Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1212 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
new file mode 100644
index 000000000..e7d4ce696
--- /dev/null
+++ b/arch/powerpc/kernel/nvram_64.c
@@ -0,0 +1,1212 @@
+/*
+ *  c 2001 PPC 64 Team, IBM Corp
+ *
+ *      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.
+ *
+ * /dev/nvram driver for PPC64
+ *
+ * This perhaps should live in drivers/char
+ *
+ * TODO: Split the /dev/nvram part (that one can use
+ *       drivers/char/generic_nvram.c) from the arch & partition
+ *       parsing code.
+ */
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/fcntl.h>
+#include <linux/nvram.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/kmsg_dump.h>
+#include <linux/pagemap.h>
+#include <linux/pstore.h>
+#include <linux/zlib.h>
+#include <linux/uaccess.h>
+#include <asm/nvram.h>
+#include <asm/rtas.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+
+#undef DEBUG_NVRAM
+
+#define NVRAM_HEADER_LEN	sizeof(struct nvram_header)
+#define NVRAM_BLOCK_LEN		NVRAM_HEADER_LEN
+
+/* If change this size, then change the size of NVNAME_LEN */
+struct nvram_header {
+	unsigned char signature;
+	unsigned char checksum;
+	unsigned short length;
+	/* Terminating null required only for names < 12 chars. */
+	char name[12];
+};
+
+struct nvram_partition {
+	struct list_head partition;
+	struct nvram_header header;
+	unsigned int index;
+};
+
+static LIST_HEAD(nvram_partitions);
+
+#ifdef CONFIG_PPC_PSERIES
+struct nvram_os_partition rtas_log_partition = {
+	.name = "ibm,rtas-log",
+	.req_size = 2079,
+	.min_size = 1055,
+	.index = -1,
+	.os_partition = true
+};
+#endif
+
+struct nvram_os_partition oops_log_partition = {
+	.name = "lnx,oops-log",
+	.req_size = 4000,
+	.min_size = 2000,
+	.index = -1,
+	.os_partition = true
+};
+
+static const char *nvram_os_partitions[] = {
+#ifdef CONFIG_PPC_PSERIES
+	"ibm,rtas-log",
+#endif
+	"lnx,oops-log",
+	NULL
+};
+
+static void oops_to_nvram(struct kmsg_dumper *dumper,
+			  enum kmsg_dump_reason reason);
+
+static struct kmsg_dumper nvram_kmsg_dumper = {
+	.dump = oops_to_nvram
+};
+
+/*
+ * For capturing and compressing an oops or panic report...
+
+ * big_oops_buf[] holds the uncompressed text we're capturing.
+ *
+ * oops_buf[] holds the compressed text, preceded by a oops header.
+ * oops header has u16 holding the version of oops header (to differentiate
+ * between old and new format header) followed by u16 holding the length of
+ * the compressed* text (*Or uncompressed, if compression fails.) and u64
+ * holding the timestamp. oops_buf[] gets written to NVRAM.
+ *
+ * oops_log_info points to the header. oops_data points to the compressed text.
+ *
+ * +- oops_buf
+ * |                                   +- oops_data
+ * v                                   v
+ * +-----------+-----------+-----------+------------------------+
+ * | version   | length    | timestamp | text                   |
+ * | (2 bytes) | (2 bytes) | (8 bytes) | (oops_data_sz bytes)   |
+ * +-----------+-----------+-----------+------------------------+
+ * ^
+ * +- oops_log_info
+ *
+ * We preallocate these buffers during init to avoid kmalloc during oops/panic.
+ */
+static size_t big_oops_buf_sz;
+static char *big_oops_buf, *oops_buf;
+static char *oops_data;
+static size_t oops_data_sz;
+
+/* Compression parameters */
+#define COMPR_LEVEL 6
+#define WINDOW_BITS 12
+#define MEM_LEVEL 4
+static struct z_stream_s stream;
+
+#ifdef CONFIG_PSTORE
+#ifdef CONFIG_PPC_POWERNV
+static struct nvram_os_partition skiboot_partition = {
+	.name = "ibm,skiboot",
+	.index = -1,
+	.os_partition = false
+};
+#endif
+
+#ifdef CONFIG_PPC_PSERIES
+static struct nvram_os_partition of_config_partition = {
+	.name = "of-config",
+	.index = -1,
+	.os_partition = false
+};
+#endif
+
+static struct nvram_os_partition common_partition = {
+	.name = "common",
+	.index = -1,
+	.os_partition = false
+};
+
+static enum pstore_type_id nvram_type_ids[] = {
+	PSTORE_TYPE_DMESG,
+	PSTORE_TYPE_PPC_COMMON,
+	-1,
+	-1,
+	-1
+};
+static int read_type;
+#endif
+
+/* nvram_write_os_partition
+ *
+ * We need to buffer the error logs into nvram to ensure that we have
+ * the failure information to decode.  If we have a severe error there
+ * is no way to guarantee that the OS or the machine is in a state to
+ * get back to user land and write the error to disk.  For example if
+ * the SCSI device driver causes a Machine Check by writing to a bad
+ * IO address, there is no way of guaranteeing that the device driver
+ * is in any state that is would also be able to write the error data
+ * captured to disk, thus we buffer it in NVRAM for analysis on the
+ * next boot.
+ *
+ * In NVRAM the partition containing the error log buffer will looks like:
+ * Header (in bytes):
+ * +-----------+----------+--------+------------+------------------+
+ * | signature | checksum | length | name       | data             |
+ * |0          |1         |2      3|4         15|16        length-1|
+ * +-----------+----------+--------+------------+------------------+
+ *
+ * The 'data' section would look like (in bytes):
+ * +--------------+------------+-----------------------------------+
+ * | event_logged | sequence # | error log                         |
+ * |0            3|4          7|8                  error_log_size-1|
+ * +--------------+------------+-----------------------------------+
+ *
+ * event_logged: 0 if event has not been logged to syslog, 1 if it has
+ * sequence #: The unique sequence # for each event. (until it wraps)
+ * error log: The error log from event_scan
+ */
+int nvram_write_os_partition(struct nvram_os_partition *part,
+			     char *buff, int length,
+			     unsigned int err_type,
+			     unsigned int error_log_cnt)
+{
+	int rc;
+	loff_t tmp_index;
+	struct err_log_info info;
+
+	if (part->index == -1)
+		return -ESPIPE;
+
+	if (length > part->size)
+		length = part->size;
+
+	info.error_type = cpu_to_be32(err_type);
+	info.seq_num = cpu_to_be32(error_log_cnt);
+
+	tmp_index = part->index;
+
+	rc = ppc_md.nvram_write((char *)&info, sizeof(info), &tmp_index);
+	if (rc <= 0) {
+		pr_err("%s: Failed nvram_write (%d)\n", __func__, rc);
+		return rc;
+	}
+
+	rc = ppc_md.nvram_write(buff, length, &tmp_index);
+	if (rc <= 0) {
+		pr_err("%s: Failed nvram_write (%d)\n", __func__, rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+/* nvram_read_partition
+ *
+ * Reads nvram partition for at most 'length'
+ */
+int nvram_read_partition(struct nvram_os_partition *part, char *buff,
+			 int length, unsigned int *err_type,
+			 unsigned int *error_log_cnt)
+{
+	int rc;
+	loff_t tmp_index;
+	struct err_log_info info;
+
+	if (part->index == -1)
+		return -1;
+
+	if (length > part->size)
+		length = part->size;
+
+	tmp_index = part->index;
+
+	if (part->os_partition) {
+		rc = ppc_md.nvram_read((char *)&info, sizeof(info), &tmp_index);
+		if (rc <= 0) {
+			pr_err("%s: Failed nvram_read (%d)\n", __func__, rc);
+			return rc;
+		}
+	}
+
+	rc = ppc_md.nvram_read(buff, length, &tmp_index);
+	if (rc <= 0) {
+		pr_err("%s: Failed nvram_read (%d)\n", __func__, rc);
+		return rc;
+	}
+
+	if (part->os_partition) {
+		*error_log_cnt = be32_to_cpu(info.seq_num);
+		*err_type = be32_to_cpu(info.error_type);
+	}
+
+	return 0;
+}
+
+/* nvram_init_os_partition
+ *
+ * This sets up a partition with an "OS" signature.
+ *
+ * The general strategy is the following:
+ * 1.) If a partition with the indicated name already exists...
+ *	- If it's large enough, use it.
+ *	- Otherwise, recycle it and keep going.
+ * 2.) Search for a free partition that is large enough.
+ * 3.) If there's not a free partition large enough, recycle any obsolete
+ * OS partitions and try again.
+ * 4.) Will first try getting a chunk that will satisfy the requested size.
+ * 5.) If a chunk of the requested size cannot be allocated, then try finding
+ * a chunk that will satisfy the minum needed.
+ *
+ * Returns 0 on success, else -1.
+ */
+int __init nvram_init_os_partition(struct nvram_os_partition *part)
+{
+	loff_t p;
+	int size;
+
+	/* Look for ours */
+	p = nvram_find_partition(part->name, NVRAM_SIG_OS, &size);
+
+	/* Found one but too small, remove it */
+	if (p && size < part->min_size) {
+		pr_info("nvram: Found too small %s partition,"
+					" removing it...\n", part->name);
+		nvram_remove_partition(part->name, NVRAM_SIG_OS, NULL);
+		p = 0;
+	}
+
+	/* Create one if we didn't find */
+	if (!p) {
+		p = nvram_create_partition(part->name, NVRAM_SIG_OS,
+					part->req_size, part->min_size);
+		if (p == -ENOSPC) {
+			pr_info("nvram: No room to create %s partition, "
+				"deleting any obsolete OS partitions...\n",
+				part->name);
+			nvram_remove_partition(NULL, NVRAM_SIG_OS,
+					nvram_os_partitions);
+			p = nvram_create_partition(part->name, NVRAM_SIG_OS,
+					part->req_size, part->min_size);
+		}
+	}
+
+	if (p <= 0) {
+		pr_err("nvram: Failed to find or create %s"
+		       " partition, err %d\n", part->name, (int)p);
+		return -1;
+	}
+
+	part->index = p;
+	part->size = nvram_get_partition_size(p) - sizeof(struct err_log_info);
+
+	return 0;
+}
+
+/* Derived from logfs_compress() */
+static int nvram_compress(const void *in, void *out, size_t inlen,
+							size_t outlen)
+{
+	int err, ret;
+
+	ret = -EIO;
+	err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
+						MEM_LEVEL, Z_DEFAULT_STRATEGY);
+	if (err != Z_OK)
+		goto error;
+
+	stream.next_in = in;
+	stream.avail_in = inlen;
+	stream.total_in = 0;
+	stream.next_out = out;
+	stream.avail_out = outlen;
+	stream.total_out = 0;
+
+	err = zlib_deflate(&stream, Z_FINISH);
+	if (err != Z_STREAM_END)
+		goto error;
+
+	err = zlib_deflateEnd(&stream);
+	if (err != Z_OK)
+		goto error;
+
+	if (stream.total_out >= stream.total_in)
+		goto error;
+
+	ret = stream.total_out;
+error:
+	return ret;
+}
+
+/* Compress the text from big_oops_buf into oops_buf. */
+static int zip_oops(size_t text_len)
+{
+	struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
+	int zipped_len = nvram_compress(big_oops_buf, oops_data, text_len,
+								oops_data_sz);
+	if (zipped_len < 0) {
+		pr_err("nvram: compression failed; returned %d\n", zipped_len);
+		pr_err("nvram: logging uncompressed oops/panic report\n");
+		return -1;
+	}
+	oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
+	oops_hdr->report_length = cpu_to_be16(zipped_len);
+	oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
+	return 0;
+}
+
+#ifdef CONFIG_PSTORE
+static int nvram_pstore_open(struct pstore_info *psi)
+{
+	/* Reset the iterator to start reading partitions again */
+	read_type = -1;
+	return 0;
+}
+
+/**
+ * nvram_pstore_write - pstore write callback for nvram
+ * @record:             pstore record to write, with @id to be set
+ *
+ * Called by pstore_dump() when an oops or panic report is logged in the
+ * printk buffer.
+ * Returns 0 on successful write.
+ */
+static int nvram_pstore_write(struct pstore_record *record)
+{
+	int rc;
+	unsigned int err_type = ERR_TYPE_KERNEL_PANIC;
+	struct oops_log_info *oops_hdr = (struct oops_log_info *) oops_buf;
+
+	/* part 1 has the recent messages from printk buffer */
+	if (record->part > 1 || (record->type != PSTORE_TYPE_DMESG))
+		return -1;
+
+	if (clobbering_unread_rtas_event())
+		return -1;
+
+	oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
+	oops_hdr->report_length = cpu_to_be16(record->size);
+	oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
+
+	if (record->compressed)
+		err_type = ERR_TYPE_KERNEL_PANIC_GZ;
+
+	rc = nvram_write_os_partition(&oops_log_partition, oops_buf,
+		(int) (sizeof(*oops_hdr) + record->size), err_type,
+		record->count);
+
+	if (rc != 0)
+		return rc;
+
+	record->id = record->part;
+	return 0;
+}
+
+/*
+ * Reads the oops/panic report, rtas, of-config and common partition.
+ * Returns the length of the data we read from each partition.
+ * Returns 0 if we've been called before.
+ */
+static ssize_t nvram_pstore_read(struct pstore_record *record)
+{
+	struct oops_log_info *oops_hdr;
+	unsigned int err_type, id_no, size = 0;
+	struct nvram_os_partition *part = NULL;
+	char *buff = NULL;
+	int sig = 0;
+	loff_t p;
+
+	read_type++;
+
+	switch (nvram_type_ids[read_type]) {
+	case PSTORE_TYPE_DMESG:
+		part = &oops_log_partition;
+		record->type = PSTORE_TYPE_DMESG;
+		break;
+	case PSTORE_TYPE_PPC_COMMON:
+		sig = NVRAM_SIG_SYS;
+		part = &common_partition;
+		record->type = PSTORE_TYPE_PPC_COMMON;
+		record->id = PSTORE_TYPE_PPC_COMMON;
+		record->time.tv_sec = 0;
+		record->time.tv_nsec = 0;
+		break;
+#ifdef CONFIG_PPC_PSERIES
+	case PSTORE_TYPE_PPC_RTAS:
+		part = &rtas_log_partition;
+		record->type = PSTORE_TYPE_PPC_RTAS;
+		record->time.tv_sec = last_rtas_event;
+		record->time.tv_nsec = 0;
+		break;
+	case PSTORE_TYPE_PPC_OF:
+		sig = NVRAM_SIG_OF;
+		part = &of_config_partition;
+		record->type = PSTORE_TYPE_PPC_OF;
+		record->id = PSTORE_TYPE_PPC_OF;
+		record->time.tv_sec = 0;
+		record->time.tv_nsec = 0;
+		break;
+#endif
+#ifdef CONFIG_PPC_POWERNV
+	case PSTORE_TYPE_PPC_OPAL:
+		sig = NVRAM_SIG_FW;
+		part = &skiboot_partition;
+		record->type = PSTORE_TYPE_PPC_OPAL;
+		record->id = PSTORE_TYPE_PPC_OPAL;
+		record->time.tv_sec = 0;
+		record->time.tv_nsec = 0;
+		break;
+#endif
+	default:
+		return 0;
+	}
+
+	if (!part->os_partition) {
+		p = nvram_find_partition(part->name, sig, &size);
+		if (p <= 0) {
+			pr_err("nvram: Failed to find partition %s, "
+				"err %d\n", part->name, (int)p);
+			return 0;
+		}
+		part->index = p;
+		part->size = size;
+	}
+
+	buff = kmalloc(part->size, GFP_KERNEL);
+
+	if (!buff)
+		return -ENOMEM;
+
+	if (nvram_read_partition(part, buff, part->size, &err_type, &id_no)) {
+		kfree(buff);
+		return 0;
+	}
+
+	record->count = 0;
+
+	if (part->os_partition)
+		record->id = id_no;
+
+	if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
+		size_t length, hdr_size;
+
+		oops_hdr = (struct oops_log_info *)buff;
+		if (be16_to_cpu(oops_hdr->version) < OOPS_HDR_VERSION) {
+			/* Old format oops header had 2-byte record size */
+			hdr_size = sizeof(u16);
+			length = be16_to_cpu(oops_hdr->version);
+			record->time.tv_sec = 0;
+			record->time.tv_nsec = 0;
+		} else {
+			hdr_size = sizeof(*oops_hdr);
+			length = be16_to_cpu(oops_hdr->report_length);
+			record->time.tv_sec = be64_to_cpu(oops_hdr->timestamp);
+			record->time.tv_nsec = 0;
+		}
+		record->buf = kmemdup(buff + hdr_size, length, GFP_KERNEL);
+		kfree(buff);
+		if (record->buf == NULL)
+			return -ENOMEM;
+
+		record->ecc_notice_size = 0;
+		if (err_type == ERR_TYPE_KERNEL_PANIC_GZ)
+			record->compressed = true;
+		else
+			record->compressed = false;
+		return length;
+	}
+
+	record->buf = buff;
+	return part->size;
+}
+
+static struct pstore_info nvram_pstore_info = {
+	.owner = THIS_MODULE,
+	.name = "nvram",
+	.flags = PSTORE_FLAGS_DMESG,
+	.open = nvram_pstore_open,
+	.read = nvram_pstore_read,
+	.write = nvram_pstore_write,
+};
+
+static int nvram_pstore_init(void)
+{
+	int rc = 0;
+
+	if (machine_is(pseries)) {
+		nvram_type_ids[2] = PSTORE_TYPE_PPC_RTAS;
+		nvram_type_ids[3] = PSTORE_TYPE_PPC_OF;
+	} else
+		nvram_type_ids[2] = PSTORE_TYPE_PPC_OPAL;
+
+	nvram_pstore_info.buf = oops_data;
+	nvram_pstore_info.bufsize = oops_data_sz;
+
+	rc = pstore_register(&nvram_pstore_info);
+	if (rc && (rc != -EPERM))
+		/* Print error only when pstore.backend == nvram */
+		pr_err("nvram: pstore_register() failed, returned %d. "
+				"Defaults to kmsg_dump\n", rc);
+
+	return rc;
+}
+#else
+static int nvram_pstore_init(void)
+{
+	return -1;
+}
+#endif
+
+void __init nvram_init_oops_partition(int rtas_partition_exists)
+{
+	int rc;
+
+	rc = nvram_init_os_partition(&oops_log_partition);
+	if (rc != 0) {
+#ifdef CONFIG_PPC_PSERIES
+		if (!rtas_partition_exists) {
+			pr_err("nvram: Failed to initialize oops partition!");
+			return;
+		}
+		pr_notice("nvram: Using %s partition to log both"
+			" RTAS errors and oops/panic reports\n",
+			rtas_log_partition.name);
+		memcpy(&oops_log_partition, &rtas_log_partition,
+						sizeof(rtas_log_partition));
+#else
+		pr_err("nvram: Failed to initialize oops partition!");
+		return;
+#endif
+	}
+	oops_buf = kmalloc(oops_log_partition.size, GFP_KERNEL);
+	if (!oops_buf) {
+		pr_err("nvram: No memory for %s partition\n",
+						oops_log_partition.name);
+		return;
+	}
+	oops_data = oops_buf + sizeof(struct oops_log_info);
+	oops_data_sz = oops_log_partition.size - sizeof(struct oops_log_info);
+
+	rc = nvram_pstore_init();
+
+	if (!rc)
+		return;
+
+	/*
+	 * Figure compression (preceded by elimination of each line's <n>
+	 * severity prefix) will reduce the oops/panic report to at most
+	 * 45% of its original size.
+	 */
+	big_oops_buf_sz = (oops_data_sz * 100) / 45;
+	big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
+	if (big_oops_buf) {
+		stream.workspace =  kmalloc(zlib_deflate_workspacesize(
+					WINDOW_BITS, MEM_LEVEL), GFP_KERNEL);
+		if (!stream.workspace) {
+			pr_err("nvram: No memory for compression workspace; "
+				"skipping compression of %s partition data\n",
+				oops_log_partition.name);
+			kfree(big_oops_buf);
+			big_oops_buf = NULL;
+		}
+	} else {
+		pr_err("No memory for uncompressed %s data; "
+			"skipping compression\n", oops_log_partition.name);
+		stream.workspace = NULL;
+	}
+
+	rc = kmsg_dump_register(&nvram_kmsg_dumper);
+	if (rc != 0) {
+		pr_err("nvram: kmsg_dump_register() failed; returned %d\n", rc);
+		kfree(oops_buf);
+		kfree(big_oops_buf);
+		kfree(stream.workspace);
+	}
+}
+
+/*
+ * This is our kmsg_dump callback, called after an oops or panic report
+ * has been written to the printk buffer.  We want to capture as much
+ * of the printk buffer as possible.  First, capture as much as we can
+ * that we think will compress sufficiently to fit in the lnx,oops-log
+ * partition.  If that's too much, go back and capture uncompressed text.
+ */
+static void oops_to_nvram(struct kmsg_dumper *dumper,
+			  enum kmsg_dump_reason reason)
+{
+	struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
+	static unsigned int oops_count = 0;
+	static bool panicking = false;
+	static DEFINE_SPINLOCK(lock);
+	unsigned long flags;
+	size_t text_len;
+	unsigned int err_type = ERR_TYPE_KERNEL_PANIC_GZ;
+	int rc = -1;
+
+	switch (reason) {
+	case KMSG_DUMP_RESTART:
+	case KMSG_DUMP_HALT:
+	case KMSG_DUMP_POWEROFF:
+		/* These are almost always orderly shutdowns. */
+		return;
+	case KMSG_DUMP_OOPS:
+		break;
+	case KMSG_DUMP_PANIC:
+		panicking = true;
+		break;
+	case KMSG_DUMP_EMERG:
+		if (panicking)
+			/* Panic report already captured. */
+			return;
+		break;
+	default:
+		pr_err("%s: ignoring unrecognized KMSG_DUMP_* reason %d\n",
+		       __func__, (int) reason);
+		return;
+	}
+
+	if (clobbering_unread_rtas_event())
+		return;
+
+	if (!spin_trylock_irqsave(&lock, flags))
+		return;
+
+	if (big_oops_buf) {
+		kmsg_dump_get_buffer(dumper, false,
+				     big_oops_buf, big_oops_buf_sz, &text_len);
+		rc = zip_oops(text_len);
+	}
+	if (rc != 0) {
+		kmsg_dump_rewind(dumper);
+		kmsg_dump_get_buffer(dumper, false,
+				     oops_data, oops_data_sz, &text_len);
+		err_type = ERR_TYPE_KERNEL_PANIC;
+		oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
+		oops_hdr->report_length = cpu_to_be16(text_len);
+		oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
+	}
+
+	(void) nvram_write_os_partition(&oops_log_partition, oops_buf,
+		(int) (sizeof(*oops_hdr) + text_len), err_type,
+		++oops_count);
+
+	spin_unlock_irqrestore(&lock, flags);
+}
+
+static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
+{
+	if (ppc_md.nvram_size == NULL)
+		return -ENODEV;
+	return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE,
+					ppc_md.nvram_size());
+}
+
+
+static ssize_t dev_nvram_read(struct file *file, char __user *buf,
+			  size_t count, loff_t *ppos)
+{
+	ssize_t ret;
+	char *tmp = NULL;
+	ssize_t size;
+
+	if (!ppc_md.nvram_size) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	size = ppc_md.nvram_size();
+	if (size < 0) {
+		ret = size;
+		goto out;
+	}
+
+	if (*ppos >= size) {
+		ret = 0;
+		goto out;
+	}
+
+	count = min_t(size_t, count, size - *ppos);
+	count = min(count, PAGE_SIZE);
+
+	tmp = kmalloc(count, GFP_KERNEL);
+	if (!tmp) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = ppc_md.nvram_read(tmp, count, ppos);
+	if (ret <= 0)
+		goto out;
+
+	if (copy_to_user(buf, tmp, ret))
+		ret = -EFAULT;
+
+out:
+	kfree(tmp);
+	return ret;
+
+}
+
+static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
+			  size_t count, loff_t *ppos)
+{
+	ssize_t ret;
+	char *tmp = NULL;
+	ssize_t size;
+
+	ret = -ENODEV;
+	if (!ppc_md.nvram_size)
+		goto out;
+
+	ret = 0;
+	size = ppc_md.nvram_size();
+	if (*ppos >= size || size < 0)
+		goto out;
+
+	count = min_t(size_t, count, size - *ppos);
+	count = min(count, PAGE_SIZE);
+
+	tmp = memdup_user(buf, count);
+	if (IS_ERR(tmp)) {
+		ret = PTR_ERR(tmp);
+		goto out;
+	}
+
+	ret = ppc_md.nvram_write(tmp, count, ppos);
+
+	kfree(tmp);
+out:
+	return ret;
+}
+
+static long dev_nvram_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg)
+{
+	switch(cmd) {
+#ifdef CONFIG_PPC_PMAC
+	case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
+		printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
+	case IOC_NVRAM_GET_OFFSET: {
+		int part, offset;
+
+		if (!machine_is(powermac))
+			return -EINVAL;
+		if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
+			return -EFAULT;
+		if (part < pmac_nvram_OF || part > pmac_nvram_NR)
+			return -EINVAL;
+		offset = pmac_get_partition(part);
+		if (offset < 0)
+			return offset;
+		if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
+			return -EFAULT;
+		return 0;
+	}
+#endif /* CONFIG_PPC_PMAC */
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct file_operations nvram_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= dev_nvram_llseek,
+	.read		= dev_nvram_read,
+	.write		= dev_nvram_write,
+	.unlocked_ioctl	= dev_nvram_ioctl,
+};
+
+static struct miscdevice nvram_dev = {
+	NVRAM_MINOR,
+	"nvram",
+	&nvram_fops
+};
+
+
+#ifdef DEBUG_NVRAM
+static void __init nvram_print_partitions(char * label)
+{
+	struct nvram_partition * tmp_part;
+	
+	printk(KERN_WARNING "--------%s---------\n", label);
+	printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
+	list_for_each_entry(tmp_part, &nvram_partitions, partition) {
+		printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%12.12s\n",
+		       tmp_part->index, tmp_part->header.signature,
+		       tmp_part->header.checksum, tmp_part->header.length,
+		       tmp_part->header.name);
+	}
+}
+#endif
+
+
+static int __init nvram_write_header(struct nvram_partition * part)
+{
+	loff_t tmp_index;
+	int rc;
+	struct nvram_header phead;
+
+	memcpy(&phead, &part->header, NVRAM_HEADER_LEN);
+	phead.length = cpu_to_be16(phead.length);
+
+	tmp_index = part->index;
+	rc = ppc_md.nvram_write((char *)&phead, NVRAM_HEADER_LEN, &tmp_index);
+
+	return rc;
+}
+
+
+static unsigned char __init nvram_checksum(struct nvram_header *p)
+{
+	unsigned int c_sum, c_sum2;
+	unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
+	c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
+
+	/* The sum may have spilled into the 3rd byte.  Fold it back. */
+	c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
+	/* The sum cannot exceed 2 bytes.  Fold it into a checksum */
+	c_sum2 = (c_sum >> 8) + (c_sum << 8);
+	c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
+	return c_sum;
+}
+
+/*
+ * Per the criteria passed via nvram_remove_partition(), should this
+ * partition be removed?  1=remove, 0=keep
+ */
+static int nvram_can_remove_partition(struct nvram_partition *part,
+		const char *name, int sig, const char *exceptions[])
+{
+	if (part->header.signature != sig)
+		return 0;
+	if (name) {
+		if (strncmp(name, part->header.name, 12))
+			return 0;
+	} else if (exceptions) {
+		const char **except;
+		for (except = exceptions; *except; except++) {
+			if (!strncmp(*except, part->header.name, 12))
+				return 0;
+		}
+	}
+	return 1;
+}
+
+/**
+ * nvram_remove_partition - Remove one or more partitions in nvram
+ * @name: name of the partition to remove, or NULL for a
+ *        signature only match
+ * @sig: signature of the partition(s) to remove
+ * @exceptions: When removing all partitions with a matching signature,
+ *        leave these alone.
+ */
+
+int __init nvram_remove_partition(const char *name, int sig,
+						const char *exceptions[])
+{
+	struct nvram_partition *part, *prev, *tmp;
+	int rc;
+
+	list_for_each_entry(part, &nvram_partitions, partition) {
+		if (!nvram_can_remove_partition(part, name, sig, exceptions))
+			continue;
+
+		/* Make partition a free partition */
+		part->header.signature = NVRAM_SIG_FREE;
+		memset(part->header.name, 'w', 12);
+		part->header.checksum = nvram_checksum(&part->header);
+		rc = nvram_write_header(part);
+		if (rc <= 0) {
+			printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
+			return rc;
+		}
+	}
+
+	/* Merge contiguous ones */
+	prev = NULL;
+	list_for_each_entry_safe(part, tmp, &nvram_partitions, partition) {
+		if (part->header.signature != NVRAM_SIG_FREE) {
+			prev = NULL;
+			continue;
+		}
+		if (prev) {
+			prev->header.length += part->header.length;
+			prev->header.checksum = nvram_checksum(&prev->header);
+			rc = nvram_write_header(prev);
+			if (rc <= 0) {
+				printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
+				return rc;
+			}
+			list_del(&part->partition);
+			kfree(part);
+		} else
+			prev = part;
+	}
+	
+	return 0;
+}
+
+/**
+ * nvram_create_partition - Create a partition in nvram
+ * @name: name of the partition to create
+ * @sig: signature of the partition to create
+ * @req_size: size of data to allocate in bytes
+ * @min_size: minimum acceptable size (0 means req_size)
+ *
+ * Returns a negative error code or a positive nvram index
+ * of the beginning of the data area of the newly created
+ * partition. If you provided a min_size smaller than req_size
+ * you need to query for the actual size yourself after the
+ * call using nvram_partition_get_size().
+ */
+loff_t __init nvram_create_partition(const char *name, int sig,
+				     int req_size, int min_size)
+{
+	struct nvram_partition *part;
+	struct nvram_partition *new_part;
+	struct nvram_partition *free_part = NULL;
+	static char nv_init_vals[16];
+	loff_t tmp_index;
+	long size = 0;
+	int rc;
+
+	/* Convert sizes from bytes to blocks */
+	req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
+	min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
+
+	/* If no minimum size specified, make it the same as the
+	 * requested size
+	 */
+	if (min_size == 0)
+		min_size = req_size;
+	if (min_size > req_size)
+		return -EINVAL;
+
+	/* Now add one block to each for the header */
+	req_size += 1;
+	min_size += 1;
+
+	/* Find a free partition that will give us the maximum needed size 
+	   If can't find one that will give us the minimum size needed */
+	list_for_each_entry(part, &nvram_partitions, partition) {
+		if (part->header.signature != NVRAM_SIG_FREE)
+			continue;
+
+		if (part->header.length >= req_size) {
+			size = req_size;
+			free_part = part;
+			break;
+		}
+		if (part->header.length > size &&
+		    part->header.length >= min_size) {
+			size = part->header.length;
+			free_part = part;
+		}
+	}
+	if (!size)
+		return -ENOSPC;
+	
+	/* Create our OS partition */
+	new_part = kzalloc(sizeof(*new_part), GFP_KERNEL);
+	if (!new_part) {
+		pr_err("%s: kmalloc failed\n", __func__);
+		return -ENOMEM;
+	}
+
+	new_part->index = free_part->index;
+	new_part->header.signature = sig;
+	new_part->header.length = size;
+	memcpy(new_part->header.name, name, strnlen(name, sizeof(new_part->header.name)));
+	new_part->header.checksum = nvram_checksum(&new_part->header);
+
+	rc = nvram_write_header(new_part);
+	if (rc <= 0) {
+		pr_err("%s: nvram_write_header failed (%d)\n", __func__, rc);
+		kfree(new_part);
+		return rc;
+	}
+	list_add_tail(&new_part->partition, &free_part->partition);
+
+	/* Adjust or remove the partition we stole the space from */
+	if (free_part->header.length > size) {
+		free_part->index += size * NVRAM_BLOCK_LEN;
+		free_part->header.length -= size;
+		free_part->header.checksum = nvram_checksum(&free_part->header);
+		rc = nvram_write_header(free_part);
+		if (rc <= 0) {
+			pr_err("%s: nvram_write_header failed (%d)\n",
+			       __func__, rc);
+			return rc;
+		}
+	} else {
+		list_del(&free_part->partition);
+		kfree(free_part);
+	} 
+
+	/* Clear the new partition */
+	for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
+	     tmp_index <  ((size - 1) * NVRAM_BLOCK_LEN);
+	     tmp_index += NVRAM_BLOCK_LEN) {
+		rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
+		if (rc <= 0) {
+			pr_err("%s: nvram_write failed (%d)\n",
+			       __func__, rc);
+			return rc;
+		}
+	}
+
+	return new_part->index + NVRAM_HEADER_LEN;
+}
+
+/**
+ * nvram_get_partition_size - Get the data size of an nvram partition
+ * @data_index: This is the offset of the start of the data of
+ *              the partition. The same value that is returned by
+ *              nvram_create_partition().
+ */
+int nvram_get_partition_size(loff_t data_index)
+{
+	struct nvram_partition *part;
+	
+	list_for_each_entry(part, &nvram_partitions, partition) {
+		if (part->index + NVRAM_HEADER_LEN == data_index)
+			return (part->header.length - 1) * NVRAM_BLOCK_LEN;
+	}
+	return -1;
+}
+
+
+/**
+ * nvram_find_partition - Find an nvram partition by signature and name
+ * @name: Name of the partition or NULL for any name
+ * @sig: Signature to test against
+ * @out_size: if non-NULL, returns the size of the data part of the partition
+ */
+loff_t nvram_find_partition(const char *name, int sig, int *out_size)
+{
+	struct nvram_partition *p;
+
+	list_for_each_entry(p, &nvram_partitions, partition) {
+		if (p->header.signature == sig &&
+		    (!name || !strncmp(p->header.name, name, 12))) {
+			if (out_size)
+				*out_size = (p->header.length - 1) *
+					NVRAM_BLOCK_LEN;
+			return p->index + NVRAM_HEADER_LEN;
+		}
+	}
+	return 0;
+}
+
+int __init nvram_scan_partitions(void)
+{
+	loff_t cur_index = 0;
+	struct nvram_header phead;
+	struct nvram_partition * tmp_part;
+	unsigned char c_sum;
+	char * header;
+	int total_size;
+	int err;
+
+	if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
+		return -ENODEV;
+	total_size = ppc_md.nvram_size();
+	
+	header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
+	if (!header) {
+		printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
+		return -ENOMEM;
+	}
+
+	while (cur_index < total_size) {
+
+		err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
+		if (err != NVRAM_HEADER_LEN) {
+			printk(KERN_ERR "nvram_scan_partitions: Error parsing "
+			       "nvram partitions\n");
+			goto out;
+		}
+
+		cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
+
+		memcpy(&phead, header, NVRAM_HEADER_LEN);
+
+		phead.length = be16_to_cpu(phead.length);
+
+		err = 0;
+		c_sum = nvram_checksum(&phead);
+		if (c_sum != phead.checksum) {
+			printk(KERN_WARNING "WARNING: nvram partition checksum"
+			       " was %02x, should be %02x!\n",
+			       phead.checksum, c_sum);
+			printk(KERN_WARNING "Terminating nvram partition scan\n");
+			goto out;
+		}
+		if (!phead.length) {
+			printk(KERN_WARNING "WARNING: nvram corruption "
+			       "detected: 0-length partition\n");
+			goto out;
+		}
+		tmp_part = kmalloc(sizeof(*tmp_part), GFP_KERNEL);
+		err = -ENOMEM;
+		if (!tmp_part) {
+			printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
+			goto out;
+		}
+		
+		memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
+		tmp_part->index = cur_index;
+		list_add_tail(&tmp_part->partition, &nvram_partitions);
+		
+		cur_index += phead.length * NVRAM_BLOCK_LEN;
+	}
+	err = 0;
+
+#ifdef DEBUG_NVRAM
+	nvram_print_partitions("NVRAM Partitions");
+#endif
+
+ out:
+	kfree(header);
+	return err;
+}
+
+static int __init nvram_init(void)
+{
+	int rc;
+	
+	BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
+
+	if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
+		return  -ENODEV;
+
+  	rc = misc_register(&nvram_dev);
+	if (rc != 0) {
+		printk(KERN_ERR "nvram_init: failed to register device\n");
+		return rc;
+	}
+  	
+  	return rc;
+}
+device_initcall(nvram_init);