From 41f4c20b57a4890ea7f56ff8717cc83fefb8d537 Mon Sep 17 00:00:00 2001 From: Borislav Petkov <bp@suse.de> Date: Tue, 12 Dec 2017 14:39:52 +0100 Subject: x86/pti: Add the pti= cmdline option and documentation Keep the "nopti" optional for traditional reasons. [ tglx: Don't allow force on when running on XEN PV and made 'on' printout conditional ] Requested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirsky <luto@kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Laight <David.Laight@aculab.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eduardo Valentin <eduval@amazon.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Link: https://lkml.kernel.org/r/20171212133952.10177-1-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/mm/pti.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) (limited to 'arch/x86/mm/pti.c') diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 375f23a758bc..a13f6b109865 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -54,21 +54,45 @@ static void __init pti_print_if_insecure(const char *reason) pr_info("%s\n", reason); } +static void __init pti_print_if_secure(const char *reason) +{ + if (!boot_cpu_has_bug(X86_BUG_CPU_INSECURE)) + pr_info("%s\n", reason); +} + void __init pti_check_boottime_disable(void) { + char arg[5]; + int ret; + if (hypervisor_is_type(X86_HYPER_XEN_PV)) { pti_print_if_insecure("disabled on XEN PV."); return; } + ret = cmdline_find_option(boot_command_line, "pti", arg, sizeof(arg)); + if (ret > 0) { + if (ret == 3 && !strncmp(arg, "off", 3)) { + pti_print_if_insecure("disabled on command line."); + return; + } + if (ret == 2 && !strncmp(arg, "on", 2)) { + pti_print_if_secure("force enabled on command line."); + goto enable; + } + if (ret == 4 && !strncmp(arg, "auto", 4)) + goto autosel; + } + if (cmdline_find_option_bool(boot_command_line, "nopti")) { pti_print_if_insecure("disabled on command line."); return; } +autosel: if (!boot_cpu_has_bug(X86_BUG_CPU_INSECURE)) return; - +enable: setup_force_cpu_cap(X86_FEATURE_PTI); } -- cgit v1.2.3-58-ga151