blob: bff8e38a7e9a020c2e74bd433519e9bdfdc71443 [file] [log] [blame]
/*
* 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 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 void memtrace_clear_range(unsigned long start_pfn,
unsigned long nr_pages)
{
unsigned long pfn;
/*
* As pages are offline, we cannot trust the memmap anymore. As HIGHMEM
* does not apply, avoid passing around "struct page" and use
* clear_page() instead 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)));
}
}
/* called with device_hotplug_lock held */
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);
return true;
}
static u64 memtrace_alloc_node(u32 nid, u64 size)
{
u64 start_pfn, end_pfn, nr_pages, pfn;
u64 base_pfn;
u64 bytes = memory_block_size_bytes();
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);
lock_device_hotplug();
for (base_pfn = end_pfn; base_pfn > start_pfn; base_pfn -= nr_pages) {
if (memtrace_offline_pages(nid, base_pfn, nr_pages) == true) {
/*
* Clear the range while we still have a linear
* mapping.
*/
memtrace_clear_range(base_pfn, nr_pages);
/*
* Remove memory in memory block size chunks so that
* iomem resources are always split to the same size and
* we never try to remove memory that spans two iomem
* resources.
*/
end_pfn = base_pfn + nr_pages;
for (pfn = base_pfn; pfn < end_pfn; pfn += bytes>> PAGE_SHIFT) {
remove_memory(nid, pfn << PAGE_SHIFT, bytes);
}
unlock_device_hotplug();
return base_pfn << PAGE_SHIFT;
}
}
unlock_device_hotplug();
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);