vserver 1.9.3

[linux-2.6.git] / arch / s390 / kernel / traps.c

diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index 6614d4b..e67ee27 100644 (file)
--- a/arch/s390/kernel/traps.c
+++ b/arch/s390/kernel/traps.c
@@ -67,54 +67,93 @@ extern pgm_check_handler_t do_monitor_call;
 #define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
 
 #ifndef CONFIG_ARCH_S390X
-#define RET_ADDR 56
 #define FOURLONG "%08lx %08lx %08lx %08lx\n"
 static int kstack_depth_to_print = 12;
-
 #else /* CONFIG_ARCH_S390X */
-#define RET_ADDR 112
 #define FOURLONG "%016lx %016lx %016lx %016lx\n"
 static int kstack_depth_to_print = 20;
-
 #endif /* CONFIG_ARCH_S390X */
 
-void show_trace(struct task_struct *task, unsigned long * stack)
+/*
+ * For show_trace we have tree different stack to consider:
+ *   - the panic stack which is used if the kernel stack has overflown
+ *   - the asynchronous interrupt stack (cpu related)
+ *   - the synchronous kernel stack (process related)
+ * The stack trace can start at any of the three stack and can potentially
+ * touch all of them. The order is: panic stack, async stack, sync stack.
+ */
+static unsigned long
+__show_trace(unsigned long sp, unsigned long low, unsigned long high)
 {
-       unsigned long backchain, low_addr, high_addr, ret_addr;
+       struct stack_frame *sf;
+       struct pt_regs *regs;
 
-       if (!stack)
-               stack = (task == NULL) ? *stack_pointer : &(task->thread.ksp);
+       while (1) {
+               sp = sp & PSW_ADDR_INSN;
+               if (sp < low || sp > high - sizeof(*sf))
+                       return sp;
+               sf = (struct stack_frame *) sp;
+               printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
+               print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
+               /* Follow the backchain. */
+               while (1) {
+                       low = sp;
+                       sp = sf->back_chain & PSW_ADDR_INSN;
+                       if (!sp)
+                               break;
+                       if (sp <= low || sp > high - sizeof(*sf))
+                               return sp;
+                       sf = (struct stack_frame *) sp;
+                       printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
+                       print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
+               }
+               /* Zero backchain detected, check for interrupt frame. */
+               sp = (unsigned long) (sf + 1);
+               if (sp <= low || sp > high - sizeof(*regs))
+                       return sp;
+               regs = (struct pt_regs *) sp;
+               printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
+               print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
+               low = sp;
+               sp = regs->gprs[15];
+       }
+}
 
+void show_trace(struct task_struct *task, unsigned long * stack)
+{
+       register unsigned long __r15 asm ("15");
+       unsigned long sp;
+
+       sp = (unsigned long) stack;
+       if (!sp)
+               sp = task ? task->thread.ksp : __r15;
        printk("Call Trace:\n");
-       low_addr = ((unsigned long) stack) & PSW_ADDR_INSN;
-       high_addr = (low_addr & (-THREAD_SIZE)) + THREAD_SIZE;
-       /* Skip the first frame (biased stack) */
-       backchain = *((unsigned long *) low_addr) & PSW_ADDR_INSN;
-       /* Print up to 8 lines */
-       while  (backchain > low_addr && backchain <= high_addr) {
-               ret_addr = *((unsigned long *) (backchain+RET_ADDR)) & PSW_ADDR_INSN;
-               printk(" [<%016lx>] ", ret_addr);
-               print_symbol("%s\n", ret_addr);
-               low_addr = backchain;
-               backchain = *((unsigned long *) backchain) & PSW_ADDR_INSN;
-       }
+#ifdef CONFIG_CHECK_STACK
+       sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
+                         S390_lowcore.panic_stack);
+#endif
+       sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
+                         S390_lowcore.async_stack);
+       if (task)
+               __show_trace(sp, (unsigned long) task->thread_info,
+                            (unsigned long) task->thread_info + THREAD_SIZE);
+       else
+               __show_trace(sp, S390_lowcore.thread_info,
+                            S390_lowcore.thread_info + THREAD_SIZE);
        printk("\n");
 }
 
 void show_stack(struct task_struct *task, unsigned long *sp)
 {
+       register unsigned long * __r15 asm ("15");
        unsigned long *stack;
        int i;
 
        // debugging aid: "show_stack(NULL);" prints the
        // back trace for this cpu.
 
-       if (!sp) {
-               if (task)
-                       sp = (unsigned long *) task->thread.ksp;
-               else
-                       sp = *stack_pointer;
-       }
+       if (!sp)
+               sp = task ? (unsigned long *) task->thread.ksp : __r15;
 
        stack = sp;
        for (i = 0; i < kstack_depth_to_print; i++) {
@@ -591,6 +630,11 @@ asmlinkage void data_exception(struct pt_regs * regs, long interruption_code)
        }
 }
 
+asmlinkage void kernel_stack_overflow(struct pt_regs * regs)
+{
+       die("Kernel stack overflow", regs, 0);
+       panic("Corrupt kernel stack, can't continue.");
+}
 
 
 /* init is done in lowcore.S and head.S */