diff options
Diffstat (limited to 'arch/powerpc/platforms/pseries/scanlog.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/scanlog.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/scanlog.c b/arch/powerpc/platforms/pseries/scanlog.c new file mode 100644 index 000000000..2879c4f0c --- /dev/null +++ b/arch/powerpc/platforms/pseries/scanlog.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * c 2001 PPC 64 Team, IBM Corp + * + * 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(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 proc_ops scanlog_proc_ops = { + .proc_read = scanlog_read, + .proc_write = scanlog_write, + .proc_open = scanlog_open, + .proc_release = scanlog_release, + .proc_lseek = 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_proc_ops); + 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"); |