Messages in this thread | | | Date | Mon, 14 Dec 2015 17:00:59 -0800 | From | "Luck, Tony" <> | Subject | Re: [PATCHV2 1/3] x86, ras: Add new infrastructure for machine check fixup tables |
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On Sat, Dec 12, 2015 at 11:11:42AM +0100, Borislav Petkov wrote: > > +config MCE_KERNEL_RECOVERY > > + depends on X86_MCE && X86_64 > > + def_bool y > > Shouldn't that depend on NVDIMM or whatnot? Looks too generic now.
Not sure what the "whatnot" would be though. Making it depend on X86_MCE should keep it out of the tiny configurations. By the time you have MCE support, this seems like a pretty small incremental change.
> > +#ifdef CONFIG_MCE_KERNEL_RECOVERY > > +int fixup_mcexception(struct pt_regs *regs, u64 addr) > > +{ > > If you move the #ifdef here, you can save yourself the ifdeffery in the > header above.
I realized I didn't need the inline stub function in the header.
> > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > > index 1781e54ea6d3..21bb20d1172a 100644 > > --- a/include/asm-generic/vmlinux.lds.h > > +++ b/include/asm-generic/vmlinux.lds.h > > @@ -473,6 +473,12 @@ > > VMLINUX_SYMBOL(__start___ex_table) = .; \ > > *(__ex_table) \ > > VMLINUX_SYMBOL(__stop___ex_table) = .; \ > > + } \ > > + . = ALIGN(align); \ > > + __mcex_table : AT(ADDR(__mcex_table) - LOAD_OFFSET) { \ > > + VMLINUX_SYMBOL(__start___mcex_table) = .; \ > > + *(__mcex_table) \ > > + VMLINUX_SYMBOL(__stop___mcex_table) = .; \ > > Of all the places, this one is missing #ifdef CONFIG_MCE_KERNEL_RECOVERY.
Is there some cpp magic to use an #ifdef inside a multi-line macro like this? Impact of not having the #ifdef is two extra symbols (the start/stop ones) in the symbol table of the final binary. If that's unacceptable I can fall back to an earlier unpublished version that had separate EXCEPTION_TABLE and MCEXCEPTION_TABLE macros with both invoked in the x86 vmlinux.lds.S file.
> You can make this one a bit more readable by doing: > > /* Given an address, look for it in the machine check exception tables. */ > const struct exception_table_entry * > search_mcexception_tables(unsigned long addr) > { > #ifdef CONFIG_MCE_KERNEL_RECOVERY > return search_extable(__start___mcex_table, > __stop___mcex_table - 1, addr); > #endif > }
I got rid of the local variable and the return ... but left the #ifdef/#endif around the whole function.
-Tony
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