1 files changed, 282 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
new file mode 100644
index 000000000000..de470caf0784
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -0,0 +1,282 @@
+/*
+ * 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 void flush_memory_region(u64 base, u64 size)
+{
+	unsigned long line_size = ppc64_caches.l1d.size;
+	u64 end = base + size;
+	u64 addr;
+
+	base = round_down(base, line_size);
+	end = round_up(end, line_size);
+
+	for (addr = base; addr < end; addr += line_size)
+		asm volatile("dcbf 0,%0" : "=r" (addr) :: "memory");
+}
+
+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);
+
+	/* RCU grace period? */
+	flush_memory_region((u64)__va(start_pfn << PAGE_SHIFT),
+			    nr_pages << PAGE_SHIFT);
+
+	lock_device_hotplug();
+	remove_memory(nid, start_pfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT);
+	unlock_device_hotplug();
+
+	return true;
+}
+
+static u64 memtrace_alloc_node(u32 nid, u64 size)
+{
+	u64 start_pfn, end_pfn, nr_pages;
+	u64 base_pfn;
+
+	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)
+			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);