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Diffstat (limited to 'Documentation/DocBook/kgdb.tmpl')
| -rw-r--r-- | Documentation/DocBook/kgdb.tmpl | 38 |
1 files changed, 24 insertions, 14 deletions
diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl index 028a8444d95..372dec20c8d 100644 --- a/Documentation/DocBook/kgdb.tmpl +++ b/Documentation/DocBook/kgdb.tmpl @@ -84,10 +84,9 @@ runs an instance of gdb against the vmlinux file which contains the symbols (not boot image such as bzImage, zImage, uImage...). In gdb the developer specifies the connection parameters and - connects to kgdb. Depending on which kgdb I/O modules exist in - the kernel for a given architecture, it may be possible to debug - the test machine's kernel with the development machine using a - rs232 or ethernet connection. + connects to kgdb. The type of connection a developer makes with + gdb depends on the availability of kgdb I/O modules compiled as + builtin's or kernel modules in the test machine's kernel. </para> </chapter> <chapter id="CompilingAKernel"> @@ -99,6 +98,24 @@ "Kernel debugging" select "KGDB: kernel debugging with remote gdb". </para> <para> + It is advised, but not required that you turn on the + CONFIG_FRAME_POINTER kernel option. This option inserts code to + into the compiled executable which saves the frame information in + registers or on the stack at different points which will allow a + debugger such as gdb to more accurately construct stack back traces + while debugging the kernel. + </para> + <para> + If the architecture that you are using supports the kernel option + CONFIG_DEBUG_RODATA, you should consider turning it off. This + option will prevent the use of software breakpoints because it + marks certain regions of the kernel's memory space as read-only. + If kgdb supports it for the architecture you are using, you can + use hardware breakpoints if you desire to run with the + CONFIG_DEBUG_RODATA option turned on, else you need to turn off + this option. + </para> + <para> Next you should choose one of more I/O drivers to interconnect debugging host and debugged target. Early boot debugging requires a KGDB I/O driver that supports early debugging and the driver must be @@ -223,7 +240,7 @@ </para> <para> IMPORTANT NOTE: Using this option with kgdb over the console - (kgdboc) or kgdb over ethernet (kgdboe) is not supported. + (kgdboc) is not supported. </para> </sect1> </chapter> @@ -249,18 +266,11 @@ (gdb) target remote /dev/ttyS0 </programlisting> <para> - Example (kgdb to a terminal server): - </para> - <programlisting> - % gdb ./vmlinux - (gdb) target remote udp:192.168.2.2:6443 - </programlisting> - <para> - Example (kgdb over ethernet): + Example (kgdb to a terminal server on tcp port 2012): </para> <programlisting> % gdb ./vmlinux - (gdb) target remote udp:192.168.2.2:6443 + (gdb) target remote 192.168.2.2:2012 </programlisting> <para> Once connected, you can debug a kernel the way you would debug an |