diff -Naurp a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
--- a/arch/x86/kernel/cpu/bugs.c 2018-08-10 13:17:43.000000000 -0300
+++ b/arch/x86/kernel/cpu/bugs.c 2018-08-15 07:09:24.365615125 -0300
@@ -26,6 +26,70 @@
#include <asm/spec_ctrl.h>
#include <linux/prctl.h>
+static int __init no_387(char *s)
+{
+ boot_cpu_data.hard_math = 0;
+ write_cr0(X86_CR0_TS | X86_CR0_EM | X86_CR0_MP | read_cr0());
+ return 1;
+}
+
+__setup("no387", no_387);
+
+static double __initdata x = 4195835.0;
+static double __initdata y = 3145727.0;
+
+/*
+ * This used to check for exceptions..
+ * However, it turns out that to support that,
+ * the XMM trap handlers basically had to
+ * be buggy. So let's have a correct XMM trap
+ * handler, and forget about printing out
+ * some status at boot.
+ *
+ * We should really only care about bugs here
+ * anyway. Not features.
+ */
+static void __init check_fpu(void)
+{
+ s32 fdiv_bug;
+
+ if (!boot_cpu_data.hard_math) {
+#ifndef CONFIG_MATH_EMULATION
+ pr_emerg("No coprocessor found and no math emulation present\n");
+ pr_emerg("Giving up\n");
+ for (;;) ;
+#endif
+ return;
+ }
+
+ kernel_fpu_begin();
+
+ /*
+ * trap_init() enabled FXSR and company _before_ testing for FP
+ * problems here.
+ *
+ * Test for the divl bug: http://en.wikipedia.org/wiki/Fdiv_bug
+ */
+ __asm__("fninit\n\t"
+ "fldl %1\n\t"
+ "fdivl %2\n\t"
+ "fmull %2\n\t"
+ "fldl %1\n\t"
+ "fsubp %%st,%%st(1)\n\t"
+ "fistpl %0\n\t"
+ "fwait\n\t"
+ "fninit"
+ : "=m" (*&fdiv_bug)
+ : "m" (*&x), "m" (*&y));
+
+ kernel_fpu_end();
+
+ if (fdiv_bug) {
+ set_cpu_bug(&boot_cpu_data, X86_BUG_FDIV);
+ pr_warn("Hmm, FPU with FDIV bug\n");
+ }
+}
+
static void __init spectre_v2_select_mitigation(void);
static void __init ssb_parse_cmdline(void);
void ssb_select_mitigation(void);
@@ -606,8 +670,10 @@ static ssize_t cpu_show_common(struct de
switch (bug) {
case X86_BUG_CPU_MELTDOWN:
+#ifdef CONFIG_KAISER
if (kaiser_enabled)
return sprintf(buf, "Mitigation: PTI\n");
+#endif
break;