On Fri, Sep 11, 2020 at 11:23:57PM +1000, Michael Ellerman wrote:
> Michal Suchánek <msucha...@suse.de> writes:
> > Hello,
> >
> > does this logic apply to "Unrecoverable System Reset" as well?
>
> Which logic do you mean?
>
> We do call die() before checking MSR_RI in system_reset_exception():
>
> /*
> * No debugger or crash dump registered, print logs then
> * panic.
> */
> die("System Reset", regs, SIGABRT);
>
> mdelay(2*MSEC_PER_SEC); /* Wait a little while for others to print */
> add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
> nmi_panic(regs, "System Reset");
>
> out:
> #ifdef CONFIG_PPC_BOOK3S_64
> BUG_ON(get_paca()->in_nmi == 0);
> if (get_paca()->in_nmi > 1)
> die("Unrecoverable nested System Reset", regs, SIGABRT);
> #endif
> /* Must die if the interrupt is not recoverable */
> if (!(regs->msr & MSR_RI))
> die("Unrecoverable System Reset", regs, SIGABRT);
>
>
> So you should see the output from die("System Reset", ...) even if
> MSR[RI] was clear when you took the system reset.
Indeed, replied to the wrong patch. I was looking at daf00ae71dad
("powerpc/traps: restore recoverability of machine_check interrupts")
which has very similar commit message.
Sorry about the confusion.
Thanks
Michal
>
> cheers
>
> > On Tue, Jan 22, 2019 at 02:11:24PM +0000, Christophe Leroy wrote:
> >> Looks like book3s/32 doesn't set RI on machine check, so
> >> checking RI before calling die() will always be fatal
> >> allthought this is not an issue in most cases.
> >>
> >> Fixes: b96672dd840f ("powerpc: Machine check interrupt is a non-maskable
> >> interrupt")
> >> Fixes: daf00ae71dad ("powerpc/traps: restore recoverability of
> >> machine_check interrupts")
> >> Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
> >> Cc: sta...@vger.kernel.org
> >> ---
> >> arch/powerpc/kernel/traps.c | 8 ++++----
> >> 1 file changed, 4 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
> >> index 64936b60d521..c740f8bfccc9 100644
> >> --- a/arch/powerpc/kernel/traps.c
> >> +++ b/arch/powerpc/kernel/traps.c
> >> @@ -763,15 +763,15 @@ void machine_check_exception(struct pt_regs *regs)
> >> if (check_io_access(regs))
> >> goto bail;
> >>
> >> - /* Must die if the interrupt is not recoverable */
> >> - if (!(regs->msr & MSR_RI))
> >> - nmi_panic(regs, "Unrecoverable Machine check");
> >> -
> >> if (!nested)
> >> nmi_exit();
> >>
> >> die("Machine check", regs, SIGBUS);
> >>
> >> + /* Must die if the interrupt is not recoverable */
> >> + if (!(regs->msr & MSR_RI))
> >> + nmi_panic(regs, "Unrecoverable Machine check");
> >> +
> >> return;
> >>
> >> bail:
> >> --
> >> 2.13.3
> >>
