Re: [PATCH 29/37] xen/arm: introduce a helper to parse device tree processor node

[Stefano Stabellini <sstabellini@kernel.org>]

On Thu, 23 Sep 2021, Wei Chen wrote:
> Processor NUMA ID information is stored in device tree's processor
> node as "numa-node-id". We need a new helper to parse this ID from
> processor node. If we get this ID from processor node, this ID's
> validity still need to be checked. Once we got a invalid NUMA ID
> from any processor node, the device tree will be marked as NUMA
> information invalid.
> 
> Signed-off-by: Wei Chen <wei.chen@arm.com>
> ---
>  xen/arch/arm/Makefile           |  1 +
>  xen/arch/arm/numa_device_tree.c | 58 +++++++++++++++++++++++++++++++++
>  2 files changed, 59 insertions(+)
>  create mode 100644 xen/arch/arm/numa_device_tree.c
> 
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index 41ca311b6b..c50df2c25d 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -36,6 +36,7 @@ obj-y += mem_access.o
>  obj-y += mm.o
>  obj-y += monitor.o
>  obj-$(CONFIG_NUMA) += numa.o
> +obj-$(CONFIG_DEVICE_TREE_NUMA) += numa_device_tree.o
>  obj-y += p2m.o
>  obj-y += percpu.o
>  obj-y += platform.o
> diff --git a/xen/arch/arm/numa_device_tree.c b/xen/arch/arm/numa_device_tree.c
> new file mode 100644
> index 0000000000..2428fbae0b
> --- /dev/null
> +++ b/xen/arch/arm/numa_device_tree.c
> @@ -0,0 +1,58 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Arm Architecture support layer for NUMA.
> + *
> + * Copyright (C) 2021 Arm Ltd
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +#include <xen/init.h>
> +#include <xen/nodemask.h>
> +#include <xen/numa.h>
> +#include <xen/libfdt/libfdt.h>
> +#include <xen/device_tree.h>
> +
> +/* Callback for device tree processor affinity */
> +static int __init fdt_numa_processor_affinity_init(nodeid_t node)
> +{
> +    if ( srat_disabled() )
> +        return -EINVAL;

fdt_numa_processor_affinity_init is called by fdt_parse_numa_cpu_node
which is already parsing NUMA related info. Should this srat_disabled
check be moved to fdt_parse_numa_cpu_node?


> +    else if ( node == NUMA_NO_NODE || node >= MAX_NUMNODES )
> +    {
> +        bad_srat();
> +        return -EINVAL;
> +	}
> +
> +    numa_set_processor_nodes_parsed(node);
> +    fw_numa = 1;
> +
> +    printk(KERN_INFO "DT: NUMA node %"PRIu7" processor parsed\n", node);
> +
> +    return 0;
> +}
> +
> +/* Parse CPU NUMA node info */
> +static int __init fdt_parse_numa_cpu_node(const void *fdt, int node)
> +{
> +    uint32_t nid;
> +
> +    nid = device_tree_get_u32(fdt, node, "numa-node-id", MAX_NUMNODES);
> +    if ( nid >= MAX_NUMNODES )
> +    {
> +        printk(XENLOG_ERR "Node id %u exceeds maximum value\n", nid);
                                      ^ PRIu32


> +        return -EINVAL;
> +    }
> +
> +    return fdt_numa_processor_affinity_init(nid);
> +}
> -- 
> 2.25.1
>