Re: [PING] [PATCH 0/8] Switch FreeBSD x86 to using register maps for GP registers

[John Baldwin <jhb@FreeBSD.org>]

On 9/14/21 8:43 AM, John Baldwin wrote:
> On 8/10/21 8:56 AM, John Baldwin wrote:
>> On 7/14/21 7:07 AM, John Baldwin wrote:
>>> The x86 architectures in GDB provide existing helpers for parsing
>>> general-purpose register sets.  However, these helpers have some
>>> limitations, such as assuming that registers are always full size.  On
>>> FreeBSD/amd64 in particular, segment registers are stored as 16-bit
>>> quantities that in some cases are packed together.  GDB for historical
>>> reasons treats these 16-bit registers as 32 bits in size.  Using the
>>> more generic regcache_map_entry to describe the GP register sets
>>> permits supporting these registers as 16-bit values.  In addition, the
>>> FreeBSD x86 signal frames have included the base address of the FS and
>>> GS segments (equivalent to the fs_base and gs_base registers), but the
>>> existing signal context helpers were written before those registers
>>> were added to GDB.
>>>
>>> Longer term my goal is to use regcache_map_entry-based register sets
>>> in FreeBSD gdbserver support to simplify the implementation.
>>>
>>> Note that patch 4 fixes an issue in regcache_collect_regset where it
>>> didn't quite do what I thought it did.  I believe the change is ok,
>>> but it definitely warrants review.
>>
>> Ping.  Patch 4 is the only one that isn't FreeBSD-specific.
> 
> Pinging again.  I could perhaps push the first 3 patches as they are
> FreeBSD specific.  Patch 4 is a prereq for the following patches however.

Pinging again.

>>> I have tested this on both FreeBSD/amd64 (32-bit and 64-bit processes)
>>> and FreeBSD/i386.
>>>
>>> John Baldwin (8):
>>>      Remove vestigal FreeBSD/i386 3.x support.
>>>      Remove support for pre-5.0 FreeBSD/i386 signal trampolines.
>>>      FreeBSD x86: Remove fallback for detecting signal trampolines by
>>>        address.
>>>      regcache: Zero-extend small registers described by a register map.
>>>      Use register maps for gp regsets on FreeBSD/x86 core dumps.
>>>      FreeBSD x86: Use tramp-frame for signal frames.
>>>      fbsd-nat: Return a bool from fetch_register_set and
>>>        store_register_set.
>>>      FreeBSD x86 nat: Use register maps for GP register sets.
>>>
>>>     gdb/amd64-bsd-nat.c   |  96 ---------
>>>     gdb/amd64-fbsd-nat.c  | 346 ++++++++++++++++++-------------
>>>     gdb/amd64-fbsd-tdep.c | 279 ++++++++++++++-----------
>>>     gdb/amd64-fbsd-tdep.h |  27 +++
>>>     gdb/amd64-tdep.h      |   5 -
>>>     gdb/configure.nat     |   4 +-
>>>     gdb/fbsd-nat.c        |   8 +-
>>>     gdb/fbsd-nat.h        |  21 +-
>>>     gdb/i386-bsd-nat.c    |  98 +--------
>>>     gdb/i386-fbsd-nat.c   | 255 +++++++++++++++++++----
>>>     gdb/i386-fbsd-tdep.c  | 461 ++++++++++++++++++------------------------
>>>     gdb/i386-fbsd-tdep.h  |   4 +
>>>     gdb/i386-tdep.h       |   4 -
>>>     gdb/regcache.c        |   7 +-
>>>     gdb/x86-bsd-nat.c     |   4 -
>>>     gdb/x86-bsd-nat.h     |   3 -
>>>     16 files changed, 844 insertions(+), 778 deletions(-)
>>>     create mode 100644 gdb/amd64-fbsd-tdep.h
>>>
>>
>>
> 
> 


-- 
John Baldwin