57 lines
1.7 KiB
Markdown
57 lines
1.7 KiB
Markdown
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# seL4 extensions for GDB
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Convenience script for GDB, adding additional facilities for
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debugging seL4 applications.
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## Features
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* Creating and removing breakpoints on address in specific thread,
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* Creating and removing breakpoint on context-switches between kernel and userspace,
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* Auto-loading symbols for CAmkES project
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* Investigating current thread
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## Usage
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Firstly, `seL4Extensions.cs` and kernel symbols have to be loaded in Renode. This can be accomplished by adding following lines to `.resc` file:
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```
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include @path/to/seL4Extensions.cs
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sysbus LoadSymbolsFrom @path/to/kernel.elf
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```
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Before simulation is started (using `start` command in Renode), the seL4 extensions have to be loaded on
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correct CPU, which can be done using `cpu CreateSeL4` command in Renode. Lastly, the Renode-GDB glue has to be sourced in GDB. All those steps can be done in single command:
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```
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$ gdb-multiarch -ex 'target remote :3333' -ex 'monitor cpu CreateSeL4' \
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-ex 'source path/to/gdbscript.py' -ex 'monitor start'
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```
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`start` at the end is optional.
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In GDB information about commands can be accessed using `info sel4` command.
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## Example
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### Create breakpoint on main function in rootserver thread
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```
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(gdb) # Wait until rootserver thread is known to seL4 extensions
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(gdb) sel4 wait-for-thread rootserver
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(gdb) # Switch symbols to rootserver's
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(gdb) sel4 switch-symbols rootserver
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(gdb) # Create temporary breakpoint on main function in rootserver thread
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(gdb) sel4 tbreak rootserver main
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(gdb) continue
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(gdb) # We can confirm, that we are indeed in rootserver thread
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(gdb) sel4 thread
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rootserver
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```
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### Return from userspace to kernel
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```
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(gdb) # Create temporary breakpoint on context-switch to kernel
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(gdb) sel4 tbreak kernel
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(gdb) continue
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(gdb) sel4 thread
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kernel
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```
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