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/mm.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <asm/processor.h>
  18 #include <asm/debug.h>
  19 #include <asm/dis.h>
  20 #include <asm/ipl.h>
  21
  22 /*
  23  * For dump_trace we have tree different stack to consider:
  24  *   - the panic stack which is used if the kernel stack has overflown
  25  *   - the asynchronous interrupt stack (cpu related)
  26  *   - the synchronous kernel stack (process related)
  27  * The stack trace can start at any of the three stacks and can potentially
  28  * touch all of them. The order is: panic stack, async stack, sync stack.
  29  */
  30 static unsigned long
  31 __dump_trace(dump_trace_func_t func, void *data, unsigned long sp,
  32              unsigned long low, unsigned long high)
  33 {
  34         struct stack_frame *sf;
  35         struct pt_regs *regs;
  36
  37         while (1) {
  38                 if (sp < low || sp > high - sizeof(*sf))
  39                         return sp;
  40                 sf = (struct stack_frame *) sp;
  41                 /* Follow the backchain. */
  42                 while (1) {
  43                         if (func(data, sf->gprs[8]))
  44                                 return sp;
  45                         low = sp;
  46                         sp = sf->back_chain;
  47                         if (!sp)
  48                                 break;
  49                         if (sp <= low || sp > high - sizeof(*sf))
  50                                 return sp;
  51                         sf = (struct stack_frame *) sp;
  52                 }
  53                 /* Zero backchain detected, check for interrupt frame. */
  54                 sp = (unsigned long) (sf + 1);
  55                 if (sp <= low || sp > high - sizeof(*regs))
  56                         return sp;
  57                 regs = (struct pt_regs *) sp;
  58                 if (!user_mode(regs)) {
  59                         if (func(data, regs->psw.addr))
  60                                 return sp;
  61                 }
  62                 low = sp;
  63                 sp = regs->gprs[15];
  64         }
  65 }
  66
  67 void dump_trace(dump_trace_func_t func, void *data, struct task_struct *task,
  68                 unsigned long sp)
  69 {
  70         unsigned long frame_size;
  71
  72         frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
  73 #ifdef CONFIG_CHECK_STACK
  74         sp = __dump_trace(func, data, sp,
  75                           S390_lowcore.panic_stack + frame_size - 4096,
  76                           S390_lowcore.panic_stack + frame_size);
  77 #endif
  78         sp = __dump_trace(func, data, sp,
  79                           S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
  80                           S390_lowcore.async_stack + frame_size);
  81         task = task ?: current;
  82         __dump_trace(func, data, sp,
  83                      (unsigned long)task_stack_page(task),
  84                      (unsigned long)task_stack_page(task) + THREAD_SIZE);
  85 }
  86 EXPORT_SYMBOL_GPL(dump_trace);
  87
  88 struct return_address_data {
  89         unsigned long address;
  90         int depth;
  91 };
  92
  93 static int __return_address(void *data, unsigned long address)
  94 {
  95         struct return_address_data *rd = data;
  96
  97         if (rd->depth--)
  98                 return 0;
  99         rd->address = address;
 100         return 1;
 101 }
 102
 103 unsigned long return_address(int depth)
 104 {
 105         struct return_address_data rd = { .depth = depth + 2 };
 106
 107         dump_trace(__return_address, &rd, NULL, current_stack_pointer());
 108         return rd.address;
 109 }
 110 EXPORT_SYMBOL_GPL(return_address);
 111
 112 static int show_address(void *data, unsigned long address)
 113 {
 114         printk("([<%016lx>] %pSR)\n", address, (void *)address);
 115         return 0;
 116 }
 117
 118 static void show_trace(struct task_struct *task, unsigned long sp)
 119 {
 120         if (!sp)
 121                 sp = task ? task->thread.ksp : current_stack_pointer();
 122         printk("Call Trace:\n");
 123         dump_trace(show_address, NULL, task, sp);
 124         if (!task)
 125                 task = current;
 126         debug_show_held_locks(task);
 127 }
 128
 129 void show_stack(struct task_struct *task, unsigned long *sp)
 130 {
 131         unsigned long *stack;
 132         int i;
 133
 134         stack = sp;
 135         if (!stack) {
 136                 if (!task)
 137                         stack = (unsigned long *)current_stack_pointer();
 138                 else
 139                         stack = (unsigned long *)task->thread.ksp;
 140         }
 141         for (i = 0; i < 20; i++) {
 142                 if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
 143                         break;
 144                 if ((i * sizeof(long) % 32) == 0)
 145                         printk("%s       ", i == 0 ? "" : "\n");
 146                 printk("%016lx ", *stack++);
 147         }
 148         printk("\n");
 149         show_trace(task, (unsigned long)sp);
 150 }
 151
 152 static void show_last_breaking_event(struct pt_regs *regs)
 153 {
 154         printk("Last Breaking-Event-Address:\n");
 155         printk(" [<%016lx>] %pSR\n", regs->args[0], (void *)regs->args[0]);
 156 }
 157
 158 void show_registers(struct pt_regs *regs)
 159 {
 160         struct psw_bits *psw = &psw_bits(regs->psw);
 161         char *mode;
 162
 163         mode = user_mode(regs) ? "User" : "Krnl";
 164         printk("%s PSW : %p %p", mode, (void *)regs->psw.mask, (void *)regs->psw.addr);
 165         if (!user_mode(regs))
 166                 printk(" (%pSR)", (void *)regs->psw.addr);
 167         printk("\n");
 168         printk("           R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
 169                "P:%x AS:%x CC:%x PM:%x", psw->r, psw->t, psw->i, psw->e,
 170                psw->key, psw->m, psw->w, psw->p, psw->as, psw->cc, psw->pm);
 171         printk(" RI:%x EA:%x", psw->ri, psw->eaba);
 172         printk("\n%s GPRS: %016lx %016lx %016lx %016lx\n", mode,
 173                regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
 174         printk("           %016lx %016lx %016lx %016lx\n",
 175                regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
 176         printk("           %016lx %016lx %016lx %016lx\n",
 177                regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
 178         printk("           %016lx %016lx %016lx %016lx\n",
 179                regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
 180         show_code(regs);
 181 }
 182
 183 void show_regs(struct pt_regs *regs)
 184 {
 185         show_regs_print_info(KERN_DEFAULT);
 186         show_registers(regs);
 187         /* Show stack backtrace if pt_regs is from kernel mode */
 188         if (!user_mode(regs))
 189                 show_trace(NULL, regs->gprs[15]);
 190         show_last_breaking_event(regs);
 191 }
 192
 193 static DEFINE_SPINLOCK(die_lock);
 194
 195 void die(struct pt_regs *regs, const char *str)
 196 {
 197         static int die_counter;
 198
 199         oops_enter();
 200         lgr_info_log();
 201         debug_stop_all();
 202         console_verbose();
 203         spin_lock_irq(&die_lock);
 204         bust_spinlocks(1);
 205         printk("%s: %04x ilc:%d [#%d] ", str, regs->int_code & 0xffff,
 206                regs->int_code >> 17, ++die_counter);
 207 #ifdef CONFIG_PREEMPT
 208         printk("PREEMPT ");
 209 #endif
 210 #ifdef CONFIG_SMP
 211         printk("SMP ");
 212 #endif
 213         if (debug_pagealloc_enabled())
 214                 printk("DEBUG_PAGEALLOC");
 215         printk("\n");
 216         notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
 217         print_modules();
 218         show_regs(regs);
 219         bust_spinlocks(0);
 220         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 221         spin_unlock_irq(&die_lock);
 222         if (in_interrupt())
 223                 panic("Fatal exception in interrupt");
 224         if (panic_on_oops)
 225                 panic("Fatal exception: panic_on_oops");
 226         oops_exit();
 227         do_exit(SIGSEGV);
 228 }