From c65e774fb3f6af212641538694b9778ff9ab4300 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 14 Feb 2018 14:16:53 +0300 Subject: x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable For boot-time switching between 4- and 5-level paging we need to be able to fold p4d page table level at runtime. It requires variable PGDIR_SHIFT and PTRS_PER_P4D. The change doesn't affect the kernel image size much: text data bss dec hex filename 8628091 4734304 1368064 14730459 e0c4db vmlinux.before 8628393 4734340 1368064 14730797 e0c62d vmlinux.after Signed-off-by: Kirill A. Shutemov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180214111656.88514-7-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/kaslr.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/boot/compressed/kaslr.c') diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index bd69e1830fbe..b18e8f9512de 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -48,6 +48,8 @@ #ifdef CONFIG_X86_5LEVEL unsigned int pgtable_l5_enabled __ro_after_init = 1; +unsigned int pgdir_shift __ro_after_init = 48; +unsigned int ptrs_per_p4d __ro_after_init = 512; #endif extern unsigned long get_cmd_line_ptr(void); -- cgit