[PATCH v3 5/6] fs/core/vmcore: Move sev_active() reference to x86 arch code

[Christoph Hellwig]

On Thu, Jul 18, 2019 at 12:28:57AM -0300, Thiago Jung Bauermann wrote:
> Secure Encrypted Virtualization is an x86-specific feature, so it shouldn't
> appear in generic kernel code because it forces non-x86 architectures to
> define the sev_active() function, which doesn't make a lot of sense.
> 
> To solve this problem, add an x86 elfcorehdr_read() function to override
> the generic weak implementation. To do that, it's necessary to make
> read_from_oldmem() public so that it can be used outside of vmcore.c.
> 
> Also, remove the export for sev_active() since it's only used in files that
> won't be built as modules.

I have to say I find the __weak overrides of the vmcore files very
confusing and which we'd have a better scheme there.  But as this fits
into that scheme and allows to remove the AMD SME vs SEV knowledge from
the core I'm fine with it.

Reviewed-by: Christoph Hellwig <hch at lst.de>