arm64/mpam: resctrl: Add helpers for init and destroy schemata list

hulk inclusion
category: feature
feature: ARM MPAM support
bugzilla: 48265
CVE: NA

--------------------------------

Initialize schemata list when mount resctrl sysfs and destroy it when
umount, each list node contains the value updated by schemata (in resctrl
sysfs) row.

Partial code is borrowed from 250656171d95 ("x86/resctrl: Stop using Lx
CODE/DATA resources"), as it illustrates:

  Now that CDP enable/disable is global, and the closid offset correction
  is based on the configuration being applied, we are using different
  hw_closid slots in the ctrl array for CODE/DATA schema. This lets
  us merge them using the same Lx resource twice for CDP's CODE/DATA
  schema. This keeps the illusion of separate caches in the resctrl code.

  When CDP is enabled for a cache, create two schema generating the names
  and setting the configuration type.

  We can now remove the initialisation of the illusionary hw_resources:
  'cdp_capable' just requires setting a flag, resctrl knows what to do
  from there.

Link: http://www.linux-arm.org/git?p=linux-jm.git;a=commit;h=250656171d95dea079cc661098a0984e7237aa25Signed-off-by: NWang ShaoBo <bobo.shaobowang@huawei.com>
Reviewed-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: NCheng Jian <cj.chengjian@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm64/include/asm/resctrl.h

@@ -75,6 +75,10 @@ struct rdtgroup {
 	struct mongroup     mon;
 };
 
+int schemata_list_init(void);
+
+void schemata_list_destroy(void);
+
 static inline int alloc_mon_id(void)
 {
 

arch/arm64/kernel/mpam/mpam_ctrlmon.c

@@ -36,6 +36,84 @@
 #include <asm/resctrl.h>
 #include "mpam_internal.h"
 
+/* schemata content list */
+LIST_HEAD(resctrl_all_schema);
+
+/* Init schemata content */
+static int add_schema(enum resctrl_conf_type t, struct resctrl_resource *r)
+{
+	char *suffix = "";
+	struct resctrl_schema *s;
+
+	s = kzalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	s->res = r;
+	s->conf_type = t;
+
+	switch (t) {
+	case CDP_CODE:
+		suffix = "CODE";
+		break;
+	case CDP_DATA:
+		suffix = "DATA";
+		break;
+	case CDP_BOTH:
+		suffix = "";
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	WARN_ON_ONCE(strlen(r->name) + strlen(suffix) + 1 > RESCTRL_NAME_LEN);
+	snprintf(s->name, sizeof(s->name), "%s%s", r->name, suffix);
+
+	INIT_LIST_HEAD(&s->list);
+	list_add_tail(&s->list, &resctrl_all_schema);
+
+	return 0;
+}
+
+int schemata_list_init(void)
+{
+	int ret;
+	struct mpam_resctrl_res *res;
+	struct resctrl_resource *r;
+
+	for_each_supported_resctrl_exports(res) {
+		r = &res->resctrl_res;
+		if (!r || !r->alloc_capable)
+			continue;
+
+		if (r->cdp_enable) {
+			ret = add_schema(CDP_CODE, r);
+			ret |= add_schema(CDP_DATA, r);
+		} else {
+			ret = add_schema(CDP_BOTH, r);
+		}
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+/*
+ * During resctrl_kill_sb(), the mba_sc state is reset before
+ * schemata_list_destroy() is called: unconditionally try to free the
+ * array.
+ */
+void schemata_list_destroy(void)
+{
+	struct resctrl_schema *s, *tmp;
+
+	list_for_each_entry_safe(s, tmp, &resctrl_all_schema, list) {
+		list_del(&s->list);
+		kfree(s);
+	}
+}
+
 /*
  * Check whether a cache bit mask is valid. The SDM says:
  *	Please note that all (and only) contiguous '1' combinations

fs/resctrlfs.c

@@ -336,6 +336,11 @@ static int resctrl_get_tree(struct fs_context *fc)
 	if (ret)
 		goto out;
 
+#ifdef CONFIG_ARM64
+	ret = schemata_list_init();
+	if (ret)
+		goto out;
+#endif
 	resctrl_id_init();
 
 	ret = resctrl_group_create_info_dir(resctrl_group_default.kn);
@@ -498,6 +503,9 @@ static void resctrl_kill_sb(struct super_block *sb)
 	mutex_lock(&resctrl_group_mutex);
 
 	resctrl_resource_reset();
+#ifdef CONFIG_ARM64
+	schemata_list_destroy();
+#endif
 
 	rmdir_all_sub();
 	static_branch_disable_cpuslocked(&resctrl_alloc_enable_key);