Subject: Re: [PATCH 1/5] dynamic logical partitioning infrastructure
From: Michael Ellerman <michael@ellerman.id.au>
Reply-To: michael@ellerman.id.au
To: Nathan Fontenot <nfont@austin.ibm.com>
Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org
In-Reply-To: <4AAABCE3.5090702@austin.ibm.com>
References: <4AAABC55.4070207@austin.ibm.com>
	 <4AAABCE3.5090702@austin.ibm.com>
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Date: Wed, 16 Sep 2009 11:33:36 +1000
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On Fri, 2009-09-11 at 16:10 -0500, Nathan Fontenot wrote:
> This patch provides the kernel DLPAR infrastructure in a new filed named
> dlpar.c.  The functionality provided is for acquiring and releasing a=20
> resource from firmware and the parsing of information returned from the
> ibm,configure-connector rtas call.  Additionally this exports the=20
> pSeries reconfiguration notifier chain so that it can be invoked when
> device tree updates are made.
>=20
> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
> ---
>=20
> Index: powerpc/arch/powerpc/platforms/pseries/dlpar.c
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ powerpc/arch/powerpc/platforms/pseries/dlpar.c	2009-09-11 12:51:52.00=
0000000 -0500
> @@ -0,0 +1,416 @@
> +/*
> + * dlpar.c - support for dynamic reconfiguration (including PCI
> + * Hotplug and Dynamic Logical Partitioning on RPA platforms).
> + *
> + * Copyright (C) 2009 Nathan Fontenot
> + * Copyright (C) 2009 IBM Corporation
> + *
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License version
> + * 2 as published by the Free Software Foundation.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/kref.h>
> +#include <linux/notifier.h>
> +#include <linux/proc_fs.h>
> +#include <linux/spinlock.h>
> +
> +#include <asm/prom.h>
> +#include <asm/machdep.h>
> +#include <asm/uaccess.h>
> +#include <asm/rtas.h>
> +#include <asm/pSeries_reconfig.h>
> +
> +#define CFG_CONN_WORK_SIZE	4096
> +static char workarea[CFG_CONN_WORK_SIZE];
> +spinlock_t workarea_lock;
> +
> +static struct property *parse_cc_property(char *workarea)
> +{
> +	struct property *prop;
> +	u32 *work_ints;
> +	char *name;
> +	char *value;
> +
> +	prop =3D kzalloc(sizeof(*prop), GFP_KERNEL);
> +	if (!prop)
> +		return NULL;
> +
> +	work_ints =3D (u32 *)workarea;
> +	name =3D workarea + work_ints[2];
> +	prop->name =3D kzalloc(strlen(name) + 1, GFP_KERNEL);
> +	if (!prop->name) {
> +		kfree(prop);
> +		return NULL;
> +	}
> +
> +	strcpy(prop->name, name);
> +
> +	prop->length =3D work_ints[3];
> +	value =3D workarea + work_ints[4];
> +	prop->value =3D kzalloc(prop->length, GFP_KERNEL);


The use of work_ints is a bit opaque, it might be clearer if you define
a struct, something like:

struct cc_prop {
	u32 ?;
	u32 ?;
	u32 name_offset;
	u32 length;
	u32 value_offset;
};

cc =3D (struct cc_prop *)workarea;

name =3D workarea + cc->name_offset;
..
prop->length =3D cc->length;
value =3D workarea + cc->value_offset;

etc.


Also I don't see any checking of the offsets into workarea (for name &
value), vs the size of workarea.

cheers


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