/*
* 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
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/kmsg_dump.h>
#include <linux/ctype.h>
#include <linux/zlib.h>
#include <asm/uaccess.h>
#include <asm/nvram.h>
#include <asm/rtas.h>
#include <asm/prom.h>
#include <asm/machdep.h>
/* Max bytes to read/write in one go */
#define NVRW_CNT 0x20
static unsigned int nvram_size;
static int nvram_fetch, nvram_store;
static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */
static DEFINE_SPINLOCK(nvram_lock);
struct err_log_info {
int error_type;
unsigned int seq_num;
};
struct nvram_os_partition {
const char *name;
int req_size; /* desired size, in bytes */
int min_size; /* minimum acceptable size (0 means req_size) */
long size; /* size of data portion (excluding err_log_info) */
long index; /* offset of data portion of partition */
};
static struct nvram_os_partition rtas_log_partition = {
.name = "ibm,rtas-log",
.req_size = 2079,
.min_size = 1055,
.index = -1
};
static struct nvram_os_partition oops_log_partition = {
.name = "lnx,oops-log",
.req_size = 4000,
.min_size = 2000,
.index = -1
};
static const char *pseries_nvram_os_partitions[] = {
"ibm,rtas-log",
"lnx,oops-log",
NULL
};
static void oops_to_nvram(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason,
const char *old_msgs, unsigned long old_len,
const char *new_msgs, unsigned long new_len);
static struct kmsg_dumper nvram_kmsg_dumper = {
.dump = oops_to_nvram
};
/* See clobbering_unread_rtas_event() */
#define NVRAM_RTAS_READ_TIMEOUT 5 /* seconds */
static unsigned long last_unread_rtas_event; /* timestamp */
/*
* 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 prefix.
* The prefix is just a u16 holding the length of the compressed* text.
* (*Or uncompressed, if compression fails.) oops_buf[] gets written
* to NVRAM.
*
* oops_len points to the prefix. oops_data points to the compressed text.
*
* +- oops_buf
* | +- oops_data
* v v
* +------------+-----------------------------------------------+
* | length | text |
* | (2 bytes) | (oops_data_sz bytes) |
* +------------+-----------------------------------------------+
* ^
* +- oops_len
*
* 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 u16 *oops_len;
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;
static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
{
unsigned int i;
unsigned long len;
int done;
unsigned long flags;
char *p = buf;
if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
return -ENODEV;
if (*index >= nvram_size)
return 0;
i = *index;
if (i + count > nvram_size)
count = nvram_size - i;
spin_lock_irqsave(&nvram_lock, flags);
for (; count != 0; count -= len) {
len = count;
if (len > NVRW_CNT)
len = NVRW_CNT;
if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf),
len) != 0) || len != done) {
spin_unlock_irqrestore(&nvram_lock, flags);
return -EIO;
}
memcpy(p, nvram_buf, len);
p += len;
i += len;
}
spin_unlock_irqrestore(&nvram_lock, flags);
*index = i;
return p - buf;
}
static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
{
unsigned int i;
unsigned long len;
int done;
unsigned long flags;
const char *p = buf;
if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
return -ENODEV;
if (*index >= nvram_size)
return 0;
i = *index;
if (i + count > nvram_size)
count = nvram_size - i;
spin_lock_irqsave(&nvram_lock, flags);
for (; count != 0; count -= len) {
len = count;
if (len > NVRW_CNT)
len = NVRW_CNT;
memcpy(nvram_buf, p, len);
if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf),
len) != 0) || len != done) {
spin_unlock_irqrestore(&nvram_lock, flags);
return -EIO;
}
p += len;
i += len;
}
spin_unlock_irqrestore(&nvram_lock, flags);
*index = i;
return p - buf;
}
static ssize_t pSeries_nvram_get_size(void)
{
return nvram_size ? nvram_size : -ENODEV;
}
/* nvram_write_os_partition, nvram_write_error_log
*
* 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 = err_type;
info.seq_num = error_log_cnt;
tmp_index = part->index;
rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info), &tmp_index);
if (rc <= 0) {
pr_err("%s: Failed nvram_write (%d)\n", __FUNCTION__, rc);
return rc;
}
rc = ppc_md.nvram_write(buff, length, &tmp_index);
if (rc <= 0) {
pr_err("%s: Failed nvram_write (%d)\n", __FUNCTION__, rc);
return rc;
}
return 0;
}
int nvram_write_error_log(char * buff, int length,
unsigned int err_type, unsigned int error_log_cnt)
{
int rc = nvram_write_os_partition(&rtas_log_partition, buff, length,
err_type, error_log_cnt);
if (!rc)
last_unread_rtas_event = get_seconds();
return rc;
}
/* nvram_read_error_log
*
* Reads nvram for error log for at most 'length'
*/
int nvram_read_error_log(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 (rtas_log_partition.index == -1)
return -1;
if (length > rtas_log_partition.size)
length = rtas_log_partition.size;
tmp_index = rtas_log_partition.index;
rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
if (rc <= 0) {
printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
return rc;
}
rc = ppc_md.nvram_read(buff, length, &tmp_index);
if (rc <= 0) {
printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
return rc;
}
*error_log_cnt = info.seq_num;
*err_type = info.error_type;
return 0;
}
/* This doesn't actually zero anything, but it sets the event_logged
* word to tell that this event is safely in syslog.
*/
int nvram_clear_error_log(void)
{
loff_t tmp_index;
int clear_word = ERR_FLAG_ALREADY_LOGGED;
int rc;
if (rtas_log_partition.index == -1)
return -1;
tmp_index = rtas_log_partition.index;
rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
if (rc <= 0) {
printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
return rc;
}
last_unread_rtas_event = 0;
return 0;
}
/* pseries_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.
*/
static int __init pseries_nvram_init_os_partition(struct nvram_os_partition
*part)
{
loff_t p;
int size;
/* Scan nvram for partitions */
nvram_scan_partitions();
/* 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,
pseries_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;
}
static void __init nvram_init_oops_partition(int rtas_partition_exists)
{
int rc;
rc = pseries_nvram_init_os_partition(&oops_log_partition);
if (rc != 0) {
if (!rtas_partition_exists)
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));
}
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_len = (u16*) oops_buf;
oops_data = oops_buf + sizeof(u16);
oops_data_sz = oops_log_partition.size - sizeof(u16);
/*
* 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);
}
}
static int __init pseries_nvram_init_log_partitions(void)
{
int rc;
rc = pseries_nvram_init_os_partition(&rtas_log_partition);
nvram_init_oops_partition(rc == 0);
return 0;
}
machine_arch_initcall(pseries, pseries_nvram_init_log_partitions);
int __init pSeries_nvram_init(void)
{
struct device_node *nvram;
const unsigned int *nbytes_p;
unsigned int proplen;
nvram = of_find_node_by_type(NULL, "nvram");
if (nvram == NULL)
return -ENODEV;
nbytes_p = of_get_property(nvram, "#bytes", &proplen);
if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
of_node_put(nvram);
return -EIO;
}
nvram_size = *nbytes_p;
nvram_fetch = rtas_token("nvram-fetch");
nvram_store = rtas_token("nvram-store");
printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
of_node_put(nvram);
ppc_md.nvram_read = pSeries_nvram_read;
ppc_md.nvram_write = pSeries_nvram_write;
ppc_md.nvram_size = pSeries_nvram_get_size;
return 0;
}
/*
* Try to capture the last capture_len bytes of the printk buffer. Return
* the amount actually captured.
*/
static size_t capture_last_msgs(const char *old_msgs, size_t old_len,
const char *new_msgs, size_t new_len,
char *captured, size_t capture_len)
{
if (new_len >= capture_len) {
memcpy(captured, new_msgs + (new_len - capture_len),
capture_len);
return capture_len;
} else {
/* Grab the end of old_msgs. */
size_t old_tail_len = min(old_len, capture_len - new_len);
memcpy(captured, old_msgs + (old_len - old_tail_len),
old_tail_len);
memcpy(captured + old_tail_len, new_msgs, new_len);
return old_tail_len + new_len;
}
}
/*
* Are we using the ibm,rtas-log for oops/panic reports? And if so,
* would logging this oops/panic overwrite an RTAS event that rtas_errd
* hasn't had a chance to read and process? Return 1 if so, else 0.
*
* We assume that if rtas_errd hasn't read the RTAS event in
* NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to.
*/
static int clobbering_unread_rtas_event(void)
{
return (oops_log_partition.index == rtas_log_partition.index
&& last_unread_rtas_event
&& get_seconds() - last_unread_rtas_event <=
NVRAM_RTAS_READ_TIMEOUT);
}
/* Squeeze out each line's <n> severity prefix. */
static size_t elide_severities(char *buf, size_t len)
{
char *in, *out, *buf_end = buf + len;
/* Assume a <n> at the very beginning marks the start of a line. */
int newline = 1;
in = out = buf;
while (in < buf_end) {
if (newline && in+3 <= buf_end &&
*in == '<' && isdigit(in[1]) && in[2] == '>') {
in += 3;
newline = 0;
} else {
newline = (*in == '\n');
*out++ = *in++;
}
}
return out - buf;
}
/* 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)
{
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_len = (u16) zipped_len;
return 0;
}
/*
* 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,
const char *old_msgs, unsigned long old_len,
const char *new_msgs, unsigned long new_len)
{
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",
__FUNCTION__, (int) reason);
return;
}
if (clobbering_unread_rtas_event())
return;
if (!spin_trylock_irqsave(&lock, flags))
return;
if (big_oops_buf) {
text_len = capture_last_msgs(old_msgs, old_len,
new_msgs, new_len, big_oops_buf, big_oops_buf_sz);
text_len = elide_severities(big_oops_buf, text_len);
rc = zip_oops(text_len);
}
if (rc != 0) {
text_len = capture_last_msgs(old_msgs, old_len,
new_msgs, new_len, oops_data, oops_data_sz);
err_type = ERR_TYPE_KERNEL_PANIC;
*oops_len = (u16) text_len;
}
(void) nvram_write_os_partition(&oops_log_partition, oops_buf,
(int) (sizeof(*oops_len) + *oops_len), err_type, ++oops_count);
spin_unlock_irqrestore(&lock, flags);
}
