diff options
Diffstat (limited to 'arch/x86/mm/setup_nx.c')
| -rw-r--r-- | arch/x86/mm/setup_nx.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/arch/x86/mm/setup_nx.c b/arch/x86/mm/setup_nx.c new file mode 100644 index 000000000..adb3c5784 --- /dev/null +++ b/arch/x86/mm/setup_nx.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/spinlock.h> +#include <linux/errno.h> +#include <linux/init.h> + +#include <asm/pgtable.h> +#include <asm/proto.h> +#include <asm/cpufeature.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 (boot_cpu_has(X86_FEATURE_NX) && !disable_nx) + __supported_pte_mask |= _PAGE_NX; + else + __supported_pte_mask &= ~_PAGE_NX; +} + +void __init x86_report_nx(void) +{ + if (!boot_cpu_has(X86_FEATURE_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 + } +} |