Commit-ID: b16e770bfa5344f1cd4f7b4ecd7bbae25001e120 Gitweb: https://git.kernel.org/tip/b16e770bfa5344f1cd4f7b4ecd7bbae25001e120 Author: Kirill A. Shutemov <[email protected]> AuthorDate: Wed, 14 Feb 2018 21:25:35 +0300 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 16 Feb 2018 10:48:47 +0100
x86/mm: Initialize 'pgdir_shift' and 'ptrs_per_p4d' at boot-time Switching between paging modes requires the folding of the p4d page table level when we only have 4 paging levels, which means we need to adjust 'pgdir_shift' and 'ptrs_per_p4d' during early boot according to paging mode. Signed-off-by: Kirill A. Shutemov <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Arjan van de Ven <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dan Williams <[email protected]> Cc: Dave Hansen <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/boot/compressed/kaslr.c | 6 ++++-- arch/x86/kernel/head64.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index d02a838..66e42a0 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -48,8 +48,8 @@ #ifdef CONFIG_X86_5LEVEL 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; +unsigned int pgdir_shift __ro_after_init = 39; +unsigned int ptrs_per_p4d __ro_after_init = 1; #endif extern unsigned long get_cmd_line_ptr(void); @@ -732,6 +732,8 @@ void choose_random_location(unsigned long input, #ifdef CONFIG_X86_5LEVEL if (__read_cr4() & X86_CR4_LA57) { pgtable_l5_enabled = 1; + pgdir_shift = 48; + ptrs_per_p4d = 512; } #endif diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index ffb31c5..8a0a485 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -42,9 +42,9 @@ pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); #ifdef CONFIG_X86_5LEVEL unsigned int pgtable_l5_enabled __ro_after_init; EXPORT_SYMBOL(pgtable_l5_enabled); -unsigned int pgdir_shift __ro_after_init = 48; +unsigned int pgdir_shift __ro_after_init = 39; EXPORT_SYMBOL(pgdir_shift); -unsigned int ptrs_per_p4d __ro_after_init = 512; +unsigned int ptrs_per_p4d __ro_after_init = 1; EXPORT_SYMBOL(ptrs_per_p4d); #endif @@ -79,6 +79,8 @@ static void __head check_la57_support(unsigned long physaddr) return; *fixup_int(&pgtable_l5_enabled, physaddr) = 1; + *fixup_int(&pgdir_shift, physaddr) = 48; + *fixup_int(&ptrs_per_p4d, physaddr) = 512; } #else static void __head check_la57_support(unsigned long physaddr) {}
