arch/arc/kernel/troubleshoot.c

   1 /*
   2  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  */
   7
   8 #include <linux/ptrace.h>
   9 #include <linux/module.h>
  10 #include <linux/mm.h>
  11 #include <linux/fs.h>
  12 #include <linux/kdev_t.h>
  13 #include <linux/fs_struct.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/file.h>
  16 #include <asm/arcregs.h>
  17
  18 /*
  19  * Common routine to print scratch regs (r0-r12) or callee regs (r13-r25)
  20  *   -Prints 3 regs per line and a CR.
  21  *   -To continue, callee regs right after scratch, special handling of CR
  22  */
  23 static noinline void print_reg_file(long *reg_rev, int start_num)
  24 {
  25         unsigned int i;
  26         char buf[512];
  27         int n = 0, len = sizeof(buf);
  28
  29         /* weird loop because pt_regs regs rev r12..r0, r25..r13 */
  30         for (i = start_num; i < start_num + 13; i++) {
  31                 n += scnprintf(buf + n, len - n, "r%02u: 0x%08lx\t",
  32                                i, (unsigned long)*reg_rev);
  33
  34                 if (((i + 1) % 3) == 0)
  35                         n += scnprintf(buf + n, len - n, "\n");
  36
  37                 reg_rev--;
  38         }
  39
  40         if (start_num != 0)
  41                 n += scnprintf(buf + n, len - n, "\n\n");
  42
  43         pr_info("%s", buf);
  44 }
  45
  46 static void show_callee_regs(struct callee_regs *cregs)
  47 {
  48         print_reg_file(&(cregs->r13), 13);
  49 }
  50
  51 void print_task_path_n_nm(struct task_struct *tsk, char *buf)
  52 {
  53         struct path path;
  54         char *path_nm = NULL;
  55         struct mm_struct *mm;
  56         struct file *exe_file;
  57
  58         mm = get_task_mm(tsk);
  59         if (!mm)
  60                 goto done;
  61
  62         exe_file = get_mm_exe_file(mm);
  63         mmput(mm);
  64
  65         if (exe_file) {
  66                 path = exe_file->f_path;
  67                 path_get(&exe_file->f_path);
  68                 fput(exe_file);
  69                 path_nm = d_path(&path, buf, 255);
  70                 path_put(&path);
  71         }
  72
  73 done:
  74         pr_info("%s, TGID %u\n", path_nm, tsk->tgid);
  75 }
  76 EXPORT_SYMBOL(print_task_path_n_nm);
  77
  78 static void show_faulting_vma(unsigned long address, char *buf)
  79 {
  80         struct vm_area_struct *vma;
  81         struct inode *inode;
  82         unsigned long ino = 0;
  83         dev_t dev = 0;
  84         char *nm = buf;
  85
  86         vma = find_vma(current->active_mm, address);
  87
  88         /* check against the find_vma( ) behaviour which returns the next VMA
  89          * if the container VMA is not found
  90          */
  91         if (vma && (vma->vm_start <= address)) {
  92                 struct file *file = vma->vm_file;
  93                 if (file) {
  94                         struct path *path = &file->f_path;
  95                         nm = d_path(path, buf, PAGE_SIZE - 1);
  96                         inode = vma->vm_file->f_path.dentry->d_inode;
  97                         dev = inode->i_sb->s_dev;
  98                         ino = inode->i_ino;
  99                 }
 100                 pr_info("    @off 0x%lx in [%s]\n"
 101                         "    VMA: 0x%08lx to 0x%08lx\n\n",
 102                        address - vma->vm_start, nm, vma->vm_start, vma->vm_end);
 103         } else
 104                 pr_info("    @No matching VMA found\n");
 105 }
 106
 107 static void show_ecr_verbose(struct pt_regs *regs)
 108 {
 109         unsigned int vec, cause_code, cause_reg;
 110         unsigned long address;
 111
 112         cause_reg = current->thread.cause_code;
 113         pr_info("\n[ECR]: 0x%08x => ", cause_reg);
 114
 115         /* For Data fault, this is data address not instruction addr */
 116         address = current->thread.fault_address;
 117
 118         vec = cause_reg >> 16;
 119         cause_code = (cause_reg >> 8) & 0xFF;
 120
 121         /* For DTLB Miss or ProtV, display the memory involved too */
 122         if (vec == ECR_V_DTLB_MISS) {
 123                 pr_cont("Invalid (%s) @ 0x%08lx by insn @ 0x%08lx\n",
 124                        (cause_code == 0x01) ? "Read From" :
 125                        ((cause_code == 0x02) ? "Write to" : "EX"),
 126                        address, regs->ret);
 127         } else if (vec == ECR_V_ITLB_MISS) {
 128                 pr_cont("Insn could not be fetched\n");
 129         } else if (vec == ECR_V_MACH_CHK) {
 130                 pr_cont("%s\n", (cause_code == 0x0) ?
 131                                         "Double Fault" : "Other Fatal Err");
 132
 133         } else if (vec == ECR_V_PROTV) {
 134                 if (cause_code == ECR_C_PROTV_INST_FETCH)
 135                         pr_cont("Execute from Non-exec Page\n");
 136                 else if (cause_code == ECR_C_PROTV_LOAD)
 137                         pr_cont("Read from Non-readable Page\n");
 138                 else if (cause_code == ECR_C_PROTV_STORE)
 139                         pr_cont("Write to Non-writable Page\n");
 140                 else if (cause_code == ECR_C_PROTV_XCHG)
 141                         pr_cont("Data exchange protection violation\n");
 142                 else if (cause_code == ECR_C_PROTV_MISALIG_DATA)
 143                         pr_cont("Misaligned r/w from 0x%08lx\n", address);
 144         } else if (vec == ECR_V_INSN_ERR) {
 145                 pr_cont("Illegal Insn\n");
 146         } else {
 147                 pr_cont("Check Programmer's Manual\n");
 148         }
 149 }
 150
 151 /************************************************************************
 152  *  API called by rest of kernel
 153  ***********************************************************************/
 154
 155 void show_regs(struct pt_regs *regs)
 156 {
 157         struct task_struct *tsk = current;
 158         struct callee_regs *cregs;
 159         char *buf;
 160
 161         buf = (char *)__get_free_page(GFP_TEMPORARY);
 162         if (!buf)
 163                 return;
 164
 165         print_task_path_n_nm(tsk, buf);
 166
 167         if (current->thread.cause_code)
 168                 show_ecr_verbose(regs);
 169
 170         pr_info("[EFA]: 0x%08lx\n", current->thread.fault_address);
 171         pr_info("[ERET]: 0x%08lx (PC of Faulting Instr)\n", regs->ret);
 172
 173         show_faulting_vma(regs->ret, buf);      /* faulting code, not data */
 174
 175         /* can't use print_vma_addr() yet as it doesn't check for
 176          * non-inclusive vma
 177          */
 178
 179         /* print special regs */
 180         pr_info("status32: 0x%08lx\n", regs->status32);
 181         pr_info(" SP: 0x%08lx\tFP: 0x%08lx\n", regs->sp, regs->fp);
 182         pr_info("BTA: 0x%08lx\tBLINK: 0x%08lx\n",
 183                 regs->bta, regs->blink);
 184         pr_info("LPS: 0x%08lx\tLPE: 0x%08lx\tLPC: 0x%08lx\n",
 185                regs->lp_start, regs->lp_end, regs->lp_count);
 186
 187         /* print regs->r0 thru regs->r12
 188          * Sequential printing was generating horrible code
 189          */
 190         print_reg_file(&(regs->r0), 0);
 191
 192         /* If Callee regs were saved, display them too */
 193         cregs = (struct callee_regs *)current->thread.callee_reg;
 194         if (cregs)
 195                 show_callee_regs(cregs);
 196
 197         free_page((unsigned long)buf);
 198 }
 199
 200 void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 201                             unsigned long address, unsigned long cause_reg)
 202 {
 203         current->thread.fault_address = address;
 204         current->thread.cause_code = cause_reg;
 205
 206         /* Caller and Callee regs */
 207         show_regs(regs);
 208
 209         /* Show stack trace if this Fatality happened in kernel mode */
 210         if (!user_mode(regs))
 211                 show_stacktrace(current, regs);
 212 }
 213
 214 #ifdef CONFIG_DEBUG_FS
 215
 216 #include <linux/module.h>
 217 #include <linux/fs.h>
 218 #include <linux/mount.h>
 219 #include <linux/pagemap.h>
 220 #include <linux/init.h>
 221 #include <linux/namei.h>
 222 #include <linux/debugfs.h>
 223
 224 static struct dentry *test_dentry;
 225 static struct dentry *test_dir;
 226 static struct dentry *test_u32_dentry;
 227
 228 static u32 clr_on_read = 1;
 229
 230 #ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
 231 u32 numitlb, numdtlb, num_pte_not_present;
 232
 233 static int fill_display_data(char *kbuf)
 234 {
 235         size_t num = 0;
 236         num += sprintf(kbuf + num, "I-TLB Miss %x\n", numitlb);
 237         num += sprintf(kbuf + num, "D-TLB Miss %x\n", numdtlb);
 238         num += sprintf(kbuf + num, "PTE not present %x\n", num_pte_not_present);
 239
 240         if (clr_on_read)
 241                 numitlb = numdtlb = num_pte_not_present = 0;
 242
 243         return num;
 244 }
 245
 246 static int tlb_stats_open(struct inode *inode, struct file *file)
 247 {
 248         file->private_data = (void *)__get_free_page(GFP_KERNEL);
 249         return 0;
 250 }
 251
 252 /* called on user read(): display the couters */
 253 static ssize_t tlb_stats_output(struct file *file,      /* file descriptor */
 254                                 char __user *user_buf,  /* user buffer */
 255                                 size_t len,             /* length of buffer */
 256                                 loff_t *offset)         /* offset in the file */
 257 {
 258         size_t num;
 259         char *kbuf = (char *)file->private_data;
 260
 261         /* All of the data can he shoved in one iteration */
 262         if (*offset != 0)
 263                 return 0;
 264
 265         num = fill_display_data(kbuf);
 266
 267         /* simple_read_from_buffer() is helper for copy to user space
 268            It copies up to @2 (num) bytes from kernel buffer @4 (kbuf) at offset
 269            @3 (offset) into the user space address starting at @1 (user_buf).
 270            @5 (len) is max size of user buffer
 271          */
 272         return simple_read_from_buffer(user_buf, num, offset, kbuf, len);
 273 }
 274
 275 /* called on user write : clears the counters */
 276 static ssize_t tlb_stats_clear(struct file *file, const char __user *user_buf,
 277                                size_t length, loff_t *offset)
 278 {
 279         numitlb = numdtlb = num_pte_not_present = 0;
 280         return length;
 281 }
 282
 283 static int tlb_stats_close(struct inode *inode, struct file *file)
 284 {
 285         free_page((unsigned long)(file->private_data));
 286         return 0;
 287 }
 288
 289 static const struct file_operations tlb_stats_file_ops = {
 290         .read = tlb_stats_output,
 291         .write = tlb_stats_clear,
 292         .open = tlb_stats_open,
 293         .release = tlb_stats_close
 294 };
 295 #endif
 296
 297 static int __init arc_debugfs_init(void)
 298 {
 299         test_dir = debugfs_create_dir("arc", NULL);
 300
 301 #ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
 302         test_dentry = debugfs_create_file("tlb_stats", 0444, test_dir, NULL,
 303                                           &tlb_stats_file_ops);
 304 #endif
 305
 306         test_u32_dentry =
 307             debugfs_create_u32("clr_on_read", 0444, test_dir, &clr_on_read);
 308
 309         return 0;
 310 }
 311
 312 module_init(arc_debugfs_init);
 313
 314 static void __exit arc_debugfs_exit(void)
 315 {
 316         debugfs_remove(test_u32_dentry);
 317         debugfs_remove(test_dentry);
 318         debugfs_remove(test_dir);
 319 }
 320 module_exit(arc_debugfs_exit);
 321
 322 #endif