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/dis.h>
  19 #include <asm/ipl.h>
  20
  21 #ifndef CONFIG_64BIT
  22 #define LONG "%08lx "
  23 #define FOURLONG "%08lx %08lx %08lx %08lx\n"
  24 static int kstack_depth_to_print = 12;
  25 #else /* CONFIG_64BIT */
  26 #define LONG "%016lx "
  27 #define FOURLONG "%016lx %016lx %016lx %016lx\n"
  28 static int kstack_depth_to_print = 20;
  29 #endif /* CONFIG_64BIT */
  30
  31 /*
  32  * For show_trace we have tree different stack to consider:
  33  *   - the panic stack which is used if the kernel stack has overflown
  34  *   - the asynchronous interrupt stack (cpu related)
  35  *   - the synchronous kernel stack (process related)
  36  * The stack trace can start at any of the three stack and can potentially
  37  * touch all of them. The order is: panic stack, async stack, sync stack.
  38  */
  39 static unsigned long
  40 __show_trace(unsigned long sp, unsigned long low, unsigned long high)
  41 {
  42         struct stack_frame *sf;
  43         struct pt_regs *regs;
  44         unsigned long addr;
  45
  46         while (1) {
  47                 sp = sp & PSW_ADDR_INSN;
  48                 if (sp < low || sp > high - sizeof(*sf))
  49                         return sp;
  50                 sf = (struct stack_frame *) sp;
  51                 addr = sf->gprs[8] & PSW_ADDR_INSN;
  52                 printk("([<%016lx>] %pSR)\n", addr, (void *)addr);
  53                 /* Follow the backchain. */
  54                 while (1) {
  55                         low = sp;
  56                         sp = sf->back_chain & PSW_ADDR_INSN;
  57                         if (!sp)
  58                                 break;
  59                         if (sp <= low || sp > high - sizeof(*sf))
  60                                 return sp;
  61                         sf = (struct stack_frame *) sp;
  62                         addr = sf->gprs[8] & PSW_ADDR_INSN;
  63                         printk(" [<%016lx>] %pSR\n", addr, (void *)addr);
  64                 }
  65                 /* Zero backchain detected, check for interrupt frame. */
  66                 sp = (unsigned long) (sf + 1);
  67                 if (sp <= low || sp > high - sizeof(*regs))
  68                         return sp;
  69                 regs = (struct pt_regs *) sp;
  70                 addr = regs->psw.addr & PSW_ADDR_INSN;
  71                 printk(" [<%016lx>] %pSR\n", addr, (void *)addr);
  72                 low = sp;
  73                 sp = regs->gprs[15];
  74         }
  75 }
  76
  77 static void show_trace(struct task_struct *task, unsigned long *stack)
  78 {
  79         const unsigned long frame_size =
  80                 STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
  81         register unsigned long __r15 asm ("15");
  82         unsigned long sp;
  83
  84         sp = (unsigned long) stack;
  85         if (!sp)
  86                 sp = task ? task->thread.ksp : __r15;
  87         printk("Call Trace:\n");
  88 #ifdef CONFIG_CHECK_STACK
  89         sp = __show_trace(sp,
  90                           S390_lowcore.panic_stack + frame_size - 4096,
  91                           S390_lowcore.panic_stack + frame_size);
  92 #endif
  93         sp = __show_trace(sp,
  94                           S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
  95                           S390_lowcore.async_stack + frame_size);
  96         if (task)
  97                 __show_trace(sp, (unsigned long) task_stack_page(task),
  98                              (unsigned long) task_stack_page(task) + THREAD_SIZE);
  99         else
 100                 __show_trace(sp, S390_lowcore.thread_info,
 101                              S390_lowcore.thread_info + THREAD_SIZE);
 102         if (!task)
 103                 task = current;
 104         debug_show_held_locks(task);
 105 }
 106
 107 void show_stack(struct task_struct *task, unsigned long *sp)
 108 {
 109         register unsigned long *__r15 asm ("15");
 110         unsigned long *stack;
 111         int i;
 112
 113         if (!sp)
 114                 stack = task ? (unsigned long *) task->thread.ksp : __r15;
 115         else
 116                 stack = sp;
 117
 118         for (i = 0; i < kstack_depth_to_print; i++) {
 119                 if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
 120                         break;
 121                 if ((i * sizeof(long) % 32) == 0)
 122                         printk("%s       ", i == 0 ? "" : "\n");
 123                 printk(LONG, *stack++);
 124         }
 125         printk("\n");
 126         show_trace(task, sp);
 127 }
 128
 129 static void show_last_breaking_event(struct pt_regs *regs)
 130 {
 131 #ifdef CONFIG_64BIT
 132         printk("Last Breaking-Event-Address:\n");
 133         printk(" [<%016lx>] %pSR\n", regs->args[0], (void *)regs->args[0]);
 134 #endif
 135 }
 136
 137 static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
 138 {
 139         return (regs->psw.mask & bits) / ((~bits + 1) & bits);
 140 }
 141
 142 void show_registers(struct pt_regs *regs)
 143 {
 144         char *mode;
 145
 146         mode = user_mode(regs) ? "User" : "Krnl";
 147         printk("%s PSW : %p %p", mode, (void *)regs->psw.mask, (void *)regs->psw.addr);
 148         if (!user_mode(regs))
 149                 printk(" (%pSR)", (void *)regs->psw.addr);
 150         printk("\n");
 151         printk("           R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
 152                "P:%x AS:%x CC:%x PM:%x", mask_bits(regs, PSW_MASK_PER),
 153                mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
 154                mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
 155                mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
 156                mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
 157                mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
 158 #ifdef CONFIG_64BIT
 159         printk(" EA:%x", mask_bits(regs, PSW_MASK_EA | PSW_MASK_BA));
 160 #endif
 161         printk("\n%s GPRS: " FOURLONG, mode,
 162                regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
 163         printk("           " FOURLONG,
 164                regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
 165         printk("           " FOURLONG,
 166                regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
 167         printk("           " FOURLONG,
 168                regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
 169         show_code(regs);
 170 }
 171
 172 void show_regs(struct pt_regs *regs)
 173 {
 174         show_regs_print_info(KERN_DEFAULT);
 175         show_registers(regs);
 176         /* Show stack backtrace if pt_regs is from kernel mode */
 177         if (!user_mode(regs))
 178                 show_trace(NULL, (unsigned long *) regs->gprs[15]);
 179         show_last_breaking_event(regs);
 180 }
 181
 182 static DEFINE_SPINLOCK(die_lock);
 183
 184 void die(struct pt_regs *regs, const char *str)
 185 {
 186         static int die_counter;
 187
 188         oops_enter();
 189         lgr_info_log();
 190         debug_stop_all();
 191         console_verbose();
 192         spin_lock_irq(&die_lock);
 193         bust_spinlocks(1);
 194         printk("%s: %04x ilc:%d [#%d] ", str, regs->int_code & 0xffff,
 195                regs->int_code >> 17, ++die_counter);
 196 #ifdef CONFIG_PREEMPT
 197         printk("PREEMPT ");
 198 #endif
 199 #ifdef CONFIG_SMP
 200         printk("SMP ");
 201 #endif
 202 #ifdef CONFIG_DEBUG_PAGEALLOC
 203         printk("DEBUG_PAGEALLOC");
 204 #endif
 205         printk("\n");
 206         notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
 207         print_modules();
 208         show_regs(regs);
 209         bust_spinlocks(0);
 210         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 211         spin_unlock_irq(&die_lock);
 212         if (in_interrupt())
 213                 panic("Fatal exception in interrupt");
 214         if (panic_on_oops)
 215                 panic("Fatal exception: panic_on_oops");
 216         oops_exit();
 217         do_exit(SIGSEGV);
 218 }