arch/s390/kernel/dumpstack.c

   1 /*
   2  * Stack dumping functions
   3  *
   4  *  Copyright IBM Corp. 1999, 2013
   5  */
   6
   7 #include <linux/kallsyms.h>
   8 #include <linux/hardirq.h>
   9 #include <linux/kprobes.h>
  10 #include <linux/utsname.h>
  11 #include <linux/export.h>
  12 #include <linux/kdebug.h>
  13 #include <linux/ptrace.h>
  14 #include <linux/module.h>
  15 #include <linux/sched.h>
  16 #include <asm/processor.h>
  17 #include <asm/debug.h>
  18 #include <asm/ipl.h>
  19
  20 #ifndef CONFIG_64BIT
  21 #define LONG "%08lx "
  22 #define FOURLONG "%08lx %08lx %08lx %08lx\n"
  23 static int kstack_depth_to_print = 12;
  24 #else /* CONFIG_64BIT */
  25 #define LONG "%016lx "
  26 #define FOURLONG "%016lx %016lx %016lx %016lx\n"
  27 static int kstack_depth_to_print = 20;
  28 #endif /* CONFIG_64BIT */
  29
  30 /*
  31  * For show_trace we have tree different stack to consider:
  32  *   - the panic stack which is used if the kernel stack has overflown
  33  *   - the asynchronous interrupt stack (cpu related)
  34  *   - the synchronous kernel stack (process related)
  35  * The stack trace can start at any of the three stack and can potentially
  36  * touch all of them. The order is: panic stack, async stack, sync stack.
  37  */
  38 static unsigned long
  39 __show_trace(unsigned long sp, unsigned long low, unsigned long high)
  40 {
  41         struct stack_frame *sf;
  42         struct pt_regs *regs;
  43
  44         while (1) {
  45                 sp = sp & PSW_ADDR_INSN;
  46                 if (sp < low || sp > high - sizeof(*sf))
  47                         return sp;
  48                 sf = (struct stack_frame *) sp;
  49                 printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
  50                 print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
  51                 /* Follow the backchain. */
  52                 while (1) {
  53                         low = sp;
  54                         sp = sf->back_chain & PSW_ADDR_INSN;
  55                         if (!sp)
  56                                 break;
  57                         if (sp <= low || sp > high - sizeof(*sf))
  58                                 return sp;
  59                         sf = (struct stack_frame *) sp;
  60                         printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
  61                         print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
  62                 }
  63                 /* Zero backchain detected, check for interrupt frame. */
  64                 sp = (unsigned long) (sf + 1);
  65                 if (sp <= low || sp > high - sizeof(*regs))
  66                         return sp;
  67                 regs = (struct pt_regs *) sp;
  68                 printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
  69                 print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
  70                 low = sp;
  71                 sp = regs->gprs[15];
  72         }
  73 }
  74
  75 static void show_trace(struct task_struct *task, unsigned long *stack)
  76 {
  77         const unsigned long frame_size =
  78                 STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
  79         register unsigned long __r15 asm ("15");
  80         unsigned long sp;
  81
  82         sp = (unsigned long) stack;
  83         if (!sp)
  84                 sp = task ? task->thread.ksp : __r15;
  85         printk("Call Trace:\n");
  86 #ifdef CONFIG_CHECK_STACK
  87         sp = __show_trace(sp,
  88                           S390_lowcore.panic_stack + frame_size - 4096,
  89                           S390_lowcore.panic_stack + frame_size);
  90 #endif
  91         sp = __show_trace(sp,
  92                           S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
  93                           S390_lowcore.async_stack + frame_size);
  94         if (task)
  95                 __show_trace(sp, (unsigned long) task_stack_page(task),
  96                              (unsigned long) task_stack_page(task) + THREAD_SIZE);
  97         else
  98                 __show_trace(sp, S390_lowcore.thread_info,
  99                              S390_lowcore.thread_info + THREAD_SIZE);
 100         if (!task)
 101                 task = current;
 102         debug_show_held_locks(task);
 103 }
 104
 105 void show_stack(struct task_struct *task, unsigned long *sp)
 106 {
 107         register unsigned long *__r15 asm ("15");
 108         unsigned long *stack;
 109         int i;
 110
 111         if (!sp)
 112                 stack = task ? (unsigned long *) task->thread.ksp : __r15;
 113         else
 114                 stack = sp;
 115
 116         for (i = 0; i < kstack_depth_to_print; i++) {
 117                 if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
 118                         break;
 119                 if ((i * sizeof(long) % 32) == 0)
 120                         printk("%s       ", i == 0 ? "" : "\n");
 121                 printk(LONG, *stack++);
 122         }
 123         printk("\n");
 124         show_trace(task, sp);
 125 }
 126
 127 static void show_last_breaking_event(struct pt_regs *regs)
 128 {
 129 #ifdef CONFIG_64BIT
 130         printk("Last Breaking-Event-Address:\n");
 131         printk(" [<%016lx>] ", regs->args[0] & PSW_ADDR_INSN);
 132         print_symbol("%s\n", regs->args[0] & PSW_ADDR_INSN);
 133 #endif
 134 }
 135
 136 static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
 137 {
 138         return (regs->psw.mask & bits) / ((~bits + 1) & bits);
 139 }
 140
 141 void show_registers(struct pt_regs *regs)
 142 {
 143         char *mode;
 144
 145         mode = user_mode(regs) ? "User" : "Krnl";
 146         printk("%s PSW : %p %p",
 147                mode, (void *) regs->psw.mask,
 148                (void *) regs->psw.addr);
 149         print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
 150         printk("           R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
 151                "P:%x AS:%x CC:%x PM:%x", mask_bits(regs, PSW_MASK_PER),
 152                mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
 153                mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
 154                mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
 155                mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
 156                mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
 157 #ifdef CONFIG_64BIT
 158         printk(" EA:%x", mask_bits(regs, PSW_MASK_EA | PSW_MASK_BA));
 159 #endif
 160         printk("\n%s GPRS: " FOURLONG, mode,
 161                regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
 162         printk("           " FOURLONG,
 163                regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
 164         printk("           " FOURLONG,
 165                regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
 166         printk("           " FOURLONG,
 167                regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
 168         show_code(regs);
 169 }
 170
 171 void show_regs(struct pt_regs *regs)
 172 {
 173         show_regs_print_info(KERN_DEFAULT);
 174         show_registers(regs);
 175         /* Show stack backtrace if pt_regs is from kernel mode */
 176         if (!user_mode(regs))
 177                 show_trace(NULL, (unsigned long *) regs->gprs[15]);
 178         show_last_breaking_event(regs);
 179 }
 180
 181 static DEFINE_SPINLOCK(die_lock);
 182
 183 void die(struct pt_regs *regs, const char *str)
 184 {
 185         static int die_counter;
 186
 187         oops_enter();
 188         lgr_info_log();
 189         debug_stop_all();
 190         console_verbose();
 191         spin_lock_irq(&die_lock);
 192         bust_spinlocks(1);
 193         printk("%s: %04x [#%d] ", str, regs->int_code & 0xffff, ++die_counter);
 194 #ifdef CONFIG_PREEMPT
 195         printk("PREEMPT ");
 196 #endif
 197 #ifdef CONFIG_SMP
 198         printk("SMP ");
 199 #endif
 200 #ifdef CONFIG_DEBUG_PAGEALLOC
 201         printk("DEBUG_PAGEALLOC");
 202 #endif
 203         printk("\n");
 204         notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
 205         print_modules();
 206         show_regs(regs);
 207         bust_spinlocks(0);
 208         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 209         spin_unlock_irq(&die_lock);
 210         if (in_interrupt())
 211                 panic("Fatal exception in interrupt");
 212         if (panic_on_oops)
 213                 panic("Fatal exception: panic_on_oops");
 214         oops_exit();
 215         do_exit(SIGSEGV);
 216 }