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