linux-kernel - [PATCH] x86/memory: Drop pud

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Message-Id: <1584925542-13034-1-git-send-email-anshuman.khandual@arm.com>
Date:   Mon, 23 Mar 2020 06:35:42 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     linux-mm@...ck.org
Cc:     jhubbard@...dia.com, Anshuman Khandual <anshuman.khandual@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Dave Hansen <dave.hansen@...el.com>,
        "Kirill A . Shutemov" <kirill@...temov.name>,
        Dan Williams <dan.j.williams@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] x86/memory: Drop pud_mknotpresent()

There is an inconsistency between PMD and PUD based THP page table helpers
like the following, as pud_present() does not test for _PAGE_PSE.

pmd_present(pmd_mknotpresent(pmd)) : True
pud_present(pud_mknotpresent(pud)) : False

This drops pud_mknotpresent() as there are no current users. If/when needed
back later, pud_present() will also have to fixed to accommodate _PAGE_PSE.

Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Kirill A. Shutemov <kirill@...temov.name>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: x86@...nel.org
Cc: linux-mm@...ck.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
This has been build and boot tested on x86.

Changes in V2:

- Dropped pud_mknotpresent() instead per Kirill

Changes in V1: (https://patchwork.kernel.org/patch/11444529/)

 arch/x86/include/asm/pgtable.h | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 7e118660bbd9..d74dc560e3ab 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -595,12 +595,6 @@ static inline pmd_t pmd_mknotpresent(pmd_t pmd)
 		      __pgprot(pmd_flags(pmd) & ~(_PAGE_PRESENT|_PAGE_PROTNONE)));
 }
 
-static inline pud_t pud_mknotpresent(pud_t pud)
-{
-	return pfn_pud(pud_pfn(pud),
-	      __pgprot(pud_flags(pud) & ~(_PAGE_PRESENT|_PAGE_PROTNONE)));
-}
-
 static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask);
 
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
-- 
2.17.1