xtensa: get rid of __ARCH_USE_5LEVEL_HACK

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@linux.ibm.com>
Message-Id: <1572964400-16542-3-git-send-email-rppt@kernel.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> [fix up
               arch/xtensa/include/asm/fixmap.h and
               arch/xtensa/mm/tlb.c]

arch/xtensa/include/asm/fixmap.h

@@ -78,8 +78,10 @@ static inline unsigned long virt_to_fix(const unsigned long vaddr)
 
 #define kmap_get_fixmap_pte(vaddr) \
 	pte_offset_kernel( \
-		pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), \
-		(vaddr) \
-	)
+		pmd_offset(pud_offset(p4d_offset(pgd_offset_k(vaddr), \
+						 (vaddr)), \
+				      (vaddr)), \
+			   (vaddr)), \
+		(vaddr))
 
 #endif

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>

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;
 

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);
 

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;

arch/xtensa/mm/tlb.c

@@ -169,6 +169,7 @@ static unsigned get_pte_for_vaddr(unsigned vaddr)
 	struct task_struct *task = get_current();
 	struct mm_struct *mm = task->mm;
 	pgd_t *pgd;
+	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
@@ -178,7 +179,10 @@ 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);