[PATCH v7 2/8] x86/crash: Introduce new options to support cpu and memory hotplug

Borislav Petkov
2022-04-19T10:32:25Z

On Mon, Apr 18, 2022 at 05:03:39PM -0500, Eric DeVolder wrote:
> I've examined the code with this thought in mind, and I'm not exactly sure how
> this code should be restructured for !HOTPLUG stubs. I'd very much appreciate
> an example in order to facilitate accommodating the request!

For example, see init_intel_microcode() in arch/x86/include/asm/microcode.h:

#ifdef CONFIG_MICROCODE_INTEL
extern struct microcode_ops * __init init_intel_microcode(void);
#else
static inline struct microcode_ops * __init init_intel_microcode(void)
{
return NULL;
}
#endif /* CONFIG_MICROCODE_INTEL */

The actual definition then is in:

arch/x86/kernel/cpu/microcode/intel.c:
struct microcode_ops * __init init_intel_microcode(void)

and it gets enabled when CONFIG_MICROCODE_INTEL is enabled in the
.config. When CONFIG_MICROCODE_INTEL=n, the static inline stub gets used
and optimized away by the compiler.

HTH.

--
Regards/Gruss,
Boris.