Have you implemented a qXfer packet response if not you can do so to use xml description provided by target.
Here is a gdb help link that describe how to client can query target.xml.
https://sourceware.org/gdb/onlinedocs/gdb/Retrieving-Descriptions.html#Retri...
On 10 November 2014 19:42, Qu, Strong strongq@qti.qualcomm.com wrote:
Thanks, Omair. I did check xml files in Linaro's source (gdb-linaro-7.6.1-2013.10). In the target.xml file our gdb server sends back to gdb client, we only include regsiters X0~X30, sp, pc and cpsr. It's close to gdb-linaro-7.6.1-2013.10\gdb\features\aarch64-core.xml, which is included in aarch64-without-fpu.xml. I don't know how the server can notify the client that it does not have FPU supported. So I assume if the target.xml does not claim feature 'org.gnu.gdb.aarch64.fpu’, it would be deemed as no FPU supporting. For now, I added some code in our code to return the value of fpsr and fpcr to make the gdb client happy.
Regards, Strong
-----Original Message----- From: Omair Javaid [mailto:omair.javaid@linaro.org] Sent: Monday, November 10, 2014 3:30 AM To: Qu, Strong Cc: linaro-toolchain@lists.linaro.org Subject: Re: [Question] Should gdb client query FP registers even if gdb server does not report having org.gnu.gdb.aarch64.fpu feature?
On 7 November 2014 02:27, Qu, Strong strongq@qti.qualcomm.com wrote:
Hello,
We have implemented gdb server in one of our project and we are using Linaro aarch64-none-elf-gdb.exe as gdb client. Our gdb server will response to packet 'qXfer:features:read:target.xml:0,fff' with a xml file which only claims feature ‘org.gnu.gdb.aarch64.core’. However, when I issue ‘info reg’ command with the gdb client, it actually sends out a packet ‘$p42#d6’, which is trying to read fpsr if I understand correctly. Is this an expected behavior or not? I just want to figure out whether our gdb server send some bad info to the gdb client and made the client thinks FP registers are valid. I hope I made my question clear and I’m really appreciate if anybody can help us on this again.
Thanks,
Strong
linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
Hi Strong,
GDB server will receive a register read request based on registers information given in xml target description on the client side.
You can find these xml in gdb sources under: binutils-gdb/gdb/features
If GDB is requesting a read for certain register that you expect it should not then you have to verify if its there in the xml description or not.
There is a chance you might have developed your gdbserver implementation with some version that doesnt match with current version of linaro-gdb.
I hope this helps. Let me know if you need to know anything further.
Thanks!
-- Omair