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