}
}
+static __always_inline void setup_umip(struct cpuinfo_x86 *c)
+{
+ /* Check the boot processor, plus build option for UMIP. */
+ if (!cpu_feature_enabled(X86_FEATURE_UMIP))
+ goto out;
+
+ /* Check the current processor's cpuid bits. */
+ if (!cpu_has(c, X86_FEATURE_UMIP))
+ goto out;
+
+ cr4_set_bits(X86_CR4_UMIP);
+
+ pr_info("x86/cpu: Activated the Intel User Mode Instruction Prevention (UMIP) CPU feature\n");
+
+ return;
+
+out:
+ /*
+ * Make sure UMIP is disabled in case it was enabled in a
+ * previous boot (e.g., via kexec).
+ */
+ cr4_clear_bits(X86_CR4_UMIP);
+}
+
/*
* Protection Keys are not available in 32-bit mode.
*/
* cache alignment.
* The others are not touched to avoid unwanted side effects.
*
- * WARNING: this function is only called on the BP. Don't add code here
- * that is supposed to run on all CPUs.
+ * WARNING: this function is only called on the boot CPU. Don't add code
+ * here that is supposed to run on all CPUs.
*/
static void __init early_identify_cpu(struct cpuinfo_x86 *c)
{
/* Disable the PN if appropriate */
squash_the_stupid_serial_number(c);
- /* Set up SMEP/SMAP */
+ /* Set up SMEP/SMAP/UMIP */
setup_smep(c);
setup_smap(c);
+ setup_umip(c);
/*
* The vendor-specific functions might have changed features.