Re: [PATCH master + 11] gdb: don't set Linux-specific displaced stepping methods in s390_gdbarch_init

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2021-07-07 11:08 a.m., Andreas Arnez wrote:
> On Wed, Jul 07 2021, Simon Marchi via Gdb-patches wrote:
> 
> [...]
> 
>> The Linux-specific callback was used
>> even for non-Linux system.  Maybe that was on purpose, because it would
>> also happen to work in some other non-Linux case, or maybe it was simply
>> a mistake.  I'll assume that this was a small mistake when
>> s390-tdep.{h,c} where factored out of s390-linux-tdep.c, in d6e589456475
>> ("s390: Split up s390-linux-tdep.c into two files").
> 
> I agree that this is probably a mistake.  It didn't cause any trouble
> right away, because GDB doesn't really support any other s390 OSs.  One
> possible additional "OS" would have been the Linux kernel runtime, but
> that hasn't manifested yet.
> 
>> Fix this by removing the setting of these displaced step callbacks from
>> s390_gdbarch_init.  Instead, pass num_disp_step_buffers=1 to
>> linux_init_abi, in s390_linux_init_abi_any.  Doing so will cause
>> linux_init_abi to register these same callbacks.  It will also mean that
>> when debugging a bare-metal s390 executable or an executable on another
>> OS that GDB doesn't know about, gdbarch_displaced_step_prepare won't be
>> set, so displaced stepping won't be used.
> 
> Sounds good to me, and the patch looks good as well.  Thanks!

Thanks for checking, I pushed it to both branches!

Simon