v4.19.13 snapshot.
diff --git a/arch/x86/mm/setup_nx.c b/arch/x86/mm/setup_nx.c
new file mode 100644
index 0000000..adb3c57
--- /dev/null
+++ b/arch/x86/mm/setup_nx.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+
+#include <asm/pgtable.h>
+#include <asm/proto.h>
+#include <asm/cpufeature.h>
+
+static int disable_nx;
+
+/*
+ * noexec = on|off
+ *
+ * Control non-executable mappings for processes.
+ *
+ * on Enable
+ * off Disable
+ */
+static int __init noexec_setup(char *str)
+{
+ if (!str)
+ return -EINVAL;
+ if (!strncmp(str, "on", 2)) {
+ disable_nx = 0;
+ } else if (!strncmp(str, "off", 3)) {
+ disable_nx = 1;
+ }
+ x86_configure_nx();
+ return 0;
+}
+early_param("noexec", noexec_setup);
+
+void x86_configure_nx(void)
+{
+ if (boot_cpu_has(X86_FEATURE_NX) && !disable_nx)
+ __supported_pte_mask |= _PAGE_NX;
+ else
+ __supported_pte_mask &= ~_PAGE_NX;
+}
+
+void __init x86_report_nx(void)
+{
+ if (!boot_cpu_has(X86_FEATURE_NX)) {
+ printk(KERN_NOTICE "Notice: NX (Execute Disable) protection "
+ "missing in CPU!\n");
+ } else {
+#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
+ if (disable_nx) {
+ printk(KERN_INFO "NX (Execute Disable) protection: "
+ "disabled by kernel command line option\n");
+ } else {
+ printk(KERN_INFO "NX (Execute Disable) protection: "
+ "active\n");
+ }
+#else
+ /* 32bit non-PAE kernel, NX cannot be used */
+ printk(KERN_NOTICE "Notice: NX (Execute Disable) protection "
+ "cannot be enabled: non-PAE kernel!\n");
+#endif
+ }
+}