linux-kernel - [PATCH RFC 09/13] mm/powerpc: Redefine pXd_huge() with pXd

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Date: Wed,  6 Mar 2024 18:41:43 +0800
From: peterx@...hat.com
To: linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Cc: linuxppc-dev@...ts.ozlabs.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Muchun Song <muchun.song@...ux.dev>,
	Jason Gunthorpe <jgg@...dia.com>,
	peterx@...hat.com,
	Matthew Wilcox <willy@...radead.org>,
	Mike Rapoport <rppt@...nel.org>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	x86@...nel.org,
	sparclinux@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@...nel.org>,
	"Naveen N. Rao" <naveen.n.rao@...ux.ibm.com>
Subject: [PATCH RFC 09/13] mm/powerpc: Redefine pXd_huge() with pXd_leaf()

From: Peter Xu <peterx@...hat.com>

PowerPC book3s 4K mostly has the same definition on both, except pXd_huge()
constantly returns 0 for hash MMUs.  AFAICT that is fine to be removed,
because pXd_huge() reflects a hugetlb entry, while it's own hugetlb pgtable
lookup function (__find_linux_pte() shared by all powerpc code) already use
pXd_leaf() irrelevant of the MMU type.  It means pXd_leaf() should work all
fine with hash MMU pgtables or something could already went wrong.

The goal should be that we will have one API pXd_leaf() to detect all kinds
of huge mappings.  AFAICT we need to use the pXd_leaf() impl (rather than
pXd_huge() ones) to make sure ie. THPs on hash MMU will also return true.

This helps to simplify a follow up patch to drop pXd_huge() treewide.

Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Nicholas Piggin <npiggin@...il.com>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@...nel.org>
Cc: "Naveen N. Rao" <naveen.n.rao@...ux.ibm.com>
Cc: linuxppc-dev@...ts.ozlabs.org
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable-4k.h | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable-4k.h b/arch/powerpc/include/asm/book3s/64/pgtable-4k.h
index 48f21820afe2..92545981bb49 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable-4k.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable-4k.h
@@ -8,22 +8,12 @@
 #ifdef CONFIG_HUGETLB_PAGE
 static inline int pmd_huge(pmd_t pmd)
 {
-	/*
-	 * leaf pte for huge page
-	 */
-	if (radix_enabled())
-		return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
-	return 0;
+	return pmd_leaf(pmd);
 }
 
 static inline int pud_huge(pud_t pud)
 {
-	/*
-	 * leaf pte for huge page
-	 */
-	if (radix_enabled())
-		return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
-	return 0;
+	return pud_leaf(pud);
 }
 
 /*
-- 
2.44.0