Our code does response to qXfer packet. Here is dump from Linaro debugger:
Sending packet: $qXfer:features:read:target.xml:0,fff#7d...Packet received: l<?x ml version="1.0"?>\n<!DOCTYPE target SYSTEM "gdb-target.dtd">\n<target version=" 1.0">\n<feature name="org.gnu.gdb.aarch64.core">\n<reg name="x0" bitsize="64" re gnum="0" save-restore="no" type="uint64" group="general"/>\n<reg name="x1" bitsi ze="64" regnum="1" save-restore="no" type="uint64" group="general"/>\n<reg name= "x2" bitsize="64" regnum="2" save-restore="no" type="uint64" group="general"/>\n <reg name="x3" bitsize="64" regnum="3" save-restore="no" type="uint64" group="ge neral"/>\n<reg name="x4" bitsize="64" regnum="4" save-restore="no" type="uint64" group="general"/>\n<reg name="x5" bitsize="64" regnum="5" save-restore="no" typ e="uint64" group="general"/>\n<reg name="x6" bitsize="64" regnum="6" save-restor e="no" type="uint64" group="general"/>\n<reg name="x7" bitsize="64" regnum="7" s ave-restore="no" type="uint64" group="general"/>\n<reg name="x8" bitsize="64" re gnum="8" save-restore="no" type="uint64" group="general"/>\n<reg name="x9" bitsi ze="64" regnum="9" save-restore="no" type="uint64" group="general"/>\n<reg name= "x10" bitsize="64" regnum="10" save-restore="no" type="uint64" group="general"/> \n<reg name="x11" bitsize="64" regnum="11" save-restore="no" type="uint64" group ="general"/>\n<reg name="x12" bitsize="64" regnum="12" save-restore="no" type="u int64" group="general"/>\n<reg name="x13" bitsize="64" regnum="13" save-restore= "no" type="uint64" group="general"/>\n<reg name="x14" bitsize="64" regnum="14" s ave-restore="no" type="uint64" group="general"/>\n<reg name="x15" bitsize="64" r egnum="15" save-restore="no" type="uint64" group="general"/>\n<reg name="x16" bi tsize="64" regnum="16" save-restore="no" type="uint64" group="general"/>\n<reg n ame="x17" bitsize="64" regnum="17" save-restore="no" type="uint64" group="genera l"/>\n<reg name="x18" bitsize="64" regnum="18" save-restore="no" type="uint64" g roup="general"/>\n<reg name="x19" bitsize="64" regnum="19" save-restore="no" typ e="uint64" group="general"/>\n<reg name="x20" bitsize="64" regnum="20" save-rest ore="no" type="uint64" group="general"/>\n<reg name="x21" bitsize="64" regnum="2 1" save-restore="no" type="uint64" group="general"/>\n<reg name="x22" bitsize="6 4" regnum="22" save-restore="no" type="uint64" group="general"/>\n<reg name="x23 " bitsize="64" regnum="23" save-restore="no" type="uint64" group="general"/>\n<r eg name="x24" bitsize="64" regnum="24" save-restore="no" type="uint64" group="ge neral"/>\n<reg name="x25" bitsize="64" regnum="25" save-restore="no" type="uint6 4" group="general"/>\n<reg name="x26" bitsize="64" regnum="26" save-restore="no" type="uint64" group="general"/>\n<reg name="x27" bitsize="64" regnum="27" save- restore="no" type="uint64" group="general"/>\n<reg name="x28" bitsize="64" regnu m="28" save-restore="no" type="uint64" group="general"/>\n<reg name="x29" bitsiz e="64" regnum="29" save-restore="no" type="uint64" group="general"/>\n<reg name= "lr" bitsize="64" regnum="30" save-restore="no" type="code_ptr" group="general"/
\n<reg name="sp" bitsize="64" regnum="31" save-restore="no" type="data_ptr" gro
up="general"/>\n<reg name="pc" bitsize="64" regnum="32" save-restore="no" type=" code_ptr" group="general"/>\n<reg name="cpsr" bitsize="32" regnum="33" save-rest ore="no" type="uint32" group="general"/>\n</feature>\n</target>\n warning: Architecture rejected target-supplied description
I don't understand why Linaro gdb debugger print the last warning message. Anyway, currently I added code to return value of fpsr and fpcr and so far everything seems ok.
Thanks, Strong Qu
-----Original Message----- From: Omair Javaid [mailto:omair.javaid@linaro.org] Sent: Tuesday, November 11, 2014 5:43 AM To: Will Newton Cc: Qu, Strong; 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?
There was discussion to put with-expat in default config options not sure if that has been done or not.
On 11 November 2014 13:39, Will Newton will.newton@linaro.org wrote:
Do we know if the Windows gdb binary links against expat? Without expat XML support is disabled.
On 11 November 2014 06:51, Omair Javaid omair.javaid@linaro.org wrote:
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.htm l#Retrieving-Descriptions
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
linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
-- Will Newton Toolchain Working Group, Linaro