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195 lines
4.9 KiB
195 lines
4.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* c 2001 PPC 64 Team, IBM Corp |
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* |
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* scan-log-data driver for PPC64 Todd Inglett <[email protected]> |
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* |
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* When ppc64 hardware fails the service processor dumps internal state |
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* of the system. After a reboot the operating system can access a dump |
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* of this data using this driver. A dump exists if the device-tree |
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* /chosen/ibm,scan-log-data property exists. |
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* |
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* This driver exports /proc/powerpc/scan-log-dump which can be read. |
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* The driver supports only sequential reads. |
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* |
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* The driver looks at a write to the driver for the single word "reset". |
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* If given, the driver will reset the scanlog so the platform can free it. |
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*/ |
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#include <linux/module.h> |
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#include <linux/types.h> |
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#include <linux/errno.h> |
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#include <linux/proc_fs.h> |
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#include <linux/init.h> |
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#include <linux/delay.h> |
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#include <linux/slab.h> |
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#include <linux/uaccess.h> |
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#include <asm/rtas.h> |
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#include <asm/prom.h> |
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#define MODULE_VERS "1.0" |
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#define MODULE_NAME "scanlog" |
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/* Status returns from ibm,scan-log-dump */ |
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#define SCANLOG_COMPLETE 0 |
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#define SCANLOG_HWERROR -1 |
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#define SCANLOG_CONTINUE 1 |
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static unsigned int ibm_scan_log_dump; /* RTAS token */ |
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static unsigned int *scanlog_buffer; /* The data buffer */ |
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static ssize_t scanlog_read(struct file *file, char __user *buf, |
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size_t count, loff_t *ppos) |
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{ |
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unsigned int *data = scanlog_buffer; |
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int status; |
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unsigned long len, off; |
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unsigned int wait_time; |
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if (count > RTAS_DATA_BUF_SIZE) |
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count = RTAS_DATA_BUF_SIZE; |
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if (count < 1024) { |
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/* This is the min supported by this RTAS call. Rather |
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* than do all the buffering we insist the user code handle |
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* larger reads. As long as cp works... :) |
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*/ |
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printk(KERN_ERR "scanlog: cannot perform a small read (%ld)\n", count); |
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return -EINVAL; |
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} |
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if (!access_ok(buf, count)) |
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return -EFAULT; |
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for (;;) { |
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wait_time = 500; /* default wait if no data */ |
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spin_lock(&rtas_data_buf_lock); |
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memcpy(rtas_data_buf, data, RTAS_DATA_BUF_SIZE); |
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status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, |
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(u32) __pa(rtas_data_buf), (u32) count); |
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memcpy(data, rtas_data_buf, RTAS_DATA_BUF_SIZE); |
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spin_unlock(&rtas_data_buf_lock); |
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pr_debug("scanlog: status=%d, data[0]=%x, data[1]=%x, " \ |
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"data[2]=%x\n", status, data[0], data[1], data[2]); |
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switch (status) { |
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case SCANLOG_COMPLETE: |
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pr_debug("scanlog: hit eof\n"); |
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return 0; |
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case SCANLOG_HWERROR: |
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pr_debug("scanlog: hardware error reading data\n"); |
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return -EIO; |
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case SCANLOG_CONTINUE: |
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/* We may or may not have data yet */ |
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len = data[1]; |
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off = data[2]; |
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if (len > 0) { |
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if (copy_to_user(buf, ((char *)data)+off, len)) |
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return -EFAULT; |
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return len; |
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} |
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/* Break to sleep default time */ |
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break; |
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default: |
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/* Assume extended busy */ |
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wait_time = rtas_busy_delay_time(status); |
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if (!wait_time) { |
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printk(KERN_ERR "scanlog: unknown error " \ |
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"from rtas: %d\n", status); |
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return -EIO; |
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} |
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} |
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/* Apparently no data yet. Wait and try again. */ |
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msleep_interruptible(wait_time); |
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} |
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/*NOTREACHED*/ |
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} |
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static ssize_t scanlog_write(struct file * file, const char __user * buf, |
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size_t count, loff_t *ppos) |
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{ |
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char stkbuf[20]; |
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int status; |
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if (count > 19) count = 19; |
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if (copy_from_user (stkbuf, buf, count)) { |
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return -EFAULT; |
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} |
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stkbuf[count] = 0; |
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if (buf) { |
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if (strncmp(stkbuf, "reset", 5) == 0) { |
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pr_debug("scanlog: reset scanlog\n"); |
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status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0); |
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pr_debug("scanlog: rtas returns %d\n", status); |
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} |
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} |
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return count; |
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} |
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static int scanlog_open(struct inode * inode, struct file * file) |
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{ |
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unsigned int *data = scanlog_buffer; |
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if (data[0] != 0) { |
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/* This imperfect test stops a second copy of the |
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* data (or a reset while data is being copied) |
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*/ |
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return -EBUSY; |
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} |
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data[0] = 0; /* re-init so we restart the scan */ |
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return 0; |
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} |
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static int scanlog_release(struct inode * inode, struct file * file) |
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{ |
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unsigned int *data = scanlog_buffer; |
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data[0] = 0; |
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return 0; |
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} |
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static const struct proc_ops scanlog_proc_ops = { |
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.proc_read = scanlog_read, |
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.proc_write = scanlog_write, |
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.proc_open = scanlog_open, |
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.proc_release = scanlog_release, |
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.proc_lseek = noop_llseek, |
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}; |
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static int __init scanlog_init(void) |
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{ |
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struct proc_dir_entry *ent; |
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int err = -ENOMEM; |
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ibm_scan_log_dump = rtas_token("ibm,scan-log-dump"); |
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if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE) |
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return -ENODEV; |
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/* Ideally we could allocate a buffer < 4G */ |
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scanlog_buffer = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL); |
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if (!scanlog_buffer) |
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goto err; |
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ent = proc_create("powerpc/rtas/scan-log-dump", 0400, NULL, |
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&scanlog_proc_ops); |
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if (!ent) |
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goto err; |
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return 0; |
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err: |
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kfree(scanlog_buffer); |
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return err; |
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} |
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static void __exit scanlog_cleanup(void) |
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{ |
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remove_proc_entry("powerpc/rtas/scan-log-dump", NULL); |
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kfree(scanlog_buffer); |
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} |
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module_init(scanlog_init); |
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module_exit(scanlog_cleanup); |
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MODULE_LICENSE("GPL");
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