From 8898ad58a0195e2d3f5ffb770fbe9c9dc978a171 Mon Sep 17 00:00:00 2001 From: Anshuman Khandual Date: Thu, 4 Jun 2020 16:47:12 -0700 Subject: [PATCH] x86/mm: define mm_p4d_folded() Patch series "mm/debug: Add tests validating architecture page table helpers", v18. This adds a test validation for architecture exported page table helpers. Patch adds basic transformation tests at various levels of the page table. This test was originally suggested by Catalin during arm64 THP migration RFC discussion earlier. Going forward it can include more specific tests with respect to various generic MM functions like THP, HugeTLB etc and platform specific tests. https://lore.kernel.org/linux-mm/20190628102003.GA56463@arrakis.emea.arm.com/ This patch (of 2): This just defines mm_p4d_folded() to check whether P4D page table level is folded at runtime. Signed-off-by: Kirill A. Shutemov Signed-off-by: Anshuman Khandual Signed-off-by: Andrew Morton Cc: Thomas Gleixner Cc: Ingo Molnar Link: http://lkml.kernel.org/r/1587436495-22033-2-git-send-email-anshuman.khandual@arm.com Link: http://lkml.kernel.org/r/1588564865-31160-2-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds --- arch/x86/include/asm/pgtable_64.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h index df1373415f11..8d03ffd43794 100644 --- a/arch/x86/include/asm/pgtable_64.h +++ b/arch/x86/include/asm/pgtable_64.h @@ -53,6 +53,12 @@ static inline void sync_initial_page_table(void) { } struct mm_struct; +#define mm_p4d_folded mm_p4d_folded +static inline bool mm_p4d_folded(struct mm_struct *mm) +{ + return !pgtable_l5_enabled(); +} + void set_pte_vaddr_p4d(p4d_t *p4d_page, unsigned long vaddr, pte_t new_pte); void set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte); -- 2.20.1