bdiGDB for BDI2000 (PowerPC 7440/7450/86xx) User Manual 40
© Copyright 1997-2015 by ABATRON AG Switzerland V 1.13
To debug the Linux kernel when MMU is enabled you may use the following load and startup se-
quence:
• Load the compressed linux image
• Set a hardware breakpoint with the Telnet at a point where MMU is enabled. For example at
"start_kernel".
BDI> BI 0xC0061550 v
• Start the code with GO at the Telnet
• The Linux kernel is decompressed and started
• The system should stop at the hardware breakpoint (e.g. at start_kernel)
• Disable the hardware breakpoint with the Telnet command CI.
• If not automatically done by the kernel, setup the page table pointers for the BDI.
• Start GDB with vmlinux as parameter
• Attach to the target
• Now you should be able to debug the Linux kernel
To setup the BDI page table information structure manually, set a hardware breakpoint at
"start_kernel" and use the Telnet to write the address of "swapper_pg_dir" to the appropriate place.
BDI>bi 0xc0061550 /* set breakpoint at start_kernel */
BDI>go
.. /* target stops at start_kernel */
BDI>ci
BDI>mm 0xf0 0xc00000f8 /* Let PTBASE point to an array of two pointers*/
BDI>mm 0xf8 0xc0057000 /* write address of swapper_pg_dir to first pointer */
BDI>mm 0xfc 0x00000000 /* clear second (user) pointer */
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