From 4c2b4058ab32581931c2caf760b689fd4b019a87 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 14 Feb 2018 21:25:34 +0300 Subject: x86/mm: Initialize 'pgtable_l5_enabled' at boot-time 'pgtable_l5_enabled' indicates which paging mode we are using. We need to initialize it at boot-time according to machine capability. 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/20180214182542.69302-2-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/kaslr.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/x86/boot') diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index b18e8f9..d02a838 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -47,7 +47,7 @@ #include #ifdef CONFIG_X86_5LEVEL -unsigned int pgtable_l5_enabled __ro_after_init = 1; +unsigned int pgtable_l5_enabled __ro_after_init; unsigned int pgdir_shift __ro_after_init = 48; unsigned int ptrs_per_p4d __ro_after_init = 512; #endif @@ -729,6 +729,12 @@ void choose_random_location(unsigned long input, return; } +#ifdef CONFIG_X86_5LEVEL + if (__read_cr4() & X86_CR4_LA57) { + pgtable_l5_enabled = 1; + } +#endif + boot_params->hdr.loadflags |= KASLR_FLAG; /* Prepare to add new identity pagetables on demand. */ -- cgit v1.1