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/proc_fs.h>
  14 #include <linux/file.h>
  15 #include <linux/sched/mm.h>
  16 #include <linux/sched/debug.h>
  17
  18 #include <asm/arcregs.h>
  19 #include <asm/irqflags.h>
  20
  21 #define ARC_PATH_MAX    256
  22
  23 /*
  24  * Common routine to print scratch regs (r0-r12) or callee regs (r13-r25)
  25  *   -Prints 3 regs per line and a CR.
  26  *   -To continue, callee regs right after scratch, special handling of CR
  27  */
  28 static noinline void print_reg_file(long *reg_rev, int start_num)
  29 {
  30         unsigned int i;
  31         char buf[512];
  32         int n = 0, len = sizeof(buf);
  33
  34         for (i = start_num; i < start_num + 13; i++) {
  35                 n += scnprintf(buf + n, len - n, "r%02u: 0x%08lx\t",
  36                                i, (unsigned long)*reg_rev);
  37
  38                 if (((i + 1) % 3) == 0)
  39                         n += scnprintf(buf + n, len - n, "\n");
  40
  41                 /* because pt_regs has regs reversed: r12..r0, r25..r13 */
  42                 if (is_isa_arcv2() && start_num == 0)
  43                         reg_rev++;
  44                 else
  45                         reg_rev--;
  46         }
  47
  48         if (start_num != 0)
  49                 n += scnprintf(buf + n, len - n, "\n\n");
  50
  51         /* To continue printing callee regs on same line as scratch regs */
  52         if (start_num == 0)
  53                 pr_info("%s", buf);
  54         else
  55                 pr_cont("%s\n", buf);
  56 }
  57
  58 static void show_callee_regs(struct callee_regs *cregs)
  59 {
  60         print_reg_file(&(cregs->r13), 13);
  61 }
  62
  63 static void print_task_path_n_nm(struct task_struct *tsk)
  64 {
  65         char *path_nm = NULL;
  66         struct mm_struct *mm;
  67         struct file *exe_file;
  68         char buf[ARC_PATH_MAX];
  69
  70         mm = get_task_mm(tsk);
  71         if (!mm)
  72                 goto done;
  73
  74         exe_file = get_mm_exe_file(mm);
  75         mmput(mm);
  76
  77         if (exe_file) {
  78                 path_nm = file_path(exe_file, buf, ARC_PATH_MAX-1);
  79                 fput(exe_file);
  80         }
  81
  82 done:
  83         pr_info("Path: %s\n", !IS_ERR(path_nm) ? path_nm : "?");
  84 }
  85
  86 static void show_faulting_vma(unsigned long address)
  87 {
  88         struct vm_area_struct *vma;
  89         struct mm_struct *active_mm = current->active_mm;
  90
  91         /* can't use print_vma_addr() yet as it doesn't check for
  92          * non-inclusive vma
  93          */
  94         down_read(&active_mm->mmap_sem);
  95         vma = find_vma(active_mm, address);
  96
  97         /* check against the find_vma( ) behaviour which returns the next VMA
  98          * if the container VMA is not found
  99          */
 100         if (vma && (vma->vm_start <= address)) {
 101                 char buf[ARC_PATH_MAX];
 102                 char *nm = "?";
 103
 104                 if (vma->vm_file) {
 105                         nm = file_path(vma->vm_file, buf, ARC_PATH_MAX-1);
 106                         if (IS_ERR(nm))
 107                                 nm = "?";
 108                 }
 109                 pr_info("    @off 0x%lx in [%s]\n"
 110                         "    VMA: 0x%08lx to 0x%08lx\n",
 111                         vma->vm_start < TASK_UNMAPPED_BASE ?
 112                                 address : address - vma->vm_start,
 113                         nm, vma->vm_start, vma->vm_end);
 114         } else
 115                 pr_info("    @No matching VMA found\n");
 116
 117         up_read(&active_mm->mmap_sem);
 118 }
 119
 120 static void show_ecr_verbose(struct pt_regs *regs)
 121 {
 122         unsigned int vec, cause_code;
 123         unsigned long address;
 124
 125         pr_info("\n[ECR   ]: 0x%08lx => ", regs->event);
 126
 127         /* For Data fault, this is data address not instruction addr */
 128         address = current->thread.fault_address;
 129
 130         vec = regs->ecr_vec;
 131         cause_code = regs->ecr_cause;
 132
 133         /* For DTLB Miss or ProtV, display the memory involved too */
 134         if (vec == ECR_V_DTLB_MISS) {
 135                 pr_cont("Invalid %s @ 0x%08lx by insn @ 0x%08lx\n",
 136                        (cause_code == 0x01) ? "Read" :
 137                        ((cause_code == 0x02) ? "Write" : "EX"),
 138                        address, regs->ret);
 139         } else if (vec == ECR_V_ITLB_MISS) {
 140                 pr_cont("Insn could not be fetched\n");
 141         } else if (vec == ECR_V_MACH_CHK) {
 142                 pr_cont("Machine Check (%s)\n", (cause_code == 0x0) ?
 143                                         "Double Fault" : "Other Fatal Err");
 144
 145         } else if (vec == ECR_V_PROTV) {
 146                 if (cause_code == ECR_C_PROTV_INST_FETCH)
 147                         pr_cont("Execute from Non-exec Page\n");
 148                 else if (cause_code == ECR_C_PROTV_MISALIG_DATA &&
 149                          IS_ENABLED(CONFIG_ISA_ARCOMPACT))
 150                         pr_cont("Misaligned r/w from 0x%08lx\n", address);
 151                 else
 152                         pr_cont("%s access not allowed on page\n",
 153                                 (cause_code == 0x01) ? "Read" :
 154                                 ((cause_code == 0x02) ? "Write" : "EX"));
 155         } else if (vec == ECR_V_INSN_ERR) {
 156                 pr_cont("Illegal Insn\n");
 157 #ifdef CONFIG_ISA_ARCV2
 158         } else if (vec == ECR_V_MEM_ERR) {
 159                 if (cause_code == 0x00)
 160                         pr_cont("Bus Error from Insn Mem\n");
 161                 else if (cause_code == 0x10)
 162                         pr_cont("Bus Error from Data Mem\n");
 163                 else
 164                         pr_cont("Bus Error, check PRM\n");
 165         } else if (vec == ECR_V_MISALIGN) {
 166                 pr_cont("Misaligned r/w from 0x%08lx\n", address);
 167 #endif
 168         } else if (vec == ECR_V_TRAP) {
 169                 if (regs->ecr_param == 5)
 170                         pr_cont("gcc generated __builtin_trap\n");
 171         } else {
 172                 pr_cont("Check Programmer's Manual\n");
 173         }
 174 }
 175
 176 /************************************************************************
 177  *  API called by rest of kernel
 178  ***********************************************************************/
 179
 180 void show_regs(struct pt_regs *regs)
 181 {
 182         struct task_struct *tsk = current;
 183         struct callee_regs *cregs;
 184
 185         /*
 186          * generic code calls us with preemption disabled, but some calls
 187          * here could sleep, so re-enable to avoid lockdep splat
 188          */
 189         preempt_enable();
 190
 191         print_task_path_n_nm(tsk);
 192         show_regs_print_info(KERN_INFO);
 193
 194         show_ecr_verbose(regs);
 195
 196         pr_info("[EFA   ]: 0x%08lx\n[BLINK ]: %pS\n[ERET  ]: %pS\n",
 197                 current->thread.fault_address,
 198                 (void *)regs->blink, (void *)regs->ret);
 199
 200         if (user_mode(regs))
 201                 show_faulting_vma(regs->ret); /* faulting code, not data */
 202
 203         pr_info("[STAT32]: 0x%08lx", regs->status32);
 204
 205 #define STS_BIT(r, bit) r->status32 & STATUS_##bit##_MASK ? #bit" " : ""
 206
 207 #ifdef CONFIG_ISA_ARCOMPACT
 208         pr_cont(" : %2s%2s%2s%2s%2s%2s%2s\n",
 209                         (regs->status32 & STATUS_U_MASK) ? "U " : "K ",
 210                         STS_BIT(regs, DE), STS_BIT(regs, AE),
 211                         STS_BIT(regs, A2), STS_BIT(regs, A1),
 212                         STS_BIT(regs, E2), STS_BIT(regs, E1));
 213 #else
 214         pr_cont(" : %2s%2s%2s%2s\n",
 215                         STS_BIT(regs, IE),
 216                         (regs->status32 & STATUS_U_MASK) ? "U " : "K ",
 217                         STS_BIT(regs, DE), STS_BIT(regs, AE));
 218 #endif
 219         pr_info("BTA: 0x%08lx\t SP: 0x%08lx\t FP: 0x%08lx\n",
 220                 regs->bta, regs->sp, regs->fp);
 221         pr_info("LPS: 0x%08lx\tLPE: 0x%08lx\tLPC: 0x%08lx\n",
 222                regs->lp_start, regs->lp_end, regs->lp_count);
 223
 224         /* print regs->r0 thru regs->r12
 225          * Sequential printing was generating horrible code
 226          */
 227         print_reg_file(&(regs->r0), 0);
 228
 229         /* If Callee regs were saved, display them too */
 230         cregs = (struct callee_regs *)current->thread.callee_reg;
 231         if (cregs)
 232                 show_callee_regs(cregs);
 233
 234         preempt_disable();
 235 }
 236
 237 void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 238                             unsigned long address)
 239 {
 240         current->thread.fault_address = address;
 241
 242         /* Show fault description */
 243         pr_info("\n%s\n", str);
 244
 245         /* Caller and Callee regs */
 246         show_regs(regs);
 247
 248         /* Show stack trace if this Fatality happened in kernel mode */
 249         if (!user_mode(regs))
 250                 show_stacktrace(current, regs);
 251 }