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back to an earlier unpublished version that had separate EXCEPTION_TABLE and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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