|
 |
e293be |
diff -Naurp a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
|
|
|
e293be |
--- a/arch/x86/kernel/cpu/bugs.c 2018-08-10 13:17:43.000000000 -0300
|
|
|
e293be |
+++ b/arch/x86/kernel/cpu/bugs.c 2018-08-15 07:09:24.365615125 -0300
|
|
|
e293be |
@@ -26,6 +26,70 @@
|
|
|
e293be |
#include <asm/spec_ctrl.h>
|
|
|
e293be |
#include <linux/prctl.h>
|
|
|
e293be |
|
|
|
e293be |
+static int __init no_387(char *s)
|
|
|
e293be |
+{
|
|
|
e293be |
+ boot_cpu_data.hard_math = 0;
|
|
|
e293be |
+ write_cr0(X86_CR0_TS | X86_CR0_EM | X86_CR0_MP | read_cr0());
|
|
|
e293be |
+ return 1;
|
|
|
e293be |
+}
|
|
|
e293be |
+
|
|
|
e293be |
+__setup("no387", no_387);
|
|
|
e293be |
+
|
|
|
e293be |
+static double __initdata x = 4195835.0;
|
|
|
e293be |
+static double __initdata y = 3145727.0;
|
|
|
e293be |
+
|
|
|
e293be |
+/*
|
|
|
e293be |
+ * This used to check for exceptions..
|
|
|
e293be |
+ * However, it turns out that to support that,
|
|
|
e293be |
+ * the XMM trap handlers basically had to
|
|
|
e293be |
+ * be buggy. So let's have a correct XMM trap
|
|
|
e293be |
+ * handler, and forget about printing out
|
|
|
e293be |
+ * some status at boot.
|
|
|
e293be |
+ *
|
|
|
e293be |
+ * We should really only care about bugs here
|
|
|
e293be |
+ * anyway. Not features.
|
|
|
e293be |
+ */
|
|
|
e293be |
+static void __init check_fpu(void)
|
|
|
e293be |
+{
|
|
|
e293be |
+ s32 fdiv_bug;
|
|
|
e293be |
+
|
|
|
e293be |
+ if (!boot_cpu_data.hard_math) {
|
|
|
e293be |
+#ifndef CONFIG_MATH_EMULATION
|
|
|
e293be |
+ pr_emerg("No coprocessor found and no math emulation present\n");
|
|
|
e293be |
+ pr_emerg("Giving up\n");
|
|
|
e293be |
+ for (;;) ;
|
|
|
e293be |
+#endif
|
|
|
e293be |
+ return;
|
|
|
e293be |
+ }
|
|
|
e293be |
+
|
|
|
e293be |
+ kernel_fpu_begin();
|
|
|
e293be |
+
|
|
|
e293be |
+ /*
|
|
|
e293be |
+ * trap_init() enabled FXSR and company _before_ testing for FP
|
|
|
e293be |
+ * problems here.
|
|
|
e293be |
+ *
|
|
|
e293be |
+ * Test for the divl bug: http://en.wikipedia.org/wiki/Fdiv_bug
|
|
|
e293be |
+ */
|
|
|
e293be |
+ __asm__("fninit\n\t"
|
|
|
e293be |
+ "fldl %1\n\t"
|
|
|
e293be |
+ "fdivl %2\n\t"
|
|
|
e293be |
+ "fmull %2\n\t"
|
|
|
e293be |
+ "fldl %1\n\t"
|
|
|
e293be |
+ "fsubp %%st,%%st(1)\n\t"
|
|
|
e293be |
+ "fistpl %0\n\t"
|
|
|
e293be |
+ "fwait\n\t"
|
|
|
e293be |
+ "fninit"
|
|
|
e293be |
+ : "=m" (*&fdiv_bug)
|
|
|
e293be |
+ : "m" (*&x), "m" (*&y);;
|
|
|
e293be |
+
|
|
|
e293be |
+ kernel_fpu_end();
|
|
|
e293be |
+
|
|
|
e293be |
+ if (fdiv_bug) {
|
|
|
e293be |
+ set_cpu_bug(&boot_cpu_data, X86_BUG_FDIV);
|
|
|
e293be |
+ pr_warn("Hmm, FPU with FDIV bug\n");
|
|
|
e293be |
+ }
|
|
|
e293be |
+}
|
|
|
e293be |
+
|
|
|
e293be |
static void __init spectre_v2_select_mitigation(void);
|
|
|
e293be |
static void __init ssb_parse_cmdline(void);
|
|
|
e293be |
void ssb_select_mitigation(void);
|
|
|
e293be |
@@ -606,8 +670,10 @@ static ssize_t cpu_show_common(struct de
|
|
|
e293be |
|
|
|
e293be |
switch (bug) {
|
|
|
e293be |
case X86_BUG_CPU_MELTDOWN:
|
|
|
e293be |
+#ifdef CONFIG_KAISER
|
|
|
e293be |
if (kaiser_enabled)
|
|
|
e293be |
return sprintf(buf, "Mitigation: PTI\n");
|
|
|
e293be |
+#endif
|
|
|
e293be |
|
|
|
e293be |
break;
|
|
|
e293be |
|