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 #include <asm/irqflags.h>
  18
  19 /*
  20  * Common routine to print scratch regs (r0-r12) or callee regs (r13-r25)
  21  *   -Prints 3 regs per line and a CR.
  22  *   -To continue, callee regs right after scratch, special handling of CR
  23  */
  24 static noinline void print_reg_file(long *reg_rev, int start_num)
  25 {
  26         unsigned int i;
  27         char buf[512];
  28         int n = 0, len = sizeof(buf);
  29
  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                 /* because pt_regs has regs reversed: r12..r0, r25..r13 */
  38                 if (is_isa_arcv2() && start_num == 0)
  39                         reg_rev++;
  40                 else
  41                         reg_rev--;
  42         }
  43
  44         if (start_num != 0)
  45                 n += scnprintf(buf + n, len - n, "\n\n");
  46
  47         /* To continue printing callee regs on same line as scratch regs */
  48         if (start_num == 0)
  49                 pr_info("%s", buf);
  50         else
  51                 pr_cont("%s\n", buf);
  52 }
  53
  54 static void show_callee_regs(struct callee_regs *cregs)
  55 {
  56         print_reg_file(&(cregs->r13), 13);
  57 }
  58
  59 static void print_task_path_n_nm(struct task_struct *tsk, char *buf)
  60 {
  61         char *path_nm = NULL;
  62         struct mm_struct *mm;
  63         struct file *exe_file;
  64
  65         mm = get_task_mm(tsk);
  66         if (!mm)
  67                 goto done;
  68
  69         exe_file = get_mm_exe_file(mm);
  70         mmput(mm);
  71
  72         if (exe_file) {
  73                 path_nm = file_path(exe_file, buf, 255);
  74                 fput(exe_file);
  75         }
  76
  77 done:
  78         pr_info("Path: %s\n", !IS_ERR(path_nm) ? path_nm : "?");
  79 }
  80
  81 static void show_faulting_vma(unsigned long address, char *buf)
  82 {
  83         struct vm_area_struct *vma;
  84         struct inode *inode;
  85         unsigned long ino = 0;
  86         dev_t dev = 0;
  87         char *nm = buf;
  88         struct mm_struct *active_mm = current->active_mm;
  89
  90         /* can't use print_vma_addr() yet as it doesn't check for
  91          * non-inclusive vma
  92          */
  93         down_read(&active_mm->mmap_sem);
  94         vma = find_vma(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                         nm = file_path(file, buf, PAGE_SIZE - 1);
 103                         inode = file_inode(vma->vm_file);
 104                         dev = inode->i_sb->s_dev;
 105                         ino = inode->i_ino;
 106                 }
 107                 pr_info("    @off 0x%lx in [%s]\n"
 108                         "    VMA: 0x%08lx to 0x%08lx\n",
 109                         vma->vm_start < TASK_UNMAPPED_BASE ?
 110                                 address : address - vma->vm_start,
 111                         nm, vma->vm_start, vma->vm_end);
 112         } else
 113                 pr_info("    @No matching VMA found\n");
 114
 115         up_read(&active_mm->mmap_sem);
 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 #ifdef CONFIG_ISA_ARCV2
 155         } else if (vec == ECR_V_MEM_ERR) {
 156                 if (cause_code == 0x00)
 157                         pr_cont("Bus Error from Insn Mem\n");
 158                 else if (cause_code == 0x10)
 159                         pr_cont("Bus Error from Data Mem\n");
 160                 else
 161                         pr_cont("Bus Error, check PRM\n");
 162 #endif
 163         } else {
 164                 pr_cont("Check Programmer's Manual\n");
 165         }
 166 }
 167
 168 /************************************************************************
 169  *  API called by rest of kernel
 170  ***********************************************************************/
 171
 172 void show_regs(struct pt_regs *regs)
 173 {
 174         struct task_struct *tsk = current;
 175         struct callee_regs *cregs;
 176         char *buf;
 177
 178         buf = (char *)__get_free_page(GFP_TEMPORARY);
 179         if (!buf)
 180                 return;
 181
 182         print_task_path_n_nm(tsk, buf);
 183         show_regs_print_info(KERN_INFO);
 184
 185         show_ecr_verbose(regs);
 186
 187         pr_info("[EFA   ]: 0x%08lx\n[BLINK ]: %pS\n[ERET  ]: %pS\n",
 188                 current->thread.fault_address,
 189                 (void *)regs->blink, (void *)regs->ret);
 190
 191         if (user_mode(regs))
 192                 show_faulting_vma(regs->ret, buf); /* faulting code, not data */
 193
 194         pr_info("[STAT32]: 0x%08lx", regs->status32);
 195
 196 #define STS_BIT(r, bit) r->status32 & STATUS_##bit##_MASK ? #bit" " : ""
 197
 198 #ifdef CONFIG_ISA_ARCOMPACT
 199         pr_cont(" : %2s%2s%2s%2s%2s%2s%2s\n",
 200                         (regs->status32 & STATUS_U_MASK) ? "U " : "K ",
 201                         STS_BIT(regs, DE), STS_BIT(regs, AE),
 202                         STS_BIT(regs, A2), STS_BIT(regs, A1),
 203                         STS_BIT(regs, E2), STS_BIT(regs, E1));
 204 #else
 205         pr_cont(" : %2s%2s%2s%2s\n",
 206                         STS_BIT(regs, IE),
 207                         (regs->status32 & STATUS_U_MASK) ? "U " : "K ",
 208                         STS_BIT(regs, DE), STS_BIT(regs, AE));
 209 #endif
 210         pr_info("BTA: 0x%08lx\t SP: 0x%08lx\t FP: 0x%08lx\n",
 211                 regs->bta, regs->sp, regs->fp);
 212         pr_info("LPS: 0x%08lx\tLPE: 0x%08lx\tLPC: 0x%08lx\n",
 213                regs->lp_start, regs->lp_end, regs->lp_count);
 214
 215         /* print regs->r0 thru regs->r12
 216          * Sequential printing was generating horrible code
 217          */
 218         print_reg_file(&(regs->r0), 0);
 219
 220         /* If Callee regs were saved, display them too */
 221         cregs = (struct callee_regs *)current->thread.callee_reg;
 222         if (cregs)
 223                 show_callee_regs(cregs);
 224
 225         free_page((unsigned long)buf);
 226 }
 227
 228 void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 229                             unsigned long address)
 230 {
 231         current->thread.fault_address = address;
 232
 233         /* Caller and Callee regs */
 234         show_regs(regs);
 235
 236         /* Show stack trace if this Fatality happened in kernel mode */
 237         if (!user_mode(regs))
 238                 show_stacktrace(current, regs);
 239 }
 240
 241 #ifdef CONFIG_DEBUG_FS
 242
 243 #include <linux/module.h>
 244 #include <linux/fs.h>
 245 #include <linux/mount.h>
 246 #include <linux/pagemap.h>
 247 #include <linux/init.h>
 248 #include <linux/namei.h>
 249 #include <linux/debugfs.h>
 250
 251 static struct dentry *test_dentry;
 252 static struct dentry *test_dir;
 253 static struct dentry *test_u32_dentry;
 254
 255 static u32 clr_on_read = 1;
 256
 257 #ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
 258 u32 numitlb, numdtlb, num_pte_not_present;
 259
 260 static int fill_display_data(char *kbuf)
 261 {
 262         size_t num = 0;
 263         num += sprintf(kbuf + num, "I-TLB Miss %x\n", numitlb);
 264         num += sprintf(kbuf + num, "D-TLB Miss %x\n", numdtlb);
 265         num += sprintf(kbuf + num, "PTE not present %x\n", num_pte_not_present);
 266
 267         if (clr_on_read)
 268                 numitlb = numdtlb = num_pte_not_present = 0;
 269
 270         return num;
 271 }
 272
 273 static int tlb_stats_open(struct inode *inode, struct file *file)
 274 {
 275         file->private_data = (void *)__get_free_page(GFP_KERNEL);
 276         return 0;
 277 }
 278
 279 /* called on user read(): display the couters */
 280 static ssize_t tlb_stats_output(struct file *file,      /* file descriptor */
 281                                 char __user *user_buf,  /* user buffer */
 282                                 size_t len,             /* length of buffer */
 283                                 loff_t *offset)         /* offset in the file */
 284 {
 285         size_t num;
 286         char *kbuf = (char *)file->private_data;
 287
 288         /* All of the data can he shoved in one iteration */
 289         if (*offset != 0)
 290                 return 0;
 291
 292         num = fill_display_data(kbuf);
 293
 294         /* simple_read_from_buffer() is helper for copy to user space
 295            It copies up to @2 (num) bytes from kernel buffer @4 (kbuf) at offset
 296            @3 (offset) into the user space address starting at @1 (user_buf).
 297            @5 (len) is max size of user buffer
 298          */
 299         return simple_read_from_buffer(user_buf, num, offset, kbuf, len);
 300 }
 301
 302 /* called on user write : clears the counters */
 303 static ssize_t tlb_stats_clear(struct file *file, const char __user *user_buf,
 304                                size_t length, loff_t *offset)
 305 {
 306         numitlb = numdtlb = num_pte_not_present = 0;
 307         return length;
 308 }
 309
 310 static int tlb_stats_close(struct inode *inode, struct file *file)
 311 {
 312         free_page((unsigned long)(file->private_data));
 313         return 0;
 314 }
 315
 316 static const struct file_operations tlb_stats_file_ops = {
 317         .read = tlb_stats_output,
 318         .write = tlb_stats_clear,
 319         .open = tlb_stats_open,
 320         .release = tlb_stats_close
 321 };
 322 #endif
 323
 324 static int __init arc_debugfs_init(void)
 325 {
 326         test_dir = debugfs_create_dir("arc", NULL);
 327
 328 #ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
 329         test_dentry = debugfs_create_file("tlb_stats", 0444, test_dir, NULL,
 330                                           &tlb_stats_file_ops);
 331 #endif
 332
 333         test_u32_dentry =
 334             debugfs_create_u32("clr_on_read", 0444, test_dir, &clr_on_read);
 335
 336         return 0;
 337 }
 338
 339 module_init(arc_debugfs_init);
 340
 341 static void __exit arc_debugfs_exit(void)
 342 {
 343         debugfs_remove(test_u32_dentry);
 344         debugfs_remove(test_dentry);
 345         debugfs_remove(test_dir);
 346 }
 347 module_exit(arc_debugfs_exit);
 348
 349 #endif