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340 lines
8.0 KiB
340 lines
8.0 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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#include <asm/cacheflush.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 int memtrace_mmap(struct file *filp, struct vm_area_struct *vma) |
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{ |
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struct memtrace_entry *ent = filp->private_data; |
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if (ent->size < vma->vm_end - vma->vm_start) |
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return -EINVAL; |
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if (vma->vm_pgoff << PAGE_SHIFT >= ent->size) |
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return -EINVAL; |
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vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); |
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return remap_pfn_range(vma, vma->vm_start, PHYS_PFN(ent->start) + vma->vm_pgoff, |
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vma->vm_end - vma->vm_start, vma->vm_page_prot); |
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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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.mmap = memtrace_mmap, |
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}; |
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#define FLUSH_CHUNK_SIZE SZ_1G |
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/** |
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* flush_dcache_range_chunked(): Write any modified data cache blocks out to |
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* memory and invalidate them, in chunks of up to FLUSH_CHUNK_SIZE |
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* Does not invalidate the corresponding instruction cache blocks. |
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* |
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* @start: the start address |
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* @stop: the stop address (exclusive) |
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* @chunk: the max size of the chunks |
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*/ |
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static void flush_dcache_range_chunked(unsigned long start, unsigned long stop, |
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unsigned long chunk) |
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{ |
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unsigned long i; |
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for (i = start; i < stop; i += chunk) { |
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flush_dcache_range(i, min(stop, i + chunk)); |
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cond_resched(); |
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} |
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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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/* As HIGHMEM does not apply, use clear_page() directly. */ |
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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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* Before we go ahead and use this range as cache inhibited range |
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* flush the cache. |
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*/ |
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flush_dcache_range_chunked((unsigned long)pfn_to_kaddr(start_pfn), |
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(unsigned long)pfn_to_kaddr(start_pfn + nr_pages), |
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FLUSH_CHUNK_SIZE); |
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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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const unsigned long nr_pages = PHYS_PFN(size); |
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unsigned long pfn, start_pfn; |
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struct page *page; |
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/* |
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* Trace memory needs to be aligned to the size, which is guaranteed |
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* by alloc_contig_pages(). |
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*/ |
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page = alloc_contig_pages(nr_pages, GFP_KERNEL | __GFP_THISNODE | |
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__GFP_NOWARN, nid, NULL); |
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if (!page) |
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return 0; |
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start_pfn = page_to_pfn(page); |
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/* |
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* Clear the range while we still have a linear mapping. |
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* |
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* TODO: use __GFP_ZERO with alloc_contig_pages() once supported. |
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*/ |
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memtrace_clear_range(start_pfn, nr_pages); |
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/* |
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* Set pages PageOffline(), to indicate that nobody (e.g., hibernation, |
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* dumping, ...) should be touching these pages. |
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*/ |
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for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) |
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__SetPageOffline(pfn_to_page(pfn)); |
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arch_remove_linear_mapping(PFN_PHYS(start_pfn), size); |
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return PFN_PHYS(start_pfn); |
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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_unsafe("trace", 0600, 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 memtrace_free(int nid, u64 start, u64 size) |
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{ |
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struct mhp_params params = { .pgprot = PAGE_KERNEL }; |
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const unsigned long nr_pages = PHYS_PFN(size); |
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const unsigned long start_pfn = PHYS_PFN(start); |
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unsigned long pfn; |
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int ret; |
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ret = arch_create_linear_mapping(nid, start, size, ¶ms); |
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if (ret) |
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return ret; |
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for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) |
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__ClearPageOffline(pfn_to_page(pfn)); |
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free_contig_range(start_pfn, nr_pages); |
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return 0; |
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} |
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/* |
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* Iterate through the chunks of memory we allocated and attempt to expose |
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* them back to the kernel. |
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*/ |
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static int memtrace_free_regions(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 freed 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 (memtrace_free(ent->nid, ent->start, ent->size)) { |
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pr_err("Failed to free trace memory on 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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/* |
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* Memory was freed successfully so clean up references to it |
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* so on reentry we can tell that this chunk was freed. |
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*/ |
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debugfs_remove_recursive(ent->dir); |
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pr_info("Freed trace memory back on 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 freed 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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/* Free all previously allocated memory. */ |
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if (memtrace_size && memtrace_free_regions()) |
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goto out_unlock; |
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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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/* Allocate 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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