[PATCH] i386: Do stacktracer conversion too

Following x86-64 patches. Reuses code from them in fact.

Convert the standard backtracer to do all output using
callbacks.   Use the x86-64 stack tracer implementation
that uses these callbacks to implement the stacktrace interface.

This allows to use the new dwarf2 unwinder for stacktrace
and get better backtraces.

Cc: mingo@elte.hu

Signed-off-by: Andi Kleen <ak@suse.de>

4 files changed, 82 insertions, 121 deletions

diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index dab497472deb..1a884b6e6e5c 100644
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -81,4 +81,5 @@ $(obj)/vsyscall-syms.o: $(src)/vsyscall.lds \
         $(call if_changed,syscall)
 
 k8-y                      += ../../x86_64/kernel/k8.o
+stacktrace-y              += ../../x86_64/kernel/stacktrace.o
 
diff --git a/arch/i386/kernel/stacktrace.c b/arch/i386/kernel/stacktrace.c
deleted file mode 100644
index ae3c32a87add..000000000000
--- a/arch/i386/kernel/stacktrace.c
+++ /dev/null
@@ -1,93 +0,0 @@
-/*
- * arch/i386/kernel/stacktrace.c
- *
- * Stack trace management functions
- *
- *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
- */
-#include <linux/sched.h>
-#include <linux/stacktrace.h>
-
-static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
-{
-        return  p > (void *)tinfo &&
-                p < (void *)tinfo + THREAD_SIZE - 3;
-}
-
-/*
- * Save stack-backtrace addresses into a stack_trace buffer:
- */
-static inline unsigned long
-save_context_stack(struct stack_trace *trace, unsigned int skip,
-                   struct thread_info *tinfo, unsigned long *stack,
-                   unsigned long ebp)
-{
-        unsigned long addr;
-
-#ifdef CONFIG_FRAME_POINTER
-        while (valid_stack_ptr(tinfo, (void *)ebp)) {
-                addr = *(unsigned long *)(ebp + 4);
-                if (!skip)
-                        trace->entries[trace->nr_entries++] = addr;
-                else
-                        skip--;
-                if (trace->nr_entries >= trace->max_entries)
-                        break;
-                /*
-                 * break out of recursive entries (such as
-                 * end_of_stack_stop_unwind_function):
-                 */
-                if (ebp == *(unsigned long *)ebp)
-                        break;
-
-                ebp = *(unsigned long *)ebp;
-        }
-#else
-        while (valid_stack_ptr(tinfo, stack)) {
-                addr = *stack++;
-                if (__kernel_text_address(addr)) {
-                        if (!skip)
-                                trace->entries[trace->nr_entries++] = addr;
-                        else
-                                skip--;
-                        if (trace->nr_entries >= trace->max_entries)
-                                break;
-                }
-        }
-#endif
-
-        return ebp;
-}
-
-/*
- * Save stack-backtrace addresses into a stack_trace buffer.
- */
-void save_stack_trace(struct stack_trace *trace, struct task_struct *task)
-{
-        unsigned long ebp;
-        unsigned long *stack = &ebp;
-
-        WARN_ON(trace->nr_entries || !trace->max_entries);
-
-        if (!task || task == current) {
-                /* Grab ebp right from our regs: */
-                asm ("movl %%ebp, %0" : "=r" (ebp));
-        } else {
-                /* ebp is the last reg pushed by switch_to(): */
-                ebp = *(unsigned long *) task->thread.esp;
-        }
-
-        while (1) {
-                struct thread_info *context = (struct thread_info *)
-                                ((unsigned long)stack & (~(THREAD_SIZE - 1)));
-
-                ebp = save_context_stack(trace, trace->skip, context, stack, ebp);
-                stack = (unsigned long *)context->previous_esp;
-                if (!stack || trace->nr_entries >= trace->max_entries)
-                        break;
-                trace->entries[trace->nr_entries++] = ULONG_MAX;
-                if (trace->nr_entries >= trace->max_entries)
-                        break;
-        }
-}
-
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 3c85c89f68d8..4ced4285163b 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -51,6 +51,7 @@
 #include <asm/smp.h>
 #include <asm/arch_hooks.h>
 #include <asm/kdebug.h>
+#include <asm/stacktrace.h>
 
 #include <linux/module.h>
 
@@ -118,26 +119,16 @@ static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
                 p < (void *)tinfo + THREAD_SIZE - 3;
 }
 
-/*
- * Print one address/symbol entries per line.
- */
-static inline void print_addr_and_symbol(unsigned long addr, char *log_lvl)
-{
-        printk(" [<%08lx>] ", addr);
-
-        print_symbol("%s\n", addr);
-}
-
 static inline unsigned long print_context_stack(struct thread_info *tinfo,
                                 unsigned long *stack, unsigned long ebp,
-                                char *log_lvl)
+                                struct stacktrace_ops *ops, void *data)
 {
         unsigned long addr;
 
 #ifdef  CONFIG_FRAME_POINTER
         while (valid_stack_ptr(tinfo, (void *)ebp)) {
                 addr = *(unsigned long *)(ebp + 4);
-                print_addr_and_symbol(addr, log_lvl);
+                ops->address(data, addr);
                 /*
                  * break out of recursive entries (such as
                  * end_of_stack_stop_unwind_function):
@@ -150,28 +141,35 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo,
         while (valid_stack_ptr(tinfo, stack)) {
                 addr = *stack++;
                 if (__kernel_text_address(addr))
-                        print_addr_and_symbol(addr, log_lvl);
+                        ops->address(data, addr);
         }
 #endif
         return ebp;
 }
 
+struct ops_and_data {
+        struct stacktrace_ops *ops;
+        void *data;
+};
+
 static asmlinkage int
-show_trace_unwind(struct unwind_frame_info *info, void *log_lvl)
+dump_trace_unwind(struct unwind_frame_info *info, void *data)
 {
+        struct ops_and_data *oad = (struct ops_and_data *)data;
         int n = 0;
 
         while (unwind(info) == 0 && UNW_PC(info)) {
                 n++;
-                print_addr_and_symbol(UNW_PC(info), log_lvl);
+                oad->ops->address(oad->data, UNW_PC(info));
                 if (arch_unw_user_mode(info))
                         break;
         }
         return n;
 }
 
-static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
-                               unsigned long *stack, char *log_lvl)
+void dump_trace(struct task_struct *task, struct pt_regs *regs,
+                unsigned long *stack,
+                struct stacktrace_ops *ops, void *data)
 {
         unsigned long ebp;
 
@@ -181,31 +179,37 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
         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, task, regs) == 0)
-                                unw_ret = show_trace_unwind(&info, log_lvl);
+                                unw_ret = dump_trace_unwind(&info, &oad);
                 } else if (task == current)
-                        unw_ret = unwind_init_running(&info, show_trace_unwind, log_lvl);
+                        unw_ret = unwind_init_running(&info, dump_trace_unwind, &oad);
                 else {
                         if (unwind_init_blocked(&info, task) == 0)
-                                unw_ret = show_trace_unwind(&info, log_lvl);
+                                unw_ret = dump_trace_unwind(&info, &oad);
                 }
                 if (unw_ret > 0) {
                         if (call_trace == 1 && !arch_unw_user_mode(&info)) {
-                                print_symbol("DWARF2 unwinder stuck at %s\n",
+                                ops->warning_symbol(data, "DWARF2 unwinder stuck at %s\n",
                                              UNW_PC(&info));
                                 if (UNW_SP(&info) >= PAGE_OFFSET) {
-                                        printk("Leftover inexact backtrace:\n");
+                                        ops->warning(data, "Leftover inexact backtrace:\n");
                                         stack = (void *)UNW_SP(&info);
                                 } else
-                                        printk("Full inexact backtrace again:\n");
+                                        ops->warning(data, "Full inexact backtrace again:\n");
                         } else if (call_trace >= 1)
                                 return;
                         else
-                                printk("Full inexact backtrace again:\n");
+                                ops->warning(data, "Full inexact backtrace again:\n");
                 } else
-                        printk("Inexact backtrace:\n");
+                        ops->warning(data, "Inexact backtrace:\n");
+        } else  if (!stack) {
+                unsigned long dummy;
+                stack = &dummy;
+                if (task && task != current)
+                        stack = (unsigned long *)task->thread.esp;
         }
 
         if (task == current) {
@@ -220,15 +224,63 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
                 struct thread_info *context;
                 context = (struct thread_info *)
                         ((unsigned long)stack & (~(THREAD_SIZE - 1)));
-                ebp = print_context_stack(context, stack, ebp, log_lvl);
+                ebp = print_context_stack(context, stack, ebp, ops, data);
+                /* Should be after the line below, but somewhere
+                   in early boot context comes out corrupted and we
+                   can't reference it -AK */
+                if (ops->stack(data, "IRQ") < 0)
+                        break;
                 stack = (unsigned long*)context->previous_esp;
                 if (!stack)
                         break;
-                printk("%s =======================\n", log_lvl);
         }
 }
+EXPORT_SYMBOL(dump_trace);
+
+static void
+print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
+{
+        printk(data);
+        print_symbol(msg, symbol);
+        printk("\n");
+}
+
+static void print_trace_warning(void *data, char *msg)
+{
+        printk("%s%s\n", (char *)data, msg);
+}
+
+static int print_trace_stack(void *data, char *name)
+{
+        return 0;
+}
+
+/*
+ * Print one address/symbol entries per line.
+ */
+static void print_trace_address(void *data, unsigned long addr)
+{
+        printk("%s [<%08lx>] ", (char *)data, addr);
+        print_symbol("%s\n", 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,
+};
+
+static void
+show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
+                   unsigned long * stack, char *log_lvl)
+{
+        dump_trace(task, regs, stack, &print_trace_ops, log_lvl);
+        printk("%s =======================\n", log_lvl);
+}
 
-void show_trace(struct task_struct *task, struct pt_regs *regs, unsigned long * stack)
+void show_trace(struct task_struct *task, struct pt_regs *regs,
+                unsigned long * stack)
 {
         show_trace_log_lvl(task, regs, stack, "");
 }
diff --git a/include/asm-i386/stacktrace.h b/include/asm-i386/stacktrace.h
new file mode 100644
index 000000000000..7d1f6a5cbfca
--- /dev/null
+++ b/include/asm-i386/stacktrace.h
@@ -0,0 +1 @@
+#include <asm-x86_64/stacktrace.h>