1 files changed, 25 insertions, 5 deletions

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 9c4bad7d7131..a34890bf309f 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -170,9 +170,13 @@ static void __init smp_build_mpidr_hash(void)
 
 static void __init setup_machine_fdt(phys_addr_t dt_phys)
 {
-	void *dt_virt = fixmap_remap_fdt(dt_phys);
+	int size;
+	void *dt_virt = fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL);
 	const char *name;
 
+	if (dt_virt)
+		memblock_reserve(dt_phys, size);
+
 	if (!dt_virt || !early_init_dt_scan(dt_virt)) {
 		pr_crit("\n"
 			"Error: invalid device tree blob at physical address %pa (virtual address 0x%p)\n"
@@ -184,6 +188,9 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys)
 			cpu_relax();
 	}
 
+	/* Early fixups are done, map the FDT as read-only now */
+	fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
+
 	name = of_flat_dt_get_machine_name();
 	if (!name)
 		return;
@@ -278,6 +285,13 @@ void __init setup_arch(char **cmdline_p)
 
 	*cmdline_p = boot_command_line;
 
+	/*
+	 * If know now we are going to need KPTI then use non-global
+	 * mappings from the start, avoiding the cost of rewriting
+	 * everything later.
+	 */
+	arm64_use_ng_mappings = kaslr_requires_kpti();
+
 	early_fixmap_init();
 	early_ioremap_init();
 
@@ -346,9 +360,6 @@ void __init setup_arch(char **cmdline_p)
 	init_task.thread_info.ttbr0 = __pa_symbol(empty_zero_page);
 #endif
 
-#ifdef CONFIG_VT
-	conswitchp = &dummy_con;
-#endif
 	if (boot_args[1] || boot_args[2] || boot_args[3]) {
 		pr_err("WARNING: x1-x3 nonzero in violation of boot protocol:\n"
 			"\tx1: %016llx\n\tx2: %016llx\n\tx3: %016llx\n"
@@ -357,6 +368,15 @@ void __init setup_arch(char **cmdline_p)
 	}
 }
 
+static inline bool cpu_can_disable(unsigned int cpu)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_can_disable)
+		return cpu_ops[cpu]->cpu_can_disable(cpu);
+#endif
+	return false;
+}
+
 static int __init topology_init(void)
 {
 	int i;
@@ -366,7 +386,7 @@ static int __init topology_init(void)
 
 	for_each_possible_cpu(i) {
 		struct cpu *cpu = &per_cpu(cpu_data.cpu, i);
-		cpu->hotpluggable = 1;
+		cpu->hotpluggable = cpu_can_disable(i);
 		register_cpu(cpu, i);
 	}