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         for (i = start_num; i < start_num + 13; i++) {
  30                 n += scnprintf(buf + n, len - n, "r%02u: 0x%08lx\t",
  31                                i, (unsigned long)*reg_rev);
  32
  33                 if (((i + 1) % 3) == 0)
  34                         n += scnprintf(buf + n, len - n, "\n");
  35
  36                 /* because pt_regs has regs reversed: r12..r0, r25..r13 */
  37                 reg_rev--;
  38         }
  39
  40         if (start_num != 0)
  41                 n += scnprintf(buf + n, len - n, "\n\n");
  42
  43         /* To continue printing callee regs on same line as scratch regs */
  44         if (start_num == 0)
  45                 pr_info("%s", buf);
  46         else
  47                 pr_cont("%s\n", buf);
  48 }
  49
  50 static void show_callee_regs(struct callee_regs *cregs)
  51 {
  52         print_reg_file(&(cregs->r13), 13);
  53 }
  54
  55 void print_task_path_n_nm(struct task_struct *tsk, char *buf)
  56 {
  57         struct path path;
  58         char *path_nm = NULL;
  59         struct mm_struct *mm;
  60         struct file *exe_file;
  61
  62         mm = get_task_mm(tsk);
  63         if (!mm)
  64                 goto done;
  65
  66         exe_file = get_mm_exe_file(mm);
  67         mmput(mm);
  68
  69         if (exe_file) {
  70                 path = exe_file->f_path;
  71                 path_get(&exe_file->f_path);
  72                 fput(exe_file);
  73                 path_nm = d_path(&path, buf, 255);
  74                 path_put(&path);
  75         }
  76
  77 done:
  78         pr_info("Path: %s\n", path_nm);
  79 }
  80 EXPORT_SYMBOL(print_task_path_n_nm);
  81
  82 static void show_faulting_vma(unsigned long address, char *buf)
  83 {
  84         struct vm_area_struct *vma;
  85         struct inode *inode;
  86         unsigned long ino = 0;
  87         dev_t dev = 0;
  88         char *nm = buf;
  89
  90         /* can't use print_vma_addr() yet as it doesn't check for
  91          * non-inclusive vma
  92          */
  93
  94         vma = find_vma(current->active_mm, address);
  95
  96         /* check against the find_vma( ) behaviour which returns the next VMA
  97          * if the container VMA is not found
  98          */
  99         if (vma && (vma->vm_start <= address)) {
 100                 struct file *file = vma->vm_file;
 101                 if (file) {
 102                         struct path *path = &file->f_path;
 103                         nm = d_path(path, buf, PAGE_SIZE - 1);
 104                         inode = file_inode(vma->vm_file);
 105                         dev = inode->i_sb->s_dev;
 106                         ino = inode->i_ino;
 107                 }
 108                 pr_info("    @off 0x%lx in [%s]\n"
 109                         "    VMA: 0x%08lx to 0x%08lx\n",
 110                         vma->vm_start < TASK_UNMAPPED_BASE ?
 111                                 address : address - vma->vm_start,
 112                         nm, vma->vm_start, vma->vm_end);
 113         } else {
 114                 pr_info("    @No matching VMA found\n");
 115         }
 116 }
 117
 118 static void show_ecr_verbose(struct pt_regs *regs)
 119 {
 120         unsigned int vec, cause_code;
 121         unsigned long address;
 122
 123         pr_info("\n[ECR   ]: 0x%08lx => ", regs->event);
 124
 125         /* For Data fault, this is data address not instruction addr */
 126         address = current->thread.fault_address;
 127
 128         vec = regs->ecr_vec;
 129         cause_code = regs->ecr_cause;
 130
 131         /* For DTLB Miss or ProtV, display the memory involved too */
 132         if (vec == ECR_V_DTLB_MISS) {
 133                 pr_cont("Invalid %s @ 0x%08lx by insn @ 0x%08lx\n",
 134                        (cause_code == 0x01) ? "Read" :
 135                        ((cause_code == 0x02) ? "Write" : "EX"),
 136                        address, regs->ret);
 137         } else if (vec == ECR_V_ITLB_MISS) {
 138                 pr_cont("Insn could not be fetched\n");
 139         } else if (vec == ECR_V_MACH_CHK) {
 140                 pr_cont("%s\n", (cause_code == 0x0) ?
 141                                         "Double Fault" : "Other Fatal Err");
 142
 143         } else if (vec == ECR_V_PROTV) {
 144                 if (cause_code == ECR_C_PROTV_INST_FETCH)
 145                         pr_cont("Execute from Non-exec Page\n");
 146                 else if (cause_code == ECR_C_PROTV_MISALIG_DATA)
 147                         pr_cont("Misaligned r/w from 0x%08lx\n", address);
 148                 else
 149                         pr_cont("%s access not allowed on page\n",
 150                                 (cause_code == 0x01) ? "Read" :
 151                                 ((cause_code == 0x02) ? "Write" : "EX"));
 152         } else if (vec == ECR_V_INSN_ERR) {
 153                 pr_cont("Illegal Insn\n");
 154         } else {
 155                 pr_cont("Check Programmer's Manual\n");
 156         }
 157 }
 158
 159 /************************************************************************
 160  *  API called by rest of kernel
 161  ***********************************************************************/
 162
 163 void show_regs(struct pt_regs *regs)
 164 {
 165         struct task_struct *tsk = current;
 166         struct callee_regs *cregs;
 167         char *buf;
 168
 169         buf = (char *)__get_free_page(GFP_TEMPORARY);
 170         if (!buf)
 171                 return;
 172
 173         print_task_path_n_nm(tsk, buf);
 174         show_regs_print_info(KERN_INFO);
 175
 176         show_ecr_verbose(regs);
 177
 178         pr_info("[EFA   ]: 0x%08lx\n[BLINK ]: %pS\n[ERET  ]: %pS\n",
 179                 current->thread.fault_address,
 180                 (void *)regs->blink, (void *)regs->ret);
 181
 182         if (user_mode(regs))
 183                 show_faulting_vma(regs->ret, buf); /* faulting code, not data */
 184
 185         pr_info("[STAT32]: 0x%08lx", regs->status32);
 186
 187 #define STS_BIT(r, bit) r->status32 & STATUS_##bit##_MASK ? #bit : ""
 188         if (!user_mode(regs))
 189                 pr_cont(" : %2s %2s %2s %2s %2s\n",
 190                         STS_BIT(regs, AE), STS_BIT(regs, A2), STS_BIT(regs, A1),
 191                         STS_BIT(regs, E2), STS_BIT(regs, E1));
 192
 193         pr_info("BTA: 0x%08lx\t SP: 0x%08lx\t FP: 0x%08lx\n",
 194                 regs->bta, regs->sp, regs->fp);
 195         pr_info("LPS: 0x%08lx\tLPE: 0x%08lx\tLPC: 0x%08lx\n",
 196                regs->lp_start, regs->lp_end, regs->lp_count);
 197
 198         /* print regs->r0 thru regs->r12
 199          * Sequential printing was generating horrible code
 200          */
 201         print_reg_file(&(regs->r0), 0);
 202
 203         /* If Callee regs were saved, display them too */
 204         cregs = (struct callee_regs *)current->thread.callee_reg;
 205         if (cregs)
 206                 show_callee_regs(cregs);
 207
 208         free_page((unsigned long)buf);
 209 }
 210
 211 void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 212                             unsigned long address)
 213 {
 214         current->thread.fault_address = address;
 215
 216         /* Caller and Callee regs */
 217         show_regs(regs);
 218
 219         /* Show stack trace if this Fatality happened in kernel mode */
 220         if (!user_mode(regs))
 221                 show_stacktrace(current, regs);
 222 }
 223
 224 #ifdef CONFIG_DEBUG_FS
 225
 226 #include <linux/module.h>
 227 #include <linux/fs.h>
 228 #include <linux/mount.h>
 229 #include <linux/pagemap.h>
 230 #include <linux/init.h>
 231 #include <linux/namei.h>
 232 #include <linux/debugfs.h>
 233
 234 static struct dentry *test_dentry;
 235 static struct dentry *test_dir;
 236 static struct dentry *test_u32_dentry;
 237
 238 static u32 clr_on_read = 1;
 239
 240 #ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
 241 u32 numitlb, numdtlb, num_pte_not_present;
 242
 243 static int fill_display_data(char *kbuf)
 244 {
 245         size_t num = 0;
 246         num += sprintf(kbuf + num, "I-TLB Miss %x\n", numitlb);
 247         num += sprintf(kbuf + num, "D-TLB Miss %x\n", numdtlb);
 248         num += sprintf(kbuf + num, "PTE not present %x\n", num_pte_not_present);
 249
 250         if (clr_on_read)
 251                 numitlb = numdtlb = num_pte_not_present = 0;
 252
 253         return num;
 254 }
 255
 256 static int tlb_stats_open(struct inode *inode, struct file *file)
 257 {
 258         file->private_data = (void *)__get_free_page(GFP_KERNEL);
 259         return 0;
 260 }
 261
 262 /* called on user read(): display the couters */
 263 static ssize_t tlb_stats_output(struct file *file,      /* file descriptor */
 264                                 char __user *user_buf,  /* user buffer */
 265                                 size_t len,             /* length of buffer */
 266                                 loff_t *offset)         /* offset in the file */
 267 {
 268         size_t num;
 269         char *kbuf = (char *)file->private_data;
 270
 271         /* All of the data can he shoved in one iteration */
 272         if (*offset != 0)
 273                 return 0;
 274
 275         num = fill_display_data(kbuf);
 276
 277         /* simple_read_from_buffer() is helper for copy to user space
 278            It copies up to @2 (num) bytes from kernel buffer @4 (kbuf) at offset
 279            @3 (offset) into the user space address starting at @1 (user_buf).
 280            @5 (len) is max size of user buffer
 281          */
 282         return simple_read_from_buffer(user_buf, num, offset, kbuf, len);
 283 }
 284
 285 /* called on user write : clears the counters */
 286 static ssize_t tlb_stats_clear(struct file *file, const char __user *user_buf,
 287                                size_t length, loff_t *offset)
 288 {
 289         numitlb = numdtlb = num_pte_not_present = 0;
 290         return length;
 291 }
 292
 293 static int tlb_stats_close(struct inode *inode, struct file *file)
 294 {
 295         free_page((unsigned long)(file->private_data));
 296         return 0;
 297 }
 298
 299 static const struct file_operations tlb_stats_file_ops = {
 300         .read = tlb_stats_output,
 301         .write = tlb_stats_clear,
 302         .open = tlb_stats_open,
 303         .release = tlb_stats_close
 304 };
 305 #endif
 306
 307 static int __init arc_debugfs_init(void)
 308 {
 309         test_dir = debugfs_create_dir("arc", NULL);
 310
 311 #ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
 312         test_dentry = debugfs_create_file("tlb_stats", 0444, test_dir, NULL,
 313                                           &tlb_stats_file_ops);
 314 #endif
 315
 316         test_u32_dentry =
 317             debugfs_create_u32("clr_on_read", 0444, test_dir, &clr_on_read);
 318
 319         return 0;
 320 }
 321
 322 module_init(arc_debugfs_init);
 323
 324 static void __exit arc_debugfs_exit(void)
 325 {
 326         debugfs_remove(test_u32_dentry);
 327         debugfs_remove(test_dentry);
 328         debugfs_remove(test_dir);
 329 }
 330 module_exit(arc_debugfs_exit);
 331
 332 #endif