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342 lines
7.7 KiB
342 lines
7.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright (C) IBM Corporation, 2014, 2017 |
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* Anton Blanchard, Rashmica Gupta. |
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*/ |
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#define pr_fmt(fmt) "memtrace: " fmt |
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#include <linux/bitops.h> |
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#include <linux/string.h> |
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#include <linux/memblock.h> |
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#include <linux/init.h> |
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#include <linux/moduleparam.h> |
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#include <linux/fs.h> |
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#include <linux/debugfs.h> |
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#include <linux/slab.h> |
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#include <linux/memory.h> |
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#include <linux/memory_hotplug.h> |
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#include <linux/numa.h> |
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#include <asm/machdep.h> |
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#include <asm/debugfs.h> |
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/* This enables us to keep track of the memory removed from each node. */ |
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struct memtrace_entry { |
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void *mem; |
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u64 start; |
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u64 size; |
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u32 nid; |
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struct dentry *dir; |
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char name[16]; |
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}; |
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static DEFINE_MUTEX(memtrace_mutex); |
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static u64 memtrace_size; |
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static struct memtrace_entry *memtrace_array; |
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static unsigned int memtrace_array_nr; |
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static ssize_t memtrace_read(struct file *filp, char __user *ubuf, |
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size_t count, loff_t *ppos) |
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{ |
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struct memtrace_entry *ent = filp->private_data; |
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return simple_read_from_buffer(ubuf, count, ppos, ent->mem, ent->size); |
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} |
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static const struct file_operations memtrace_fops = { |
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.llseek = default_llseek, |
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.read = memtrace_read, |
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.open = simple_open, |
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}; |
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static int check_memblock_online(struct memory_block *mem, void *arg) |
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{ |
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if (mem->state != MEM_ONLINE) |
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return -1; |
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return 0; |
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} |
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static int change_memblock_state(struct memory_block *mem, void *arg) |
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{ |
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unsigned long state = (unsigned long)arg; |
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mem->state = state; |
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return 0; |
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} |
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static void memtrace_clear_range(unsigned long start_pfn, |
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unsigned long nr_pages) |
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{ |
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unsigned long pfn; |
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/* |
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* As pages are offline, we cannot trust the memmap anymore. As HIGHMEM |
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* does not apply, avoid passing around "struct page" and use |
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* clear_page() instead directly. |
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*/ |
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for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) { |
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if (IS_ALIGNED(pfn, PAGES_PER_SECTION)) |
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cond_resched(); |
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clear_page(__va(PFN_PHYS(pfn))); |
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} |
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} |
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/* called with device_hotplug_lock held */ |
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static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages) |
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{ |
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const unsigned long start = PFN_PHYS(start_pfn); |
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const unsigned long size = PFN_PHYS(nr_pages); |
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if (walk_memory_blocks(start, size, NULL, check_memblock_online)) |
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return false; |
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walk_memory_blocks(start, size, (void *)MEM_GOING_OFFLINE, |
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change_memblock_state); |
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if (offline_pages(start_pfn, nr_pages)) { |
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walk_memory_blocks(start, size, (void *)MEM_ONLINE, |
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change_memblock_state); |
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return false; |
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} |
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walk_memory_blocks(start, size, (void *)MEM_OFFLINE, |
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change_memblock_state); |
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return true; |
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} |
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static u64 memtrace_alloc_node(u32 nid, u64 size) |
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{ |
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u64 start_pfn, end_pfn, nr_pages, pfn; |
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u64 base_pfn; |
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u64 bytes = memory_block_size_bytes(); |
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if (!node_spanned_pages(nid)) |
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return 0; |
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start_pfn = node_start_pfn(nid); |
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end_pfn = node_end_pfn(nid); |
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nr_pages = size >> PAGE_SHIFT; |
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/* Trace memory needs to be aligned to the size */ |
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end_pfn = round_down(end_pfn - nr_pages, nr_pages); |
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lock_device_hotplug(); |
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for (base_pfn = end_pfn; base_pfn > start_pfn; base_pfn -= nr_pages) { |
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if (memtrace_offline_pages(nid, base_pfn, nr_pages) == true) { |
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/* |
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* Clear the range while we still have a linear |
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* mapping. |
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*/ |
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memtrace_clear_range(base_pfn, nr_pages); |
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/* |
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* Remove memory in memory block size chunks so that |
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* iomem resources are always split to the same size and |
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* we never try to remove memory that spans two iomem |
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* resources. |
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*/ |
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end_pfn = base_pfn + nr_pages; |
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for (pfn = base_pfn; pfn < end_pfn; pfn += bytes>> PAGE_SHIFT) { |
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__remove_memory(nid, pfn << PAGE_SHIFT, bytes); |
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} |
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unlock_device_hotplug(); |
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return base_pfn << PAGE_SHIFT; |
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} |
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} |
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unlock_device_hotplug(); |
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return 0; |
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} |
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static int memtrace_init_regions_runtime(u64 size) |
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{ |
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u32 nid; |
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u64 m; |
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memtrace_array = kcalloc(num_online_nodes(), |
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sizeof(struct memtrace_entry), GFP_KERNEL); |
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if (!memtrace_array) { |
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pr_err("Failed to allocate memtrace_array\n"); |
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return -EINVAL; |
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} |
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for_each_online_node(nid) { |
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m = memtrace_alloc_node(nid, size); |
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/* |
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* A node might not have any local memory, so warn but |
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* continue on. |
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*/ |
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if (!m) { |
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pr_err("Failed to allocate trace memory on node %d\n", nid); |
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continue; |
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} |
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pr_info("Allocated trace memory on node %d at 0x%016llx\n", nid, m); |
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memtrace_array[memtrace_array_nr].start = m; |
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memtrace_array[memtrace_array_nr].size = size; |
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memtrace_array[memtrace_array_nr].nid = nid; |
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memtrace_array_nr++; |
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} |
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return 0; |
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} |
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static struct dentry *memtrace_debugfs_dir; |
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static int memtrace_init_debugfs(void) |
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{ |
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int ret = 0; |
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int i; |
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for (i = 0; i < memtrace_array_nr; i++) { |
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struct dentry *dir; |
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struct memtrace_entry *ent = &memtrace_array[i]; |
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ent->mem = ioremap(ent->start, ent->size); |
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/* Warn but continue on */ |
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if (!ent->mem) { |
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pr_err("Failed to map trace memory at 0x%llx\n", |
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ent->start); |
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ret = -1; |
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continue; |
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} |
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snprintf(ent->name, 16, "%08x", ent->nid); |
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dir = debugfs_create_dir(ent->name, memtrace_debugfs_dir); |
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ent->dir = dir; |
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debugfs_create_file("trace", 0400, dir, ent, &memtrace_fops); |
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debugfs_create_x64("start", 0400, dir, &ent->start); |
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debugfs_create_x64("size", 0400, dir, &ent->size); |
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} |
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return ret; |
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} |
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static int online_mem_block(struct memory_block *mem, void *arg) |
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{ |
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return device_online(&mem->dev); |
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} |
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/* |
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* Iterate through the chunks of memory we have removed from the kernel |
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* and attempt to add them back to the kernel. |
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*/ |
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static int memtrace_online(void) |
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{ |
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int i, ret = 0; |
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struct memtrace_entry *ent; |
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for (i = memtrace_array_nr - 1; i >= 0; i--) { |
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ent = &memtrace_array[i]; |
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/* We have onlined this chunk previously */ |
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if (ent->nid == NUMA_NO_NODE) |
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continue; |
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/* Remove from io mappings */ |
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if (ent->mem) { |
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iounmap(ent->mem); |
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ent->mem = 0; |
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} |
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if (add_memory(ent->nid, ent->start, ent->size, MHP_NONE)) { |
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pr_err("Failed to add trace memory to node %d\n", |
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ent->nid); |
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ret += 1; |
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continue; |
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} |
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lock_device_hotplug(); |
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walk_memory_blocks(ent->start, ent->size, NULL, |
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online_mem_block); |
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unlock_device_hotplug(); |
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/* |
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* Memory was added successfully so clean up references to it |
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* so on reentry we can tell that this chunk was added. |
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*/ |
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debugfs_remove_recursive(ent->dir); |
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pr_info("Added trace memory back to node %d\n", ent->nid); |
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ent->size = ent->start = ent->nid = NUMA_NO_NODE; |
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} |
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if (ret) |
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return ret; |
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/* If all chunks of memory were added successfully, reset globals */ |
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kfree(memtrace_array); |
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memtrace_array = NULL; |
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memtrace_size = 0; |
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memtrace_array_nr = 0; |
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return 0; |
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} |
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static int memtrace_enable_set(void *data, u64 val) |
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{ |
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int rc = -EAGAIN; |
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u64 bytes; |
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/* |
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* Don't attempt to do anything if size isn't aligned to a memory |
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* block or equal to zero. |
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*/ |
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bytes = memory_block_size_bytes(); |
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if (val & (bytes - 1)) { |
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pr_err("Value must be aligned with 0x%llx\n", bytes); |
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return -EINVAL; |
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} |
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mutex_lock(&memtrace_mutex); |
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/* Re-add/online previously removed/offlined memory */ |
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if (memtrace_size) { |
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if (memtrace_online()) |
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goto out_unlock; |
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} |
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if (!val) { |
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rc = 0; |
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goto out_unlock; |
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} |
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/* Offline and remove memory */ |
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if (memtrace_init_regions_runtime(val)) |
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goto out_unlock; |
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if (memtrace_init_debugfs()) |
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goto out_unlock; |
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memtrace_size = val; |
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rc = 0; |
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out_unlock: |
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mutex_unlock(&memtrace_mutex); |
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return rc; |
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} |
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static int memtrace_enable_get(void *data, u64 *val) |
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{ |
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*val = memtrace_size; |
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return 0; |
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} |
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DEFINE_SIMPLE_ATTRIBUTE(memtrace_init_fops, memtrace_enable_get, |
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memtrace_enable_set, "0x%016llx\n"); |
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static int memtrace_init(void) |
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{ |
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memtrace_debugfs_dir = debugfs_create_dir("memtrace", |
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powerpc_debugfs_root); |
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debugfs_create_file("enable", 0600, memtrace_debugfs_dir, |
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NULL, &memtrace_init_fops); |
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return 0; |
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} |
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machine_device_initcall(powernv, memtrace_init);
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