arch/nios2/kernel/traps.c

   1 /*
   2  * Hardware exception handling
   3  *
   4  * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
   5  * Copyright (C) 2004 Microtronix Datacom Ltd.
   6  * Copyright (C) 2001 Vic Phillips
   7  *
   8  * This file is subject to the terms and conditions of the GNU General
   9  * Public License.  See the file COPYING in the main directory of this
  10  * archive for more details.
  11  */
  12
  13 #include <linux/sched.h>
  14 #include <linux/sched/debug.h>
  15 #include <linux/kernel.h>
  16 #include <linux/signal.h>
  17 #include <linux/export.h>
  18 #include <linux/mm.h>
  19 #include <linux/ptrace.h>
  20
  21 #include <asm/traps.h>
  22 #include <asm/sections.h>
  23 #include <linux/uaccess.h>
  24
  25 static DEFINE_SPINLOCK(die_lock);
  26
  27 static void _send_sig(int signo, int code, unsigned long addr)
  28 {
  29         siginfo_t info;
  30
  31         info.si_signo = signo;
  32         info.si_errno = 0;
  33         info.si_code = code;
  34         info.si_addr = (void __user *) addr;
  35         force_sig_info(signo, &info, current);
  36 }
  37
  38 void die(const char *str, struct pt_regs *regs, long err)
  39 {
  40         console_verbose();
  41         spin_lock_irq(&die_lock);
  42         pr_warn("Oops: %s, sig: %ld\n", str, err);
  43         show_regs(regs);
  44         spin_unlock_irq(&die_lock);
  45         /*
  46          * do_exit() should take care of panic'ing from an interrupt
  47          * context so we don't handle it here
  48          */
  49         do_exit(err);
  50 }
  51
  52 void _exception(int signo, struct pt_regs *regs, int code, unsigned long addr)
  53 {
  54         if (!user_mode(regs))
  55                 die("Exception in kernel mode", regs, signo);
  56
  57         _send_sig(signo, code, addr);
  58 }
  59
  60 /*
  61  * The show_stack is an external API which we do not use ourselves.
  62  */
  63
  64 int kstack_depth_to_print = 48;
  65
  66 void show_stack(struct task_struct *task, unsigned long *stack)
  67 {
  68         unsigned long *endstack, addr;
  69         int i;
  70
  71         if (!stack) {
  72                 if (task)
  73                         stack = (unsigned long *)task->thread.ksp;
  74                 else
  75                         stack = (unsigned long *)&stack;
  76         }
  77
  78         addr = (unsigned long) stack;
  79         endstack = (unsigned long *) PAGE_ALIGN(addr);
  80
  81         pr_emerg("Stack from %08lx:", (unsigned long)stack);
  82         for (i = 0; i < kstack_depth_to_print; i++) {
  83                 if (stack + 1 > endstack)
  84                         break;
  85                 if (i % 8 == 0)
  86                         pr_emerg("\n       ");
  87                 pr_emerg(" %08lx", *stack++);
  88         }
  89
  90         pr_emerg("\nCall Trace:");
  91         i = 0;
  92         while (stack + 1 <= endstack) {
  93                 addr = *stack++;
  94                 /*
  95                  * If the address is either in the text segment of the
  96                  * kernel, or in the region which contains vmalloc'ed
  97                  * memory, it *may* be the address of a calling
  98                  * routine; if so, print it so that someone tracing
  99                  * down the cause of the crash will be able to figure
 100                  * out the call path that was taken.
 101                  */
 102                 if (((addr >= (unsigned long) _stext) &&
 103                      (addr <= (unsigned long) _etext))) {
 104                         if (i % 4 == 0)
 105                                 pr_emerg("\n       ");
 106                         pr_emerg(" [<%08lx>]", addr);
 107                         i++;
 108                 }
 109         }
 110         pr_emerg("\n");
 111 }
 112
 113 void __init trap_init(void)
 114 {
 115         /* Nothing to do here */
 116 }
 117
 118 /* Breakpoint handler */
 119 asmlinkage void breakpoint_c(struct pt_regs *fp)
 120 {
 121         /*
 122          * The breakpoint entry code has moved the PC on by 4 bytes, so we must
 123          * move it back. This could be done on the host but we do it here
 124          * because monitor.S of JTAG gdbserver does it too.
 125          */
 126         fp->ea -= 4;
 127         _exception(SIGTRAP, fp, TRAP_BRKPT, fp->ea);
 128 }
 129
 130 #ifndef CONFIG_NIOS2_ALIGNMENT_TRAP
 131 /* Alignment exception handler */
 132 asmlinkage void handle_unaligned_c(struct pt_regs *fp, int cause)
 133 {
 134         unsigned long addr = RDCTL(CTL_BADADDR);
 135
 136         cause >>= 2;
 137         fp->ea -= 4;
 138
 139         if (fixup_exception(fp))
 140                 return;
 141
 142         if (!user_mode(fp)) {
 143                 pr_alert("Unaligned access from kernel mode, this might be a hardware\n");
 144                 pr_alert("problem, dump registers and restart the instruction\n");
 145                 pr_alert("  BADADDR 0x%08lx\n", addr);
 146                 pr_alert("  cause   %d\n", cause);
 147                 pr_alert("  op-code 0x%08lx\n", *(unsigned long *)(fp->ea));
 148                 show_regs(fp);
 149                 return;
 150         }
 151
 152         _exception(SIGBUS, fp, BUS_ADRALN, addr);
 153 }
 154 #endif /* CONFIG_NIOS2_ALIGNMENT_TRAP */
 155
 156 /* Illegal instruction handler */
 157 asmlinkage void handle_illegal_c(struct pt_regs *fp)
 158 {
 159         fp->ea -= 4;
 160         _exception(SIGILL, fp, ILL_ILLOPC, fp->ea);
 161 }
 162
 163 /* Supervisor instruction handler */
 164 asmlinkage void handle_supervisor_instr(struct pt_regs *fp)
 165 {
 166         fp->ea -= 4;
 167         _exception(SIGILL, fp, ILL_PRVOPC, fp->ea);
 168 }
 169
 170 /* Division error handler */
 171 asmlinkage void handle_diverror_c(struct pt_regs *fp)
 172 {
 173         fp->ea -= 4;
 174         _exception(SIGFPE, fp, FPE_INTDIV, fp->ea);
 175 }
 176
 177 /* Unhandled exception handler */
 178 asmlinkage void unhandled_exception(struct pt_regs *regs, int cause)
 179 {
 180         unsigned long addr = RDCTL(CTL_BADADDR);
 181
 182         cause /= 4;
 183
 184         pr_emerg("Unhandled exception #%d in %s mode (badaddr=0x%08lx)\n",
 185                         cause, user_mode(regs) ? "user" : "kernel", addr);
 186
 187         regs->ea -= 4;
 188         show_regs(regs);
 189
 190         pr_emerg("opcode: 0x%08lx\n", *(unsigned long *)(regs->ea));
 191 }
 192
 193 asmlinkage void handle_trap_1_c(struct pt_regs *fp)
 194 {
 195         _send_sig(SIGUSR1, 0, fp->ea);
 196 }
 197
 198 asmlinkage void handle_trap_2_c(struct pt_regs *fp)
 199 {
 200         _send_sig(SIGUSR2, 0, fp->ea);
 201 }
 202
 203 asmlinkage void handle_trap_3_c(struct pt_regs *fp)
 204 {
 205         _send_sig(SIGILL, ILL_ILLTRP, fp->ea);
 206 }