1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2025, Intel Corporation.
4 *
5 * Memory Range and Region Mapping (MRRM) structure
6 *
7 * Parse and report the platform's MRRM table in /sys.
8 */
9
10#define pr_fmt(fmt) "acpi/mrrm: " fmt
11
12#include <linux/acpi.h>
13#include <linux/init.h>
14#include <linux/string.h>
15#include <linux/sysfs.h>
16
17/* Default assume one memory region covering all system memory, per the spec */
18static int max_mem_region = 1;
19
20/* Access for use by resctrl file system */
21int acpi_mrrm_max_mem_region(void)
22{
23 return max_mem_region;
24}
25
26struct mrrm_mem_range_entry {
27 u64 base;
28 u64 length;
29 int node;
30 u8 local_region_id;
31 u8 remote_region_id;
32};
33
34static struct mrrm_mem_range_entry *mrrm_mem_range_entry;
35static u32 mrrm_mem_entry_num;
36
37static int get_node_num(struct mrrm_mem_range_entry *e)
38{
39 unsigned int nid;
40
41 for_each_online_node(nid) {
42 for (int z = 0; z < MAX_NR_ZONES; z++) {
43 struct zone *zone = NODE_DATA(nid)->node_zones + z;
44
45 if (!populated_zone(zone))
46 continue;
47 if (zone_intersects(zone, PHYS_PFN(e->base), PHYS_PFN(e->length)))
48 return zone_to_nid(zone);
49 }
50 }
51
52 return -ENOENT;
53}
54
55static __init int acpi_parse_mrrm(struct acpi_table_header *table)
56{
57 struct acpi_mrrm_mem_range_entry *mre_entry;
58 struct acpi_table_mrrm *mrrm;
59 void *mre, *mrrm_end;
60 int mre_count = 0;
61
62 mrrm = (struct acpi_table_mrrm *)table;
63 if (!mrrm)
64 return -ENODEV;
65
66 if (mrrm->flags & ACPI_MRRM_FLAGS_REGION_ASSIGNMENT_OS)
67 return -EOPNOTSUPP;
68
69 mrrm_end = (void *)mrrm + mrrm->header.length - 1;
70 mre = (void *)mrrm + sizeof(struct acpi_table_mrrm);
71 while (mre < mrrm_end) {
72 mre_entry = mre;
73 mre_count++;
74 mre += mre_entry->header.length;
75 }
76 if (!mre_count) {
77 pr_info(FW_BUG "No ranges listed in MRRM table\n");
78 return -EINVAL;
79 }
80
81 mrrm_mem_range_entry = kmalloc_array(mre_count, sizeof(*mrrm_mem_range_entry),
82 GFP_KERNEL | __GFP_ZERO);
83 if (!mrrm_mem_range_entry)
84 return -ENOMEM;
85
86 mre = (void *)mrrm + sizeof(struct acpi_table_mrrm);
87 while (mre < mrrm_end) {
88 struct mrrm_mem_range_entry *e;
89
90 mre_entry = mre;
91 e = mrrm_mem_range_entry + mrrm_mem_entry_num;
92
93 e->base = mre_entry->addr_base;
94 e->length = mre_entry->addr_len;
95 e->node = get_node_num(e);
96
97 if (mre_entry->region_id_flags & ACPI_MRRM_VALID_REGION_ID_FLAGS_LOCAL)
98 e->local_region_id = mre_entry->local_region_id;
99 else
100 e->local_region_id = -1;
101 if (mre_entry->region_id_flags & ACPI_MRRM_VALID_REGION_ID_FLAGS_REMOTE)
102 e->remote_region_id = mre_entry->remote_region_id;
103 else
104 e->remote_region_id = -1;
105
106 mrrm_mem_entry_num++;
107 mre += mre_entry->header.length;
108 }
109
110 max_mem_region = mrrm->max_mem_region;
111
112 return 0;
113}
114
115#define RANGE_ATTR(name, fmt) \
116static ssize_t name##_show(struct kobject *kobj, \
117 struct kobj_attribute *attr, char *buf) \
118{ \
119 struct mrrm_mem_range_entry *mre; \
120 const char *kname = kobject_name(kobj); \
121 int n, ret; \
122 \
123 ret = kstrtoint(kname + 5, 10, &n); \
124 if (ret) \
125 return ret; \
126 \
127 mre = mrrm_mem_range_entry + n; \
128 \
129 return sysfs_emit(buf, fmt, mre->name); \
130} \
131static struct kobj_attribute name##_attr = __ATTR_RO(name)
132
133RANGE_ATTR(base, "0x%llx\n");
134RANGE_ATTR(length, "0x%llx\n");
135RANGE_ATTR(node, "%d\n");
136RANGE_ATTR(local_region_id, "%d\n");
137RANGE_ATTR(remote_region_id, "%d\n");
138
139static struct attribute *memory_range_attrs[] = {
140 &base_attr.attr,
141 &length_attr.attr,
142 &node_attr.attr,
143 &local_region_id_attr.attr,
144 &remote_region_id_attr.attr,
145 NULL
146};
147
148ATTRIBUTE_GROUPS(memory_range);
149
150static __init int add_boot_memory_ranges(void)
151{
152 struct kobject *pkobj, *kobj;
153 int ret = -EINVAL;
154 char *name;
155
156 pkobj = kobject_create_and_add(name: "memory_ranges", parent: acpi_kobj);
157
158 for (int i = 0; i < mrrm_mem_entry_num; i++) {
159 name = kasprintf(GFP_KERNEL, fmt: "range%d", i);
160 if (!name) {
161 ret = -ENOMEM;
162 break;
163 }
164
165 kobj = kobject_create_and_add(name, parent: pkobj);
166
167 ret = sysfs_create_groups(kobj, groups: memory_range_groups);
168 if (ret)
169 return ret;
170 }
171
172 return ret;
173}
174
175static __init int mrrm_init(void)
176{
177 int ret;
178
179 ret = acpi_table_parse(ACPI_SIG_MRRM, handler: acpi_parse_mrrm);
180 if (ret < 0)
181 return ret;
182
183 return add_boot_memory_ranges();
184}
185device_initcall(mrrm_init);
186