root/arch/arc/kernel/troubleshoot.c

DEFINITIONS

1. print_reg_file
2. show_callee_regs
3. print_task_path_n_nm
4. show_faulting_vma
5. show_ecr_verbose
6. show_regs
7. show_kernel_fault_diag

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   4  */
   5 
   6 #include <linux/ptrace.h>
   7 #include <linux/module.h>
   8 #include <linux/mm.h>
   9 #include <linux/fs.h>
  10 #include <linux/kdev_t.h>
  11 #include <linux/proc_fs.h>
  12 #include <linux/file.h>
  13 #include <linux/sched/mm.h>
  14 #include <linux/sched/debug.h>
  15 
  16 #include <asm/arcregs.h>
  17 #include <asm/irqflags.h>
  18 
  19 #define ARC_PATH_MAX    256
  20 
  21 /*
  22  * Common routine to print scratch regs (r0-r12) or callee regs (r13-r25)
  23  *   -Prints 3 regs per line and a CR.
  24  *   -To continue, callee regs right after scratch, special handling of CR
  25  */
  26 static noinline void print_reg_file(long *reg_rev, int start_num)
  27 {
  28         unsigned int i;
  29         char buf[512];
  30         int n = 0, len = sizeof(buf);
  31 
  32         for (i = start_num; i < start_num + 13; i++) {
  33                 n += scnprintf(buf + n, len - n, "r%02u: 0x%08lx\t",
  34                                i, (unsigned long)*reg_rev);
  35 
  36                 if (((i + 1) % 3) == 0)
  37                         n += scnprintf(buf + n, len - n, "\n");
  38 
  39                 /* because pt_regs has regs reversed: r12..r0, r25..r13 */
  40                 if (is_isa_arcv2() && start_num == 0)
  41                         reg_rev++;
  42                 else
  43                         reg_rev--;
  44         }
  45 
  46         if (start_num != 0)
  47                 n += scnprintf(buf + n, len - n, "\n\n");
  48 
  49         /* To continue printing callee regs on same line as scratch regs */
  50         if (start_num == 0)
  51                 pr_info("%s", buf);
  52         else
  53                 pr_cont("%s\n", buf);
  54 }
  55 
  56 static void show_callee_regs(struct callee_regs *cregs)
  57 {
  58         print_reg_file(&(cregs->r13), 13);
  59 }
  60 
  61 static void print_task_path_n_nm(struct task_struct *tsk)
  62 {
  63         char *path_nm = NULL;
  64         struct mm_struct *mm;
  65         struct file *exe_file;
  66         char buf[ARC_PATH_MAX];
  67 
  68         mm = get_task_mm(tsk);
  69         if (!mm)
  70                 goto done;
  71 
  72         exe_file = get_mm_exe_file(mm);
  73         mmput(mm);
  74 
  75         if (exe_file) {
  76                 path_nm = file_path(exe_file, buf, ARC_PATH_MAX-1);
  77                 fput(exe_file);
  78         }
  79 
  80 done:
  81         pr_info("Path: %s\n", !IS_ERR(path_nm) ? path_nm : "?");
  82 }
  83 
  84 static void show_faulting_vma(unsigned long address)
  85 {
  86         struct vm_area_struct *vma;
  87         struct mm_struct *active_mm = current->active_mm;
  88 
  89         /* can't use print_vma_addr() yet as it doesn't check for
  90          * non-inclusive vma
  91          */
  92         down_read(&active_mm->mmap_sem);
  93         vma = find_vma(active_mm, address);
  94 
  95         /* check against the find_vma( ) behaviour which returns the next VMA
  96          * if the container VMA is not found
  97          */
  98         if (vma && (vma->vm_start <= address)) {
  99                 char buf[ARC_PATH_MAX];
 100                 char *nm = "?";
 101 
 102                 if (vma->vm_file) {
 103                         nm = file_path(vma->vm_file, buf, ARC_PATH_MAX-1);
 104                         if (IS_ERR(nm))
 105                                 nm = "?";
 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("Machine Check (%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                          IS_ENABLED(CONFIG_ISA_ARCOMPACT))
 148                         pr_cont("Misaligned r/w from 0x%08lx\n", address);
 149                 else
 150                         pr_cont("%s access not allowed on page\n",
 151                                 (cause_code == 0x01) ? "Read" :
 152                                 ((cause_code == 0x02) ? "Write" : "EX"));
 153         } else if (vec == ECR_V_INSN_ERR) {
 154                 pr_cont("Illegal Insn\n");
 155 #ifdef CONFIG_ISA_ARCV2
 156         } else if (vec == ECR_V_MEM_ERR) {
 157                 if (cause_code == 0x00)
 158                         pr_cont("Bus Error from Insn Mem\n");
 159                 else if (cause_code == 0x10)
 160                         pr_cont("Bus Error from Data Mem\n");
 161                 else
 162                         pr_cont("Bus Error, check PRM\n");
 163         } else if (vec == ECR_V_MISALIGN) {
 164                 pr_cont("Misaligned r/w from 0x%08lx\n", address);
 165 #endif
 166         } else if (vec == ECR_V_TRAP) {
 167                 if (regs->ecr_param == 5)
 168                         pr_cont("gcc generated __builtin_trap\n");
 169         } else {
 170                 pr_cont("Check Programmer's Manual\n");
 171         }
 172 }
 173 
 174 /************************************************************************
 175  *  API called by rest of kernel
 176  ***********************************************************************/
 177 
 178 void show_regs(struct pt_regs *regs)
 179 {
 180         struct task_struct *tsk = current;
 181         struct callee_regs *cregs;
 182 
 183         /*
 184          * generic code calls us with preemption disabled, but some calls
 185          * here could sleep, so re-enable to avoid lockdep splat
 186          */
 187         preempt_enable();
 188 
 189         print_task_path_n_nm(tsk);
 190         show_regs_print_info(KERN_INFO);
 191 
 192         show_ecr_verbose(regs);
 193 
 194         pr_info("[EFA   ]: 0x%08lx\n[BLINK ]: %pS\n[ERET  ]: %pS\n",
 195                 current->thread.fault_address,
 196                 (void *)regs->blink, (void *)regs->ret);
 197 
 198         if (user_mode(regs))
 199                 show_faulting_vma(regs->ret); /* faulting code, not data */
 200 
 201         pr_info("[STAT32]: 0x%08lx", regs->status32);
 202 
 203 #define STS_BIT(r, bit) r->status32 & STATUS_##bit##_MASK ? #bit" " : ""
 204 
 205 #ifdef CONFIG_ISA_ARCOMPACT
 206         pr_cont(" : %2s%2s%2s%2s%2s%2s%2s\n",
 207                         (regs->status32 & STATUS_U_MASK) ? "U " : "K ",
 208                         STS_BIT(regs, DE), STS_BIT(regs, AE),
 209                         STS_BIT(regs, A2), STS_BIT(regs, A1),
 210                         STS_BIT(regs, E2), STS_BIT(regs, E1));
 211 #else
 212         pr_cont(" : %2s%2s%2s%2s\n",
 213                         STS_BIT(regs, IE),
 214                         (regs->status32 & STATUS_U_MASK) ? "U " : "K ",
 215                         STS_BIT(regs, DE), STS_BIT(regs, AE));
 216 #endif
 217         pr_info("BTA: 0x%08lx\t SP: 0x%08lx\t FP: 0x%08lx\n",
 218                 regs->bta, regs->sp, regs->fp);
 219         pr_info("LPS: 0x%08lx\tLPE: 0x%08lx\tLPC: 0x%08lx\n",
 220                regs->lp_start, regs->lp_end, regs->lp_count);
 221 
 222         /* print regs->r0 thru regs->r12
 223          * Sequential printing was generating horrible code
 224          */
 225         print_reg_file(&(regs->r0), 0);
 226 
 227         /* If Callee regs were saved, display them too */
 228         cregs = (struct callee_regs *)current->thread.callee_reg;
 229         if (cregs)
 230                 show_callee_regs(cregs);
 231 
 232         preempt_disable();
 233 }
 234 
 235 void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 236                             unsigned long address)
 237 {
 238         current->thread.fault_address = address;
 239 
 240         /* Show fault description */
 241         pr_info("\n%s\n", str);
 242 
 243         /* Caller and Callee regs */
 244         show_regs(regs);
 245 
 246         /* Show stack trace if this Fatality happened in kernel mode */
 247         if (!user_mode(regs))
 248                 show_stacktrace(current, regs);
 249 }