diff options
| -rw-r--r-- | arch/powerpc/platforms/powernv/Kconfig | 8 | ||||
| -rw-r--r-- | arch/powerpc/platforms/powernv/Makefile | 1 | ||||
| -rw-r--r-- | arch/powerpc/platforms/powernv/memtrace.c | 282 |
3 files changed, 291 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig index 6a6f4ef46b9e..d7bacb20529c 100644 --- a/arch/powerpc/platforms/powernv/Kconfig +++ b/arch/powerpc/platforms/powernv/Kconfig @@ -30,3 +30,11 @@ config OPAL_PRD help This enables the opal-prd driver, a facility to run processor recovery diagnostics on OpenPower machines + +config PPC_MEMTRACE + bool "Enable removal of RAM from kernel mappings for tracing" + depends on PPC_POWERNV && MEMORY_HOTREMOVE + default n + help + Enabling this option allows for the removal of memory (RAM) + from the kernel mappings to be used for hardware tracing. diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile index 177b3d4542b5..e1b0d4ea683a 100644 --- a/arch/powerpc/platforms/powernv/Makefile +++ b/arch/powerpc/platforms/powernv/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_MEMORY_FAILURE) += opal-memory-errors.o obj-$(CONFIG_TRACEPOINTS) += opal-tracepoints.o obj-$(CONFIG_OPAL_PRD) += opal-prd.o obj-$(CONFIG_PERF_EVENTS) += opal-imc.o +obj-$(CONFIG_PPC_MEMTRACE) += memtrace.o 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); |