Re: Re: I compile gdbserver for RISCV on gdb10.1 version, and there is a error

Re: Re: I compile gdbserver for RISCV on gdb10.1 version, and there is a error

[Jim Wilson]

On Mon, Nov 16, 2020 at 5:38 AM <hilihui@sina.com> wrote:

> So do you mean that the gdb for RISCV on some project is not supported,
> because these projects still use the old linux kernel system.
>
> Now i am working on "https://github.com/pulp-platform/ariane-sdk"
> project, and the project still use the old linux kernel system, so the gdb
> on the platform is not available.
>

If you have an old linux kernel, gdb will not work due to bugs in the linux
kernel ptrace support.  I submitted two patches to fix two problems in Fall
2018.  Then there was a third patch to add support for FP registers but you
only need that one if you want to look at FP registers.  You definitely
need the first two patches in the kernel.

Jim

Re: I compile gdbserver for RISCV on gdb10.1 version, and there is a error

[Rodney M. Bates]

On 11/16/20 3:55 PM, Jim Wilson wrote:
> On Mon, Nov 16, 2020 at 5:38 AM <hilihui@sina.com> wrote:
> 
>> So do you mean that the gdb for RISCV on some project is not supported,
>> because these projects still use the old linux kernel system.
>>
>> Now i am working on "https://github.com/pulp-platform/ariane-sdk"
>> project, and the project still use the old linux kernel system, so the gdb
>> on the platform is not available.
>>
> 
> If you have an old linux kernel, gdb will not work due to bugs in the linux
> kernel ptrace support.  I submitted two patches to fix two problems in Fall
> 2018.  Then there was a third patch to add support for FP registers but you
> only need that one if you want to look at FP registers.  You definitely

How old a Linux kernel has these bugs?

> need the first two patches in the kernel.
> 
> Jim
> 

-- 
Rodney Bates
rodney.m.bates@acm.org

Re: I compile gdbserver for RISCV on gdb10.1 version, and there is a error

[Jim Wilson]

On Fri, Nov 20, 2020 at 7:48 AM Rodney M. Bates <rodney_bates@lcwb.coop>
wrote:

> On 11/16/20 3:55 PM, Jim Wilson wrote:
> > If you have an old linux kernel, gdb will not work due to bugs in the
> linux
> > kernel ptrace support.  I submitted two patches to fix two problems in
> Fall
> > 2018.  Then there was a third patch to add support for FP registers but
> you
> > only need that one if you want to look at FP registers.  You definitely
>
> How old a Linux kernel has these bugs?
>

Fall 2018.  I don't know linux kernel version numbers.  You can look it
up.  Certainly 4.15 won't work without patches.  But another person pointed
at a patched 4.15 tree that has the two most important patches.

Jim

Re: I compile gdbserver for RISCV on gdb10.1 version, and there is a error

[Rodney M. Bates]

On 11/20/20 2:37 PM, Jim Wilson wrote:
> On Fri, Nov 20, 2020 at 7:48 AM Rodney M. Bates <rodney_bates@lcwb.coop>
> wrote:
> 
>> On 11/16/20 3:55 PM, Jim Wilson wrote:
>>> If you have an old linux kernel, gdb will not work due to bugs in the
>> linux
>>> kernel ptrace support.  I submitted two patches to fix two problems in
>> Fall
>>> 2018.  Then there was a third patch to add support for FP registers but
>> you
>>> only need that one if you want to look at FP registers.  You definitely
>>
>> How old a Linux kernel has these bugs?
>>
> 
> Fall 2018.  I don't know linux kernel version numbers.  You can look it
> up.  Certainly 4.15 won't work without patches.  But another person pointed
> at a patched 4.15 tree that has the two most important patches.
> 

OK, thanks.

> Jim
> 

-- 
Rodney Bates
rodney.m.bates@acm.org

Re: I compile gdbserver for RISCV on gdb10.1 version, and there is a error

[Jim Wilson]

On Fri, Nov 13, 2020 at 5:13 AM Simon Marchi <simark@simark.ca> wrote:

> On 2020-11-12 9:43 p.m., hilihui@sina.com wrote:
> > ../../gdbserver/linux-riscv-low.cc:170:42: error: invalid application of
> 'sizeof' to incomplete type '__riscv_mc_q_ext_state'     sizeof (struct
> __riscv_mc_q_ext_state), OPTIONAL_REGS,
>       ^It seems that  "__riscv_mc_q_ext_state" is not defined. How to
> resolve this question? Thanks!
> >
>
> In glibc, this type is provided here:
>
>
> https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/riscv/sys/ucontext.h;h=a4e49fe37a1397fa1babeb0dcefb77341f1e7ad1;hb=HEAD#l65
>
> And it appears to have been there since the beginning of the RISC-V
> support.
>

Since the beginning of upstream support, yes.  But it was an academic
project for years before it was upstreamed and some people are stuck with
old stuff because they forked a while back and never upgraded.  Or maybe
haven't upgraded yet.  The ETH Zurich pulp project for instance.

> What libc is your system using?
>

He sent me private mail too.  I suspect he is missing the linux kernel
RISC-V specific ptrace support also.  That came after the glibc support.

Jim

Re: I compile gdbserver for RISCV on gdb10.1 version, and there is a error

[Simon Marchi]

On 2020-11-12 9:43 p.m., hilihui@sina.com wrote:
> ../../gdbserver/linux-riscv-low.cc:170:42: error: invalid application of 'sizeof' to incomplete type '__riscv_mc_q_ext_state'     sizeof (struct __riscv_mc_q_ext_state), OPTIONAL_REGS,                                          ^It seems that  "__riscv_mc_q_ext_state" is not defined. How to resolve this question? Thanks!
> 

In glibc, this type is provided here:

https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/riscv/sys/ucontext.h;h=a4e49fe37a1397fa1babeb0dcefb77341f1e7ad1;hb=HEAD#l65

And it appears to have been there since the beginning of the RISC-V support.

What libc is your system using?

Simon

I compile gdbserver for RISCV on gdb10.1 version, and there is a error

[hilihui]

../../gdbserver/linux-riscv-low.cc:170:42: error: invalid application of 'sizeof' to incomplete type '__riscv_mc_q_ext_state'     sizeof (struct __riscv_mc_q_ext_state), OPTIONAL_REGS,                                          ^It seems that  "__riscv_mc_q_ext_state" is not defined. How to resolve this question? Thanks!