1 /* 2 * Copyright (C) IBM Corporation, 2014, 2017 3 * Anton Blanchard, Rashmica Gupta. 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 */ 10 11 #define pr_fmt(fmt) "memtrace: " fmt 12 13 #include <linux/bitops.h> 14 #include <linux/string.h> 15 #include <linux/memblock.h> 16 #include <linux/init.h> 17 #include <linux/moduleparam.h> 18 #include <linux/fs.h> 19 #include <linux/debugfs.h> 20 #include <linux/slab.h> 21 #include <linux/memory.h> 22 #include <linux/memory_hotplug.h> 23 #include <asm/machdep.h> 24 #include <asm/debugfs.h> 25 26 /* This enables us to keep track of the memory removed from each node. */ 27 struct memtrace_entry { 28 void *mem; 29 u64 start; 30 u64 size; 31 u32 nid; 32 struct dentry *dir; 33 char name[16]; 34 }; 35 36 static u64 memtrace_size; 37 38 static struct memtrace_entry *memtrace_array; 39 static unsigned int memtrace_array_nr; 40 41 42 static ssize_t memtrace_read(struct file *filp, char __user *ubuf, 43 size_t count, loff_t *ppos) 44 { 45 struct memtrace_entry *ent = filp->private_data; 46 47 return simple_read_from_buffer(ubuf, count, ppos, ent->mem, ent->size); 48 } 49 50 static bool valid_memtrace_range(struct memtrace_entry *dev, 51 unsigned long start, unsigned long size) 52 { 53 if ((start >= dev->start) && 54 ((start + size) <= (dev->start + dev->size))) 55 return true; 56 57 return false; 58 } 59 60 static int memtrace_mmap(struct file *filp, struct vm_area_struct *vma) 61 { 62 unsigned long size = vma->vm_end - vma->vm_start; 63 struct memtrace_entry *dev = filp->private_data; 64 65 if (!valid_memtrace_range(dev, vma->vm_pgoff << PAGE_SHIFT, size)) 66 return -EINVAL; 67 68 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 69 70 if (remap_pfn_range(vma, vma->vm_start, 71 vma->vm_pgoff + (dev->start >> PAGE_SHIFT), 72 size, vma->vm_page_prot)) 73 return -EAGAIN; 74 75 return 0; 76 } 77 78 static const struct file_operations memtrace_fops = { 79 .llseek = default_llseek, 80 .read = memtrace_read, 81 .mmap = memtrace_mmap, 82 .open = simple_open, 83 }; 84 85 static int check_memblock_online(struct memory_block *mem, void *arg) 86 { 87 if (mem->state != MEM_ONLINE) 88 return -1; 89 90 return 0; 91 } 92 93 static int change_memblock_state(struct memory_block *mem, void *arg) 94 { 95 unsigned long state = (unsigned long)arg; 96 97 mem->state = state; 98 99 return 0; 100 } 101 102 static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages) 103 { 104 u64 end_pfn = start_pfn + nr_pages - 1; 105 106 if (walk_memory_range(start_pfn, end_pfn, NULL, 107 check_memblock_online)) 108 return false; 109 110 walk_memory_range(start_pfn, end_pfn, (void *)MEM_GOING_OFFLINE, 111 change_memblock_state); 112 113 if (offline_pages(start_pfn, nr_pages)) { 114 walk_memory_range(start_pfn, end_pfn, (void *)MEM_ONLINE, 115 change_memblock_state); 116 return false; 117 } 118 119 walk_memory_range(start_pfn, end_pfn, (void *)MEM_OFFLINE, 120 change_memblock_state); 121 122 lock_device_hotplug(); 123 remove_memory(nid, start_pfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT); 124 unlock_device_hotplug(); 125 126 return true; 127 } 128 129 static u64 memtrace_alloc_node(u32 nid, u64 size) 130 { 131 u64 start_pfn, end_pfn, nr_pages; 132 u64 base_pfn; 133 134 if (!node_spanned_pages(nid)) 135 return 0; 136 137 start_pfn = node_start_pfn(nid); 138 end_pfn = node_end_pfn(nid); 139 nr_pages = size >> PAGE_SHIFT; 140 141 /* Trace memory needs to be aligned to the size */ 142 end_pfn = round_down(end_pfn - nr_pages, nr_pages); 143 144 for (base_pfn = end_pfn; base_pfn > start_pfn; base_pfn -= nr_pages) { 145 if (memtrace_offline_pages(nid, base_pfn, nr_pages) == true) 146 return base_pfn << PAGE_SHIFT; 147 } 148 149 return 0; 150 } 151 152 static int memtrace_init_regions_runtime(u64 size) 153 { 154 u32 nid; 155 u64 m; 156 157 memtrace_array = kcalloc(num_online_nodes(), 158 sizeof(struct memtrace_entry), GFP_KERNEL); 159 if (!memtrace_array) { 160 pr_err("Failed to allocate memtrace_array\n"); 161 return -EINVAL; 162 } 163 164 for_each_online_node(nid) { 165 m = memtrace_alloc_node(nid, size); 166 167 /* 168 * A node might not have any local memory, so warn but 169 * continue on. 170 */ 171 if (!m) { 172 pr_err("Failed to allocate trace memory on node %d\n", nid); 173 continue; 174 } 175 176 pr_info("Allocated trace memory on node %d at 0x%016llx\n", nid, m); 177 178 memtrace_array[memtrace_array_nr].start = m; 179 memtrace_array[memtrace_array_nr].size = size; 180 memtrace_array[memtrace_array_nr].nid = nid; 181 memtrace_array_nr++; 182 } 183 184 return 0; 185 } 186 187 static struct dentry *memtrace_debugfs_dir; 188 189 static int memtrace_init_debugfs(void) 190 { 191 int ret = 0; 192 int i; 193 194 for (i = 0; i < memtrace_array_nr; i++) { 195 struct dentry *dir; 196 struct memtrace_entry *ent = &memtrace_array[i]; 197 198 ent->mem = ioremap(ent->start, ent->size); 199 /* Warn but continue on */ 200 if (!ent->mem) { 201 pr_err("Failed to map trace memory at 0x%llx\n", 202 ent->start); 203 ret = -1; 204 continue; 205 } 206 207 snprintf(ent->name, 16, "%08x", ent->nid); 208 dir = debugfs_create_dir(ent->name, memtrace_debugfs_dir); 209 if (!dir) 210 return -1; 211 212 ent->dir = dir; 213 debugfs_create_file("trace", 0400, dir, ent, &memtrace_fops); 214 debugfs_create_x64("start", 0400, dir, &ent->start); 215 debugfs_create_x64("size", 0400, dir, &ent->size); 216 } 217 218 return ret; 219 } 220 221 static int memtrace_enable_set(void *data, u64 val) 222 { 223 if (memtrace_size) 224 return -EINVAL; 225 226 if (!val) 227 return -EINVAL; 228 229 /* Make sure size is aligned to a memory block */ 230 if (val & (memory_block_size_bytes() - 1)) 231 return -EINVAL; 232 233 if (memtrace_init_regions_runtime(val)) 234 return -EINVAL; 235 236 if (memtrace_init_debugfs()) 237 return -EINVAL; 238 239 memtrace_size = val; 240 241 return 0; 242 } 243 244 static int memtrace_enable_get(void *data, u64 *val) 245 { 246 *val = memtrace_size; 247 return 0; 248 } 249 250 DEFINE_SIMPLE_ATTRIBUTE(memtrace_init_fops, memtrace_enable_get, 251 memtrace_enable_set, "0x%016llx\n"); 252 253 static int memtrace_init(void) 254 { 255 memtrace_debugfs_dir = debugfs_create_dir("memtrace", 256 powerpc_debugfs_root); 257 if (!memtrace_debugfs_dir) 258 return -1; 259 260 debugfs_create_file("enable", 0600, memtrace_debugfs_dir, 261 NULL, &memtrace_init_fops); 262 263 return 0; 264 } 265 machine_device_initcall(powernv, memtrace_init); 266