2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-24 05:04:00 +08:00
linux-next/arch/powerpc/platforms/pseries/scanlog.c
Russell Currey 57ad583f20 powerpc: Use octal numbers for file permissions
Symbolic macros are unintuitive and hard to read, whereas octal constants
are much easier to interpret.  Replace macros for the basic permission
flags (user/group/other read/write/execute) with numeric constants
instead, across the whole powerpc tree.

Introducing a significant number of changes across the tree for no runtime
benefit isn't exactly desirable, but so long as these macros are still
used in the tree people will keep sending patches that add them.  Not only
are they hard to parse at a glance, there are multiple ways of coming to
the same value (as you can see with 0444 and 0644 in this patch) which
hurts readability.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-22 05:48:33 +11:00

201 lines
5.1 KiB
C

/*
* 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.
*
* scan-log-data driver for PPC64 Todd Inglett <tinglett@vnet.ibm.com>
*
* When ppc64 hardware fails the service processor dumps internal state
* of the system. After a reboot the operating system can access a dump
* of this data using this driver. A dump exists if the device-tree
* /chosen/ibm,scan-log-data property exists.
*
* This driver exports /proc/powerpc/scan-log-dump which can be read.
* The driver supports only sequential reads.
*
* The driver looks at a write to the driver for the single word "reset".
* If given, the driver will reset the scanlog so the platform can free it.
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <asm/rtas.h>
#include <asm/prom.h>
#define MODULE_VERS "1.0"
#define MODULE_NAME "scanlog"
/* Status returns from ibm,scan-log-dump */
#define SCANLOG_COMPLETE 0
#define SCANLOG_HWERROR -1
#define SCANLOG_CONTINUE 1
static unsigned int ibm_scan_log_dump; /* RTAS token */
static unsigned int *scanlog_buffer; /* The data buffer */
static ssize_t scanlog_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
unsigned int *data = scanlog_buffer;
int status;
unsigned long len, off;
unsigned int wait_time;
if (count > RTAS_DATA_BUF_SIZE)
count = RTAS_DATA_BUF_SIZE;
if (count < 1024) {
/* This is the min supported by this RTAS call. Rather
* than do all the buffering we insist the user code handle
* larger reads. As long as cp works... :)
*/
printk(KERN_ERR "scanlog: cannot perform a small read (%ld)\n", count);
return -EINVAL;
}
if (!access_ok(VERIFY_WRITE, buf, count))
return -EFAULT;
for (;;) {
wait_time = 500; /* default wait if no data */
spin_lock(&rtas_data_buf_lock);
memcpy(rtas_data_buf, data, RTAS_DATA_BUF_SIZE);
status = rtas_call(ibm_scan_log_dump, 2, 1, NULL,
(u32) __pa(rtas_data_buf), (u32) count);
memcpy(data, rtas_data_buf, RTAS_DATA_BUF_SIZE);
spin_unlock(&rtas_data_buf_lock);
pr_debug("scanlog: status=%d, data[0]=%x, data[1]=%x, " \
"data[2]=%x\n", status, data[0], data[1], data[2]);
switch (status) {
case SCANLOG_COMPLETE:
pr_debug("scanlog: hit eof\n");
return 0;
case SCANLOG_HWERROR:
pr_debug("scanlog: hardware error reading data\n");
return -EIO;
case SCANLOG_CONTINUE:
/* We may or may not have data yet */
len = data[1];
off = data[2];
if (len > 0) {
if (copy_to_user(buf, ((char *)data)+off, len))
return -EFAULT;
return len;
}
/* Break to sleep default time */
break;
default:
/* Assume extended busy */
wait_time = rtas_busy_delay_time(status);
if (!wait_time) {
printk(KERN_ERR "scanlog: unknown error " \
"from rtas: %d\n", status);
return -EIO;
}
}
/* Apparently no data yet. Wait and try again. */
msleep_interruptible(wait_time);
}
/*NOTREACHED*/
}
static ssize_t scanlog_write(struct file * file, const char __user * buf,
size_t count, loff_t *ppos)
{
char stkbuf[20];
int status;
if (count > 19) count = 19;
if (copy_from_user (stkbuf, buf, count)) {
return -EFAULT;
}
stkbuf[count] = 0;
if (buf) {
if (strncmp(stkbuf, "reset", 5) == 0) {
pr_debug("scanlog: reset scanlog\n");
status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0);
pr_debug("scanlog: rtas returns %d\n", status);
}
}
return count;
}
static int scanlog_open(struct inode * inode, struct file * file)
{
unsigned int *data = scanlog_buffer;
if (data[0] != 0) {
/* This imperfect test stops a second copy of the
* data (or a reset while data is being copied)
*/
return -EBUSY;
}
data[0] = 0; /* re-init so we restart the scan */
return 0;
}
static int scanlog_release(struct inode * inode, struct file * file)
{
unsigned int *data = scanlog_buffer;
data[0] = 0;
return 0;
}
static const struct file_operations scanlog_fops = {
.owner = THIS_MODULE,
.read = scanlog_read,
.write = scanlog_write,
.open = scanlog_open,
.release = scanlog_release,
.llseek = noop_llseek,
};
static int __init scanlog_init(void)
{
struct proc_dir_entry *ent;
int err = -ENOMEM;
ibm_scan_log_dump = rtas_token("ibm,scan-log-dump");
if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE)
return -ENODEV;
/* Ideally we could allocate a buffer < 4G */
scanlog_buffer = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
if (!scanlog_buffer)
goto err;
ent = proc_create("powerpc/rtas/scan-log-dump", 0400, NULL,
&scanlog_fops);
if (!ent)
goto err;
return 0;
err:
kfree(scanlog_buffer);
return err;
}
static void __exit scanlog_cleanup(void)
{
remove_proc_entry("powerpc/rtas/scan-log-dump", NULL);
kfree(scanlog_buffer);
}
module_init(scanlog_init);
module_exit(scanlog_cleanup);
MODULE_LICENSE("GPL");