| /* |
| * Copyright (C) IBM Corporation, 2014, 2017 |
| * Anton Blanchard, Rashmica Gupta. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| */ |
| |
| #define pr_fmt(fmt) "memtrace: " fmt |
| |
| #include <linux/bitops.h> |
| #include <linux/string.h> |
| #include <linux/memblock.h> |
| #include <linux/init.h> |
| #include <linux/moduleparam.h> |
| #include <linux/fs.h> |
| #include <linux/debugfs.h> |
| #include <linux/slab.h> |
| #include <linux/memory.h> |
| #include <linux/memory_hotplug.h> |
| #include <asm/machdep.h> |
| #include <asm/debugfs.h> |
| |
| /* This enables us to keep track of the memory removed from each node. */ |
| struct memtrace_entry { |
| void *mem; |
| u64 start; |
| u64 size; |
| u32 nid; |
| struct dentry *dir; |
| char name[16]; |
| }; |
| |
| static u64 memtrace_size; |
| |
| static struct memtrace_entry *memtrace_array; |
| static unsigned int memtrace_array_nr; |
| |
| |
| static ssize_t memtrace_read(struct file *filp, char __user *ubuf, |
| size_t count, loff_t *ppos) |
| { |
| struct memtrace_entry *ent = filp->private_data; |
| |
| return simple_read_from_buffer(ubuf, count, ppos, ent->mem, ent->size); |
| } |
| |
| static bool valid_memtrace_range(struct memtrace_entry *dev, |
| unsigned long start, unsigned long size) |
| { |
| if ((start >= dev->start) && |
| ((start + size) <= (dev->start + dev->size))) |
| return true; |
| |
| return false; |
| } |
| |
| static int memtrace_mmap(struct file *filp, struct vm_area_struct *vma) |
| { |
| unsigned long size = vma->vm_end - vma->vm_start; |
| struct memtrace_entry *dev = filp->private_data; |
| |
| if (!valid_memtrace_range(dev, vma->vm_pgoff << PAGE_SHIFT, size)) |
| return -EINVAL; |
| |
| vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); |
| |
| if (remap_pfn_range(vma, vma->vm_start, |
| vma->vm_pgoff + (dev->start >> PAGE_SHIFT), |
| size, vma->vm_page_prot)) |
| return -EAGAIN; |
| |
| return 0; |
| } |
| |
| static const struct file_operations memtrace_fops = { |
| .llseek = default_llseek, |
| .read = memtrace_read, |
| .mmap = memtrace_mmap, |
| .open = simple_open, |
| }; |
| |
| static int check_memblock_online(struct memory_block *mem, void *arg) |
| { |
| if (mem->state != MEM_ONLINE) |
| return -1; |
| |
| return 0; |
| } |
| |
| static int change_memblock_state(struct memory_block *mem, void *arg) |
| { |
| unsigned long state = (unsigned long)arg; |
| |
| mem->state = state; |
| |
| return 0; |
| } |
| |
| static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages) |
| { |
| u64 end_pfn = start_pfn + nr_pages - 1; |
| |
| if (walk_memory_range(start_pfn, end_pfn, NULL, |
| check_memblock_online)) |
| return false; |
| |
| walk_memory_range(start_pfn, end_pfn, (void *)MEM_GOING_OFFLINE, |
| change_memblock_state); |
| |
| if (offline_pages(start_pfn, nr_pages)) { |
| walk_memory_range(start_pfn, end_pfn, (void *)MEM_ONLINE, |
| change_memblock_state); |
| return false; |
| } |
| |
| walk_memory_range(start_pfn, end_pfn, (void *)MEM_OFFLINE, |
| change_memblock_state); |
| |
| |
| return true; |
| } |
| |
| static u64 memtrace_alloc_node(u32 nid, u64 size) |
| { |
| u64 start_pfn, end_pfn, nr_pages, pfn; |
| u64 base_pfn; |
| u64 bytes = memory_block_size_bytes(); |
| |
| if (!NODE_DATA(nid) || !node_spanned_pages(nid)) |
| return 0; |
| |
| start_pfn = node_start_pfn(nid); |
| end_pfn = node_end_pfn(nid); |
| nr_pages = size >> PAGE_SHIFT; |
| |
| /* Trace memory needs to be aligned to the size */ |
| end_pfn = round_down(end_pfn - nr_pages, nr_pages); |
| |
| for (base_pfn = end_pfn; base_pfn > start_pfn; base_pfn -= nr_pages) { |
| if (memtrace_offline_pages(nid, base_pfn, nr_pages) == true) { |
| /* |
| * Remove memory in memory block size chunks so that |
| * iomem resources are always split to the same size and |
| * we never try to remove memory that spans two iomem |
| * resources. |
| */ |
| lock_device_hotplug(); |
| end_pfn = base_pfn + nr_pages; |
| for (pfn = base_pfn; pfn < end_pfn; pfn += bytes>> PAGE_SHIFT) { |
| remove_memory(nid, pfn << PAGE_SHIFT, bytes); |
| } |
| unlock_device_hotplug(); |
| return base_pfn << PAGE_SHIFT; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int memtrace_init_regions_runtime(u64 size) |
| { |
| u32 nid; |
| u64 m; |
| |
| memtrace_array = kcalloc(num_online_nodes(), |
| sizeof(struct memtrace_entry), GFP_KERNEL); |
| if (!memtrace_array) { |
| pr_err("Failed to allocate memtrace_array\n"); |
| return -EINVAL; |
| } |
| |
| for_each_online_node(nid) { |
| m = memtrace_alloc_node(nid, size); |
| |
| /* |
| * A node might not have any local memory, so warn but |
| * continue on. |
| */ |
| if (!m) { |
| pr_err("Failed to allocate trace memory on node %d\n", nid); |
| continue; |
| } |
| |
| pr_info("Allocated trace memory on node %d at 0x%016llx\n", nid, m); |
| |
| memtrace_array[memtrace_array_nr].start = m; |
| memtrace_array[memtrace_array_nr].size = size; |
| memtrace_array[memtrace_array_nr].nid = nid; |
| memtrace_array_nr++; |
| } |
| |
| return 0; |
| } |
| |
| static struct dentry *memtrace_debugfs_dir; |
| |
| static int memtrace_init_debugfs(void) |
| { |
| int ret = 0; |
| int i; |
| |
| for (i = 0; i < memtrace_array_nr; i++) { |
| struct dentry *dir; |
| struct memtrace_entry *ent = &memtrace_array[i]; |
| |
| ent->mem = ioremap(ent->start, ent->size); |
| /* Warn but continue on */ |
| if (!ent->mem) { |
| pr_err("Failed to map trace memory at 0x%llx\n", |
| ent->start); |
| ret = -1; |
| continue; |
| } |
| |
| snprintf(ent->name, 16, "%08x", ent->nid); |
| dir = debugfs_create_dir(ent->name, memtrace_debugfs_dir); |
| if (!dir) |
| return -1; |
| |
| ent->dir = dir; |
| debugfs_create_file("trace", 0400, dir, ent, &memtrace_fops); |
| debugfs_create_x64("start", 0400, dir, &ent->start); |
| debugfs_create_x64("size", 0400, dir, &ent->size); |
| } |
| |
| return ret; |
| } |
| |
| static int memtrace_enable_set(void *data, u64 val) |
| { |
| if (memtrace_size) |
| return -EINVAL; |
| |
| if (!val) |
| return -EINVAL; |
| |
| /* Make sure size is aligned to a memory block */ |
| if (val & (memory_block_size_bytes() - 1)) |
| return -EINVAL; |
| |
| if (memtrace_init_regions_runtime(val)) |
| return -EINVAL; |
| |
| if (memtrace_init_debugfs()) |
| return -EINVAL; |
| |
| memtrace_size = val; |
| |
| return 0; |
| } |
| |
| static int memtrace_enable_get(void *data, u64 *val) |
| { |
| *val = memtrace_size; |
| return 0; |
| } |
| |
| DEFINE_SIMPLE_ATTRIBUTE(memtrace_init_fops, memtrace_enable_get, |
| memtrace_enable_set, "0x%016llx\n"); |
| |
| static int memtrace_init(void) |
| { |
| memtrace_debugfs_dir = debugfs_create_dir("memtrace", |
| powerpc_debugfs_root); |
| if (!memtrace_debugfs_dir) |
| return -1; |
| |
| debugfs_create_file("enable", 0600, memtrace_debugfs_dir, |
| NULL, &memtrace_init_fops); |
| |
| return 0; |
| } |
| machine_device_initcall(powernv, memtrace_init); |