1 files changed, 50 insertions, 23 deletions

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 809eda03c527..cc9e980c68ec 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -804,21 +804,20 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
 		identify_cpu_without_cpuid(c);
 
 	/* cyrix could have cpuid enabled via c_identify()*/
-	if (!have_cpuid_p())
-		return;
-
-	cpu_detect(c);
-	get_cpu_vendor(c);
-	get_cpu_cap(c);
+	if (have_cpuid_p()) {
+		cpu_detect(c);
+		get_cpu_vendor(c);
+		get_cpu_cap(c);
 
-	if (this_cpu->c_early_init)
-		this_cpu->c_early_init(c);
+		if (this_cpu->c_early_init)
+			this_cpu->c_early_init(c);
 
-	c->cpu_index = 0;
-	filter_cpuid_features(c, false);
+		c->cpu_index = 0;
+		filter_cpuid_features(c, false);
 
-	if (this_cpu->c_bsp_init)
-		this_cpu->c_bsp_init(c);
+		if (this_cpu->c_bsp_init)
+			this_cpu->c_bsp_init(c);
+	}
 
 	setup_force_cpu_cap(X86_FEATURE_ALWAYS);
 	fpu__init_system(c);
@@ -980,6 +979,35 @@ static void x86_init_cache_qos(struct cpuinfo_x86 *c)
 }
 
 /*
+ * The physical to logical package id mapping is initialized from the
+ * acpi/mptables information. Make sure that CPUID actually agrees with
+ * that.
+ */
+static void sanitize_package_id(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_SMP
+	unsigned int pkg, apicid, cpu = smp_processor_id();
+
+	apicid = apic->cpu_present_to_apicid(cpu);
+	pkg = apicid >> boot_cpu_data.x86_coreid_bits;
+
+	if (apicid != c->initial_apicid) {
+		pr_err(FW_BUG "CPU%u: APIC id mismatch. Firmware: %x CPUID: %x\n",
+		       cpu, apicid, c->initial_apicid);
+		c->initial_apicid = apicid;
+	}
+	if (pkg != c->phys_proc_id) {
+		pr_err(FW_BUG "CPU%u: Using firmware package id %u instead of %u\n",
+		       cpu, pkg, c->phys_proc_id);
+		c->phys_proc_id = pkg;
+	}
+	c->logical_proc_id = topology_phys_to_logical_pkg(pkg);
+#else
+	c->logical_proc_id = 0;
+#endif
+}
+
+/*
  * This does the hard work of actually picking apart the CPU stuff...
  */
 static void identify_cpu(struct cpuinfo_x86 *c)
@@ -1104,8 +1132,7 @@ static void identify_cpu(struct cpuinfo_x86 *c)
 #ifdef CONFIG_NUMA
 	numa_add_cpu(smp_processor_id());
 #endif
-	/* The boot/hotplug time assigment got cleared, restore it */
-	c->logical_proc_id = topology_phys_to_logical_pkg(c->phys_proc_id);
+	sanitize_package_id(c);
 }
 
 /*
@@ -1265,9 +1292,14 @@ static __init int setup_disablecpuid(char *arg)
 __setup("clearcpuid=", setup_disablecpuid);
 
 #ifdef CONFIG_X86_64
-struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
-struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1,
-				    (unsigned long) debug_idt_table };
+struct desc_ptr idt_descr __ro_after_init = {
+	.size = NR_VECTORS * 16 - 1,
+	.address = (unsigned long) idt_table,
+};
+const struct desc_ptr debug_idt_descr = {
+	.size = NR_VECTORS * 16 - 1,
+	.address = (unsigned long) debug_idt_table,
+};
 
 DEFINE_PER_CPU_FIRST(union irq_stack_union,
 		     irq_stack_union) __aligned(PAGE_SIZE) __visible;
@@ -1281,7 +1313,7 @@ DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
 EXPORT_PER_CPU_SYMBOL(current_task);
 
 DEFINE_PER_CPU(char *, irq_stack_ptr) =
-	init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64;
+	init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE;
 
 DEFINE_PER_CPU(unsigned int, irq_count) __visible = -1;
 
@@ -1305,11 +1337,6 @@ static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
 /* May not be marked __init: used by software suspend */
 void syscall_init(void)
 {
-	/*
-	 * LSTAR and STAR live in a bit strange symbiosis.
-	 * They both write to the same internal register. STAR allows to
-	 * set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
-	 */
 	wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS);
 	wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64);