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[V17,1/2] x86/mm: Define mm_p4d_folded()

Message ID 1587436495-22033-2-git-send-email-anshuman.khandual@arm.com (mailing list archive)
State New, archived
Headers show
Series mm/debug: Add tests validating architecture page table helpers | expand

Commit Message

Anshuman Khandual April 21, 2020, 2:34 a.m. UTC 
This just defines mm_p4d_folded() to check whether P4D page table level is
folded at runtime.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/x86/include/asm/pgtable_64.h | 6 ++++++
 1 file changed, 6 insertions(+)
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Patch

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);