v4.19.13 snapshot.
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
new file mode 100644
index 0000000..3c0e470
--- /dev/null
+++ b/arch/um/kernel/mem.c
@@ -0,0 +1,237 @@
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <linux/stddef.h>
+#include <linux/module.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/slab.h>
+#include <asm/fixmap.h>
+#include <asm/page.h>
+#include <as-layout.h>
+#include <init.h>
+#include <kern.h>
+#include <kern_util.h>
+#include <mem_user.h>
+#include <os.h>
+
+/* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
+unsigned long *empty_zero_page = NULL;
+EXPORT_SYMBOL(empty_zero_page);
+
+/*
+ * Initialized during boot, and readonly for initializing page tables
+ * afterwards
+ */
+pgd_t swapper_pg_dir[PTRS_PER_PGD];
+
+/* Initialized at boot time, and readonly after that */
+unsigned long long highmem;
+int kmalloc_ok = 0;
+
+/* Used during early boot */
+static unsigned long brk_end;
+
+void __init mem_init(void)
+{
+ /* clear the zero-page */
+ memset(empty_zero_page, 0, PAGE_SIZE);
+
+ /* Map in the area just after the brk now that kmalloc is about
+ * to be turned on.
+ */
+ brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
+ map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
+ free_bootmem(__pa(brk_end), uml_reserved - brk_end);
+ uml_reserved = brk_end;
+
+ /* this will put all low memory onto the freelists */
+ free_all_bootmem();
+ max_low_pfn = totalram_pages;
+ max_pfn = totalram_pages;
+ mem_init_print_info(NULL);
+ kmalloc_ok = 1;
+}
+
+/*
+ * Create a page table and place a pointer to it in a middle page
+ * directory entry.
+ */
+static void __init one_page_table_init(pmd_t *pmd)
+{
+ if (pmd_none(*pmd)) {
+ pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+ set_pmd(pmd, __pmd(_KERNPG_TABLE +
+ (unsigned long) __pa(pte)));
+ if (pte != pte_offset_kernel(pmd, 0))
+ BUG();
+ }
+}
+
+static void __init one_md_table_init(pud_t *pud)
+{
+#ifdef CONFIG_3_LEVEL_PGTABLES
+ pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+ set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
+ if (pmd_table != pmd_offset(pud, 0))
+ BUG();
+#endif
+}
+
+static void __init fixrange_init(unsigned long start, unsigned long end,
+ pgd_t *pgd_base)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ int i, j;
+ unsigned long vaddr;
+
+ vaddr = start;
+ i = pgd_index(vaddr);
+ j = pmd_index(vaddr);
+ pgd = pgd_base + i;
+
+ for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
+ pud = pud_offset(pgd, vaddr);
+ if (pud_none(*pud))
+ one_md_table_init(pud);
+ pmd = pmd_offset(pud, vaddr);
+ for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
+ one_page_table_init(pmd);
+ vaddr += PMD_SIZE;
+ }
+ j = 0;
+ }
+}
+
+static void __init fixaddr_user_init( void)
+{
+#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
+ long size = FIXADDR_USER_END - FIXADDR_USER_START;
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ phys_t p;
+ unsigned long v, vaddr = FIXADDR_USER_START;
+
+ if (!size)
+ return;
+
+ fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
+ v = (unsigned long) alloc_bootmem_low_pages(size);
+ memcpy((void *) v , (void *) FIXADDR_USER_START, size);
+ p = __pa(v);
+ for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
+ p += PAGE_SIZE) {
+ pgd = swapper_pg_dir + pgd_index(vaddr);
+ pud = pud_offset(pgd, vaddr);
+ pmd = pmd_offset(pud, vaddr);
+ pte = pte_offset_kernel(pmd, vaddr);
+ pte_set_val(*pte, p, PAGE_READONLY);
+ }
+#endif
+}
+
+void __init paging_init(void)
+{
+ unsigned long zones_size[MAX_NR_ZONES], vaddr;
+ int i;
+
+ empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
+ for (i = 0; i < ARRAY_SIZE(zones_size); i++)
+ zones_size[i] = 0;
+
+ zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
+ (uml_physmem >> PAGE_SHIFT);
+ free_area_init(zones_size);
+
+ /*
+ * Fixed mappings, only the page table structure has to be
+ * created - mappings will be set by set_fixmap():
+ */
+ vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
+ fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
+
+ fixaddr_user_init();
+}
+
+/*
+ * This can't do anything because nothing in the kernel image can be freed
+ * since it's not in kernel physical memory.
+ */
+
+void free_initmem(void)
+{
+}
+
+#ifdef CONFIG_BLK_DEV_INITRD
+void free_initrd_mem(unsigned long start, unsigned long end)
+{
+ free_reserved_area((void *)start, (void *)end, -1, "initrd");
+}
+#endif
+
+/* Allocate and free page tables. */
+
+pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+ pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
+
+ if (pgd) {
+ memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
+ memcpy(pgd + USER_PTRS_PER_PGD,
+ swapper_pg_dir + USER_PTRS_PER_PGD,
+ (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
+ }
+ return pgd;
+}
+
+void pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+ free_page((unsigned long) pgd);
+}
+
+pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
+{
+ pte_t *pte;
+
+ pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
+ return pte;
+}
+
+pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+ struct page *pte;
+
+ pte = alloc_page(GFP_KERNEL|__GFP_ZERO);
+ if (!pte)
+ return NULL;
+ if (!pgtable_page_ctor(pte)) {
+ __free_page(pte);
+ return NULL;
+ }
+ return pte;
+}
+
+#ifdef CONFIG_3_LEVEL_PGTABLES
+pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+ pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
+
+ if (pmd)
+ memset(pmd, 0, PAGE_SIZE);
+
+ return pmd;
+}
+#endif
+
+void *uml_kmalloc(int size, int flags)
+{
+ return kmalloc(size, flags);
+}