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From: David Howells <dhowells@redhat.com>
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To: lukas@wunner.de
Cc: dhowells@redhat.com, linux-efi@vger.kernel.org,
        linux-security-module@vger.kernel.org, keyrings@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/6] arm/efi: Allow invocation of arbitrary runtime services [ver #2]
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Date: Wed, 23 Nov 2016 09:34:03 +0000
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David Howells <dhowells@redhat.com> wrote:

> +#define efi_call_runtime(f, ...)	sys_table_arg->runtime->f(__VA_ARGS__)

Turns out it's not that simple - of course.  runtime->get_variable is just a
void pointer.  The old arm stub was casting it by virtue of assignment to a
function pointer variable.

The x86_64 appears to be doing bypassing all the compile-time type checking by
passing the arguments through an ellipsis and then fixing up the argument list
in the ->call() function.

What I've changed the ARM and ARM64 things to is:

	#define efi_call_runtime(f, ...)	((efi_##f##_t *)sys_table_arg->runtime->f)(__VA_ARGS__)

David