ffffffbffb000000       ffffffbffbbfffff          12MB          [guard]
 
-ffffffbffbc00000       ffffffbffbdfffff           2MB          earlyprintk device
+ffffffbffbc00000       ffffffbffbdfffff           2MB          fixed mappings
 
 ffffffbffbe00000       ffffffbffbffffff           2MB          [guard]
 
 
 fffffdfffb000000       fffffdfffbbfffff          12MB          [guard]
 
-fffffdfffbc00000       fffffdfffbdfffff           2MB          earlyprintk device
+fffffdfffbc00000       fffffdfffbdfffff           2MB          fixed mappings
 
 fffffdfffbe00000       fffffdfffbffffff           2MB          [guard]
 
 
        select GENERIC_CLOCKEVENTS
        select GENERIC_CLOCKEVENTS_BROADCAST if SMP
        select GENERIC_CPU_AUTOPROBE
+       select GENERIC_EARLY_IOREMAP
        select GENERIC_IOMAP
        select GENERIC_IRQ_PROBE
        select GENERIC_IRQ_SHOW
 
 generic-y += div64.h
 generic-y += dma.h
 generic-y += emergency-restart.h
+generic-y += early_ioremap.h
 generic-y += errno.h
 generic-y += ftrace.h
 generic-y += hash.h
 
--- /dev/null
+/*
+ * fixmap.h: compile-time virtual memory allocation
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1998 Ingo Molnar
+ * Copyright (C) 2013 Mark Salter <msalter@redhat.com>
+ *
+ * Adapted from arch/x86_64 version.
+ *
+ */
+
+#ifndef _ASM_ARM64_FIXMAP_H
+#define _ASM_ARM64_FIXMAP_H
+
+#ifndef __ASSEMBLY__
+#include <linux/kernel.h>
+#include <asm/page.h>
+
+/*
+ * Here we define all the compile-time 'special' virtual
+ * addresses. The point is to have a constant address at
+ * compile time, but to set the physical address only
+ * in the boot process.
+ *
+ * These 'compile-time allocated' memory buffers are
+ * page-sized. Use set_fixmap(idx,phys) to associate
+ * physical memory with fixmap indices.
+ *
+ */
+enum fixed_addresses {
+       FIX_EARLYCON_MEM_BASE,
+       __end_of_permanent_fixed_addresses,
+
+       /*
+        * Temporary boot-time mappings, used by early_ioremap(),
+        * before ioremap() is functional.
+        */
+#ifdef CONFIG_ARM64_64K_PAGES
+#define NR_FIX_BTMAPS          4
+#else
+#define NR_FIX_BTMAPS          64
+#endif
+#define FIX_BTMAPS_SLOTS       7
+#define TOTAL_FIX_BTMAPS       (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+
+       FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
+       FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
+       __end_of_fixed_addresses
+};
+
+#define FIXADDR_SIZE   (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_START  (FIXADDR_TOP - FIXADDR_SIZE)
+
+#define FIXMAP_PAGE_IO     __pgprot(PROT_DEVICE_nGnRE)
+
+extern void __early_set_fixmap(enum fixed_addresses idx,
+                              phys_addr_t phys, pgprot_t flags);
+
+#define __set_fixmap __early_set_fixmap
+
+#include <asm-generic/fixmap.h>
+
+#endif /* !__ASSEMBLY__ */
+#endif /* _ASM_ARM64_FIXMAP_H */
 
 #include <asm/byteorder.h>
 #include <asm/barrier.h>
 #include <asm/pgtable.h>
+#include <asm/early_ioremap.h>
 
 #include <xen/xen.h>
 
 
 #define PAGE_OFFSET            (UL(0xffffffffffffffff) << (VA_BITS - 1))
 #define MODULES_END            (PAGE_OFFSET)
 #define MODULES_VADDR          (MODULES_END - SZ_64M)
-#define EARLYCON_IOBASE                (MODULES_VADDR - SZ_4M)
+#define FIXADDR_TOP            (MODULES_VADDR - SZ_2M - PAGE_SIZE)
 #define TASK_SIZE_64           (UL(1) << VA_BITS)
 
 #ifdef CONFIG_COMPAT
 
 #include <linux/amba/serial.h>
 #include <linux/serial_reg.h>
 
+#include <asm/fixmap.h>
+
 static void __iomem *early_base;
 static void (*printch)(char ch);
 
        }
        /* no options parsing yet */
 
-       if (paddr)
-               early_base = early_io_map(paddr, EARLYCON_IOBASE);
+       if (paddr) {
+               set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr);
+               early_base = (void __iomem *)fix_to_virt(FIX_EARLYCON_MEM_BASE);
+       }
 
        printch = match->printch;
        early_console = &early_console_dev;
 
  *   - identity mapping to enable the MMU (low address, TTBR0)
  *   - first few MB of the kernel linear mapping to jump to once the MMU has
  *     been enabled, including the FDT blob (TTBR1)
- *   - UART mapping if CONFIG_EARLY_PRINTK is enabled (TTBR1)
+ *   - pgd entry for fixed mappings (TTBR1)
  */
 __create_page_tables:
        pgtbl   x25, x26, x24                   // idmap_pg_dir and swapper_pg_dir addresses
        sub     x6, x6, #1                      // inclusive range
        create_block_map x0, x7, x3, x5, x6
 1:
-#ifdef CONFIG_EARLY_PRINTK
        /*
-        * Create the pgd entry for the UART mapping. The full mapping is done
-        * later based earlyprintk kernel parameter.
+        * Create the pgd entry for the fixed mappings.
         */
-       ldr     x5, =EARLYCON_IOBASE            // UART virtual address
+       ldr     x5, =FIXADDR_TOP                // Fixed mapping virtual address
        add     x0, x26, #2 * PAGE_SIZE         // section table address
        create_pgd_entry x26, x0, x5, x6, x7
-#endif
        ret
 ENDPROC(__create_page_tables)
        .ltorg
 
 #include <linux/of_fdt.h>
 #include <linux/of_platform.h>
 
+#include <asm/fixmap.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
 #include <asm/cputable.h>
        *cmdline_p = boot_command_line;
 
        init_mem_pgprot();
+       early_ioremap_init();
 
        parse_early_param();
 
 
 #include <linux/vmalloc.h>
 #include <linux/io.h>
 
+#include <asm/fixmap.h>
+#include <asm/tlbflush.h>
+#include <asm/pgalloc.h>
+
 static void __iomem *__ioremap_caller(phys_addr_t phys_addr, size_t size,
                                      pgprot_t prot, void *caller)
 {
                                __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_cache);
+
+#ifndef CONFIG_ARM64_64K_PAGES
+static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
+#endif
+
+static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+
+       pgd = pgd_offset_k(addr);
+       BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
+
+       pud = pud_offset(pgd, addr);
+       BUG_ON(pud_none(*pud) || pud_bad(*pud));
+
+       return pmd_offset(pud, addr);
+}
+
+static inline pte_t * __init early_ioremap_pte(unsigned long addr)
+{
+       pmd_t *pmd = early_ioremap_pmd(addr);
+
+       BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd));
+
+       return pte_offset_kernel(pmd, addr);
+}
+
+void __init early_ioremap_init(void)
+{
+       pmd_t *pmd;
+
+       pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
+#ifndef CONFIG_ARM64_64K_PAGES
+       /* need to populate pmd for 4k pagesize only */
+       pmd_populate_kernel(&init_mm, pmd, bm_pte);
+#endif
+       /*
+        * The boot-ioremap range spans multiple pmds, for which
+        * we are not prepared:
+        */
+       BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
+                    != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
+
+       if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
+               WARN_ON(1);
+               pr_warn("pmd %p != %p\n",
+                       pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
+               pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
+                       fix_to_virt(FIX_BTMAP_BEGIN));
+               pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
+                       fix_to_virt(FIX_BTMAP_END));
+
+               pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
+               pr_warn("FIX_BTMAP_BEGIN:     %d\n",
+                       FIX_BTMAP_BEGIN);
+       }
+
+       early_ioremap_setup();
+}
+
+void __init __early_set_fixmap(enum fixed_addresses idx,
+                              phys_addr_t phys, pgprot_t flags)
+{
+       unsigned long addr = __fix_to_virt(idx);
+       pte_t *pte;
+
+       if (idx >= __end_of_fixed_addresses) {
+               BUG();
+               return;
+       }
+
+       pte = early_ioremap_pte(addr);
+
+       if (pgprot_val(flags))
+               set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
+       else {
+               pte_clear(&init_mm, addr, pte);
+               flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
+       }
+}
 
        } while (pgd++, addr = next, addr != end);
 }
 
-#ifdef CONFIG_EARLY_PRINTK
-/*
- * Create an early I/O mapping using the pgd/pmd entries already populated
- * in head.S as this function is called too early to allocated any memory. The
- * mapping size is 2MB with 4KB pages or 64KB or 64KB pages.
- */
-void __iomem * __init early_io_map(phys_addr_t phys, unsigned long virt)
-{
-       unsigned long size, mask;
-       bool page64k = IS_ENABLED(CONFIG_ARM64_64K_PAGES);
-       pgd_t *pgd;
-       pud_t *pud;
-       pmd_t *pmd;
-       pte_t *pte;
-
-       /*
-        * No early pte entries with !ARM64_64K_PAGES configuration, so using
-        * sections (pmd).
-        */
-       size = page64k ? PAGE_SIZE : SECTION_SIZE;
-       mask = ~(size - 1);
-
-       pgd = pgd_offset_k(virt);
-       pud = pud_offset(pgd, virt);
-       if (pud_none(*pud))
-               return NULL;
-       pmd = pmd_offset(pud, virt);
-
-       if (page64k) {
-               if (pmd_none(*pmd))
-                       return NULL;
-               pte = pte_offset_kernel(pmd, virt);
-               set_pte(pte, __pte((phys & mask) | PROT_DEVICE_nGnRE));
-       } else {
-               set_pmd(pmd, __pmd((phys & mask) | PROT_SECT_DEVICE_nGnRE));
-       }
-
-       return (void __iomem *)((virt & mask) + (phys & ~mask));
-}
-#endif
-
 static void __init map_mem(void)
 {
        struct memblock_region *reg;