[PATCH v6 02/17] xen/arm: implement helpers to get and update NUMA status

[Henry Wang <Henry.Wang@xxxxxxx>]

From: Wei Chen <wei.chen@xxxxxxx>

NUMA has one global and one implementation specific switches. For
ACPI NUMA implementation, Xen has acpi_numa, so we introduce
device_tree_numa for device tree NUMA implementation. And use
enumerations to indicate init, off and on status.

arch_numa_disabled will get device_tree_numa status, but for
arch_numa_setup we have not provided boot arguments to setup
device_tree_numa. So we just return -EINVAL in this patch.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
Signed-off-by: Henry Wang <Henry.Wang@xxxxxxx>
---
v3 -> v6:
- Rebase on top of staging without code changes.
v2 -> v3:
- Rename the first entry of enum dt_numa_status as DT_NUMA_DEFAULT.
- Make enum dt_numa_status device_tree_numa as __ro_after_init and
- assign it explicitly to DT_NUMA_DEFAULT.
- Update the year in copyright to 2023.
- Don't move the x86 numa_disabled() and make Arm's numa_disabled()
  a static inline function for !CONFIG_NUMA.
v1 -> v2:
- Use arch_numa_disabled to replace numa_enable_with_firmware.
- Introduce enumerations for device tree numa status.
- Use common numa_disabled, drop Arm version numa_disabled.
- Introduce arch_numa_setup for Arm.
- Rename bad_srat to numa_bad.
- Add numa_enable_with_firmware helper.
- Add numa_disabled helper.
- Refine commit message.
---
 xen/arch/arm/include/asm/numa.h | 17 +++++++++++
 xen/arch/arm/numa.c             | 50 +++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 xen/arch/arm/numa.c

diff --git a/xen/arch/arm/include/asm/numa.h b/xen/arch/arm/include/asm/numa.h
index 7d6ae36a19..83f60ad05b 100644
--- a/xen/arch/arm/include/asm/numa.h
+++ b/xen/arch/arm/include/asm/numa.h
@@ -22,6 +22,8 @@ typedef u8 nodeid_t;
  */
 #define NR_NODE_MEMBLKS NR_MEM_BANKS
 
+extern bool numa_disabled(void);
+
 #else
 
 /* Fake one node for now. See also node_online_map. */
@@ -39,6 +41,21 @@ extern mfn_t first_valid_mfn;
 #define node_start_pfn(nid) (mfn_x(first_valid_mfn))
 #define __node_distance(a, b) (20)
 
+static inline bool numa_disabled(void)
+{
+    return true;
+}
+
+static inline bool arch_numa_unavailable(void)
+{
+    return true;
+}
+
+static inline bool arch_numa_broken(void)
+{
+    return true;
+}
+
 #endif
 
 #define arch_want_default_dmazone() (false)
diff --git a/xen/arch/arm/numa.c b/xen/arch/arm/numa.c
new file mode 100644
index 0000000000..eb5d0632cb
--- /dev/null
+++ b/xen/arch/arm/numa.c
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Arm Architecture support layer for NUMA.
+ *
+ * Copyright (C) 2023 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/numa.h>
+
+enum dt_numa_status {
+    DT_NUMA_DEFAULT,
+    DT_NUMA_ON,
+    DT_NUMA_OFF,
+};
+
+static enum dt_numa_status __ro_after_init device_tree_numa = DT_NUMA_DEFAULT;
+
+void __init numa_fw_bad(void)
+{
+    printk(KERN_ERR "NUMA: device tree numa info table not used.\n");
+    device_tree_numa = DT_NUMA_OFF;
+}
+
+bool __init arch_numa_unavailable(void)
+{
+    return device_tree_numa != DT_NUMA_ON;
+}
+
+bool arch_numa_disabled(void)
+{
+    return device_tree_numa == DT_NUMA_OFF;
+}
+
+int __init arch_numa_setup(const char *opt)
+{
+    return -EINVAL;
+}
-- 
2.25.1