Hi John,

Sorry it took so long, but I did eventually figure out what the problem was
and I believe I have fixed it.  Would you mind applying patch #20028
<https://gem5-review.googlesource.com/c/public/gem5/+/20028/1> and seeing
if it lets you do what you need?  If so, please give it a review and let me
know.

Thanks,
Alec Roelke

On Sat, Jul 20, 2019 at 2:12 PM Alec Roelke <[email protected]> wrote:

> Hi John,
>
> The GDB you're using should be fine.  Your error is most likely a bug in
> the GDB implementation in the RISC-V ISA within gem5.  I can take a look at
> it over the next week or so, but if you find a fix for it yourself don't
> hesitate to submit a patch.
>
> -Alec Roelke
>
> On Wed, Jul 17, 2019 at 3:19 PM John Liu <[email protected]> wrote:
>
>> Hi, colleges,
>>
>> I'm trying to use remote gdb debug for RISCV/gem5.debug in FS mode. The
>> binaries file I used to try this interface is the Berkely boot loader and
>> it has been able to boot in FS mode.
>>
>> * I enabled the "wait_for_remote_gdb" Params in BaseCPU.py and this
>> Params worked.
>>   But GDB part (riscv64-unknown-elf-gdb) returned glitch.
>>
>> * I tried the "hello world" binary with riscv64-unknown-elf-gdb in SE
>> mode.
>>   The similar glitch happened.
>>
>> * I also tried the remote debug the Berkeley boot loader in Qemu with the
>> same gdb tool. It works.
>>
>> Did I pick the wrong Riscv GDB tool for gem5? Did I miss anything?
>>
>> Any opinion will be helpful. I appreciate your time and help!
>>
>> Attached are the commands I used and the message I got:
>> ** Commands
>> *** The command I used for FS mode is :
>>       build/RISCV/gem5.debug configs/example/riscv_fs.py
>> *** The command  I used for remote gdb is:
>>       riscv64-unknown-elf-gdb -f bbl3
>>       (gdb) target remote : 7000
>>
>> ** Messages
>> *** The message I got from Gem5:
>> gem5 Simulator System.  http://gem5.org
>> gem5 is copyrighted software; use the --copyright option for details.
>>
>> gem5 compiled Jul 17 2019 11:55:28
>> gem5 started Jul 17 2019 11:59:25
>> gem5 executing on riscv_fs, pid 14710
>> command line: build/RISCV/gem5.debug configs/example/riscv_fs.py
>>
>>
>> Global frequency set at 1000000000000 ticks per second
>> warn: DRAM device capacity (8192 Mbytes) does not match the address range
>> assigned (32768 Mbytes)
>> info: kernel located at: /home/ riscv_fs/gem5/gem5_ad2039/bbl3
>> 0: system.remote_gdb: listening for remote gdb on port 7000
>> info: system.cpu: Waiting for a remote GDB connection on port 7000.
>>       0: system.remote_gdb: remote gdb attached
>> start load DTB file/home/riscv_fs/gem5/gem5_ad2039/cpu.dtb
>> Beginning simulation!
>> info: Entering event queue @ 0.  Starting simulation...
>> warn: Couldn't read data from debugger.
>>       0: system.remote_gdb: remote gdb detached
>> This is bbl's dummy_payload.  To boot a real kernel, reconfigure bbl
>> with the flag --with-payload=PATH, then rebuild bbl. Alternatively,
>> bbl can be used in firmware-only mode by adding device-tree nodes
>> for an external payload and use QEMU's -bios and -kernel options.
>>
>>     chosen {
>>         riscv,kernel-start = <payload_start>;
>>         riscv,kernel-end = <payload_end>;
>>     };
>> *** message I got from gdb is:
>> Remote debugging using : 7000
>> Remote 'g' packet reply is too long (expected 532 bytes, got 1468 bytes):
>> 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000080000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000003000000000000002d111400000000000000000000000000000000000000000000000000002000000a0000000000000000000000000000000000000000000000000000003f702f5d000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000700000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000700000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>>
>>
>>
>>
>> _______________________________________________
>> gem5-users mailing list
>> [email protected]
>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
>
>
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