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

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (C) IBM Corporation, 2014, 2017
  * Anton Blanchard, Rashmica Gupta.
  */

 #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 <linux/numa.h>
 #include <asm/machdep.h>
 #include <asm/debugfs.h>
 #include <asm/cacheflush.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 DEFINE_MUTEX(memtrace_mutex);
 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 int memtrace_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct memtrace_entry *ent = filp->private_data;

 	if (ent->size < vma->vm_end - vma->vm_start)
 		return -EINVAL;

 	if (vma->vm_pgoff << PAGE_SHIFT >= ent->size)
 		return -EINVAL;

 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 	return remap_pfn_range(vma, vma->vm_start, PHYS_PFN(ent->start) + vma->vm_pgoff,
 			       vma->vm_end - vma->vm_start, vma->vm_page_prot);
 }

 static const struct file_operations memtrace_fops = {
 	.llseek = default_llseek,
 	.read	= memtrace_read,
 	.open	= simple_open,
 	.mmap   = memtrace_mmap,
 };

 #define FLUSH_CHUNK_SIZE SZ_1G
 /**
  * flush_dcache_range_chunked(): Write any modified data cache blocks out to
  * memory and invalidate them, in chunks of up to FLUSH_CHUNK_SIZE
  * Does not invalidate the corresponding instruction cache blocks.
  *
  * @start: the start address
  * @stop: the stop address (exclusive)
  * @chunk: the max size of the chunks
  */
 static void flush_dcache_range_chunked(unsigned long start, unsigned long stop,
 				       unsigned long chunk)
 {
 	unsigned long i;

 	for (i = start; i < stop; i += chunk) {
 		flush_dcache_range(i, min(stop, i + chunk));
 		cond_resched();
 	}
 }

 static void memtrace_clear_range(unsigned long start_pfn,
 				 unsigned long nr_pages)
 {
 	unsigned long pfn;

 	/* As HIGHMEM does not apply, use clear_page() directly. */
 	for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) {
 		if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
 			cond_resched();
 		clear_page(__va(PFN_PHYS(pfn)));
 	}
 	/*
 	 * Before we go ahead and use this range as cache inhibited range
 	 * flush the cache.
 	 */
 	flush_dcache_range_chunked((unsigned long)pfn_to_kaddr(start_pfn),
 				   (unsigned long)pfn_to_kaddr(start_pfn + nr_pages),
 				   FLUSH_CHUNK_SIZE);
 }

 static u64 memtrace_alloc_node(u32 nid, u64 size)
 {
 	const unsigned long nr_pages = PHYS_PFN(size);
 	unsigned long pfn, start_pfn;
 	struct page *page;

 	/*
 	 * Trace memory needs to be aligned to the size, which is guaranteed
 	 * by alloc_contig_pages().
 	 */
 	page = alloc_contig_pages(nr_pages, GFP_KERNEL | __GFP_THISNODE |
 				  __GFP_NOWARN, nid, NULL);
 	if (!page)
 		return 0;
 	start_pfn = page_to_pfn(page);

 	/*
 	 * Clear the range while we still have a linear mapping.
 	 *
 	 * TODO: use __GFP_ZERO with alloc_contig_pages() once supported.
 	 */
 	memtrace_clear_range(start_pfn, nr_pages);

 	/*
 	 * Set pages PageOffline(), to indicate that nobody (e.g., hibernation,
 	 * dumping, ...) should be touching these pages.
 	 */
 	for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++)
 		__SetPageOffline(pfn_to_page(pfn));

 	arch_remove_linear_mapping(PFN_PHYS(start_pfn), size);

 	return PFN_PHYS(start_pfn);
 }

 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);

 		ent->dir = dir;
 		debugfs_create_file_unsafe("trace", 0600, 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_free(int nid, u64 start, u64 size)
 {
 	struct mhp_params params = { .pgprot = PAGE_KERNEL };
 	const unsigned long nr_pages = PHYS_PFN(size);
 	const unsigned long start_pfn = PHYS_PFN(start);
 	unsigned long pfn;
 	int ret;

 	ret = arch_create_linear_mapping(nid, start, size, &params);
 	if (ret)
 		return ret;

 	for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++)
 		__ClearPageOffline(pfn_to_page(pfn));

 	free_contig_range(start_pfn, nr_pages);
 	return 0;
 }

 /*
  * Iterate through the chunks of memory we allocated and attempt to expose
  * them back to the kernel.
  */
 static int memtrace_free_regions(void)
 {
 	int i, ret = 0;
 	struct memtrace_entry *ent;

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

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

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

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

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

 	/* If all chunks of memory were freed 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)
 {
 	int rc = -EAGAIN;
 	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;
 	}

 	mutex_lock(&memtrace_mutex);

 	/* Free all previously allocated memory. */
 	if (memtrace_size && memtrace_free_regions())
 		goto out_unlock;

 	if (!val) {
 		rc = 0;
 		goto out_unlock;
 	}

 	/* Allocate memory. */
 	if (memtrace_init_regions_runtime(val))
 		goto out_unlock;

 	if (memtrace_init_debugfs())
 		goto out_unlock;

 	memtrace_size = val;
 	rc = 0;
 out_unlock:
 	mutex_unlock(&memtrace_mutex);
 	return rc;
 }

 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);

 	debugfs_create_file("enable", 0600, memtrace_debugfs_dir,
 			    NULL, &memtrace_init_fops);

 	return 0;
 }
 machine_device_initcall(powernv, memtrace_init);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (C) IBM Corporation, 2014, 2017
	* Anton Blanchard, Rashmica Gupta.
	*/

	#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 <linux/numa.h>
	#include <asm/machdep.h>
	#include <asm/debugfs.h>
	#include <asm/cacheflush.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 DEFINE_MUTEX(memtrace_mutex);
	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 int memtrace_mmap(struct file filp, struct vm_area_struct vma)
	{
	struct memtrace_entry *ent = filp->private_data;

	if (ent->size < vma->vm_end - vma->vm_start)
	return -EINVAL;

	if (vma->vm_pgoff << PAGE_SHIFT >= ent->size)
	return -EINVAL;

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	return remap_pfn_range(vma, vma->vm_start, PHYS_PFN(ent->start) + vma->vm_pgoff,
	vma->vm_end - vma->vm_start, vma->vm_page_prot);
	}

	static const struct file_operations memtrace_fops = {
	.llseek = default_llseek,
	.read = memtrace_read,
	.open = simple_open,
	.mmap = memtrace_mmap,
	};

	#define FLUSH_CHUNK_SIZE SZ_1G
	/**
	* flush_dcache_range_chunked(): Write any modified data cache blocks out to
	* memory and invalidate them, in chunks of up to FLUSH_CHUNK_SIZE
	* Does not invalidate the corresponding instruction cache blocks.
	*
	* @start: the start address
	* @stop: the stop address (exclusive)
	* @chunk: the max size of the chunks
	*/
	static void flush_dcache_range_chunked(unsigned long start, unsigned long stop,
	unsigned long chunk)
	{
	unsigned long i;

	for (i = start; i < stop; i += chunk) {
	flush_dcache_range(i, min(stop, i + chunk));
	cond_resched();
	}
	}

	static void memtrace_clear_range(unsigned long start_pfn,
	unsigned long nr_pages)
	{
	unsigned long pfn;

	/* As HIGHMEM does not apply, use clear_page() directly. */
	for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) {
	if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
	cond_resched();
	clear_page(__va(PFN_PHYS(pfn)));
	}
	/*
	* Before we go ahead and use this range as cache inhibited range
	* flush the cache.
	*/
	flush_dcache_range_chunked((unsigned long)pfn_to_kaddr(start_pfn),
	(unsigned long)pfn_to_kaddr(start_pfn + nr_pages),
	FLUSH_CHUNK_SIZE);
	}

	static u64 memtrace_alloc_node(u32 nid, u64 size)
	{
	const unsigned long nr_pages = PHYS_PFN(size);
	unsigned long pfn, start_pfn;
	struct page *page;

	/*
	* Trace memory needs to be aligned to the size, which is guaranteed
	* by alloc_contig_pages().
	*/
	page = alloc_contig_pages(nr_pages, GFP_KERNEL \| __GFP_THISNODE \|
	__GFP_NOWARN, nid, NULL);
	if (!page)
	return 0;
	start_pfn = page_to_pfn(page);

	/*
	* Clear the range while we still have a linear mapping.
	*
	* TODO: use __GFP_ZERO with alloc_contig_pages() once supported.
	*/
	memtrace_clear_range(start_pfn, nr_pages);

	/*
	* Set pages PageOffline(), to indicate that nobody (e.g., hibernation,
	* dumping, ...) should be touching these pages.
	*/
	for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++)
	__SetPageOffline(pfn_to_page(pfn));

	arch_remove_linear_mapping(PFN_PHYS(start_pfn), size);

	return PFN_PHYS(start_pfn);
	}

	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);

	ent->dir = dir;
	debugfs_create_file_unsafe("trace", 0600, 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_free(int nid, u64 start, u64 size)
	{
	struct mhp_params params = { .pgprot = PAGE_KERNEL };
	const unsigned long nr_pages = PHYS_PFN(size);
	const unsigned long start_pfn = PHYS_PFN(start);
	unsigned long pfn;
	int ret;

	ret = arch_create_linear_mapping(nid, start, size, &params);
	if (ret)
	return ret;

	for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++)
	__ClearPageOffline(pfn_to_page(pfn));

	free_contig_range(start_pfn, nr_pages);
	return 0;
	}

	/*
	* Iterate through the chunks of memory we allocated and attempt to expose
	* them back to the kernel.
	*/
	static int memtrace_free_regions(void)
	{
	int i, ret = 0;
	struct memtrace_entry *ent;

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

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

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

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

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

	/* If all chunks of memory were freed 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)
	{
	int rc = -EAGAIN;
	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;
	}

	mutex_lock(&memtrace_mutex);

	/* Free all previously allocated memory. */
	if (memtrace_size && memtrace_free_regions())
	goto out_unlock;

	if (!val) {
	rc = 0;
	goto out_unlock;
	}

	/* Allocate memory. */
	if (memtrace_init_regions_runtime(val))
	goto out_unlock;

	if (memtrace_init_debugfs())
	goto out_unlock;

	memtrace_size = val;
	rc = 0;
	out_unlock:
	mutex_unlock(&memtrace_mutex);
	return rc;
	}

	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);

	debugfs_create_file("enable", 0600, memtrace_debugfs_dir,
	NULL, &memtrace_init_fops);

	return 0;
	}
	machine_device_initcall(powernv, memtrace_init);