You can import the uClinux-dist to Nios2 IDE, ie Eclipse, and debug kernel.

The debug info (-g) is disabled by default. To enable debug info,

Kernel hacking -->
[*] Kernel debugging
 [*] Compile the kernel with debug info


1. Open Nios2 IDE from a shell, ie, run "nios2-ide" .

2. From IDE menu, import the uClinux-dist dir. After you press [finish], it will take some time scanning the dir.
File > Import > Altera Nios II > Existing Nios II software build tools project or folder into workspace
Project contents :  < brow to your uClinux-dist dir >
Project name : < eg, uclinux  >  # you cannot use uClinux-dist as project name, it doesn't like "-".

3. Connect jtag cable to your board, and configure your fpga with nios2-configure-sof if it is not configured yet.

4. Select project uclinux from the left-hand side of the windows.Set Up a Debug Configuration.
Run > Debug As > Nios II Hardware

5. A Debug Configuration Manager will come out,
Nios II ELF Excutable: linux-2.6.x/vmlinux
SOPC Builder System PTF File: < brow to your system.ptf >
Click [Apply]
Click [Debug]

6. If the Confirm Perspective Switch dialog box appears, click Yes. You can debug the kernel now.




Ref,
Nios II Software Developer’s Handbook, ch3. Introduction to the Nios II Software Build Tools
Nios II IDE help, Running and Debugging on Hardware