[PATCH] uml: stack dump fix

Copy (and adapt) to UML the stack code dumper used in i386 when
CONFIG_FRAME_POINTER is enabled.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 79 insertions, 1 deletions

diff --git a/arch/um/sys-i386/sysrq.c b/arch/um/sys-i386/sysrq.c
index 281fc7b8ca00..e3706d15c4f5 100644
--- a/arch/um/sys-i386/sysrq.c
+++ b/arch/um/sys-i386/sysrq.c
@@ -3,12 +3,15 @@
  * Licensed under the GPL
  */
 
+#include "linux/config.h"
 #include "linux/kernel.h"
 #include "linux/smp.h"
 #include "linux/sched.h"
+#include "linux/kallsyms.h"
 #include "asm/ptrace.h"
 #include "sysrq.h"
 
+/* This is declared by <linux/sched.h> */
 void show_regs(struct pt_regs *regs)
 {
         printk("\n");
@@ -31,5 +34,80 @@ void show_regs(struct pt_regs *regs)
                0xffff & PT_REGS_DS(regs), 
                0xffff & PT_REGS_ES(regs));
 
-        show_trace((unsigned long *) &regs);
+        show_trace(NULL, (unsigned long *) &regs);
 }
+
+/* Copied from i386. */
+static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
+{
+        return  p > (void *)tinfo &&
+                p < (void *)tinfo + THREAD_SIZE - 3;
+}
+
+/* Adapted from i386 (we also print the address we read from). */
+static inline unsigned long print_context_stack(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);
+                printk("%08lx:  [<%08lx>]", ebp + 4, addr);
+                print_symbol(" %s", addr);
+                printk("\n");
+                ebp = *(unsigned long *)ebp;
+        }
+#else
+        while (valid_stack_ptr(tinfo, stack)) {
+                addr = *stack;
+                if (__kernel_text_address(addr)) {
+                        printk("%08lx:  [<%08lx>]", (unsigned long) stack, addr);
+                        print_symbol(" %s", addr);
+                        printk("\n");
+                }
+                stack++;
+        }
+#endif
+        return ebp;
+}
+
+void show_trace(struct task_struct* task, unsigned long * stack)
+{
+        unsigned long ebp;
+        struct thread_info *context;
+
+        /* Turn this into BUG_ON if possible. */
+        if (!stack) {
+                stack = (unsigned long*) &stack;
+                printk("show_trace: got NULL stack, implicit assumption task == current");
+                WARN_ON(1);
+        }
+
+        if (!task)
+                task = current;
+
+        if (task != current) {
+                //ebp = (unsigned long) KSTK_EBP(task);
+                /* Which one? No actual difference - just coding style.*/
+                ebp = (unsigned long) PT_REGS_EBP(&task->thread.regs);
+        } else {
+                asm ("movl %%ebp, %0" : "=r" (ebp) : );
+        }
+
+        context = (struct thread_info *)
+                ((unsigned long)stack & (~(THREAD_SIZE - 1)));
+        print_context_stack(context, stack, ebp);
+
+        /*while (((long) stack & (THREAD_SIZE-1)) != 0) {
+                addr = *stack;
+                if (__kernel_text_address(addr)) {
+                        printk("%08lx:  [<%08lx>]", (unsigned long) stack, addr);
+                        print_symbol(" %s", addr);
+                        printk("\n");
+                }
+                stack++;
+        }*/
+        printk("\n");
+}
+