Re: [PATCH v5 32/32] x86/mm: Add support to make use of Secure Memory Encryption

From: Borislav Petkov
Date: Tue May 30 2017 - 11:04:33 EST


On Tue, May 30, 2017 at 09:38:36AM -0500, Tom Lendacky wrote:
> In this case we're running identity mapped and the "on" constant ends up
> as kernel address (0xffffffff81...) which results in a segfault.

Would

static const char *__on_str = "on";

...

if (!strncmp(buffer, __pa_nodebug(__on_str), 2))
...

work?

__phys_addr_nodebug() seems to pay attention to phys_base and
PAGE_OFFSET and so on...

I'd like to avoid that rip-relative address finding in inline asm which
looks fragile to me.

Thanks.

--
Regards/Gruss,
Boris.

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