arch/powerpc/platforms/powernv/memtrace.c - linux - Git at Google

 /*
  * 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 const struct file_operations memtrace_fops = {
 	.llseek = default_llseek,
 	.read	= memtrace_read,
 	.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);

 	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_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) {
 			pr_err("Failed to create debugfs directory for node %d\n",
 				ent->nid);
 			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 online_mem_block(struct memory_block *mem, void *arg)
 {
 	return device_online(&mem->dev);
 }

 /*
  * Iterate through the chunks of memory we have removed from the kernel
  * and attempt to add them back to the kernel.
  */
 static int memtrace_online(void)
 {
 	int i, ret = 0;
 	struct memtrace_entry *ent;

 	for (i = memtrace_array_nr - 1; i >= 0; i--) {
 		ent = &memtrace_array[i];

 		/* We have onlined this chunk previously */
 		if (ent->nid == -1)
 			continue;

 		/* Remove from io mappings */
 		if (ent->mem) {
 			iounmap(ent->mem);
 			ent->mem = 0;
 		}

 		if (add_memory(ent->nid, ent->start, ent->size)) {
 			pr_err("Failed to add trace memory to node %d\n",
 				ent->nid);
 			ret += 1;
 			continue;
 		}

 		/*
 		 * If kernel isn't compiled with the auto online option
 		 * we need to online the memory ourselves.
 		 */
 		if (!memhp_auto_online) {
 			walk_memory_range(PFN_DOWN(ent->start),
 					  PFN_UP(ent->start + ent->size - 1),
 					  NULL, online_mem_block);
 		}

 		/*
 		 * Memory was added successfully so clean up references to it
 		 * so on reentry we can tell that this chunk was added.
 		 */
 		debugfs_remove_recursive(ent->dir);
 		pr_info("Added trace memory back to node %d\n", ent->nid);
 		ent->size = ent->start = ent->nid = -1;
 	}
 	if (ret)
 		return ret;

 	/* If all chunks of memory were added successfully, reset globals */
 	kfree(memtrace_array);
 	memtrace_array = NULL;
 	memtrace_size = 0;
 	memtrace_array_nr = 0;
 	return 0;
 }

 static int memtrace_enable_set(void *data, u64 val)
 {
 	u64 bytes;

 	/*
 	 * Don't attempt to do anything if size isn't aligned to a memory
 	 * block or equal to zero.
 	 */
 	bytes = memory_block_size_bytes();
 	if (val & (bytes - 1)) {
 		pr_err("Value must be aligned with 0x%llx\n", bytes);
 		return -EINVAL;
 	}

 	/* Re-add/online previously removed/offlined memory */
 	if (memtrace_size) {
 		if (memtrace_online())
 			return -EAGAIN;
 	}

 	if (!val)
 		return 0;

 	/* Offline and remove memory */
 	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);
	/*
	* 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 const struct file_operations memtrace_fops = {
	.llseek = default_llseek,
	.read = memtrace_read,
	.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);

	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_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) {
	pr_err("Failed to create debugfs directory for node %d\n",
	ent->nid);
	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 online_mem_block(struct memory_block mem, void arg)
	{
	return device_online(&mem->dev);
	}

	/*
	* Iterate through the chunks of memory we have removed from the kernel
	* and attempt to add them back to the kernel.
	*/
	static int memtrace_online(void)
	{
	int i, ret = 0;
	struct memtrace_entry *ent;

	for (i = memtrace_array_nr - 1; i >= 0; i--) {
	ent = &memtrace_array[i];

	/* We have onlined this chunk previously */
	if (ent->nid == -1)
	continue;

	/* Remove from io mappings */
	if (ent->mem) {
	iounmap(ent->mem);
	ent->mem = 0;
	}

	if (add_memory(ent->nid, ent->start, ent->size)) {
	pr_err("Failed to add trace memory to node %d\n",
	ent->nid);
	ret += 1;
	continue;
	}

	/*
	* If kernel isn't compiled with the auto online option
	* we need to online the memory ourselves.
	*/
	if (!memhp_auto_online) {
	walk_memory_range(PFN_DOWN(ent->start),
	PFN_UP(ent->start + ent->size - 1),
	NULL, online_mem_block);
	}

	/*
	* Memory was added successfully so clean up references to it
	* so on reentry we can tell that this chunk was added.
	*/
	debugfs_remove_recursive(ent->dir);
	pr_info("Added trace memory back to node %d\n", ent->nid);
	ent->size = ent->start = ent->nid = -1;
	}
	if (ret)
	return ret;

	/* If all chunks of memory were added successfully, reset globals */
	kfree(memtrace_array);
	memtrace_array = NULL;
	memtrace_size = 0;
	memtrace_array_nr = 0;
	return 0;
	}

	static int memtrace_enable_set(void *data, u64 val)
	{
	u64 bytes;

	/*
	* Don't attempt to do anything if size isn't aligned to a memory
	* block or equal to zero.
	*/
	bytes = memory_block_size_bytes();
	if (val & (bytes - 1)) {
	pr_err("Value must be aligned with 0x%llx\n", bytes);
	return -EINVAL;
	}

	/* Re-add/online previously removed/offlined memory */
	if (memtrace_size) {
	if (memtrace_online())
	return -EAGAIN;
	}

	if (!val)
	return 0;

	/* Offline and remove memory */
	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);