1. Home
  2. Embedded Linux
  3. embedded Linux : how to co-ordinate System.map with PC address

embedded Linux : how to co-ordinate System.map with PC address

Hi, I have a linux kernel build and try to load it to a PowerPC development board. I use a JTAG debugger to download the kernal.

Linux boot hangs in middle, and in the JTAG debugger I can see that PC is 0x00001200, from my limited knowledge I should check out System.map to guess which driver function is the problem.

But this time it is weired, in System.map, there is no address around that 0x00001200 I can see, all function addresses are above 0xC0000000.

I wonder what is the problem. That knowledge worked for me before, is it accidently true?

I also run "objdump -S" against the kernel ELF file, it seems true that all addresses are above 0xc0000000.

Could you give me any suggestion?

Reply to
linq936
Loading thread data ...

What you are seeing is the Physical Address of the PC. This means that the Kernel has not enabled the MMU yet, so the CPU is still using Physical Addresses. One of the first things that the kernel does is to enable the MMU, which will map Physical Addresses at 0x00000000 to Virtual Addresses at 0xc00000000. When you look at the System.map, you will see the entire kernel being mapped to the Virtual Address of 0xc00000000.

If you want to translate the Physical Address of 0x1200, just add

0xc0000000 to it (or in this case, 0xc0001200).

Also, 0x00001200 is a PowerPC Exception Vector for an Instruction TLB Miss. This means that your TLB table is not being initialized correctly prior to the kernel being executed, so you might want to look at the code which initializes your TLBs.

Chuck

Reply to
Chuck Gales

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.