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Date: Mon, 19 May 2014 14:39:00 +0100
From: Andrew Cooper <andrew.cooper3@citrix.com>
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To: Daniel Kiper <daniel.kiper@oracle.com>
CC: <linux-efi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
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Subject: Re: [Xen-devel] [PATCH v4 3/5] xen: Put EFI machinery in place
References: <1400272904-31121-1-git-send-email-daniel.kiper@oracle.com> <1400272904-31121-4-git-send-email-daniel.kiper@oracle.com>
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On 16/05/14 21:41, Daniel Kiper wrote:
> @@ -0,0 +1,374 @@
> +/*
> + * EFI support for Xen.
> + *
> + * Copyright (C) 1999 VA Linux Systems
> + * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
> + * Copyright (C) 1999-2002 Hewlett-Packard Co.
> + *	David Mosberger-Tang <davidm@hpl.hp.com>
> + *	Stephane Eranian <eranian@hpl.hp.com>
> + * Copyright (C) 2005-2008 Intel Co.
> + *	Fenghua Yu <fenghua.yu@intel.com>
> + *	Bibo Mao <bibo.mao@intel.com>
> + *	Chandramouli Narayanan <mouli@linux.intel.com>
> + *	Huang Ying <ying.huang@intel.com>
> + * Copyright (C) 2011 Novell Co.
> + *	Jan Beulich <JBeulich@suse.com>
> + * Copyright (C) 2011-2012 Oracle Co.
> + *	Liang Tang <liang.tang@oracle.com>
> + * Copyright (c) 2014 Daniel Kiper, Oracle Corporation
> + */
> +
> +#include <linux/bug.h>
> +#include <linux/efi.h>
> +#include <linux/init.h>
> +#include <linux/string.h>
> +
> +#include <xen/interface/xen.h>
> +#include <xen/interface/platform.h>
> +
> +#include <asm/xen/hypercall.h>
> +
> +#define call (op.u.efi_runtime_call)

I think not.

> +#define DECLARE_CALL(what) \
> +	struct xen_platform_op op; \
> +	op.cmd = XENPF_efi_runtime_call; \
> +	call.function = XEN_EFI_##what; \
> +	call.misc = 0

Macros like this which explicitly create local variable with implicit
names are evil when reading code.

If you want to do initialisation like this, then at least do something like:

#define INIT_EFI_CALL(what) \
{ .cmd = XENPF_efi_runtime_call, \
   .u.efi_runtime_call.function = XEN_EFI_##what, \
   .u.efi_runtime_call.misc = 0 }

And use it as:

struct xen_platform_op op = INIT_EFI_CALL(foo);

~Andrew