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authorBorislav Petkov <bp@suse.de>2017-12-12 14:39:52 +0100
committerIngo Molnar <mingo@kernel.org>2017-12-23 21:12:59 +0100
commit41f4c20b57a4890ea7f56ff8717cc83fefb8d537 (patch)
treeb10e8ac40d397b3ad539384ce4b4a3182f3eb63f /arch/x86/mm/pti.c
parentaa8c6248f8c75acfd610fe15d8cae23cf70d9d09 (diff)
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>
Diffstat (limited to 'arch/x86/mm/pti.c')
-rw-r--r--arch/x86/mm/pti.c26
1 files changed, 25 insertions, 1 deletions
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);
}