linux-kernel - [PATCH 2/2] xtensa: get rid of __ARCH_USE_5LEVEL

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Date:   Tue,  5 Nov 2019 16:33:20 +0200
From:   Mike Rapoport <rppt@...nel.org>
To:     Chris Zankel <chris@...kel.net>, Max Filippov <jcmvbkbc@...il.com>
Cc:     linux-xtensa@...ux-xtensa.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Mike Rapoport <rppt@...nel.org>,
        Mike Rapoport <rppt@...ux.ibm.com>
Subject: [PATCH 2/2] xtensa: get rid of __ARCH_USE_5LEVEL_HACK

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

xtensa has 2-level page tables and already uses pgtable-nopmd for page
table folding.

Add walks of p4d level where appropriate and drop usage of
__ARCH_USE_5LEVEL_HACK.

Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
---
 arch/xtensa/include/asm/pgtable.h |  1 -
 arch/xtensa/mm/fault.c            | 10 ++++++++--
 arch/xtensa/mm/kasan_init.c       |  6 ++++--
 arch/xtensa/mm/mmu.c              |  3 ++-
 arch/xtensa/mm/tlb.c              |  5 ++++-
 5 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index af72f02..27ac17c 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h
@@ -8,7 +8,6 @@
 #ifndef _XTENSA_PGTABLE_H
 #define _XTENSA_PGTABLE_H
 
-#define __ARCH_USE_5LEVEL_HACK
 #include <asm/page.h>
 #include <asm/kmem_layout.h>
 #include <asm-generic/pgtable-nopmd.h>
diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c
index 68a0414..bee30a7 100644
--- a/arch/xtensa/mm/fault.c
+++ b/arch/xtensa/mm/fault.c
@@ -197,6 +197,7 @@ void do_page_fault(struct pt_regs *regs)
 		struct mm_struct *act_mm = current->active_mm;
 		int index = 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;
@@ -212,8 +213,13 @@ void do_page_fault(struct pt_regs *regs)
 
 		pgd_val(*pgd) = pgd_val(*pgd_k);
 
-		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) || !p4d_present(*p4d_k))
+			goto bad_page_fault;
+
+		pud = pud_offset(p4d, address);
+		pud_k = pud_offset(p4d_k, address);
 		if (!pud_present(*pud) || !pud_present(*pud_k))
 			goto bad_page_fault;
 
diff --git a/arch/xtensa/mm/kasan_init.c b/arch/xtensa/mm/kasan_init.c
index ace98bd..9c95779 100644
--- a/arch/xtensa/mm/kasan_init.c
+++ b/arch/xtensa/mm/kasan_init.c
@@ -20,7 +20,8 @@ void __init kasan_early_init(void)
 {
 	unsigned long vaddr = KASAN_SHADOW_START;
 	pgd_t *pgd = pgd_offset_k(vaddr);
-	pud_t *pud = pud_offset(pgd, vaddr);
+	p4d_t *p4d = p4d_offset(pgd, vaddr);
+	pud_t *pud = pud_offset(p4d, vaddr);
 	pmd_t *pmd = pmd_offset(pud, vaddr);
 	int i;
 
@@ -43,7 +44,8 @@ static void __init populate(void *start, void *end)
 	unsigned long i, j;
 	unsigned long vaddr = (unsigned long)start;
 	pgd_t *pgd = pgd_offset_k(vaddr);
-	pud_t *pud = pud_offset(pgd, vaddr);
+	p4d_t *p4d = p4d_offset(pgd, vaddr);
+	pud_t *pud = pud_offset(p4d, vaddr);
 	pmd_t *pmd = pmd_offset(pud, vaddr);
 	pte_t *pte = memblock_alloc(n_pages * sizeof(pte_t), PAGE_SIZE);
 
diff --git a/arch/xtensa/mm/mmu.c b/arch/xtensa/mm/mmu.c
index 018dda2..37e478a 100644
--- a/arch/xtensa/mm/mmu.c
+++ b/arch/xtensa/mm/mmu.c
@@ -22,7 +22,8 @@
 static void * __init init_pmd(unsigned long vaddr, unsigned long n_pages)
 {
 	pgd_t *pgd = pgd_offset_k(vaddr);
-	pud_t *pud = pud_offset(pgd, vaddr);
+	p4d_t *p4d = p4d_offset(pgd, vaddr);
+	pud_t *pud = pud_offset(p4d, vaddr);
 	pmd_t *pmd = pmd_offset(pud, vaddr);
 	pte_t *pte;
 	unsigned long i;
diff --git a/arch/xtensa/mm/tlb.c b/arch/xtensa/mm/tlb.c
index 164a2ca..a460474 100644
--- a/arch/xtensa/mm/tlb.c
+++ b/arch/xtensa/mm/tlb.c
@@ -178,7 +178,10 @@ static unsigned get_pte_for_vaddr(unsigned vaddr)
 	pgd = pgd_offset(mm, vaddr);
 	if (pgd_none_or_clear_bad(pgd))
 		return 0;
-	pud = pud_offset(pgd, vaddr);
+	p4d = p4d_offset(pgd, vaddr);
+	if (p4d_none_or_clear_bad(p4d))
+		return 0;
+	pud = pud_offset(p4d, vaddr);
 	if (pud_none_or_clear_bad(pud))
 		return 0;
 	pmd = pmd_offset(pud, vaddr);
-- 
2.7.4