64fa9fa6247027c4d84056a0a492dee0f 100644 (file)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -59,14 +59,12 @@ unsigned int ptrs_per_p4d __ro_after_init = 1;
 EXPORT_SYMBOL(ptrs_per_p4d);
 #endif
 
-#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_L4;
 EXPORT_SYMBOL(vmalloc_base);
 unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4;
 EXPORT_SYMBOL(vmemmap_base);
-#endif
 
 /* Wipe all early page tables except for the kernel symbol map */
 static void __init reset_early_page_tables(void)

diff --git a/scripts/gdb/linux/pgtable.py b/scripts/gdb/linux/pgtable.py
index 30d837f3dfae1f5a9e76e6c3230a7d70b89b5c7d..09aac2421fb848cf5eab32a75b59540c65bdd84f 100644 (file)
--- a/scripts/gdb/linux/pgtable.py
+++ b/scripts/gdb/linux/pgtable.py
@@ -29,11 +29,9 @@ def page_mask(level=1):
         raise Exception(f'Unknown page level: {level}')
 
 
-#page_offset_base in case CONFIG_DYNAMIC_MEMORY_LAYOUT is disabled
-POB_NO_DYNAMIC_MEM_LAYOUT = '0xffff888000000000'
 def _page_offset_base():
     pob_symbol = gdb.lookup_global_symbol('page_offset_base')
-    pob = pob_symbol.name if pob_symbol else POB_NO_DYNAMIC_MEM_LAYOUT
+    pob = pob_symbol.name
     return gdb.parse_and_eval(pob)