linux-kernel - [PATCH v3 06/14] openrisc: add support for folded p4d page tables

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Date:   Thu, 27 Feb 2020 10:46:00 +0200
From:   Mike Rapoport <rppt@...nel.org>
To:     linux-kernel@...r.kernel.org
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Brian Cain <bcain@...eaurora.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Christophe Leroy <christophe.leroy@....fr>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Guan Xuetao <gxt@....edu.cn>,
        James Morse <james.morse@....com>,
        Jonas Bonn <jonas@...thpole.se>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Ley Foon Tan <ley.foon.tan@...el.com>,
        Marc Zyngier <maz@...nel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Paul Mackerras <paulus@...ba.org>,
        Rich Felker <dalias@...c.org>,
        Russell King <linux@...linux.org.uk>,
        Stafford Horne <shorne@...il.com>,
        Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Tony Luck <tony.luck@...el.com>, Will Deacon <will@...nel.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        kvmarm@...ts.cs.columbia.edu, kvm-ppc@...r.kernel.org,
        linux-arch@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-hexagon@...r.kernel.org, linux-ia64@...r.kernel.org,
        linux-mm@...ck.org, linuxppc-dev@...ts.ozlabs.org,
        linux-sh@...r.kernel.org, nios2-dev@...ts.rocketboards.org,
        openrisc@...ts.librecores.org,
        uclinux-h8-devel@...ts.sourceforge.jp,
        Mike Rapoport <rppt@...nel.org>,
        Mike Rapoport <rppt@...ux.ibm.com>
Subject: [PATCH v3 06/14] openrisc: add support for folded p4d page tables

From: Mike Rapoport <rppt@...ux.ibm.com>

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate and remove usage of __ARCH_USE_5LEVEL_HACK.

Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
---
 arch/openrisc/include/asm/pgtable.h |  1 -
 arch/openrisc/mm/fault.c            | 10 ++++++++--
 arch/openrisc/mm/init.c             |  4 +++-
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
index 248d22d8faa7..c072943fc721 100644
--- a/arch/openrisc/include/asm/pgtable.h
+++ b/arch/openrisc/include/asm/pgtable.h
@@ -21,7 +21,6 @@
 #ifndef __ASM_OPENRISC_PGTABLE_H
 #define __ASM_OPENRISC_PGTABLE_H
 
-#define __ARCH_USE_5LEVEL_HACK
 #include <asm-generic/pgtable-nopmd.h>
 
 #ifndef __ASSEMBLY__
diff --git a/arch/openrisc/mm/fault.c b/arch/openrisc/mm/fault.c
index 5d4d3a9691d0..44aa04545de3 100644
--- a/arch/openrisc/mm/fault.c
+++ b/arch/openrisc/mm/fault.c
@@ -296,6 +296,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address,
 
 		int offset = pgd_index(address);
 		pgd_t *pgd, *pgd_k;
+		p4d_t *p4d, *p4d_k;
 		pud_t *pud, *pud_k;
 		pmd_t *pmd, *pmd_k;
 		pte_t *pte_k;
@@ -322,8 +323,13 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address,
 		 * it exists.
 		 */
 
-		pud = pud_offset(pgd, address);
-		pud_k = pud_offset(pgd_k, address);
+		p4d = p4d_offset(pgd, address);
+		p4d_k = p4d_offset(pgd_k, address);
+		if (!p4d_present(*p4d_k))
+			goto no_context;
+
+		pud = pud_offset(p4d, address);
+		pud_k = pud_offset(p4d_k, address);
 		if (!pud_present(*pud_k))
 			goto no_context;
 
diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c
index 1f87b524db78..2536aeae0975 100644
--- a/arch/openrisc/mm/init.c
+++ b/arch/openrisc/mm/init.c
@@ -71,6 +71,7 @@ static void __init map_ram(void)
 	unsigned long v, p, e;
 	pgprot_t prot;
 	pgd_t *pge;
+	p4d_t *p4e;
 	pud_t *pue;
 	pmd_t *pme;
 	pte_t *pte;
@@ -90,7 +91,8 @@ static void __init map_ram(void)
 
 		while (p < e) {
 			int j;
-			pue = pud_offset(pge, v);
+			p4e = p4d_offset(pge, v);
+			pue = pud_offset(p4e, v);
 			pme = pmd_offset(pue, v);
 
 			if ((u32) pue != (u32) pge || (u32) pme != (u32) pge) {
-- 
2.24.0