Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 "Here are the main arm64 updates for 4.6.  There are some relatively
  intrusive changes to support KASLR, the reworking of the kernel
  virtual memory layout and initial page table creation.

  Summary:

   - Initial page table creation reworked to avoid breaking large block
     mappings (huge pages) into smaller ones.  The ARM architecture
     requires break-before-make in such cases to avoid TLB conflicts but
     that's not always possible on live page tables

   - Kernel virtual memory layout: the kernel image is no longer linked
     to the bottom of the linear mapping (PAGE_OFFSET) but at the bottom
     of the vmalloc space, allowing the kernel to be loaded (nearly)
     anywhere in physical RAM

   - Kernel ASLR: position independent kernel Image and modules being
     randomly mapped in the vmalloc space with the randomness is
     provided by UEFI (efi_get_random_bytes() patches merged via the
     arm64 tree, acked by Matt Fleming)

   - Implement relative exception tables for arm64, required by KASLR
     (initial code for ARCH_HAS_RELATIVE_EXTABLE added to lib/extable.c
     but actual x86 conversion to deferred to 4.7 because of the merge
     dependencies)

   - Support for the User Access Override feature of ARMv8.2: this
     allows uaccess functions (get_user etc.) to be implemented using
     LDTR/STTR instructions.  Such instructions, when run by the kernel,
     perform unprivileged accesses adding an extra level of protection.
     The set_fs() macro is used to "upgrade" such instruction to
     privileged accesses via the UAO bit

   - Half-precision floating point support (part of ARMv8.2)

   - Optimisations for CPUs with or without a hardware prefetcher (using
     run-time code patching)

   - copy_page performance improvement to deal with 128 bytes at a time

   - Sanity checks on the CPU capabilities (via CPUID) to prevent
     incompatible secondary CPUs from being brought up (e.g.  weird
     big.LITTLE configurations)

   - valid_user_regs() reworked for better sanity check of the
     sigcontext information (restored pstate information)

   - ACPI parking protocol implementation

   - CONFIG_DEBUG_RODATA enabled by default

   - VDSO code marked as read-only

   - DEBUG_PAGEALLOC support

   - ARCH_HAS_UBSAN_SANITIZE_ALL enabled

   - Erratum workaround Cavium ThunderX SoC

   - set_pte_at() fix for PROT_NONE mappings

   - Code clean-ups"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (99 commits)
  arm64: kasan: Fix zero shadow mapping overriding kernel image shadow
  arm64: kasan: Use actual memory node when populating the kernel image shadow
  arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE permission
  arm64: Fix misspellings in comments.
  arm64: efi: add missing frame pointer assignment
  arm64: make mrs_s prefixing implicit in read_cpuid
  arm64: enable CONFIG_DEBUG_RODATA by default
  arm64: Rework valid_user_regs
  arm64: mm: check at build time that PAGE_OFFSET divides the VA space evenly
  arm64: KVM: Move kvm_call_hyp back to its original localtion
  arm64: mm: treat memstart_addr as a signed quantity
  arm64: mm: list kernel sections in order
  arm64: lse: deal with clobbered IP registers after branch via PLT
  arm64: mm: dump: Use VA_START directly instead of private LOWEST_ADDR
  arm64: kconfig: add submenu for 8.2 architectural features
  arm64: kernel: acpi: fix ioremap in ACPI parking protocol cpu_postboot
  arm64: Add support for Half precision floating point
  arm64: Remove fixmap include fragility
  arm64: Add workaround for Cavium erratum 27456
  arm64: mm: Mark .rodata as RO
  ...

9 files changed, 655 insertions, 268 deletions

diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index e87f53ff5f58..c90c3c5f46af 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -24,6 +24,7 @@
 
 #include <asm/cpufeature.h>
 #include <asm/mmu_context.h>
+#include <asm/smp.h>
 #include <asm/tlbflush.h>
 
 static u32 asid_bits;
@@ -40,6 +41,45 @@ static cpumask_t tlb_flush_pending;
 #define ASID_FIRST_VERSION	(1UL << asid_bits)
 #define NUM_USER_ASIDS		ASID_FIRST_VERSION
 
+/* Get the ASIDBits supported by the current CPU */
+static u32 get_cpu_asid_bits(void)
+{
+	u32 asid;
+	int fld = cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64MMFR0_EL1),
+						ID_AA64MMFR0_ASID_SHIFT);
+
+	switch (fld) {
+	default:
+		pr_warn("CPU%d: Unknown ASID size (%d); assuming 8-bit\n",
+					smp_processor_id(),  fld);
+		/* Fallthrough */
+	case 0:
+		asid = 8;
+		break;
+	case 2:
+		asid = 16;
+	}
+
+	return asid;
+}
+
+/* Check if the current cpu's ASIDBits is compatible with asid_bits */
+void verify_cpu_asid_bits(void)
+{
+	u32 asid = get_cpu_asid_bits();
+
+	if (asid < asid_bits) {
+		/*
+		 * We cannot decrease the ASID size at runtime, so panic if we support
+		 * fewer ASID bits than the boot CPU.
+		 */
+		pr_crit("CPU%d: smaller ASID size(%u) than boot CPU (%u)\n",
+				smp_processor_id(), asid, asid_bits);
+		update_cpu_boot_status(CPU_PANIC_KERNEL);
+		cpu_park_loop();
+	}
+}
+
 static void flush_context(unsigned int cpu)
 {
 	int i;
@@ -187,19 +227,7 @@ switch_mm_fastpath:
 
 static int asids_init(void)
 {
-	int fld = cpuid_feature_extract_field(read_cpuid(ID_AA64MMFR0_EL1), 4);
-
-	switch (fld) {
-	default:
-		pr_warn("Unknown ASID size (%d); assuming 8-bit\n", fld);
-		/* Fallthrough */
-	case 0:
-		asid_bits = 8;
-		break;
-	case 2:
-		asid_bits = 16;
-	}
-
+	asid_bits = get_cpu_asid_bits();
 	/* If we end up with more CPUs than ASIDs, expect things to crash */
 	WARN_ON(NUM_USER_ASIDS < num_possible_cpus());
 	atomic64_set(&asid_generation, ASID_FIRST_VERSION);
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index 0adbebbc2803..f9271cb2f5e3 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c
@@ -27,15 +27,15 @@
 #include <asm/pgtable.h>
 #include <asm/pgtable-hwdef.h>
 
-#define LOWEST_ADDR	(UL(0xffffffffffffffff) << VA_BITS)
-
 struct addr_marker {
 	unsigned long start_address;
 	const char *name;
 };
 
 enum address_markers_idx {
-	VMALLOC_START_NR = 0,
+	MODULES_START_NR = 0,
+	MODULES_END_NR,
+	VMALLOC_START_NR,
 	VMALLOC_END_NR,
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 	VMEMMAP_START_NR,
@@ -45,12 +45,12 @@ enum address_markers_idx {
 	FIXADDR_END_NR,
 	PCI_START_NR,
 	PCI_END_NR,
-	MODULES_START_NR,
-	MODULES_END_NR,
 	KERNEL_SPACE_NR,
 };
 
 static struct addr_marker address_markers[] = {
+	{ MODULES_VADDR,	"Modules start" },
+	{ MODULES_END,		"Modules end" },
 	{ VMALLOC_START,	"vmalloc() Area" },
 	{ VMALLOC_END,		"vmalloc() End" },
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
@@ -61,9 +61,7 @@ static struct addr_marker address_markers[] = {
 	{ FIXADDR_TOP,		"Fixmap end" },
 	{ PCI_IO_START,		"PCI I/O start" },
 	{ PCI_IO_END,		"PCI I/O end" },
-	{ MODULES_VADDR,	"Modules start" },
-	{ MODULES_END,		"Modules end" },
-	{ PAGE_OFFSET,		"Kernel Mapping" },
+	{ PAGE_OFFSET,		"Linear Mapping" },
 	{ -1,			NULL },
 };
 
@@ -90,6 +88,11 @@ struct prot_bits {
 
 static const struct prot_bits pte_bits[] = {
 	{
+		.mask	= PTE_VALID,
+		.val	= PTE_VALID,
+		.set	= " ",
+		.clear	= "F",
+	}, {
 		.mask	= PTE_USER,
 		.val	= PTE_USER,
 		.set	= "USR",
@@ -316,7 +319,7 @@ static int ptdump_show(struct seq_file *m, void *v)
 		.marker = address_markers,
 	};
 
-	walk_pgd(&st, &init_mm, LOWEST_ADDR);
+	walk_pgd(&st, &init_mm, VA_START);
 
 	note_page(&st, 0, 0, 0);
 	return 0;
diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c
index 79444279ba8c..81acd4706878 100644
--- a/arch/arm64/mm/extable.c
+++ b/arch/arm64/mm/extable.c
@@ -11,7 +11,7 @@ int fixup_exception(struct pt_regs *regs)
 
 	fixup = search_exception_tables(instruction_pointer(regs));
 	if (fixup)
-		regs->pc = fixup->fixup;
+		regs->pc = (unsigned long)&fixup->fixup + fixup->fixup;
 
 	return fixup != NULL;
 }
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index abe2a9542b3a..0077674b2b38 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -192,6 +192,14 @@ out:
 	return fault;
 }
 
+static inline int permission_fault(unsigned int esr)
+{
+	unsigned int ec       = (esr & ESR_ELx_EC_MASK) >> ESR_ELx_EC_SHIFT;
+	unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
+
+	return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM);
+}
+
 static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 				   struct pt_regs *regs)
 {
@@ -225,12 +233,13 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 		mm_flags |= FAULT_FLAG_WRITE;
 	}
 
-	/*
-	 * PAN bit set implies the fault happened in kernel space, but not
-	 * in the arch's user access functions.
-	 */
-	if (IS_ENABLED(CONFIG_ARM64_PAN) && (regs->pstate & PSR_PAN_BIT))
-		goto no_context;
+	if (permission_fault(esr) && (addr < USER_DS)) {
+		if (get_fs() == KERNEL_DS)
+			die("Accessing user space memory with fs=KERNEL_DS", regs, esr);
+
+		if (!search_exception_tables(regs->pc))
+			die("Accessing user space memory outside uaccess.h routines", regs, esr);
+	}
 
 	/*
 	 * As per x86, we may deadlock here. However, since the kernel only
@@ -568,3 +577,16 @@ void cpu_enable_pan(void *__unused)
 	config_sctlr_el1(SCTLR_EL1_SPAN, 0);
 }
 #endif /* CONFIG_ARM64_PAN */
+
+#ifdef CONFIG_ARM64_UAO
+/*
+ * Kernel threads have fs=KERNEL_DS by default, and don't need to call
+ * set_fs(), devtmpfs in particular relies on this behaviour.
+ * We need to enable the feature at runtime (instead of adding it to
+ * PSR_MODE_EL1h) as the feature may not be implemented by the cpu.
+ */
+void cpu_enable_uao(void *__unused)
+{
+	asm(SET_PSTATE_UAO(1));
+}
+#endif /* CONFIG_ARM64_UAO */
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 7802f216a67a..61a38eaf0895 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -35,7 +35,10 @@
 #include <linux/efi.h>
 #include <linux/swiotlb.h>
 
+#include <asm/boot.h>
 #include <asm/fixmap.h>
+#include <asm/kasan.h>
+#include <asm/kernel-pgtable.h>
 #include <asm/memory.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
@@ -45,7 +48,13 @@
 
 #include "mm.h"
 
-phys_addr_t memstart_addr __read_mostly = 0;
+/*
+ * We need to be able to catch inadvertent references to memstart_addr
+ * that occur (potentially in generic code) before arm64_memblock_init()
+ * executes, which assigns it its actual value. So use a default value
+ * that cannot be mistaken for a real physical address.
+ */
+s64 memstart_addr __read_mostly = -1;
 phys_addr_t arm64_dma_phys_limit __read_mostly;
 
 #ifdef CONFIG_BLK_DEV_INITRD
@@ -58,8 +67,8 @@ static int __init early_initrd(char *p)
 	if (*endp == ',') {
 		size = memparse(endp + 1, NULL);
 
-		initrd_start = (unsigned long)__va(start);
-		initrd_end = (unsigned long)__va(start + size);
+		initrd_start = start;
+		initrd_end = start + size;
 	}
 	return 0;
 }
@@ -159,7 +168,57 @@ early_param("mem", early_mem);
 
 void __init arm64_memblock_init(void)
 {
-	memblock_enforce_memory_limit(memory_limit);
+	const s64 linear_region_size = -(s64)PAGE_OFFSET;
+
+	/*
+	 * Ensure that the linear region takes up exactly half of the kernel
+	 * virtual address space. This way, we can distinguish a linear address
+	 * from a kernel/module/vmalloc address by testing a single bit.
+	 */
+	BUILD_BUG_ON(linear_region_size != BIT(VA_BITS - 1));
+
+	/*
+	 * Select a suitable value for the base of physical memory.
+	 */
+	memstart_addr = round_down(memblock_start_of_DRAM(),
+				   ARM64_MEMSTART_ALIGN);
+
+	/*
+	 * Remove the memory that we will not be able to cover with the
+	 * linear mapping. Take care not to clip the kernel which may be
+	 * high in memory.
+	 */
+	memblock_remove(max_t(u64, memstart_addr + linear_region_size, __pa(_end)),
+			ULLONG_MAX);
+	if (memblock_end_of_DRAM() > linear_region_size)
+		memblock_remove(0, memblock_end_of_DRAM() - linear_region_size);
+
+	/*
+	 * Apply the memory limit if it was set. Since the kernel may be loaded
+	 * high up in memory, add back the kernel region that must be accessible
+	 * via the linear mapping.
+	 */
+	if (memory_limit != (phys_addr_t)ULLONG_MAX) {
+		memblock_enforce_memory_limit(memory_limit);
+		memblock_add(__pa(_text), (u64)(_end - _text));
+	}
+
+	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
+		extern u16 memstart_offset_seed;
+		u64 range = linear_region_size -
+			    (memblock_end_of_DRAM() - memblock_start_of_DRAM());
+
+		/*
+		 * If the size of the linear region exceeds, by a sufficient
+		 * margin, the size of the region that the available physical
+		 * memory spans, randomize the linear region as well.
+		 */
+		if (memstart_offset_seed > 0 && range >= ARM64_MEMSTART_ALIGN) {
+			range = range / ARM64_MEMSTART_ALIGN + 1;
+			memstart_addr -= ARM64_MEMSTART_ALIGN *
+					 ((range * memstart_offset_seed) >> 16);
+		}
+	}
 
 	/*
 	 * Register the kernel text, kernel data, initrd, and initial
@@ -167,8 +226,13 @@ void __init arm64_memblock_init(void)
 	 */
 	memblock_reserve(__pa(_text), _end - _text);
 #ifdef CONFIG_BLK_DEV_INITRD
-	if (initrd_start)
-		memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
+	if (initrd_start) {
+		memblock_reserve(initrd_start, initrd_end - initrd_start);
+
+		/* the generic initrd code expects virtual addresses */
+		initrd_start = __phys_to_virt(initrd_start);
+		initrd_end = __phys_to_virt(initrd_end);
+	}
 #endif
 
 	early_init_fdt_scan_reserved_mem();
@@ -302,35 +366,38 @@ void __init mem_init(void)
 #ifdef CONFIG_KASAN
 		  "    kasan   : 0x%16lx - 0x%16lx   (%6ld GB)\n"
 #endif
+		  "    modules : 0x%16lx - 0x%16lx   (%6ld MB)\n"
 		  "    vmalloc : 0x%16lx - 0x%16lx   (%6ld GB)\n"
+		  "      .text : 0x%p" " - 0x%p" "   (%6ld KB)\n"
+		  "    .rodata : 0x%p" " - 0x%p" "   (%6ld KB)\n"
+		  "      .init : 0x%p" " - 0x%p" "   (%6ld KB)\n"
+		  "      .data : 0x%p" " - 0x%p" "   (%6ld KB)\n"
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 		  "    vmemmap : 0x%16lx - 0x%16lx   (%6ld GB maximum)\n"
 		  "              0x%16lx - 0x%16lx   (%6ld MB actual)\n"
 #endif
 		  "    fixed   : 0x%16lx - 0x%16lx   (%6ld KB)\n"
 		  "    PCI I/O : 0x%16lx - 0x%16lx   (%6ld MB)\n"
-		  "    modules : 0x%16lx - 0x%16lx   (%6ld MB)\n"
-		  "    memory  : 0x%16lx - 0x%16lx   (%6ld MB)\n"
-		  "      .init : 0x%p" " - 0x%p" "   (%6ld KB)\n"
-		  "      .text : 0x%p" " - 0x%p" "   (%6ld KB)\n"
-		  "      .data : 0x%p" " - 0x%p" "   (%6ld KB)\n",
+		  "    memory  : 0x%16lx - 0x%16lx   (%6ld MB)\n",
 #ifdef CONFIG_KASAN
 		  MLG(KASAN_SHADOW_START, KASAN_SHADOW_END),
 #endif
+		  MLM(MODULES_VADDR, MODULES_END),
 		  MLG(VMALLOC_START, VMALLOC_END),
+		  MLK_ROUNDUP(_text, __start_rodata),
+		  MLK_ROUNDUP(__start_rodata, _etext),
+		  MLK_ROUNDUP(__init_begin, __init_end),
+		  MLK_ROUNDUP(_sdata, _edata),
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 		  MLG(VMEMMAP_START,
 		      VMEMMAP_START + VMEMMAP_SIZE),
-		  MLM((unsigned long)virt_to_page(PAGE_OFFSET),
+		  MLM((unsigned long)phys_to_page(memblock_start_of_DRAM()),
 		      (unsigned long)virt_to_page(high_memory)),
 #endif
 		  MLK(FIXADDR_START, FIXADDR_TOP),
 		  MLM(PCI_IO_START, PCI_IO_END),
-		  MLM(MODULES_VADDR, MODULES_END),
-		  MLM(PAGE_OFFSET, (unsigned long)high_memory),
-		  MLK_ROUNDUP(__init_begin, __init_end),
-		  MLK_ROUNDUP(_text, _etext),
-		  MLK_ROUNDUP(_sdata, _edata));
+		  MLM(__phys_to_virt(memblock_start_of_DRAM()),
+		      (unsigned long)high_memory));
 
 #undef MLK
 #undef MLM
@@ -343,8 +410,6 @@ void __init mem_init(void)
 #ifdef CONFIG_COMPAT
 	BUILD_BUG_ON(TASK_SIZE_32			> TASK_SIZE_64);
 #endif
-	BUILD_BUG_ON(TASK_SIZE_64			> MODULES_VADDR);
-	BUG_ON(TASK_SIZE_64				> MODULES_VADDR);
 
 	if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
 		extern int sysctl_overcommit_memory;
@@ -358,8 +423,8 @@ void __init mem_init(void)
 
 void free_initmem(void)
 {
-	fixup_init();
 	free_initmem_default(0);
+	fixup_init();
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD
@@ -380,3 +445,28 @@ static int __init keepinitrd_setup(char *__unused)
 
 __setup("keepinitrd", keepinitrd_setup);
 #endif
+
+/*
+ * Dump out memory limit information on panic.
+ */
+static int dump_mem_limit(struct notifier_block *self, unsigned long v, void *p)
+{
+	if (memory_limit != (phys_addr_t)ULLONG_MAX) {
+		pr_emerg("Memory Limit: %llu MB\n", memory_limit >> 20);
+	} else {
+		pr_emerg("Memory Limit: none\n");
+	}
+	return 0;
+}
+
+static struct notifier_block mem_limit_notifier = {
+	.notifier_call = dump_mem_limit,
+};
+
+static int __init register_mem_limit_dumper(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list,
+				       &mem_limit_notifier);
+	return 0;
+}
+__initcall(register_mem_limit_dumper);
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index cab7a5be40aa..757009daa9ed 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -16,9 +16,12 @@
 #include <linux/memblock.h>
 #include <linux/start_kernel.h>
 
+#include <asm/mmu_context.h>
+#include <asm/kernel-pgtable.h>
 #include <asm/page.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
+#include <asm/sections.h>
 #include <asm/tlbflush.h>
 
 static pgd_t tmp_pg_dir[PTRS_PER_PGD] __initdata __aligned(PGD_SIZE);
@@ -32,7 +35,7 @@ static void __init kasan_early_pte_populate(pmd_t *pmd, unsigned long addr,
 	if (pmd_none(*pmd))
 		pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
 
-	pte = pte_offset_kernel(pmd, addr);
+	pte = pte_offset_kimg(pmd, addr);
 	do {
 		next = addr + PAGE_SIZE;
 		set_pte(pte, pfn_pte(virt_to_pfn(kasan_zero_page),
@@ -50,7 +53,7 @@ static void __init kasan_early_pmd_populate(pud_t *pud,
 	if (pud_none(*pud))
 		pud_populate(&init_mm, pud, kasan_zero_pmd);
 
-	pmd = pmd_offset(pud, addr);
+	pmd = pmd_offset_kimg(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
 		kasan_early_pte_populate(pmd, addr, next);
@@ -67,7 +70,7 @@ static void __init kasan_early_pud_populate(pgd_t *pgd,
 	if (pgd_none(*pgd))
 		pgd_populate(&init_mm, pgd, kasan_zero_pud);
 
-	pud = pud_offset(pgd, addr);
+	pud = pud_offset_kimg(pgd, addr);
 	do {
 		next = pud_addr_end(addr, end);
 		kasan_early_pmd_populate(pud, addr, next);
@@ -96,6 +99,21 @@ asmlinkage void __init kasan_early_init(void)
 	kasan_map_early_shadow();
 }
 
+/*
+ * Copy the current shadow region into a new pgdir.
+ */
+void __init kasan_copy_shadow(pgd_t *pgdir)
+{
+	pgd_t *pgd, *pgd_new, *pgd_end;
+
+	pgd = pgd_offset_k(KASAN_SHADOW_START);
+	pgd_end = pgd_offset_k(KASAN_SHADOW_END);
+	pgd_new = pgd_offset_raw(pgdir, KASAN_SHADOW_START);
+	do {
+		set_pgd(pgd_new, *pgd);
+	} while (pgd++, pgd_new++, pgd != pgd_end);
+}
+
 static void __init clear_pgds(unsigned long start,
 			unsigned long end)
 {
@@ -108,20 +126,19 @@ static void __init clear_pgds(unsigned long start,
 		set_pgd(pgd_offset_k(start), __pgd(0));
 }
 
-static void __init cpu_set_ttbr1(unsigned long ttbr1)
-{
-	asm(
-	"	msr	ttbr1_el1, %0\n"
-	"	isb"
-	:
-	: "r" (ttbr1));
-}
-
 void __init kasan_init(void)
 {
+	u64 kimg_shadow_start, kimg_shadow_end;
+	u64 mod_shadow_start, mod_shadow_end;
 	struct memblock_region *reg;
 	int i;
 
+	kimg_shadow_start = (u64)kasan_mem_to_shadow(_text);
+	kimg_shadow_end = (u64)kasan_mem_to_shadow(_end);
+
+	mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR);
+	mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END);
+
 	/*
 	 * We are going to perform proper setup of shadow memory.
 	 * At first we should unmap early shadow (clear_pgds() call bellow).
@@ -130,13 +147,33 @@ void __init kasan_init(void)
 	 * setup will be finished.
 	 */
 	memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(tmp_pg_dir));
-	cpu_set_ttbr1(__pa(tmp_pg_dir));
-	flush_tlb_all();
+	dsb(ishst);
+	cpu_replace_ttbr1(tmp_pg_dir);
 
 	clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
 
+	vmemmap_populate(kimg_shadow_start, kimg_shadow_end,
+			 pfn_to_nid(virt_to_pfn(_text)));
+
+	/*
+	 * vmemmap_populate() has populated the shadow region that covers the
+	 * kernel image with SWAPPER_BLOCK_SIZE mappings, so we have to round
+	 * the start and end addresses to SWAPPER_BLOCK_SIZE as well, to prevent
+	 * kasan_populate_zero_shadow() from replacing the page table entries
+	 * (PMD or PTE) at the edges of the shadow region for the kernel
+	 * image.
+	 */
+	kimg_shadow_start = round_down(kimg_shadow_start, SWAPPER_BLOCK_SIZE);
+	kimg_shadow_end = round_up(kimg_shadow_end, SWAPPER_BLOCK_SIZE);
+
 	kasan_populate_zero_shadow((void *)KASAN_SHADOW_START,
-			kasan_mem_to_shadow((void *)MODULES_VADDR));
+				   (void *)mod_shadow_start);
+	kasan_populate_zero_shadow((void *)kimg_shadow_end,
+				   kasan_mem_to_shadow((void *)PAGE_OFFSET));
+
+	if (kimg_shadow_start > mod_shadow_end)
+		kasan_populate_zero_shadow((void *)mod_shadow_end,
+					   (void *)kimg_shadow_start);
 
 	for_each_memblock(memory, reg) {
 		void *start = (void *)__phys_to_virt(reg->base);
@@ -165,8 +202,7 @@ void __init kasan_init(void)
 			pfn_pte(virt_to_pfn(kasan_zero_page), PAGE_KERNEL_RO));
 
 	memset(kasan_zero_page, 0, PAGE_SIZE);
-	cpu_set_ttbr1(__pa(swapper_pg_dir));
-	flush_tlb_all();
+	cpu_replace_ttbr1(swapper_pg_dir);
 
 	/* At this point kasan is fully initialized. Enable error messages */
 	init_task.kasan_depth = 0;
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 58faeaa7fbdc..d2d8b8c2e17f 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -30,8 +30,10 @@
 #include <linux/slab.h>
 #include <linux/stop_machine.h>
 
+#include <asm/barrier.h>
 #include <asm/cputype.h>
 #include <asm/fixmap.h>
+#include <asm/kasan.h>
 #include <asm/kernel-pgtable.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
@@ -44,13 +46,20 @@
 
 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
 
+u64 kimage_voffset __read_mostly;
+EXPORT_SYMBOL(kimage_voffset);
+
 /*
  * Empty_zero_page is a special page that is used for zero-initialized data
  * and COW.
  */
-struct page *empty_zero_page;
+unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
 EXPORT_SYMBOL(empty_zero_page);
 
+static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
+static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
+static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
+
 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 			      unsigned long size, pgprot_t vma_prot)
 {
@@ -62,16 +71,30 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 }
 EXPORT_SYMBOL(phys_mem_access_prot);
 
-static void __init *early_alloc(unsigned long sz)
+static phys_addr_t __init early_pgtable_alloc(void)
 {
 	phys_addr_t phys;
 	void *ptr;
 
-	phys = memblock_alloc(sz, sz);
+	phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 	BUG_ON(!phys);
-	ptr = __va(phys);
-	memset(ptr, 0, sz);
-	return ptr;
+
+	/*
+	 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
+	 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
+	 * any level of table.
+	 */
+	ptr = pte_set_fixmap(phys);
+
+	memset(ptr, 0, PAGE_SIZE);
+
+	/*
+	 * Implicit barriers also ensure the zeroed page is visible to the page
+	 * table walker
+	 */
+	pte_clear_fixmap();
+
+	return phys;
 }
 
 /*
@@ -95,24 +118,30 @@ static void split_pmd(pmd_t *pmd, pte_t *pte)
 static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
 				  unsigned long end, unsigned long pfn,
 				  pgprot_t prot,
-				  void *(*alloc)(unsigned long size))
+				  phys_addr_t (*pgtable_alloc)(void))
 {
 	pte_t *pte;
 
 	if (pmd_none(*pmd) || pmd_sect(*pmd)) {
-		pte = alloc(PTRS_PER_PTE * sizeof(pte_t));
+		phys_addr_t pte_phys;
+		BUG_ON(!pgtable_alloc);
+		pte_phys = pgtable_alloc();
+		pte = pte_set_fixmap(pte_phys);
 		if (pmd_sect(*pmd))
 			split_pmd(pmd, pte);
-		__pmd_populate(pmd, __pa(pte), PMD_TYPE_TABLE);
+		__pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE);
 		flush_tlb_all();
+		pte_clear_fixmap();
 	}
 	BUG_ON(pmd_bad(*pmd));
 
-	pte = pte_offset_kernel(pmd, addr);
+	pte = pte_set_fixmap_offset(pmd, addr);
 	do {
 		set_pte(pte, pfn_pte(pfn, prot));
 		pfn++;
 	} while (pte++, addr += PAGE_SIZE, addr != end);
+
+	pte_clear_fixmap();
 }
 
 static void split_pud(pud_t *old_pud, pmd_t *pmd)
@@ -127,10 +156,29 @@ static void split_pud(pud_t *old_pud, pmd_t *pmd)
 	} while (pmd++, i++, i < PTRS_PER_PMD);
 }
 
-static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
-				  unsigned long addr, unsigned long end,
+#ifdef CONFIG_DEBUG_PAGEALLOC
+static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void))
+{
+
+	/*
+	 * If debug_page_alloc is enabled we must map the linear map
+	 * using pages. However, other mappings created by
+	 * create_mapping_noalloc must use sections in some cases. Allow
+	 * sections to be used in those cases, where no pgtable_alloc
+	 * function is provided.
+	 */
+	return !pgtable_alloc || !debug_pagealloc_enabled();
+}
+#else
+static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void))
+{
+	return true;
+}
+#endif
+
+static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 				  phys_addr_t phys, pgprot_t prot,
-				  void *(*alloc)(unsigned long size))
+				  phys_addr_t (*pgtable_alloc)(void))
 {
 	pmd_t *pmd;
 	unsigned long next;
@@ -139,7 +187,10 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
 	 * Check for initial section mappings in the pgd/pud and remove them.
 	 */
 	if (pud_none(*pud) || pud_sect(*pud)) {
-		pmd = alloc(PTRS_PER_PMD * sizeof(pmd_t));
+		phys_addr_t pmd_phys;
+		BUG_ON(!pgtable_alloc);
+		pmd_phys = pgtable_alloc();
+		pmd = pmd_set_fixmap(pmd_phys);
 		if (pud_sect(*pud)) {
 			/*
 			 * need to have the 1G of mappings continue to be
@@ -147,16 +198,18 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
 			 */
 			split_pud(pud, pmd);
 		}
-		pud_populate(mm, pud, pmd);
+		__pud_populate(pud, pmd_phys, PUD_TYPE_TABLE);
 		flush_tlb_all();
+		pmd_clear_fixmap();
 	}
 	BUG_ON(pud_bad(*pud));
 
-	pmd = pmd_offset(pud, addr);
+	pmd = pmd_set_fixmap_offset(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
 		/* try section mapping first */
-		if (((addr | next | phys) & ~SECTION_MASK) == 0) {
+		if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
+		      block_mappings_allowed(pgtable_alloc)) {
 			pmd_t old_pmd =*pmd;
 			set_pmd(pmd, __pmd(phys |
 					   pgprot_val(mk_sect_prot(prot))));
@@ -167,17 +220,19 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
 			if (!pmd_none(old_pmd)) {
 				flush_tlb_all();
 				if (pmd_table(old_pmd)) {
-					phys_addr_t table = __pa(pte_offset_map(&old_pmd, 0));
+					phys_addr_t table = pmd_page_paddr(old_pmd);
 					if (!WARN_ON_ONCE(slab_is_available()))
 						memblock_free(table, PAGE_SIZE);
 				}
 			}
 		} else {
 			alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
-				       prot, alloc);
+				       prot, pgtable_alloc);
 		}
 		phys += next - addr;
 	} while (pmd++, addr = next, addr != end);
+
+	pmd_clear_fixmap();
 }
 
 static inline bool use_1G_block(unsigned long addr, unsigned long next,
@@ -192,28 +247,30 @@ static inline bool use_1G_block(unsigned long addr, unsigned long next,
 	return true;
 }
 
-static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
-				  unsigned long addr, unsigned long end,
+static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 				  phys_addr_t phys, pgprot_t prot,
-				  void *(*alloc)(unsigned long size))
+				  phys_addr_t (*pgtable_alloc)(void))
 {
 	pud_t *pud;
 	unsigned long next;
 
 	if (pgd_none(*pgd)) {
-		pud = alloc(PTRS_PER_PUD * sizeof(pud_t));
-		pgd_populate(mm, pgd, pud);
+		phys_addr_t pud_phys;
+		BUG_ON(!pgtable_alloc);
+		pud_phys = pgtable_alloc();
+		__pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE);
 	}
 	BUG_ON(pgd_bad(*pgd));
 
-	pud = pud_offset(pgd, addr);
+	pud = pud_set_fixmap_offset(pgd, addr);
 	do {
 		next = pud_addr_end(addr, end);
 
 		/*
 		 * For 4K granule only, attempt to put down a 1GB block
 		 */
-		if (use_1G_block(addr, next, phys)) {
+		if (use_1G_block(addr, next, phys) &&
+		    block_mappings_allowed(pgtable_alloc)) {
 			pud_t old_pud = *pud;
 			set_pud(pud, __pud(phys |
 					   pgprot_val(mk_sect_prot(prot))));
@@ -228,26 +285,28 @@ static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd,
 			if (!pud_none(old_pud)) {
 				flush_tlb_all();
 				if (pud_table(old_pud)) {
-					phys_addr_t table = __pa(pmd_offset(&old_pud, 0));
+					phys_addr_t table = pud_page_paddr(old_pud);
 					if (!WARN_ON_ONCE(slab_is_available()))
 						memblock_free(table, PAGE_SIZE);
 				}
 			}
 		} else {
-			alloc_init_pmd(mm, pud, addr, next, phys, prot, alloc);
+			alloc_init_pmd(pud, addr, next, phys, prot,
+				       pgtable_alloc);
 		}
 		phys += next - addr;
 	} while (pud++, addr = next, addr != end);
+
+	pud_clear_fixmap();
 }
 
 /*
  * Create the page directory entries and any necessary page tables for the
  * mapping specified by 'md'.
  */
-static void  __create_mapping(struct mm_struct *mm, pgd_t *pgd,
-				    phys_addr_t phys, unsigned long virt,
+static void init_pgd(pgd_t *pgd, phys_addr_t phys, unsigned long virt,
 				    phys_addr_t size, pgprot_t prot,
-				    void *(*alloc)(unsigned long size))
+				    phys_addr_t (*pgtable_alloc)(void))
 {
 	unsigned long addr, length, end, next;
 
@@ -265,22 +324,35 @@ static void  __create_mapping(struct mm_struct *mm, pgd_t *pgd,
 	end = addr + length;
 	do {
 		next = pgd_addr_end(addr, end);
-		alloc_init_pud(mm, pgd, addr, next, phys, prot, alloc);
+		alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc);
 		phys += next - addr;
 	} while (pgd++, addr = next, addr != end);
 }
 
-static void *late_alloc(unsigned long size)
+static phys_addr_t late_pgtable_alloc(void)
 {
-	void *ptr;
-
-	BUG_ON(size > PAGE_SIZE);
-	ptr = (void *)__get_free_page(PGALLOC_GFP);
+	void *ptr = (void *)__get_free_page(PGALLOC_GFP);
 	BUG_ON(!ptr);
-	return ptr;
+
+	/* Ensure the zeroed page is visible to the page table walker */
+	dsb(ishst);
+	return __pa(ptr);
 }
 
-static void __init create_mapping(phys_addr_t phys, unsigned long virt,
+static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
+				 unsigned long virt, phys_addr_t size,
+				 pgprot_t prot,
+				 phys_addr_t (*alloc)(void))
+{
+	init_pgd(pgd_offset_raw(pgdir, virt), phys, virt, size, prot, alloc);
+}
+
+/*
+ * This function can only be used to modify existing table entries,
+ * without allocating new levels of table. Note that this permits the
+ * creation of new section or page entries.
+ */
+static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 				  phys_addr_t size, pgprot_t prot)
 {
 	if (virt < VMALLOC_START) {
@@ -288,16 +360,16 @@ static void __init create_mapping(phys_addr_t phys, unsigned long virt,
 			&phys, virt);
 		return;
 	}
-	__create_mapping(&init_mm, pgd_offset_k(virt), phys, virt,
-			 size, prot, early_alloc);
+	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
+			     NULL);
 }
 
 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 			       unsigned long virt, phys_addr_t size,
 			       pgprot_t prot)
 {
-	__create_mapping(mm, pgd_offset(mm, virt), phys, virt, size, prot,
-				late_alloc);
+	__create_pgd_mapping(mm->pgd, phys, virt, size, prot,
+			     late_pgtable_alloc);
 }
 
 static void create_mapping_late(phys_addr_t phys, unsigned long virt,
@@ -309,69 +381,57 @@ static void create_mapping_late(phys_addr_t phys, unsigned long virt,
 		return;
 	}
 
-	return __create_mapping(&init_mm, pgd_offset_k(virt),
-				phys, virt, size, prot, late_alloc);
+	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
+			     late_pgtable_alloc);
 }
 
-#ifdef CONFIG_DEBUG_RODATA
-static void __init __map_memblock(phys_addr_t start, phys_addr_t end)
+static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end)
 {
+	unsigned long kernel_start = __pa(_stext);
+	unsigned long kernel_end = __pa(_etext);
+
 	/*
-	 * Set up the executable regions using the existing section mappings
-	 * for now. This will get more fine grained later once all memory
-	 * is mapped
+	 * Take care not to create a writable alias for the
+	 * read-only text and rodata sections of the kernel image.
 	 */
-	unsigned long kernel_x_start = round_down(__pa(_stext), SWAPPER_BLOCK_SIZE);
-	unsigned long kernel_x_end = round_up(__pa(__init_end), SWAPPER_BLOCK_SIZE);
-
-	if (end < kernel_x_start) {
-		create_mapping(start, __phys_to_virt(start),
-			end - start, PAGE_KERNEL);
-	} else if (start >= kernel_x_end) {
-		create_mapping(start, __phys_to_virt(start),
-			end - start, PAGE_KERNEL);
-	} else {
-		if (start < kernel_x_start)
-			create_mapping(start, __phys_to_virt(start),
-				kernel_x_start - start,
-				PAGE_KERNEL);
-		create_mapping(kernel_x_start,
-				__phys_to_virt(kernel_x_start),
-				kernel_x_end - kernel_x_start,
-				PAGE_KERNEL_EXEC);
-		if (kernel_x_end < end)
-			create_mapping(kernel_x_end,
-				__phys_to_virt(kernel_x_end),
-				end - kernel_x_end,
-				PAGE_KERNEL);
+
+	/* No overlap with the kernel text */
+	if (end < kernel_start || start >= kernel_end) {
+		__create_pgd_mapping(pgd, start, __phys_to_virt(start),
+				     end - start, PAGE_KERNEL,
+				     early_pgtable_alloc);
+		return;
 	}
 
+	/*
+	 * This block overlaps the kernel text mapping.
+	 * Map the portion(s) which don't overlap.
+	 */
+	if (start < kernel_start)
+		__create_pgd_mapping(pgd, start,
+				     __phys_to_virt(start),
+				     kernel_start - start, PAGE_KERNEL,
+				     early_pgtable_alloc);
+	if (kernel_end < end)
+		__create_pgd_mapping(pgd, kernel_end,
+				     __phys_to_virt(kernel_end),
+				     end - kernel_end, PAGE_KERNEL,
+				     early_pgtable_alloc);
+
+	/*
+	 * Map the linear alias of the [_stext, _etext) interval as
+	 * read-only/non-executable. This makes the contents of the
+	 * region accessible to subsystems such as hibernate, but
+	 * protects it from inadvertent modification or execution.
+	 */
+	__create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
+			     kernel_end - kernel_start, PAGE_KERNEL_RO,
+			     early_pgtable_alloc);
 }
-#else
-static void __init __map_memblock(phys_addr_t start, phys_addr_t end)
-{
-	create_mapping(start, __phys_to_virt(start), end - start,
-			PAGE_KERNEL_EXEC);
-}
-#endif
 
-static void __init map_mem(void)
+static void __init map_mem(pgd_t *pgd)
 {
 	struct memblock_region *reg;
-	phys_addr_t limit;
-
-	/*
-	 * Temporarily limit the memblock range. We need to do this as
-	 * create_mapping requires puds, pmds and ptes to be allocated from
-	 * memory addressable from the initial direct kernel mapping.
-	 *
-	 * The initial direct kernel mapping, located at swapper_pg_dir, gives
-	 * us PUD_SIZE (with SECTION maps) or PMD_SIZE (without SECTION maps,
-	 * memory starting from PHYS_OFFSET (which must be aligned to 2MB as
-	 * per Documentation/arm64/booting.txt).
-	 */
-	limit = PHYS_OFFSET + SWAPPER_INIT_MAP_SIZE;
-	memblock_set_current_limit(limit);
 
 	/* map all the memory banks */
 	for_each_memblock(memory, reg) {
@@ -383,69 +443,94 @@ static void __init map_mem(void)
 		if (memblock_is_nomap(reg))
 			continue;
 
-		if (ARM64_SWAPPER_USES_SECTION_MAPS) {
-			/*
-			 * For the first memory bank align the start address and
-			 * current memblock limit to prevent create_mapping() from
-			 * allocating pte page tables from unmapped memory. With
-			 * the section maps, if the first block doesn't end on section
-			 * size boundary, create_mapping() will try to allocate a pte
-			 * page, which may be returned from an unmapped area.
-			 * When section maps are not used, the pte page table for the
-			 * current limit is already present in swapper_pg_dir.
-			 */
-			if (start < limit)
-				start = ALIGN(start, SECTION_SIZE);
-			if (end < limit) {
-				limit = end & SECTION_MASK;
-				memblock_set_current_limit(limit);
-			}
-		}
-		__map_memblock(start, end);
+		__map_memblock(pgd, start, end);
 	}
-
-	/* Limit no longer required. */
-	memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
 }
 
-static void __init fixup_executable(void)
+void mark_rodata_ro(void)
 {
-#ifdef CONFIG_DEBUG_RODATA
-	/* now that we are actually fully mapped, make the start/end more fine grained */
-	if (!IS_ALIGNED((unsigned long)_stext, SWAPPER_BLOCK_SIZE)) {
-		unsigned long aligned_start = round_down(__pa(_stext),
-							 SWAPPER_BLOCK_SIZE);
+	unsigned long section_size;
 
-		create_mapping(aligned_start, __phys_to_virt(aligned_start),
-				__pa(_stext) - aligned_start,
-				PAGE_KERNEL);
-	}
+	section_size = (unsigned long)__start_rodata - (unsigned long)_stext;
+	create_mapping_late(__pa(_stext), (unsigned long)_stext,
+			    section_size, PAGE_KERNEL_ROX);
+	/*
+	 * mark .rodata as read only. Use _etext rather than __end_rodata to
+	 * cover NOTES and EXCEPTION_TABLE.
+	 */
+	section_size = (unsigned long)_etext - (unsigned long)__start_rodata;
+	create_mapping_late(__pa(__start_rodata), (unsigned long)__start_rodata,
+			    section_size, PAGE_KERNEL_RO);
+}
 
-	if (!IS_ALIGNED((unsigned long)__init_end, SWAPPER_BLOCK_SIZE)) {
-		unsigned long aligned_end = round_up(__pa(__init_end),
-							  SWAPPER_BLOCK_SIZE);
-		create_mapping(__pa(__init_end), (unsigned long)__init_end,
-				aligned_end - __pa(__init_end),
-				PAGE_KERNEL);
-	}
-#endif
+void fixup_init(void)
+{
+	/*
+	 * Unmap the __init region but leave the VM area in place. This
+	 * prevents the region from being reused for kernel modules, which
+	 * is not supported by kallsyms.
+	 */
+	unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
 }
 
-#ifdef CONFIG_DEBUG_RODATA
-void mark_rodata_ro(void)
+static void __init map_kernel_chunk(pgd_t *pgd, void *va_start, void *va_end,
+				    pgprot_t prot, struct vm_struct *vma)
 {
-	create_mapping_late(__pa(_stext), (unsigned long)_stext,
-				(unsigned long)_etext - (unsigned long)_stext,
-				PAGE_KERNEL_ROX);
+	phys_addr_t pa_start = __pa(va_start);
+	unsigned long size = va_end - va_start;
+
+	BUG_ON(!PAGE_ALIGNED(pa_start));
+	BUG_ON(!PAGE_ALIGNED(size));
+
+	__create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
+			     early_pgtable_alloc);
+
+	vma->addr	= va_start;
+	vma->phys_addr	= pa_start;
+	vma->size	= size;
+	vma->flags	= VM_MAP;
+	vma->caller	= __builtin_return_address(0);
 
+	vm_area_add_early(vma);
 }
-#endif
 
-void fixup_init(void)
+/*
+ * Create fine-grained mappings for the kernel.
+ */
+static void __init map_kernel(pgd_t *pgd)
 {
-	create_mapping_late(__pa(__init_begin), (unsigned long)__init_begin,
-			(unsigned long)__init_end - (unsigned long)__init_begin,
-			PAGE_KERNEL);
+	static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data;
+
+	map_kernel_chunk(pgd, _stext, __start_rodata, PAGE_KERNEL_EXEC, &vmlinux_text);
+	map_kernel_chunk(pgd, __start_rodata, _etext, PAGE_KERNEL, &vmlinux_rodata);
+	map_kernel_chunk(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
+			 &vmlinux_init);
+	map_kernel_chunk(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
+
+	if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) {
+		/*
+		 * The fixmap falls in a separate pgd to the kernel, and doesn't
+		 * live in the carveout for the swapper_pg_dir. We can simply
+		 * re-use the existing dir for the fixmap.
+		 */
+		set_pgd(pgd_offset_raw(pgd, FIXADDR_START),
+			*pgd_offset_k(FIXADDR_START));
+	} else if (CONFIG_PGTABLE_LEVELS > 3) {
+		/*
+		 * The fixmap shares its top level pgd entry with the kernel
+		 * mapping. This can really only occur when we are running
+		 * with 16k/4 levels, so we can simply reuse the pud level
+		 * entry instead.
+		 */
+		BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
+		set_pud(pud_set_fixmap_offset(pgd, FIXADDR_START),
+			__pud(__pa(bm_pmd) | PUD_TYPE_TABLE));
+		pud_clear_fixmap();
+	} else {
+		BUG();
+	}
+
+	kasan_copy_shadow(pgd);
 }
 
 /*
@@ -454,28 +539,35 @@ void fixup_init(void)
  */
 void __init paging_init(void)
 {
-	void *zero_page;
+	phys_addr_t pgd_phys = early_pgtable_alloc();
+	pgd_t *pgd = pgd_set_fixmap(pgd_phys);
 
-	map_mem();
-	fixup_executable();
+	map_kernel(pgd);
+	map_mem(pgd);
 
-	/* allocate the zero page. */
-	zero_page = early_alloc(PAGE_SIZE);
-
-	bootmem_init();
-
-	empty_zero_page = virt_to_page(zero_page);
+	/*
+	 * We want to reuse the original swapper_pg_dir so we don't have to
+	 * communicate the new address to non-coherent secondaries in
+	 * secondary_entry, and so cpu_switch_mm can generate the address with
+	 * adrp+add rather than a load from some global variable.
+	 *
+	 * To do this we need to go via a temporary pgd.
+	 */
+	cpu_replace_ttbr1(__va(pgd_phys));
+	memcpy(swapper_pg_dir, pgd, PAGE_SIZE);
+	cpu_replace_ttbr1(swapper_pg_dir);
 
-	/* Ensure the zero page is visible to the page table walker */
-	dsb(ishst);
+	pgd_clear_fixmap();
+	memblock_free(pgd_phys, PAGE_SIZE);
 
 	/*
-	 * TTBR0 is only used for the identity mapping at this stage. Make it
-	 * point to zero page to avoid speculatively fetching new entries.
+	 * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd
+	 * allocated with it.
 	 */
-	cpu_set_reserved_ttbr0();
-	local_flush_tlb_all();
-	cpu_set_default_tcr_t0sz();
+	memblock_free(__pa(swapper_pg_dir) + PAGE_SIZE,
+		      SWAPPER_DIR_SIZE - PAGE_SIZE);
+
+	bootmem_init();
 }
 
 /*
@@ -562,21 +654,13 @@ void vmemmap_free(unsigned long start, unsigned long end)
 }
 #endif	/* CONFIG_SPARSEMEM_VMEMMAP */
 
-static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
-#if CONFIG_PGTABLE_LEVELS > 2
-static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss;
-#endif
-#if CONFIG_PGTABLE_LEVELS > 3
-static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss;
-#endif
-
 static inline pud_t * fixmap_pud(unsigned long addr)
 {
 	pgd_t *pgd = pgd_offset_k(addr);
 
 	BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
 
-	return pud_offset(pgd, addr);
+	return pud_offset_kimg(pgd, addr);
 }
 
 static inline pmd_t * fixmap_pmd(unsigned long addr)
@@ -585,16 +669,12 @@ static inline pmd_t * fixmap_pmd(unsigned long addr)
 
 	BUG_ON(pud_none(*pud) || pud_bad(*pud));
 
-	return pmd_offset(pud, addr);
+	return pmd_offset_kimg(pud, addr);
 }
 
 static inline pte_t * fixmap_pte(unsigned long addr)
 {
-	pmd_t *pmd = fixmap_pmd(addr);
-
-	BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd));
-
-	return pte_offset_kernel(pmd, addr);
+	return &bm_pte[pte_index(addr)];
 }
 
 void __init early_fixmap_init(void)
@@ -605,15 +685,26 @@ void __init early_fixmap_init(void)
 	unsigned long addr = FIXADDR_START;
 
 	pgd = pgd_offset_k(addr);
-	pgd_populate(&init_mm, pgd, bm_pud);
-	pud = pud_offset(pgd, addr);
+	if (CONFIG_PGTABLE_LEVELS > 3 &&
+	    !(pgd_none(*pgd) || pgd_page_paddr(*pgd) == __pa(bm_pud))) {
+		/*
+		 * We only end up here if the kernel mapping and the fixmap
+		 * share the top level pgd entry, which should only happen on
+		 * 16k/4 levels configurations.
+		 */
+		BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
+		pud = pud_offset_kimg(pgd, addr);
+	} else {
+		pgd_populate(&init_mm, pgd, bm_pud);
+		pud = fixmap_pud(addr);
+	}
 	pud_populate(&init_mm, pud, bm_pmd);
-	pmd = pmd_offset(pud, addr);
+	pmd = fixmap_pmd(addr);
 	pmd_populate_kernel(&init_mm, pmd, bm_pte);
 
 	/*
 	 * The boot-ioremap range spans multiple pmds, for which
-	 * we are not preparted:
+	 * we are not prepared:
 	 */
 	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
 		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
@@ -652,11 +743,10 @@ void __set_fixmap(enum fixed_addresses idx,
 	}
 }
 
-void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
+void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 {
 	const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
-	pgprot_t prot = PAGE_KERNEL_RO;
-	int size, offset;
+	int offset;
 	void *dt_virt;
 
 	/*
@@ -673,7 +763,7 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
 	/*
 	 * Make sure that the FDT region can be mapped without the need to
 	 * allocate additional translation table pages, so that it is safe
-	 * to call create_mapping() this early.
+	 * to call create_mapping_noalloc() this early.
 	 *
 	 * On 64k pages, the FDT will be mapped using PTEs, so we need to
 	 * be in the same PMD as the rest of the fixmap.
@@ -689,21 +779,73 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
 	dt_virt = (void *)dt_virt_base + offset;
 
 	/* map the first chunk so we can read the size from the header */
-	create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
-		       SWAPPER_BLOCK_SIZE, prot);
+	create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
+			dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
 
 	if (fdt_check_header(dt_virt) != 0)
 		return NULL;
 
-	size = fdt_totalsize(dt_virt);
-	if (size > MAX_FDT_SIZE)
+	*size = fdt_totalsize(dt_virt);
+	if (*size > MAX_FDT_SIZE)
 		return NULL;
 
-	if (offset + size > SWAPPER_BLOCK_SIZE)
-		create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
-			       round_up(offset + size, SWAPPER_BLOCK_SIZE), prot);
+	if (offset + *size > SWAPPER_BLOCK_SIZE)
+		create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
+			       round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
 
-	memblock_reserve(dt_phys, size);
+	return dt_virt;
+}
+
+void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
+{
+	void *dt_virt;
+	int size;
+
+	dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
+	if (!dt_virt)
+		return NULL;
 
+	memblock_reserve(dt_phys, size);
 	return dt_virt;
 }
+
+int __init arch_ioremap_pud_supported(void)
+{
+	/* only 4k granule supports level 1 block mappings */
+	return IS_ENABLED(CONFIG_ARM64_4K_PAGES);
+}
+
+int __init arch_ioremap_pmd_supported(void)
+{
+	return 1;
+}
+
+int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
+{
+	BUG_ON(phys & ~PUD_MASK);
+	set_pud(pud, __pud(phys | PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
+	return 1;
+}
+
+int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
+{
+	BUG_ON(phys & ~PMD_MASK);
+	set_pmd(pmd, __pmd(phys | PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
+	return 1;
+}
+
+int pud_clear_huge(pud_t *pud)
+{
+	if (!pud_sect(*pud))
+		return 0;
+	pud_clear(pud);
+	return 1;
+}
+
+int pmd_clear_huge(pmd_t *pmd)
+{
+	if (!pmd_sect(*pmd))
+		return 0;
+	pmd_clear(pmd);
+	return 1;
+}
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 0795c3a36d8f..ca6d268e3313 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -37,14 +37,31 @@ static int change_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,
 	return 0;
 }
 
+/*
+ * This function assumes that the range is mapped with PAGE_SIZE pages.
+ */
+static int __change_memory_common(unsigned long start, unsigned long size,
+				pgprot_t set_mask, pgprot_t clear_mask)
+{
+	struct page_change_data data;
+	int ret;
+
+	data.set_mask = set_mask;
+	data.clear_mask = clear_mask;
+
+	ret = apply_to_page_range(&init_mm, start, size, change_page_range,
+					&data);
+
+	flush_tlb_kernel_range(start, start + size);
+	return ret;
+}
+
 static int change_memory_common(unsigned long addr, int numpages,
 				pgprot_t set_mask, pgprot_t clear_mask)
 {
 	unsigned long start = addr;
 	unsigned long size = PAGE_SIZE*numpages;
 	unsigned long end = start + size;
-	int ret;
-	struct page_change_data data;
 	struct vm_struct *area;
 
 	if (!PAGE_ALIGNED(addr)) {
@@ -75,14 +92,7 @@ static int change_memory_common(unsigned long addr, int numpages,
 	if (!numpages)
 		return 0;
 
-	data.set_mask = set_mask;
-	data.clear_mask = clear_mask;
-
-	ret = apply_to_page_range(&init_mm, start, size, change_page_range,
-					&data);
-
-	flush_tlb_kernel_range(start, end);
-	return ret;
+	return __change_memory_common(start, size, set_mask, clear_mask);
 }
 
 int set_memory_ro(unsigned long addr, int numpages)
@@ -114,3 +124,19 @@ int set_memory_x(unsigned long addr, int numpages)
 					__pgprot(PTE_PXN));
 }
 EXPORT_SYMBOL_GPL(set_memory_x);
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+void __kernel_map_pages(struct page *page, int numpages, int enable)
+{
+	unsigned long addr = (unsigned long) page_address(page);
+
+	if (enable)
+		__change_memory_common(addr, PAGE_SIZE * numpages,
+					__pgprot(PTE_VALID),
+					__pgprot(0));
+	else
+		__change_memory_common(addr, PAGE_SIZE * numpages,
+					__pgprot(0),
+					__pgprot(PTE_VALID));
+}
+#endif
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index c164d2cb35c0..543f5198005a 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -25,6 +25,8 @@
 #include <asm/hwcap.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
+#include <asm/cpufeature.h>
+#include <asm/alternative.h>
 
 #include "proc-macros.S"
 
@@ -137,9 +139,47 @@ ENTRY(cpu_do_switch_mm)
 	bfi	x0, x1, #48, #16		// set the ASID
 	msr	ttbr0_el1, x0			// set TTBR0
 	isb
+alternative_if_not ARM64_WORKAROUND_CAVIUM_27456
 	ret
+	nop
+	nop
+	nop
+alternative_else
+	ic	iallu
+	dsb	nsh
+	isb
+	ret
+alternative_endif
 ENDPROC(cpu_do_switch_mm)
 
+	.pushsection ".idmap.text", "ax"
+/*
+ * void idmap_cpu_replace_ttbr1(phys_addr_t new_pgd)
+ *
+ * This is the low-level counterpart to cpu_replace_ttbr1, and should not be
+ * called by anything else. It can only be executed from a TTBR0 mapping.
+ */
+ENTRY(idmap_cpu_replace_ttbr1)
+	mrs	x2, daif
+	msr	daifset, #0xf
+
+	adrp	x1, empty_zero_page
+	msr	ttbr1_el1, x1
+	isb
+
+	tlbi	vmalle1
+	dsb	nsh
+	isb
+
+	msr	ttbr1_el1, x0
+	isb
+
+	msr	daif, x2
+
+	ret
+ENDPROC(idmap_cpu_replace_ttbr1)
+	.popsection
+
 /*
  *	__cpu_setup
  *