I have a Raspberry Pi zero 2 W. I am b uilding on an X86 Ubuntu 22.04 host. I was able to follow the steps to cross-compile the kernel from source located https://www.raspberrypi.com/documentati ... ernel.html. The build was successful and I booted off of it an all seems OK.
I want to enable KGDB in the kernel. When I run find on vmlinux it says "not stripped" but doesn't say "with debug_info".
I found this page about KGDB https://linuxlink.timesys.com/docs/how_to_use_kgdb. It seems to imply that menuconfig will just have an enable debug info option in kernel hacking.
Include Kernel Hacking -> Compile the Kernel with debug info
But that doesn't seem to be the case in my version of Kernel Hacking.
When I go into Kernel Hacking I see "Compile-time checks and compiler options", in there it says "Debug Information" and I get these options:
(X) Disable debug information
( ) Rely on the toolchain's implicit default DWARF version
( ) Generate DWARF Version 4 debuiginfo
( ) Generate DWARF Version 5 debuginfo.
I have picked the "Rely on the toolchain's implicit default DWARF version".
I was able to save that configuration and rebuild the image and modules and it succeeded. Now find shows:
$ file vmlinux
vmlinux: ELF 64-bit LSB pie executable, ARM aarch64, version 1 (SYSV), statically linked, BuildID[sha1]=30973decdf1b9ea04d09d087839f4942e55c5cee, with debug_info, not stripped
So, I do get the debug information and gdb seems to be happy with it.
$ gdb -f vmlinux
GNU gdb (Ubuntu 12.1-0ubuntu1~22.04.2) 12.1
<copyright stuff>
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from vmlinux...
(gdb)
which is better than before. I still need to figure out how to activate KGDB in the kernel when it is running and get gdb to connect to it. I'll start working on that.
I am wondering if I picked the correct DWARF option or if I should be selecting one of the others?
Thanks
Chris
I want to enable KGDB in the kernel. When I run find on vmlinux it says "not stripped" but doesn't say "with debug_info".
I found this page about KGDB https://linuxlink.timesys.com/docs/how_to_use_kgdb. It seems to imply that menuconfig will just have an enable debug info option in kernel hacking.
Include Kernel Hacking -> Compile the Kernel with debug info
But that doesn't seem to be the case in my version of Kernel Hacking.
When I go into Kernel Hacking I see "Compile-time checks and compiler options", in there it says "Debug Information" and I get these options:
(X) Disable debug information
( ) Rely on the toolchain's implicit default DWARF version
( ) Generate DWARF Version 4 debuiginfo
( ) Generate DWARF Version 5 debuginfo.
I have picked the "Rely on the toolchain's implicit default DWARF version".
I was able to save that configuration and rebuild the image and modules and it succeeded. Now find shows:
$ file vmlinux
vmlinux: ELF 64-bit LSB pie executable, ARM aarch64, version 1 (SYSV), statically linked, BuildID[sha1]=30973decdf1b9ea04d09d087839f4942e55c5cee, with debug_info, not stripped
So, I do get the debug information and gdb seems to be happy with it.
$ gdb -f vmlinux
GNU gdb (Ubuntu 12.1-0ubuntu1~22.04.2) 12.1
<copyright stuff>
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from vmlinux...
(gdb)
which is better than before. I still need to figure out how to activate KGDB in the kernel when it is running and get gdb to connect to it. I'll start working on that.
I am wondering if I picked the correct DWARF option or if I should be selecting one of the others?
Thanks
Chris
Statistics: Posted by chriskot870 — Mon Aug 12, 2024 11:55 pm
