Messages in this thread | | | Date | Thu, 7 Jan 2021 13:58:21 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH 6/6] x86/mce: Dont use noinstr for now |
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On Thu, Jan 07, 2021 at 11:06:26AM +0100, Borislav Petkov wrote: > On Wed, Jan 06, 2021 at 03:57:55PM +0100, Boris Petkov wrote: > > Another thing that we could do is carve out only the stuff which needs > > to be noinstr into a separate compilation unit and disable tracing > > only for that while keeping the rest traceable. Need to try it to see > > how ugly it'll get... > > Something like the below, it barely builds. > > I haven't found out whether I can even do > > ccflags-remove > > on a per-file basis, I guess I cannot so that's not there yet. > > core_noinstr.c ended up containing all the code needed by the #MC > handler so that should be ok-ish, carve-out-wise. > > Also, I've exported a bunch of functions which are in mce/core.c through > the internal.h header so that core_noinstr.c can call them. There are > no more objtool warnings but if it turns out that we have to move those > functions: > > +/* core_noinstr.c */ > +bool mce_check_crashing_cpu(void); > +void print_mce(struct mce *m); > +void mce_reset(void); > +bool whole_page(struct mce *m); > +u64 mce_rdmsrl(u32 msr); > +void mce_wrmsrl(u32 msr, u64 v); > +void mce_read_aux(struct mce *m, int i); > +void mce_gather_info(struct mce *m, struct pt_regs *regs); > > to core_noinstr.c after all, then we can do your solution directly. > > Ok, gnight. :-) > > --- > diff --git a/arch/x86/kernel/cpu/mce/Makefile b/arch/x86/kernel/cpu/mce/Makefile > index 9f020c994154..2fa36118a05f 100644 > --- a/arch/x86/kernel/cpu/mce/Makefile > +++ b/arch/x86/kernel/cpu/mce/Makefile > @@ -1,5 +1,10 @@ > # SPDX-License-Identifier: GPL-2.0 > -obj-y = core.o severity.o genpool.o > +# No instrumentation for #MC handler code > +KASAN_SANITIZE_core_instr.o := n > +UBSAN_SANITIZE_core_instr.o := n > +KCOV_INSTRUMENT_core_instr.o := n
ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_core_instr.o = $(CC_FLAGS_FTRACE) endif
> + > +obj-y = core.o core_noinstr.o severity.o genpool.o
I'm thinking
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