[PATCH] i386/x86-64: fall back to old-style call trace if no unwinding

[powerpc.git] / arch / x86_64 / kernel / traps.c

diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index cea335e..bd0891f 100644 (file)
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -6,8 +6,6 @@
  *
  *  Pentium III FXSR, SSE support
  *     Gareth Hughes <gareth@valinux.com>, May 2000
- *
- *  $Id: traps.c,v 1.36 2002/03/24 11:09:10 ak Exp $
  */
 
 /*
@@ -31,6 +29,7 @@
 #include <linux/nmi.h>
 #include <linux/kprobes.h>
 #include <linux/kexec.h>
+#include <linux/unwind.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -41,7 +40,7 @@
 #include <asm/i387.h>
 #include <asm/kdebug.h>
 #include <asm/processor.h>
-
+#include <asm/unwind.h>
 #include <asm/smp.h>
 #include <asm/pgalloc.h>
 #include <asm/pda.h>
@@ -108,6 +107,7 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
 }
 
 static int kstack_depth_to_print = 10;
+static int call_trace = 1;
 
 #ifdef CONFIG_KALLSYMS
 #include <linux/kallsyms.h> 
@@ -191,6 +191,25 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
        return NULL;
 }
 
+static int show_trace_unwind(struct unwind_frame_info *info, void *context)
+{
+       int i = 11, n = 0;
+
+       while (unwind(info) == 0 && UNW_PC(info)) {
+               ++n;
+               if (i > 50) {
+                       printk("\n       ");
+                       i = 7;
+               } else
+                       i += printk(" ");
+               i += printk_address(UNW_PC(info));
+               if (arch_unw_user_mode(info))
+                       break;
+       }
+       printk("\n");
+       return n;
+}
+
 /*
  * x86-64 can have upto three kernel stacks: 
  * process stack
@@ -198,15 +217,39 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  */
 
-void show_trace(unsigned long *stack)
+void show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * stack)
 {
        const unsigned cpu = safe_smp_processor_id();
        unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
-       int i;
+       int i = 11;
        unsigned used = 0;
 
        printk("\nCall Trace:");
 
+       if (!tsk)
+               tsk = current;
+
+       if (call_trace >= 0) {
+               int unw_ret = 0;
+               struct unwind_frame_info info;
+
+               if (regs) {
+                       if (unwind_init_frame_info(&info, tsk, regs) == 0)
+                               unw_ret = show_trace_unwind(&info, NULL);
+               } else if (tsk == current)
+                       unw_ret = unwind_init_running(&info, show_trace_unwind, NULL);
+               else {
+                       if (unwind_init_blocked(&info, tsk) == 0)
+                               unw_ret = show_trace_unwind(&info, NULL);
+               }
+               if (unw_ret > 0) {
+                       if (call_trace > 0)
+                               return;
+                       printk("Legacy call trace:");
+                       i = 18;
+               }
+       }
+
 #define HANDLE_STACK(cond) \
        do while (cond) { \
                unsigned long addr = *stack++; \
@@ -229,7 +272,7 @@ void show_trace(unsigned long *stack)
                } \
        } while (0)
 
-       for(i = 11; ; ) {
+       for(; ; ) {
                const char *id;
                unsigned long *estack_end;
                estack_end = in_exception_stack(cpu, (unsigned long)stack,
@@ -264,7 +307,7 @@ void show_trace(unsigned long *stack)
        printk("\n");
 }
 
-void show_stack(struct task_struct *tsk, unsigned long * rsp)
+static void _show_stack(struct task_struct *tsk, struct pt_regs *regs, unsigned long * rsp)
 {
        unsigned long *stack;
        int i;
@@ -298,7 +341,12 @@ void show_stack(struct task_struct *tsk, unsigned long * rsp)
                printk("%016lx ", *stack++);
                touch_nmi_watchdog();
        }
-       show_trace((unsigned long *)rsp);
+       show_trace(tsk, regs, rsp);
+}
+
+void show_stack(struct task_struct *tsk, unsigned long * rsp)
+{
+       _show_stack(tsk, NULL, rsp);
 }
 
 /*
@@ -307,7 +355,7 @@ void show_stack(struct task_struct *tsk, unsigned long * rsp)
 void dump_stack(void)
 {
        unsigned long dummy;
-       show_trace(&dummy);
+       show_trace(NULL, NULL, &dummy);
 }
 
 EXPORT_SYMBOL(dump_stack);
@@ -334,7 +382,7 @@ void show_registers(struct pt_regs *regs)
        if (in_kernel) {
 
                printk("Stack: ");
-               show_stack(NULL, (unsigned long*)rsp);
+               _show_stack(NULL, regs, (unsigned long*)rsp);
 
                printk("\nCode: ");
                if (regs->rip < PAGE_OFFSET)
@@ -1012,3 +1060,14 @@ static int __init kstack_setup(char *s)
 }
 __setup("kstack=", kstack_setup);
 
+static int __init call_trace_setup(char *s)
+{
+       if (strcmp(s, "old") == 0)
+               call_trace = -1;
+       else if (strcmp(s, "both") == 0)
+               call_trace = 0;
+       else if (strcmp(s, "new") == 0)
+               call_trace = 1;
+       return 1;
+}
+__setup("call_trace=", call_trace_setup);