x86: unify noexec handling
This patch unifies noexec handling on 32-bit and 64-bit.
[ Impact: cleanup ]
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
[ mingo@elte.hu: build fix ]
LKML-Reference: <1240303167.771.69.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index fd3da1d..fedde53 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -22,6 +22,69 @@
#endif
;
+int nx_enabled;
+
+#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
+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)) {
+ __supported_pte_mask |= _PAGE_NX;
+ disable_nx = 0;
+ } else if (!strncmp(str, "off", 3)) {
+ disable_nx = 1;
+ __supported_pte_mask &= ~_PAGE_NX;
+ }
+ return 0;
+}
+early_param("noexec", noexec_setup);
+#endif
+
+#ifdef CONFIG_X86_PAE
+static void __init set_nx(void)
+{
+ unsigned int v[4], l, h;
+
+ if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
+ cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
+
+ if ((v[3] & (1 << 20)) && !disable_nx) {
+ rdmsr(MSR_EFER, l, h);
+ l |= EFER_NX;
+ wrmsr(MSR_EFER, l, h);
+ nx_enabled = 1;
+ __supported_pte_mask |= _PAGE_NX;
+ }
+ }
+}
+#else
+static inline void set_nx(void)
+{
+}
+#endif
+
+#ifdef CONFIG_X86_64
+void __cpuinit check_efer(void)
+{
+ unsigned long efer;
+
+ rdmsrl(MSR_EFER, efer);
+ if (!(efer & EFER_NX) || disable_nx)
+ __supported_pte_mask &= ~_PAGE_NX;
+}
+#endif
+
static void __init find_early_table_space(unsigned long end, int use_pse,
int use_gbpages)
{
@@ -158,12 +221,9 @@
use_gbpages = direct_gbpages;
#endif
-#ifdef CONFIG_X86_32
-#ifdef CONFIG_X86_PAE
set_nx();
if (nx_enabled)
printk(KERN_INFO "NX (Execute Disable) protection: active\n");
-#endif
/* Enable PSE if available */
if (cpu_has_pse)
@@ -174,7 +234,6 @@
set_in_cr4(X86_CR4_PGE);
__supported_pte_mask |= _PAGE_GLOBAL;
}
-#endif
if (use_gbpages)
page_size_mask |= 1 << PG_LEVEL_1G;