Merge to Fedora kernel-2.6.18-1.2224_FC5 patched with stable patch-2.6.18.1-vs2.0...
[linux-2.6.git] / arch / x86_64 / kernel / traps.c
index 584f5dd..2df603e 100644 (file)
@@ -6,15 +6,12 @@
  *
  *  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 $
  */
 
 /*
  * 'Traps.c' handles hardware traps and faults after we have saved some
  * state in 'entry.S'.
  */
-#include <linux/config.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
@@ -31,6 +28,7 @@
 #include <linux/nmi.h>
 #include <linux/kprobes.h>
 #include <linux/kexec.h>
+#include <linux/unwind.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
 #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>
 #include <asm/proto.h>
 #include <asm/nmi.h>
+#include <asm/stacktrace.h>
 
 asmlinkage void divide_error(void);
 asmlinkage void debug(void);
@@ -71,6 +70,7 @@ asmlinkage void machine_check(void);
 asmlinkage void spurious_interrupt_bug(void);
 
 ATOMIC_NOTIFIER_HEAD(die_chain);
+EXPORT_SYMBOL(die_chain);
 
 extern char last_sysfs_file[];
 
@@ -79,13 +79,13 @@ int register_die_notifier(struct notifier_block *nb)
        vmalloc_sync_all();
        return atomic_notifier_chain_register(&die_chain, nb);
 }
-EXPORT_SYMBOL(register_die_notifier);
+EXPORT_SYMBOL(register_die_notifier); /* used modular by kdb */
 
 int unregister_die_notifier(struct notifier_block *nb)
 {
        return atomic_notifier_chain_unregister(&die_chain, nb);
 }
-EXPORT_SYMBOL(unregister_die_notifier);
+EXPORT_SYMBOL(unregister_die_notifier); /* used modular by kdb */
 
 static inline void conditional_sti(struct pt_regs *regs)
 {
@@ -109,35 +109,43 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
        preempt_enable_no_resched();
 }
 
-static int kstack_depth_to_print = 10;
+static int kstack_depth_to_print = 12;
+#ifdef CONFIG_STACK_UNWIND
+static int call_trace = 1;
+#else
+#define call_trace (-1)
+#endif
 
 #ifdef CONFIG_KALLSYMS
-#include <linux/kallsyms.h> 
-int printk_address(unsigned long address)
-{ 
+# include <linux/kallsyms.h>
+void printk_address(unsigned long address)
+{
        unsigned long offset = 0, symsize;
        const char *symname;
        char *modname;
-       char *delim = ":"; 
+       char *delim = ":";
        char namebuf[128];
 
-       symname = kallsyms_lookup(address, &symsize, &offset, &modname, namebuf); 
-       if (!symname) 
-               return printk("[<%016lx>]", address);
-       if (!modname) 
+       symname = kallsyms_lookup(address, &symsize, &offset,
+                                       &modname, namebuf);
+       if (!symname) {
+               printk(" [<%016lx>]\n", address);
+               return;
+       }
+       if (!modname)
                modname = delim = "";           
-        return printk("<%016lx>{%s%s%s%s%+ld}",
-                     address, delim, modname, delim, symname, offset); 
-} 
+       printk(" [<%016lx>] %s%s%s%s+0x%lx/0x%lx\n",
+               address, delim, modname, delim, symname, offset, symsize);
+}
 #else
-int printk_address(unsigned long address)
-{ 
-       return printk("[<%016lx>]", address);
-} 
+void printk_address(unsigned long address)
+{
+       printk(" [<%016lx>]\n", address);
+}
 #endif
 
 static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
-                                       unsigned *usedp, const char **idp)
+                                       unsigned *usedp, char **idp)
 {
        static char ids[][8] = {
                [DEBUG_STACK - 1] = "#DB",
@@ -151,32 +159,68 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
        };
        unsigned k;
 
+       /*
+        * Iterate over all exception stacks, and figure out whether
+        * 'stack' is in one of them:
+        */
        for (k = 0; k < N_EXCEPTION_STACKS; k++) {
                unsigned long end;
 
+               /*
+                * set 'end' to the end of the exception stack.
+                */
                switch (k + 1) {
+               /*
+                * TODO: this block is not needed i think, because
+                * setup64.c:cpu_init() sets up t->ist[DEBUG_STACK]
+                * properly too.
+                */
 #if DEBUG_STKSZ > EXCEPTION_STKSZ
                case DEBUG_STACK:
                        end = cpu_pda(cpu)->debugstack + DEBUG_STKSZ;
                        break;
 #endif
                default:
-                       end = per_cpu(init_tss, cpu).ist[k];
+                       end = per_cpu(orig_ist, cpu).ist[k];
                        break;
                }
+               /*
+                * Is 'stack' above this exception frame's end?
+                * If yes then skip to the next frame.
+                */
                if (stack >= end)
                        continue;
+               /*
+                * Is 'stack' above this exception frame's start address?
+                * If yes then we found the right frame.
+                */
                if (stack >= end - EXCEPTION_STKSZ) {
+                       /*
+                        * Make sure we only iterate through an exception
+                        * stack once. If it comes up for the second time
+                        * then there's something wrong going on - just
+                        * break out and return NULL:
+                        */
                        if (*usedp & (1U << k))
                                break;
                        *usedp |= 1U << k;
                        *idp = ids[k];
                        return (unsigned long *)end;
                }
+               /*
+                * If this is a debug stack, and if it has a larger size than
+                * the usual exception stacks, then 'stack' might still
+                * be within the lower portion of the debug stack:
+                */
 #if DEBUG_STKSZ > EXCEPTION_STKSZ
                if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
                        unsigned j = N_EXCEPTION_STACKS - 1;
 
+                       /*
+                        * Black magic. A large debug stack is composed of
+                        * multiple exception stack entries, which we
+                        * iterate through now. Dont look:
+                        */
                        do {
                                ++j;
                                end -= EXCEPTION_STKSZ;
@@ -193,6 +237,25 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
        return NULL;
 }
 
+struct ops_and_data {
+       struct stacktrace_ops *ops;
+       void *data;
+};
+
+static int dump_trace_unwind(struct unwind_frame_info *info, void *context)
+{
+       struct ops_and_data *oad = (struct ops_and_data *)context;
+       int n = 0;
+
+       while (unwind(info) == 0 && UNW_PC(info)) {
+               n++;
+               oad->ops->address(oad->data, UNW_PC(info));
+               if (arch_unw_user_mode(info))
+                       break;
+       }
+       return n;
+}
+
 /*
  * x86-64 can have upto three kernel stacks: 
  * process stack
@@ -200,25 +263,64 @@ 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 dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * stack,
+               struct stacktrace_ops *ops, void *data)
 {
        const unsigned cpu = safe_smp_processor_id();
        unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
-       int i;
        unsigned used = 0;
 
-       printk("\nCall Trace:");
+       if (!tsk)
+               tsk = current;
+
+       if (call_trace >= 0) {
+               int unw_ret = 0;
+               struct unwind_frame_info info;
+               struct ops_and_data oad = { .ops = ops, .data = data };
+
+               if (regs) {
+                       if (unwind_init_frame_info(&info, tsk, regs) == 0)
+                               unw_ret = dump_trace_unwind(&info, &oad);
+               } else if (tsk == current)
+                       unw_ret = unwind_init_running(&info, dump_trace_unwind, &oad);
+               else {
+                       if (unwind_init_blocked(&info, tsk) == 0)
+                               unw_ret = dump_trace_unwind(&info, &oad);
+               }
+               if (unw_ret > 0) {
+                       if (call_trace == 1 && !arch_unw_user_mode(&info)) {
+                               ops->warning_symbol(data, "DWARF2 unwinder stuck at %s",
+                                            UNW_PC(&info));
+                               if ((long)UNW_SP(&info) < 0) {
+                                       ops->warning(data, "Leftover inexact backtrace:");
+                                       stack = (unsigned long *)UNW_SP(&info);
+                                       if (!stack)
+                                               return;
+                               } else
+                                       ops->warning(data, "Full inexact backtrace again:");
+                       } else if (call_trace >= 1)
+                               return;
+                       else
+                               ops->warning(data, "Full inexact backtrace again:");
+               } else
+                       ops->warning(data, "Inexact backtrace:");
+       }
+       if (!stack) {
+               unsigned long dummy;
+               stack = &dummy;
+               if (tsk && tsk != current)
+                       stack = (unsigned long *)tsk->thread.rsp;
+       }
 
+       /*
+        * Print function call entries within a stack. 'cond' is the
+        * "end of stackframe" condition, that the 'stack++'
+        * iteration will eventually trigger.
+        */
 #define HANDLE_STACK(cond) \
        do while (cond) { \
                unsigned long addr = *stack++; \
                if (kernel_text_address(addr)) { \
-                       if (i > 50) { \
-                               printk("\n       "); \
-                               i = 0; \
-                       } \
-                       else \
-                               i += printk(" "); \
                        /* \
                         * If the address is either in the text segment of the \
                         * kernel, or in the region which contains vmalloc'ed \
@@ -227,20 +329,31 @@ void show_trace(unsigned long *stack)
                         * down the cause of the crash will be able to figure \
                         * out the call path that was taken. \
                         */ \
-                       i += printk_address(addr); \
+                       ops->address(data, addr);   \
                } \
        } while (0)
 
-       for(i = 11; ; ) {
-               const char *id;
+       /*
+        * Print function call entries in all stacks, starting at the
+        * current stack address. If the stacks consist of nested
+        * exceptions
+        */
+       for (;;) {
+               char *id;
                unsigned long *estack_end;
                estack_end = in_exception_stack(cpu, (unsigned long)stack,
                                                &used, &id);
 
                if (estack_end) {
-                       i += printk(" <%s>", id);
+                       if (ops->stack(data, id) < 0)
+                               break;
                        HANDLE_STACK (stack < estack_end);
-                       i += printk(" <EOE>");
+                       ops->stack(data, "<EOE>");
+                       /*
+                        * We link to the next stack via the
+                        * second-to-last pointer (index -2 to end) in the
+                        * exception stack:
+                        */
                        stack = (unsigned long *) estack_end[-2];
                        continue;
                }
@@ -250,23 +363,71 @@ void show_trace(unsigned long *stack)
                                (IRQSTACKSIZE - 64) / sizeof(*irqstack);
 
                        if (stack >= irqstack && stack < irqstack_end) {
-                               i += printk(" <IRQ>");
+                               if (ops->stack(data, "IRQ") < 0)
+                                       break;
                                HANDLE_STACK (stack < irqstack_end);
+                               /*
+                                * We link to the next stack (which would be
+                                * the process stack normally) the last
+                                * pointer (index -1 to end) in the IRQ stack:
+                                */
                                stack = (unsigned long *) (irqstack_end[-1]);
                                irqstack_end = NULL;
-                               i += printk(" <EOI>");
+                               ops->stack(data, "EOI");
                                continue;
                        }
                }
                break;
        }
 
+       /*
+        * This handles the process stack:
+        */
        HANDLE_STACK (((long) stack & (THREAD_SIZE-1)) != 0);
 #undef HANDLE_STACK
+}
+EXPORT_SYMBOL(dump_trace);
+
+static void
+print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
+{
+       print_symbol(msg, symbol);
        printk("\n");
 }
 
-void show_stack(struct task_struct *tsk, unsigned long * rsp)
+static void print_trace_warning(void *data, char *msg)
+{
+       printk("%s\n", msg);
+}
+
+static int print_trace_stack(void *data, char *name)
+{
+       printk(" <%s> ", name);
+       return 0;
+}
+
+static void print_trace_address(void *data, unsigned long addr)
+{
+       printk_address(addr);
+}
+
+static struct stacktrace_ops print_trace_ops = {
+       .warning = print_trace_warning,
+       .warning_symbol = print_trace_warning_symbol,
+       .stack = print_trace_stack,
+       .address = print_trace_address,
+};
+
+void
+show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long *stack)
+{
+       printk("\nCall Trace:\n");
+       dump_trace(tsk, regs, stack, &print_trace_ops, NULL);
+       printk("\n");
+}
+
+static void
+_show_stack(struct task_struct *tsk, struct pt_regs *regs, unsigned long *rsp)
 {
        unsigned long *stack;
        int i;
@@ -296,11 +457,16 @@ void show_stack(struct task_struct *tsk, unsigned long * rsp)
                        break;
                }
                if (i && ((i % 4) == 0))
-                       printk("\n       ");
-               printk("%016lx ", *stack++);
+                       printk("\n");
+               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);
 }
 
 /*
@@ -309,7 +475,7 @@ 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);
@@ -337,7 +503,7 @@ 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)
@@ -386,6 +552,7 @@ void out_of_line_bug(void)
 { 
        BUG(); 
 } 
+EXPORT_SYMBOL(out_of_line_bug);
 #endif
 
 static DEFINE_SPINLOCK(die_lock);
@@ -424,7 +591,7 @@ void __kprobes oops_end(unsigned long flags)
                /* Nest count reaches zero, release the lock. */
                spin_unlock_irqrestore(&die_lock, flags);
        if (panic_on_oops)
-               panic("Oops");
+               panic("Fatal exception");
 }
 
 void __kprobes __die(const char * str, struct pt_regs * regs, long err)
@@ -764,14 +931,6 @@ asmlinkage void __kprobes do_debug(struct pt_regs * regs,
                 */
                 if (!user_mode(regs))
                        goto clear_TF_reenable;
-               /*
-                * Was the TF flag set by a debugger? If so, clear it now,
-                * so that register information is correct.
-                */
-               if (tsk->ptrace & PT_DTRACE) {
-                       regs->eflags &= ~TF_MASK;
-                       tsk->ptrace &= ~PT_DTRACE;
-               }
        }
 
        /* Ok, finally something we can handle */
@@ -1018,3 +1177,18 @@ static int __init kstack_setup(char *s)
 }
 __setup("kstack=", kstack_setup);
 
+#ifdef CONFIG_STACK_UNWIND
+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, "newfallback") == 0)
+               call_trace = 1;
+       else if (strcmp(s, "new") == 0)
+               call_trace = 2;
+       return 1;
+}
+__setup("call_trace=", call_trace_setup);
+#endif