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authorSrikant Patnaik2015-01-13 15:08:24 +0530
committerSrikant Patnaik2015-01-13 15:08:24 +0530
commit97327692361306d1e6259021bc425e32832fdb50 (patch)
treefe9088f3248ec61e24f404f21b9793cb644b7f01 /arch/x86/mm/setup_nx.c
parent2d05a8f663478a44e088d122e0d62109bbc801d0 (diff)
parenta3a8b90b61e21be3dde9101c4e86c881e0f06210 (diff)
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dirty fix to merging
Diffstat (limited to 'arch/x86/mm/setup_nx.c')
-rw-r--r--arch/x86/mm/setup_nx.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/arch/x86/mm/setup_nx.c b/arch/x86/mm/setup_nx.c
new file mode 100644
index 00000000..410531d3
--- /dev/null
+++ b/arch/x86/mm/setup_nx.c
@@ -0,0 +1,60 @@
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+
+#include <asm/pgtable.h>
+#include <asm/proto.h>
+
+static int disable_nx __cpuinitdata;
+
+/*
+ * 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 __cpuinit x86_configure_nx(void)
+{
+ if (cpu_has_nx && !disable_nx)
+ __supported_pte_mask |= _PAGE_NX;
+ else
+ __supported_pte_mask &= ~_PAGE_NX;
+}
+
+void __init x86_report_nx(void)
+{
+ if (!cpu_has_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
+ }
+}