From: Vlastimil Babka CONFIG_PAGE_TABLE_ISOLATION is relatively new and intrusive feature that may still have some corner cases which could take some time to manifest and be fixed. It would be useful to have Oops messages indicate whether it was enabled for building the kernel, and whether it was disabled during boot. Example of fully enabled: Oops: 0001 [#1] SMP PTI Example of enabled during build, but disabled during boot: Oops: 0001 [#1] SMP NOPTI We can decide to remove this after the feature has been tested in the field long enough. [ tglx: Made it use boot_cpu_has() as requested by Borislav ] Signed-off-by: Vlastimil Babka Signed-off-by: Thomas Gleixner Reviewed-by: Eduardo Valentin Acked-by: Dave Hansen Cc: Juergen Gross Cc: Denys Vlasenko Cc: aliguori@amazon.com Cc: Brian Gerst Cc: Peter Zijlstra Cc: jkosina@suse.cz Cc: keescook@google.com Cc: hughd@google.com Cc: Will Deacon Cc: daniel.gruss@iaik.tugraz.at Cc: David Laight Cc: Josh Poimboeuf Cc: Andy Lutomirsky Cc: Greg KH Cc: Boris Ostrovsky Cc: bpetkov@suse.de Cc: Linus Torvalds --- arch/x86/kernel/dumpstack.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -297,11 +297,13 @@ int __die(const char *str, struct pt_reg unsigned long sp; #endif printk(KERN_DEFAULT - "%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter, + "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter, IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "", IS_ENABLED(CONFIG_SMP) ? " SMP" : "", debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "", - IS_ENABLED(CONFIG_KASAN) ? " KASAN" : ""); + IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "", + IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION) ? + (boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : ""); if (notify_die(DIE_OOPS, str, regs, err, current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)