x86/cpu: Merge bugs.c and bugs_64.c

CVE-2017-5715 (Spectre v2 retpoline)

commit 62a67e12 upstream.

Should be easier when following boot paths. It probably is a left over
from the x86 unification eons ago.

No functionality change.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161024173844.23038-3-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Razvan Ghitulete <rga@amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 9718bf5f)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

arch/x86/kernel/cpu/Makefile

@@ -16,13 +16,11 @@ obj-y			:= intel_cacheinfo.o scattered.o topology.o
 obj-y			+= common.o
 obj-y			+= rdrand.o
 obj-y			+= match.o
+obj-y			+= bugs.o
 
 obj-$(CONFIG_PROC_FS)	+= proc.o
 obj-$(CONFIG_X86_FEATURE_NAMES) += capflags.o powerflags.o
 
-obj-$(CONFIG_X86_32)	+= bugs.o
-obj-$(CONFIG_X86_64)	+= bugs_64.o
-
 obj-$(CONFIG_CPU_SUP_INTEL)		+= intel.o
 obj-$(CONFIG_CPU_SUP_AMD)		+= amd.o
 obj-$(CONFIG_CPU_SUP_CYRIX_32)		+= cyrix.o

arch/x86/kernel/cpu/bugs.c

@@ -16,6 +16,8 @@
 #include <asm/msr.h>
 #include <asm/paravirt.h>
 #include <asm/alternative.h>
+#include <asm/pgtable.h>
+#include <asm/cacheflush.h>
 
 void __init check_bugs(void)
 {
@@ -28,11 +30,13 @@ void __init check_bugs(void)
 #endif
 
 	identify_boot_cpu();
-#ifndef CONFIG_SMP
-	pr_info("CPU: ");
-	print_cpu_info(&boot_cpu_data);
-#endif
 
+	if (!IS_ENABLED(CONFIG_SMP)) {
+		pr_info("CPU: ");
+		print_cpu_info(&boot_cpu_data);
+	}
+
+#ifdef CONFIG_X86_32
 	/*
 	 * Check whether we are able to run this kernel safely on SMP.
 	 *
@@ -48,4 +52,18 @@ void __init check_bugs(void)
 	alternative_instructions();
 
 	fpu__init_check_bugs();
+#else /* CONFIG_X86_64 */
+	alternative_instructions();
+
+	/*
+	 * Make sure the first 2MB area is not mapped by huge pages
+	 * There are typically fixed size MTRRs in there and overlapping
+	 * MTRRs into large pages causes slow downs.
+	 *
+	 * Right now we don't do that with gbpages because there seems
+	 * very little benefit for that case.
+	 */
+	if (!direct_gbpages)
+		set_memory_4k((unsigned long)__va(0), 1);
+#endif
 }

arch/x86/kernel/cpu/bugs_64.c

-/*
- *  Copyright (C) 1994  Linus Torvalds
- *  Copyright (C) 2000  SuSE
- */
-
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <asm/alternative.h>
-#include <asm/bugs.h>
-#include <asm/processor.h>
-#include <asm/mtrr.h>
-#include <asm/cacheflush.h>
-
-void __init check_bugs(void)
-{
-	identify_boot_cpu();
-#if !defined(CONFIG_SMP)
-	printk(KERN_INFO "CPU: ");
-	print_cpu_info(&boot_cpu_data);
-#endif
-	alternative_instructions();
-
-	/*
-	 * Make sure the first 2MB area is not mapped by huge pages
-	 * There are typically fixed size MTRRs in there and overlapping
-	 * MTRRs into large pages causes slow downs.
-	 *
-	 * Right now we don't do that with gbpages because there seems
-	 * very little benefit for that case.
-	 */
-	if (!direct_gbpages)
-		set_memory_4k((unsigned long)__va(0), 1);
-}