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-rw-r--r--arch/powerpc/platforms/powernv/Kconfig8
-rw-r--r--arch/powerpc/platforms/powernv/Makefile1
-rw-r--r--arch/powerpc/platforms/powernv/memtrace.c282
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);
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-19 14:20:50 +0300