1 #include <linux/spinlock.h> 2 #include <linux/errno.h> 3 #include <linux/init.h> 4 5 #include <asm/pgtable.h> 6 #include <asm/proto.h> 7 8 static int disable_nx; 9 10 /* 11 * noexec = on|off 12 * 13 * Control non-executable mappings for processes. 14 * 15 * on Enable 16 * off Disable 17 */ noexec_setup(char * str)18static int __init noexec_setup(char *str) 19 { 20 if (!str) 21 return -EINVAL; 22 if (!strncmp(str, "on", 2)) { 23 disable_nx = 0; 24 } else if (!strncmp(str, "off", 3)) { 25 disable_nx = 1; 26 } 27 x86_configure_nx(); 28 return 0; 29 } 30 early_param("noexec", noexec_setup); 31 x86_configure_nx(void)32void x86_configure_nx(void) 33 { 34 if (cpu_has_nx && !disable_nx) 35 __supported_pte_mask |= _PAGE_NX; 36 else 37 __supported_pte_mask &= ~_PAGE_NX; 38 } 39 x86_report_nx(void)40void __init x86_report_nx(void) 41 { 42 if (!cpu_has_nx) { 43 printk(KERN_NOTICE "Notice: NX (Execute Disable) protection " 44 "missing in CPU!\n"); 45 } else { 46 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE) 47 if (disable_nx) { 48 printk(KERN_INFO "NX (Execute Disable) protection: " 49 "disabled by kernel command line option\n"); 50 } else { 51 printk(KERN_INFO "NX (Execute Disable) protection: " 52 "active\n"); 53 } 54 #else 55 /* 32bit non-PAE kernel, NX cannot be used */ 56 printk(KERN_NOTICE "Notice: NX (Execute Disable) protection " 57 "cannot be enabled: non-PAE kernel!\n"); 58 #endif 59 } 60 } 61