stack backtrace

@@ -116,8 +116,129 @@
 	printk("\n");
 }
 
-void show_trace(struct task_struct *task, unsigned long *stack)
+#include <asm/inst.h>
+
+static struct mips_frame_info {
+	void *func;
+	int omit_fp;	/* compiled without fno-omit-frame-pointer */
+	int frame_offset;
+	int pc_offset;
+} tmp_frame;
+
+static int get_frame_info(void *func,struct mips_frame_info *info)
+{
+	int i;
+	union mips_instruction *ip = (union mips_instruction *)func;
+	info->pc_offset = -1;
+	info->frame_offset = -1;
+	for (i = 0; i < 128; i++, ip++) {
+		/* if jal, jalr, jr, stop. */
+		if (ip->j_format.opcode == jal_op ||
+		    (ip->r_format.opcode == spec_op &&
+		     (ip->r_format.func == jalr_op ||
+		      ip->r_format.func == jr_op)))
+			break;
+
+		if (
+#ifdef CONFIG_32BIT
+		    ip->i_format.opcode == sw_op &&
+#endif
+#ifdef CONFIG_64BIT
+		    ip->i_format.opcode == sd_op &&
+#endif
+		    ip->i_format.rs == 29)
+		{
+			/* sw / sd $ra, offset($sp) */
+			if (ip->i_format.rt == 31) {
+				if (info->pc_offset != -1)
+					continue;
+				info->pc_offset =
+					ip->i_format.simmediate / sizeof(long);
+			}
+			/* sw / sd $s8, offset($sp) */
+			if (ip->i_format.rt == 30) {
+//#if 0	/* gcc 3.4 does aggressive optimization... */
+				if (info->frame_offset != -1)
+					continue;
+//#endif
+				info->frame_offset =
+					ip->i_format.simmediate / sizeof(long);
+			}
+		}
+	}
+	if (info->pc_offset == -1 || info->frame_offset == -1) {
+		printk("Can't analyze prologue code at %p\n", func);
+		info->pc_offset = -1;
+		info->frame_offset = -1;
+		return -1;
+	}
+
+	return 0;
+}
+
+static void show_trace(struct task_struct *task, void *regs_in)
 {
+	unsigned long prev_sp,stack_top;
+	unsigned long count = 0;
+	unsigned long frame, pc;
+	char namebuf[KSYM_NAME_LEN+1];
+	const char *name;
+	char *modname;
+	unsigned long size,offset;
+	struct pt_regs *regs;
+	int in_exception = 0;
+
+	if (regs_in) /* called from show_registers */
+	  regs = (struct pt_regs*) regs_in;
+	else
+	  regs = (struct pt_regs *) ((unsigned long) task->thread_info +
+	      THREAD_SIZE - 32 - sizeof(struct pt_regs));
+
+	printk("Call Trace:\n");
+
+	prev_sp = (unsigned long) (task->thread_info + 1);
+	stack_top = (unsigned long) task->thread_info + THREAD_SIZE;
+
+	pc = (unsigned long)show_trace;
+
+	if (get_frame_info((void*)pc,&tmp_frame))
+	  return;
+
+	__asm__ volatile ("addu %0,$0,$30" : "=r" (frame));
+
+	do {
+		pc = ((unsigned long *)frame)[tmp_frame.pc_offset];
+		frame = ((unsigned long *)frame)[tmp_frame.frame_offset];
+		if (frame < prev_sp || frame > stack_top) {
+		  printk("out of range sp %08lx,give up!\n",frame);
+		  break;
+		}
+
+	    retry_pc:
+		if (!__kernel_text_address(pc)) {
+		  printk("out of text addr %08lx,give up!\n",pc);
+		  break;
+		}
+
+		name = kallsyms_lookup(pc, &size, &offset, &modname, namebuf);
+		if (!name) {
+		  printk("no function found at %08lx\n",pc);
+		  return;
+		}
+		printk("%s at %08lx,frame=%08lx",name,pc,frame);
+
+		pc = pc - offset;
+		if (get_frame_info((void*)pc,&tmp_frame) && !in_exception) {
+		  printk("get frame information failed, assume exceptions\n");
+		  in_exception = 1;
+		  pc = regs->cp0_epc;
+		  frame = regs->regs[30];
+		  printk("epc = %08lx,frame=%08lx\n",pc,frame);
+		  goto retry_pc;
+		}
+	} while (count++ < 16);
+
+#if 0
 	const int field = 2 * sizeof(unsigned long);
 	unsigned long addr;
 

@@ -140,6 +261,7 @@
 		}
 	}
 	printk("\n");
+#endif
 }
 
 /*

@@ -147,9 +269,10 @@
  */
 void dump_stack(void)
 {
-	unsigned long stack;
+	//unsigned long stack;
 
-	show_trace(current, &stack);
+	//show_trace(current, &stack);
+	show_trace(current, NULL);
 }
 
 EXPORT_SYMBOL(dump_stack);

@@ -269,7 +392,8 @@
 	printk("Process %s (pid: %d, threadinfo=%p, task=%p)\n",
 	        current->comm, current->pid, current_thread_info(), current);
 	show_stack(current, (long *) regs->regs[29]);
-	show_trace(current, (long *) regs->regs[29]);
+	//show_trace(current, (long *) regs->regs[29]);
+	show_trace(current,(void*) regs);
 	show_code((unsigned int *) regs->cp0_epc);
 	printk("\n");
 }

@@ -314,6 +314,9 @@
 	int i;
 	void *func = info->func;
 	union mips_instruction *ip = (union mips_instruction *)func;
+#ifdef CONFIG_FRAME_POINTER
+	info->omit_fp = 0;
+#endif
 	info->pc_offset = -1;
 	info->frame_offset = info->omit_fp ? 0 : -1;
 	for (i = 0; i < 128; i++, ip++) {