Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cpu updates from Ingo Molnar:
 "Two changes:

   - Extend 32-bit double fault debugging aid to 64-bit
   - Fix a build warning"

* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/intel/cacheinfo: Shut up last long-standing warning
  x86: Extend #DF debugging aid to 64-bit

arch/x86/Kconfig.debug

@@ -122,7 +122,6 @@ config DEBUG_NX_TEST
 config DOUBLEFAULT
 	default y
 	bool "Enable doublefault exception handler" if EXPERT
-	depends on X86_32
 	---help---
 	  This option allows trapping of rare doublefault exceptions that
 	  would otherwise cause a system to silently reboot. Disabling this

arch/x86/include/asm/processor.h

@@ -981,5 +981,5 @@ bool xen_set_default_idle(void);
 #endif
 
 void stop_this_cpu(void *dummy);
-
+void df_debug(struct pt_regs *regs, long error_code);
 #endif /* _ASM_X86_PROCESSOR_H */

arch/x86/kernel/Makefile

@@ -67,7 +67,7 @@ obj-$(CONFIG_KEXEC)		+= relocate_kernel_$(BITS).o crash.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump_$(BITS).o
 obj-y				+= kprobes/
 obj-$(CONFIG_MODULES)		+= module.o
-obj-$(CONFIG_DOUBLEFAULT) 	+= doublefault_32.o
+obj-$(CONFIG_DOUBLEFAULT)	+= doublefault.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_VM86)		+= vm86_32.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o

arch/x86/kernel/cpu/intel_cacheinfo.c

@@ -618,18 +618,18 @@ unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c)
 		 * parameters cpuid leaf to find the cache details
 		 */
 		for (i = 0; i < num_cache_leaves; i++) {
-			struct _cpuid4_info_regs this_leaf;
+			struct _cpuid4_info_regs this_leaf = {};
 			int retval;
 
 			retval = cpuid4_cache_lookup_regs(i, &this_leaf);
-			if (retval >= 0) {
+			if (retval < 0)
+				continue;
+
 			switch (this_leaf.eax.split.level) {
 			case 1:
-					if (this_leaf.eax.split.type ==
-							CACHE_TYPE_DATA)
+				if (this_leaf.eax.split.type == CACHE_TYPE_DATA)
 					new_l1d = this_leaf.size/1024;
-					else if (this_leaf.eax.split.type ==
-							CACHE_TYPE_INST)
+				else if (this_leaf.eax.split.type == CACHE_TYPE_INST)
 					new_l1i = this_leaf.size/1024;
 				break;
 			case 2:
@@ -641,8 +641,7 @@ unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c)
 			case 3:
 				new_l3 = this_leaf.size/1024;
 				num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing;
-					index_msb = get_count_order(
-							num_threads_sharing);
+				index_msb = get_count_order(num_threads_sharing);
 				l3_id = c->apicid & ~((1 << index_msb) - 1);
 				break;
 			default:
@@ -650,7 +649,6 @@ unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c)
 			}
 		}
 	}
-	}
 	/*
 	 * Don't use cpuid2 if cpuid4 is supported. For P4, we use cpuid2 for
 	 * trace cache

arch/x86/kernel/doublefault_32.c → arch/x86/kernel/doublefault.c

@@ -9,6 +9,8 @@
 #include <asm/processor.h>
 #include <asm/desc.h>
 
+#ifdef CONFIG_X86_32
+
 #define DOUBLEFAULT_STACKSIZE (1024)
 static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
 #define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
@@ -67,3 +69,16 @@ struct tss_struct doublefault_tss __cacheline_aligned = {
 		.__cr3		= __pa_nodebug(swapper_pg_dir),
 	}
 };
+
+/* dummy for do_double_fault() call */
+void df_debug(struct pt_regs *regs, long error_code) {}
+
+#else /* !CONFIG_X86_32 */
+
+void df_debug(struct pt_regs *regs, long error_code)
+{
+	pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
+	show_regs(regs);
+	panic("Machine halted.");
+}
+#endif

arch/x86/kernel/traps.c

@@ -254,6 +254,9 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 	tsk->thread.error_code = error_code;
 	tsk->thread.trap_nr = X86_TRAP_DF;
 
+#ifdef CONFIG_DOUBLEFAULT
+	df_debug(regs, error_code);
+#endif
 	/*
 	 * This is always a kernel trap and never fixable (and thus must
 	 * never return).