path: root/drivers/nvdimm/label.c

/*
 * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */
#include <linux/device.h>
#include <linux/ndctl.h>
#include <linux/uuid.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/nd.h>
#include "nd-core.h"
#include "label.h"
#include "nd.h"

static guid_t nvdimm_btt_guid;
static guid_t nvdimm_btt2_guid;
static guid_t nvdimm_pfn_guid;
static guid_t nvdimm_dax_guid;

static const char NSINDEX_SIGNATURE[] = "NAMESPACE_INDEX\0";

static u32 best_seq(u32 a, u32 b)
{
	a &= NSINDEX_SEQ_MASK;
	b &= NSINDEX_SEQ_MASK;

	if (a == 0 || a == b)
		return b;
	else if (b == 0)
		return a;
	else if (nd_inc_seq(a) == b)
		return b;
	else
		return a;
}

unsigned sizeof_namespace_label(struct nvdimm_drvdata *ndd)
{
	return ndd->nslabel_size;
}

static size_t __sizeof_namespace_index(u32 nslot)
{
	return ALIGN(sizeof(struct nd_namespace_index) + DIV_ROUND_UP(nslot, 8),
			NSINDEX_ALIGN);
}

static int __nvdimm_num_label_slots(struct nvdimm_drvdata *ndd,
		size_t index_size)
{
	return (ndd->nsarea.config_size - index_size * 2) /
			sizeof_namespace_label(ndd);
}

int nvdimm_num_label_slots(struct nvdimm_drvdata *ndd)
{
	u32 tmp_nslot, n;

	tmp_nslot = ndd->nsarea.config_size / sizeof_namespace_label(ndd);
	n = __sizeof_namespace_index(tmp_nslot) / NSINDEX_ALIGN;

	return __nvdimm_num_label_slots(ndd, NSINDEX_ALIGN * n);
}

size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd)
{
	u32 nslot, space, size;

	/*
	 * Per UEFI 2.7, the minimum size of the Label Storage Area is large
	 * enough to hold 2 index blocks and 2 labels.  The minimum index
	 * block size is 256 bytes, and the minimum label size is 256 bytes.
	 */
	nslot = nvdimm_num_label_slots(ndd);
	space = ndd->nsarea.config_size - nslot * sizeof_namespace_label(ndd);
	size = __sizeof_namespace_index(nslot) * 2;
	if (size <= space && nslot >= 2)
		return size / 2;

	dev_err(ndd->dev, "label area (%d) too small to host (%d byte) labels\n",
			ndd->nsarea.config_size, sizeof_namespace_label(ndd));
	return 0;
}

static int __nd_label_validate(struct nvdimm_drvdata *ndd)
{
	/*
	 * On media label format consists of two index blocks followed
	 * by an array of labels.  None of these structures are ever
	 * updated in place.  A sequence number tracks the current
	 * active index and the next one to write, while labels are
	 * written to free slots.
	 *
	 *     +------------+
	 *     |            |
	 *     |  nsindex0  |
	 *     |            |
	 *     +------------+
	 *     |            |
	 *     |  nsindex1  |
	 *     |            |
	 *     +------------+
	 *     |   label0   |
	 *     +------------+
	 *     |   label1   |
	 *     +------------+
	 *     |            |
	 *      ....nslot...
	 *     |            |
	 *     +------------+
	 *     |   labelN   |
	 *     +------------+
	 */
	struct nd_namespace_index *nsindex[] = {
		to_namespace_index(ndd, 0),
		to_namespace_index(ndd, 1),
	};
	const int num_index = ARRAY_SIZE(nsindex);
	struct device *dev = ndd->dev;
	bool valid[2] = { 0 };
	int i, num_valid = 0;
	u32 seq;

	for (i = 0; i < num_index; i++) {
		u32 nslot;
		u8 sig[NSINDEX_SIG_LEN];
		u64 sum_save, sum, size;
		unsigned int version, labelsize;

		memcpy(sig, nsindex[i]->sig, NSINDEX_SIG_LEN);
		if (memcmp(sig, NSINDEX_SIGNATURE, NSINDEX_SIG_LEN) != 0) {
			dev_dbg(dev, "nsindex%d signature invalid\n", i<