diff options
Diffstat (limited to 'kernel/arch/x86/mm/setup_nx.c')
| -rw-r--r-- | kernel/arch/x86/mm/setup_nx.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/kernel/arch/x86/mm/setup_nx.c b/kernel/arch/x86/mm/setup_nx.c new file mode 100644 index 000000000..90555bf60 --- /dev/null +++ b/kernel/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; + +/* + * 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 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 + } +} |