From 6f9dd329717f696f578347c0781a0247db957596 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 14 Feb 2018 21:25:39 +0300 Subject: x86/mm: Support boot-time switching of paging modes in the early boot code Early boot code should be able to initialize page tables for both 4- and 5-level paging modes. Signed-off-by: Kirill A. Shutemov Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: David Woodhouse Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180214182542.69302-7-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/head_64.S | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'arch/x86/kernel/head_64.S') diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index d3f8b43d541a..145d7b95ae29 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -124,7 +124,10 @@ ENTRY(secondary_startup_64) /* Enable PAE mode, PGE and LA57 */ movl $(X86_CR4_PAE | X86_CR4_PGE), %ecx #ifdef CONFIG_X86_5LEVEL + testl $1, pgtable_l5_enabled(%rip) + jz 1f orl $X86_CR4_LA57, %ecx +1: #endif movq %rcx, %cr4 @@ -372,12 +375,7 @@ GLOBAL(name) __INITDATA NEXT_PGD_PAGE(early_top_pgt) - .fill 511,8,0 -#ifdef CONFIG_X86_5LEVEL - .quad level4_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC -#else - .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC -#endif + .fill 512,8,0 .fill PTI_USER_PGD_FILL,8,0 NEXT_PAGE(early_dynamic_pgts) -- cgit v1.2.3