drivers/scsi/fnic/fnic_trace.c

   1 /*
   2  * Copyright 2012 Cisco Systems, Inc.  All rights reserved.
   3  *
   4  * This program is free software; you may redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   9  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  10  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  11  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  12  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  13  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  14  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  15  * SOFTWARE.
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/mempool.h>
  20 #include <linux/errno.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/kallsyms.h>
  23 #include "fnic_io.h"
  24 #include "fnic.h"
  25
  26 unsigned int trace_max_pages;
  27 static int fnic_max_trace_entries;
  28
  29 static unsigned long fnic_trace_buf_p;
  30 static DEFINE_SPINLOCK(fnic_trace_lock);
  31
  32 static fnic_trace_dbg_t fnic_trace_entries;
  33 int fnic_tracing_enabled = 1;
  34
  35 /*
  36  * fnic_trace_get_buf - Give buffer pointer to user to fill up trace information
  37  *
  38  * Description:
  39  * This routine gets next available trace buffer entry location @wr_idx
  40  * from allocated trace buffer pages and give that memory location
  41  * to user to store the trace information.
  42  *
  43  * Return Value:
  44  * This routine returns pointer to next available trace entry
  45  * @fnic_buf_head for user to fill trace information.
  46  */
  47 fnic_trace_data_t *fnic_trace_get_buf(void)
  48 {
  49         unsigned long fnic_buf_head;
  50         unsigned long flags;
  51
  52         spin_lock_irqsave(&fnic_trace_lock, flags);
  53
  54         /*
  55          * Get next available memory location for writing trace information
  56          * at @wr_idx and increment @wr_idx
  57          */
  58         fnic_buf_head =
  59                 fnic_trace_entries.page_offset[fnic_trace_entries.wr_idx];
  60         fnic_trace_entries.wr_idx++;
  61
  62         /*
  63          * Verify if trace buffer is full then change wd_idx to
  64          * start from zero
  65          */
  66         if (fnic_trace_entries.wr_idx >= fnic_max_trace_entries)
  67                 fnic_trace_entries.wr_idx = 0;
  68
  69         /*
  70          * Verify if write index @wr_idx and read index @rd_idx are same then
  71          * increment @rd_idx to move to next entry in trace buffer
  72          */
  73         if (fnic_trace_entries.wr_idx == fnic_trace_entries.rd_idx) {
  74                 fnic_trace_entries.rd_idx++;
  75                 if (fnic_trace_entries.rd_idx >= fnic_max_trace_entries)
  76                         fnic_trace_entries.rd_idx = 0;
  77         }
  78         spin_unlock_irqrestore(&fnic_trace_lock, flags);
  79         return (fnic_trace_data_t *)fnic_buf_head;
  80 }
  81
  82 /*
  83  * fnic_get_trace_data - Copy trace buffer to a memory file
  84  * @fnic_dbgfs_t: pointer to debugfs trace buffer
  85  *
  86  * Description:
  87  * This routine gathers the fnic trace debugfs data from the fnic_trace_data_t
  88  * buffer and dumps it to fnic_dbgfs_t. It will start at the rd_idx entry in
  89  * the log and process the log until the end of the buffer. Then it will gather
  90  * from the beginning of the log and process until the current entry @wr_idx.
  91  *
  92  * Return Value:
  93  * This routine returns the amount of bytes that were dumped into fnic_dbgfs_t
  94  */
  95 int fnic_get_trace_data(fnic_dbgfs_t *fnic_dbgfs_prt)
  96 {
  97         int rd_idx;
  98         int wr_idx;
  99         int len = 0;
 100         unsigned long flags;
 101         char str[KSYM_SYMBOL_LEN];
 102         struct timespec val;
 103         fnic_trace_data_t *tbp;
 104
 105         spin_lock_irqsave(&fnic_trace_lock, flags);
 106         rd_idx = fnic_trace_entries.rd_idx;
 107         wr_idx = fnic_trace_entries.wr_idx;
 108         if (wr_idx < rd_idx) {
 109                 while (1) {
 110                         /* Start from read index @rd_idx */
 111                         tbp = (fnic_trace_data_t *)
 112                                   fnic_trace_entries.page_offset[rd_idx];
 113                         if (!tbp) {
 114                                 spin_unlock_irqrestore(&fnic_trace_lock, flags);
 115                                 return 0;
 116                         }
 117                         /* Convert function pointer to function name */
 118                         if (sizeof(unsigned long) < 8) {
 119                                 sprint_symbol(str, tbp->fnaddr.low);
 120                                 jiffies_to_timespec(tbp->timestamp.low, &val);
 121                         } else {
 122                                 sprint_symbol(str, tbp->fnaddr.val);
 123                                 jiffies_to_timespec(tbp->timestamp.val, &val);
 124                         }
 125                         /*
 126                          * Dump trace buffer entry to memory file
 127                          * and increment read index @rd_idx
 128                          */
 129                         len += snprintf(fnic_dbgfs_prt->buffer + len,
 130                                   (trace_max_pages * PAGE_SIZE * 3) - len,
 131                                   "%16lu.%16lu %-50s %8x %8x %16llx %16llx "
 132                                   "%16llx %16llx %16llx\n", val.tv_sec,
 133                                   val.tv_nsec, str, tbp->host_no, tbp->tag,
 134                                   tbp->data[0], tbp->data[1], tbp->data[2],
 135                                   tbp->data[3], tbp->data[4]);
 136                         rd_idx++;
 137                         /*
 138                          * If rd_idx is reached to maximum trace entries
 139                          * then move rd_idx to zero
 140                          */
 141                         if (rd_idx > (fnic_max_trace_entries-1))
 142                                 rd_idx = 0;
 143                         /*
 144                          * Continure dumpping trace buffer entries into
 145                          * memory file till rd_idx reaches write index
 146                          */
 147                         if (rd_idx == wr_idx)
 148                                 break;
 149                 }
 150         } else if (wr_idx > rd_idx) {
 151                 while (1) {
 152                         /* Start from read index @rd_idx */
 153                         tbp = (fnic_trace_data_t *)
 154                                   fnic_trace_entries.page_offset[rd_idx];
 155                         if (!tbp) {
 156                                 spin_unlock_irqrestore(&fnic_trace_lock, flags);
 157                                 return 0;
 158                         }
 159                         /* Convert function pointer to function name */
 160                         if (sizeof(unsigned long) < 8) {
 161                                 sprint_symbol(str, tbp->fnaddr.low);
 162                                 jiffies_to_timespec(tbp->timestamp.low, &val);
 163                         } else {
 164                                 sprint_symbol(str, tbp->fnaddr.val);
 165                                 jiffies_to_timespec(tbp->timestamp.val, &val);
 166                         }
 167                         /*
 168                          * Dump trace buffer entry to memory file
 169                          * and increment read index @rd_idx
 170                          */
 171                         len += snprintf(fnic_dbgfs_prt->buffer + len,
 172                                   (trace_max_pages * PAGE_SIZE * 3) - len,
 173                                   "%16lu.%16lu %-50s %8x %8x %16llx %16llx "
 174                                   "%16llx %16llx %16llx\n", val.tv_sec,
 175                                   val.tv_nsec, str, tbp->host_no, tbp->tag,
 176                                   tbp->data[0], tbp->data[1], tbp->data[2],
 177                                   tbp->data[3], tbp->data[4]);
 178                         rd_idx++;
 179                         /*
 180                          * Continue dumpping trace buffer entries into
 181                          * memory file till rd_idx reaches write index
 182                          */
 183                         if (rd_idx == wr_idx)
 184                                 break;
 185                 }
 186         }
 187         spin_unlock_irqrestore(&fnic_trace_lock, flags);
 188         return len;
 189 }
 190
 191 /*
 192  * fnic_trace_buf_init - Initialize fnic trace buffer logging facility
 193  *
 194  * Description:
 195  * Initialize trace buffer data structure by allocating required memory and
 196  * setting page_offset information for every trace entry by adding trace entry
 197  * length to previous page_offset value.
 198  */
 199 int fnic_trace_buf_init(void)
 200 {
 201         unsigned long fnic_buf_head;
 202         int i;
 203         int err = 0;
 204
 205         trace_max_pages = fnic_trace_max_pages;
 206         fnic_max_trace_entries = (trace_max_pages * PAGE_SIZE)/
 207                                           FNIC_ENTRY_SIZE_BYTES;
 208
 209         fnic_trace_buf_p = (unsigned long)vmalloc((trace_max_pages * PAGE_SIZE));
 210         if (!fnic_trace_buf_p) {
 211                 printk(KERN_ERR PFX "Failed to allocate memory "
 212                                   "for fnic_trace_buf_p\n");
 213                 err = -ENOMEM;
 214                 goto err_fnic_trace_buf_init;
 215         }
 216         memset((void *)fnic_trace_buf_p, 0, (trace_max_pages * PAGE_SIZE));
 217
 218         fnic_trace_entries.page_offset = vmalloc(fnic_max_trace_entries *
 219                                                   sizeof(unsigned long));
 220         if (!fnic_trace_entries.page_offset) {
 221                 printk(KERN_ERR PFX "Failed to allocate memory for"
 222                                   " page_offset\n");
 223                 if (fnic_trace_buf_p) {
 224                         vfree((void *)fnic_trace_buf_p);
 225                         fnic_trace_buf_p = 0;
 226                 }
 227                 err = -ENOMEM;
 228                 goto err_fnic_trace_buf_init;
 229         }
 230         memset((void *)fnic_trace_entries.page_offset, 0,
 231                   (fnic_max_trace_entries * sizeof(unsigned long)));
 232         fnic_trace_entries.wr_idx = fnic_trace_entries.rd_idx = 0;
 233         fnic_buf_head = fnic_trace_buf_p;
 234
 235         /*
 236          * Set page_offset field of fnic_trace_entries struct by
 237          * calculating memory location for every trace entry using
 238          * length of each trace entry
 239          */
 240         for (i = 0; i < fnic_max_trace_entries; i++) {
 241                 fnic_trace_entries.page_offset[i] = fnic_buf_head;
 242                 fnic_buf_head += FNIC_ENTRY_SIZE_BYTES;
 243         }
 244         err = fnic_trace_debugfs_init();
 245         if (err < 0) {
 246                 printk(KERN_ERR PFX "Failed to initialize debugfs for tracing\n");
 247                 goto err_fnic_trace_debugfs_init;
 248         }
 249         printk(KERN_INFO PFX "Successfully Initialized Trace Buffer\n");
 250         return err;
 251 err_fnic_trace_debugfs_init:
 252         fnic_trace_free();
 253 err_fnic_trace_buf_init:
 254         return err;
 255 }
 256
 257 /*
 258  * fnic_trace_free - Free memory of fnic trace data structures.
 259  */
 260 void fnic_trace_free(void)
 261 {
 262         fnic_tracing_enabled = 0;
 263         fnic_trace_debugfs_terminate();
 264         if (fnic_trace_entries.page_offset) {
 265                 vfree((void *)fnic_trace_entries.page_offset);
 266                 fnic_trace_entries.page_offset = NULL;
 267         }
 268         if (fnic_trace_buf_p) {
 269                 vfree((void *)fnic_trace_buf_p);
 270                 fnic_trace_buf_p = 0;
 271         }
 272         printk(KERN_INFO PFX "Successfully Freed Trace Buffer\n");
 273 }