On Mon, Oct 05, 2020 at 06:32:47PM +0200, Borislav Petkov wrote: > On Wed, Sep 30, 2020 at 04:26:10PM -0700, Tony Luck wrote: > > arch/x86/kernel/cpu/mce/core.c | 33 +++++++++++++++++++++------------ > > include/linux/sched.h | 2 ++ > > 2 files changed, 23 insertions(+), 12 deletions(-) > > Isn't that just simpler?
Yes. A helper function avoids making the code a mess of if/else with subtle fall through cases. > diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c > index 4d2cf08820af..dc6c83aa2ec1 100644 > --- a/arch/x86/kernel/cpu/mce/core.c > +++ b/arch/x86/kernel/cpu/mce/core.c > @@ -1261,6 +1261,21 @@ static void kill_me_maybe(struct callback_head *cb) > kill_me_now(cb); > } > > +static inline void queue_task_work(struct mce *m, int kill_it) Does it need to be "inline" though? I hope machine check processing is never in the critical code path for anyone! > +{ > + current->mce_addr = m->addr; > + current->mce_kflags = m->kflags; > + current->mce_ripv = !!(m->mcgstatus & MCG_STATUS_RIPV); > + current->mce_whole_page = whole_page(m); > + > + if (kill_it) > + current->mce_kill_me.func = kill_me_now; > + else > + current->mce_kill_me.func = kill_me_maybe; > + > + task_work_add(current, ¤t->mce_kill_me, true); > +} > + > /* > * The actual machine check handler. This only handles real > * exceptions when something got corrupted coming in through int 18. > @@ -1402,13 +1417,8 @@ noinstr void do_machine_check(struct pt_regs *regs) > /* If this triggers there is no way to recover. Die hard. */ > BUG_ON(!on_thread_stack() || !user_mode(regs)); > > - current->mce_addr = m.addr; > - current->mce_ripv = !!(m.mcgstatus & MCG_STATUS_RIPV); > - current->mce_whole_page = whole_page(&m); > - current->mce_kill_me.func = kill_me_maybe; > - if (kill_it) > - current->mce_kill_me.func = kill_me_now; > - task_work_add(current, ¤t->mce_kill_me, true); > + queue_task_work(&m, kill_it); > + > } else { > /* > * Handle an MCE which has happened in kernel space but from > @@ -1423,6 +1433,9 @@ noinstr void do_machine_check(struct pt_regs *regs) > if (!fixup_exception(regs, X86_TRAP_MC, 0, 0)) > mce_panic("Failed kernel mode recovery", &m, > msg); > } > + > + if (m.kflags & MCE_IN_KERNEL_COPYIN) > + queue_task_work(&m, kill_it); > } > out: > mce_wrmsrl(MSR_IA32_MCG_STATUS, 0); -Tony