1 #include <linux/spinlock.h>
2 #include <linux/errno.h>
3 #include <linux/init.h>
5 #include <asm/pgtable.h>
9 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
10 static int disable_nx __cpuinitdata;
15 * Control non-executable mappings for processes.
20 static int __init noexec_setup(char *str)
24 if (!strncmp(str, "on", 2)) {
25 __supported_pte_mask |= _PAGE_NX;
27 } else if (!strncmp(str, "off", 3)) {
29 __supported_pte_mask &= ~_PAGE_NX;
33 early_param("noexec", noexec_setup);
37 void __init set_nx(void)
39 unsigned int v[4], l, h;
41 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
42 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
44 if ((v[3] & (1 << 20)) && !disable_nx) {
45 rdmsr(MSR_EFER, l, h);
47 wrmsr(MSR_EFER, l, h);
49 __supported_pte_mask |= _PAGE_NX;
60 void __cpuinit check_efer(void)
64 rdmsrl(MSR_EFER, efer);
65 if (!(efer & EFER_NX) || disable_nx)
66 __supported_pte_mask &= ~_PAGE_NX;