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 8static int disable_nx __cpuinitdata; 9 10/* 11 * noexec = on|off 12 * 13 * Control non-executable mappings for processes. 14 * 15 * on Enable 16 * off Disable 17 */ 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} 30early_param("noexec", noexec_setup); 31 32void __cpuinit 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 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 or disabled in BIOS!\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