On Mon, 08 Oct 2018 15:08:31 +1100 Benjamin Herrenschmidt <b...@kernel.crashing.org> wrote:
> HMIs will crash the kernel due to > > BRANCH_LINK_TO_FAR(hmi_exception_realmode) > > Calling into the OPD instead of the actual code. > > Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org> > --- > > This hack fixes it for me, but it's not great. Nick, any better idea ? Is it a hack because the ifdef gunk, or because there's something deeper wrong with using the .sym? I guess all those handlers that load label address by hand could have the bug silently creep in. Can we have them use the DOTSYM() macro? Thanks, Nick > > diff --git a/arch/powerpc/kernel/exceptions-64s.S > b/arch/powerpc/kernel/exceptions-64s.S > index ea04dfb..752709cc8 100644 > --- a/arch/powerpc/kernel/exceptions-64s.S > +++ b/arch/powerpc/kernel/exceptions-64s.S > @@ -1119,7 +1119,11 @@ TRAMP_REAL_BEGIN(hmi_exception_early) > EXCEPTION_PROLOG_COMMON_2(PACA_EXGEN) > EXCEPTION_PROLOG_COMMON_3(0xe60) > addi r3,r1,STACK_FRAME_OVERHEAD > +#ifdef PPC64_ELF_ABI_v1 > + BRANCH_LINK_TO_FAR(.hmi_exception_realmode) /* Function call ABI */ > +#else > BRANCH_LINK_TO_FAR(hmi_exception_realmode) /* Function call ABI */ > +#endif > cmpdi cr0,r3,0 > > /* Windup the stack. */ > >
