v4.19.13 snapshot.
diff --git a/arch/arm/mm/pgd.c b/arch/arm/mm/pgd.c
new file mode 100644
index 0000000..a1606d9
--- /dev/null
+++ b/arch/arm/mm/pgd.c
@@ -0,0 +1,174 @@
+/*
+ * linux/arch/arm/mm/pgd.c
+ *
+ * Copyright (C) 1998-2005 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/mm.h>
+#include <linux/gfp.h>
+#include <linux/highmem.h>
+#include <linux/slab.h>
+
+#include <asm/cp15.h>
+#include <asm/pgalloc.h>
+#include <asm/page.h>
+#include <asm/tlbflush.h>
+
+#include "mm.h"
+
+#ifdef CONFIG_ARM_LPAE
+#define __pgd_alloc() kmalloc_array(PTRS_PER_PGD, sizeof(pgd_t), GFP_KERNEL)
+#define __pgd_free(pgd) kfree(pgd)
+#else
+#define __pgd_alloc() (pgd_t *)__get_free_pages(GFP_KERNEL, 2)
+#define __pgd_free(pgd) free_pages((unsigned long)pgd, 2)
+#endif
+
+/*
+ * need to get a 16k page for level 1
+ */
+pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+ pgd_t *new_pgd, *init_pgd;
+ pud_t *new_pud, *init_pud;
+ pmd_t *new_pmd, *init_pmd;
+ pte_t *new_pte, *init_pte;
+
+ new_pgd = __pgd_alloc();
+ if (!new_pgd)
+ goto no_pgd;
+
+ memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
+
+ /*
+ * Copy over the kernel and IO PGD entries
+ */
+ init_pgd = pgd_offset_k(0);
+ memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
+ (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
+
+ clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
+
+#ifdef CONFIG_ARM_LPAE
+ /*
+ * Allocate PMD table for modules and pkmap mappings.
+ */
+ new_pud = pud_alloc(mm, new_pgd + pgd_index(MODULES_VADDR),
+ MODULES_VADDR);
+ if (!new_pud)
+ goto no_pud;
+
+ new_pmd = pmd_alloc(mm, new_pud, 0);
+ if (!new_pmd)
+ goto no_pmd;
+#endif
+
+ if (!vectors_high()) {
+ /*
+ * On ARM, first page must always be allocated since it
+ * contains the machine vectors. The vectors are always high
+ * with LPAE.
+ */
+ new_pud = pud_alloc(mm, new_pgd, 0);
+ if (!new_pud)
+ goto no_pud;
+
+ new_pmd = pmd_alloc(mm, new_pud, 0);
+ if (!new_pmd)
+ goto no_pmd;
+
+ new_pte = pte_alloc_map(mm, new_pmd, 0);
+ if (!new_pte)
+ goto no_pte;
+
+#ifndef CONFIG_ARM_LPAE
+ /*
+ * Modify the PTE pointer to have the correct domain. This
+ * needs to be the vectors domain to avoid the low vectors
+ * being unmapped.
+ */
+ pmd_val(*new_pmd) &= ~PMD_DOMAIN_MASK;
+ pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS);
+#endif
+
+ init_pud = pud_offset(init_pgd, 0);
+ init_pmd = pmd_offset(init_pud, 0);
+ init_pte = pte_offset_map(init_pmd, 0);
+ set_pte_ext(new_pte + 0, init_pte[0], 0);
+ set_pte_ext(new_pte + 1, init_pte[1], 0);
+ pte_unmap(init_pte);
+ pte_unmap(new_pte);
+ }
+
+ return new_pgd;
+
+no_pte:
+ pmd_free(mm, new_pmd);
+ mm_dec_nr_pmds(mm);
+no_pmd:
+ pud_free(mm, new_pud);
+no_pud:
+ __pgd_free(new_pgd);
+no_pgd:
+ return NULL;
+}
+
+void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pgtable_t pte;
+
+ if (!pgd_base)
+ return;
+
+ pgd = pgd_base + pgd_index(0);
+ if (pgd_none_or_clear_bad(pgd))
+ goto no_pgd;
+
+ pud = pud_offset(pgd, 0);
+ if (pud_none_or_clear_bad(pud))
+ goto no_pud;
+
+ pmd = pmd_offset(pud, 0);
+ if (pmd_none_or_clear_bad(pmd))
+ goto no_pmd;
+
+ pte = pmd_pgtable(*pmd);
+ pmd_clear(pmd);
+ pte_free(mm, pte);
+ mm_dec_nr_ptes(mm);
+no_pmd:
+ pud_clear(pud);
+ pmd_free(mm, pmd);
+ mm_dec_nr_pmds(mm);
+no_pud:
+ pgd_clear(pgd);
+ pud_free(mm, pud);
+no_pgd:
+#ifdef CONFIG_ARM_LPAE
+ /*
+ * Free modules/pkmap or identity pmd tables.
+ */
+ for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) {
+ if (pgd_none_or_clear_bad(pgd))
+ continue;
+ if (pgd_val(*pgd) & L_PGD_SWAPPER)
+ continue;
+ pud = pud_offset(pgd, 0);
+ if (pud_none_or_clear_bad(pud))
+ continue;
+ pmd = pmd_offset(pud, 0);
+ pud_clear(pud);
+ pmd_free(mm, pmd);
+ mm_dec_nr_pmds(mm);
+ pgd_clear(pgd);
+ pud_free(mm, pud);
+ }
+#endif
+ __pgd_free(pgd_base);
+}