Commit Graph

462 Commits

Author SHA1 Message Date
Simon Marchi
1d43b17eac {gdb,gdbserver}/Makefile.in: remove unnecessary intermediary variables
Remove `INTERNAL_CFLAGS_BASE` and `INTERNAL_WARN_CFLAGS`, inline their
contents in `INTERNAL_CFLAGS`.  Not functional changes expected.

Change-Id: I6a09794835ca2cfd4a88a3e9f2e627c8f5bd569f
Approved-By: Pedro Alves <pedro@palves.net>
2024-03-26 21:09:19 -04:00
Simon Marchi
2f3dfa7f90 gdb, gdbserver, gdbsupport: reformat some Makefile variables, one entry per line
Reformat some variables definitions.  I think it makes them easier to
read, and it also makes diffs clearer.

Change-Id: I82f63ba0e6d0fe268eb1f1ad5ab22c3cd016ab02
Approved-By: Pedro Alves <pedro@palves.net>
2024-03-26 21:09:19 -04:00
Andrew Burgess
56f703d39d Revert "gdbserver: convert have_ptrace_getregset to a tribool"
This reverts commit 5920765d75.
2024-03-26 18:53:31 +00:00
Andrew Burgess
59b198a616 Revert "gdbserver/x86: move no-xml code earlier in x86_linux_read_description"
This reverts commit 0a7bb97ad2.
2024-03-26 18:53:05 +00:00
Andrew Burgess
f06daade43 Revert "gdb/gdbserver: share I386_LINUX_XSAVE_XCR0_OFFSET definition"
This reverts commit 7816b81e9b.
2024-03-26 18:52:51 +00:00
Andrew Burgess
49a7660fb5 Revert "gdb/gdbserver: share some code relating to target description creation"
This reverts commit cd9b374ffe.
2024-03-26 18:52:44 +00:00
Andrew Burgess
cba2791ca6 Revert "gdbserver: update target description creation for x86/linux"
This reverts commit 61bb321605.
2024-03-26 18:52:27 +00:00
Andrew Burgess
69324a74e3 Revert "gdb/gdbserver: share x86/linux tdesc caching"
This reverts commit 198ff6ff81.
2024-03-26 18:52:17 +00:00
Andrew Burgess
57d8b51d90 Revert "gdbserver/Makefile.in: add missing -x c++"
This reverts commit c7c9820071.
2024-03-26 18:52:01 +00:00
Simon Marchi
c7c9820071 gdbserver/Makefile.in: add missing -x c++
When building with Clang, I get:

      CXX    nat/x86-linux-tdesc-ipa.o
    clang++: error: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Werror,-Wdeprecated]

Fix that by adding the missing `-x c++` in the rule building
`gdb/nat/*.c` files for the in-process agent.

Change-Id: Ie53e4b9a8b57bef9669397fdfaf21617107c7180
Approved-By: Tom Tromey <tom@tromey.com>
2024-03-25 21:48:24 -04:00
Andrew Burgess
198ff6ff81 gdb/gdbserver: share x86/linux tdesc caching
This commit builds on the previous series of commits to share the
target description caching code between GDB and gdbserver for
x86/Linux targets.

The objective of this commit is to move the four functions (2 each of)
i386_linux_read_description and amd64_linux_read_description into
gdb/nat/x86-linux-tdesc.c and combine them so we have just a single
copy of each.  Then both GDB and gdbserver will link against these
shared functions.

It is worth reading the description of the previous commit to see why
this merging is not as simple as it seems: on the gdbserver side we
actually have two users of these functions, gdbserver itself, and the
in process agent (IPA).

However, the previous commit streamlined the gdbserver code, and so
now it is simple to move the two functions along with all their
support functions from the gdbserver directory into the gdb/nat/
directory, and then GDB is fine to call these functions.

One small curiosity with this patch is the function
x86_linux_post_init_tdesc.  On the gdbserver side the two functions
amd64_linux_read_description and i386_linux_read_description have some
functionality that is not present on the GDB side, that is some
additional configuration that is performed as each target description
is created to setup the expedited registers.

To support this I've added the function x86_linux_post_init_tdesc.
This function is called from the two *_linux_read_description
functions, but is implemented separately for GDB and gdbserver.

This does mean adding back some non-shared code when this whole series
has been about sharing code, but now the only non-shared bit is the
single line that is actually different between GDB and gdbserver, all
the rest, which is identical, is now shared.

I did need to add a new rule to the gdbserver Makefile, this is to
allow the nat/x86-linux-tdesc.c file to be compiled for the IPA.

Approved-By: John Baldwin <jhb@FreeBSD.org>
2024-03-25 17:14:19 +00:00
Andrew Burgess
61bb321605 gdbserver: update target description creation for x86/linux
This commit is part of a series which aims to share more of the target
description creation between GDB and gdbserver for x86/Linux.

After some refactoring, the previous commit actually started to share
some code, we added the shared x86_linux_tdesc_for_tid function into
nat/x86-linux-tdesc.c.  However, this function still relies on
amd64_linux_read_description and i386_linux_read_description which are
implemented separately for both gdbserver and GDB.  Given that at
their core, all these functions to is:

  1. take an xcr0 value as input,
  2. mask out some feature bits,
  3. look for a cached pre-generated target description and return it
     if found,
  4. if no cached target description is found then call either
     amd64_create_target_description or
     i386_create_target_description to create a new target
     description, which is then added to the cache.  Return the newly
     created target description.

The inner functions amd64_create_target_description and
i386_create_target_description are already shared between GDB and
gdbserver (in the gdb/arch/ directory), so the only thing that
the *_read_description functions really do is add the caching layer,
and it feels like this really could be shared.

However, we have a small problem.

On the GDB side we create target descriptions using a different set of
cpu features than on the gdbserver side!  This means that for the
exact same target, we might get a different target description when
using native GDB vs using gdbserver.  This surely feels like a
mistake, I would expect to get the same target description on each.

The table below shows the number of possible different target
descriptions that we can create on the GDB side vs on the gdbserver
side for each target type:

        | GDB | gdbserver
  ------|-----|----------
  i386  | 64  | 7
  amd64 | 32  | 7
  x32   | 16  | 7

So in theory, all I want to do is move the GDB version
of *_read_description into the nat/ directory and have gdbserver use
that, then both GDB and gdbserver would be able to create any of the
possible target descriptions.

Unfortunately it's a little more complex than that due to the in
process agent (IPA).

When the IPA is in use, gdbserver sends a target description index to
the IPA, and the IPA uses this to find the correct target description
to use.

** START OF AN ASIDE **

Back in the day I suspect this approach made perfect sense.  However
since this commit:

  commit a880623024
  Date:   Thu Dec 7 17:07:01 2017 +0000

      Initialize target description early in IPA

I think passing the index is now more trouble than its worth.

We used to pass the index, and then use that index to lookup which
target description to instantiate and use.  However, the above commit
fixed an issue where we can't call malloc() within (certain parts of)
the IPA (apparently), so instead we now pre-compute _every_ possible
target description within the IPA.  The index is now only used to
lookup which of the (many) pre-computed target descriptions to use.

It would (I think) have been easier all around if the IPA just
self-inspected, figured out its own xcr0 value, and used that to
create the one target description that is required.  So long as the
xcr0 to target description code is shared (at compile time) with
gdbserver, then we can be sure that the IPA will derive the same
target description as gdbserver, and we would avoid all this index
passing business, which has made this commit so very, very painful.

** END OF AN ASIDE **

Currently then for x86/linux, gdbserver sends a number between 0 and 7
to the IPA, and the IPA uses this to create a target description.

However, I am proposing that gdbserver should now create one of (up
to) 64 different target descriptions for i386, so this 0 to 7 index
isn't going to be good enough any more (amd64 and x32 have slightly
fewer possible target descriptions, but still more than 8, so the
problem is the same).

For a while I wondered if I was going to have to try and find some
backward compatible solution for this mess.  But after seeing how
lightly the IPA is actually documented, I wonder if it is not the case
that there is a tight coupling between a version of gdbserver and a
version of the IPA?  At least I'm hoping so.

In this commit I have thrown out the old IPA target description index
numbering scheme, and switched to a completely new numbering scheme.
Instead of the index that is passed being arbitrary, the index is
instead calculated from the set of cpu features that are present on
the target.  Within the IPA we can then reverse this logic to recreate
the xcr0 value based on the index, and from the xcr0 value we can
create the correct target description.

With the gdbserver to IPA numbering scheme issue resolved I have then
update the gdbserver versions of amd64_linux_read_description and
i386_linux_read_description so that they create target descriptions
using the same set of cpu features as GDB itself.

After this gdbserver should now always come up with the same target
description as GDB does on any x86/Linux target.

This commit does not introduce any new code sharing between GDB and
gdbserver as previous commits in this series does.  Instead this
commit is all about bringing GDB and gdbserver into alignment
functionally so that the next commit can merge the GDB and gdbserver
versions of these functions.

Approved-By: John Baldwin <jhb@FreeBSD.org>
2024-03-25 17:14:19 +00:00
Andrew Burgess
cd9b374ffe gdb/gdbserver: share some code relating to target description creation
This commit is part of a series to share more of the x86 target
description creation code between GDB and gdbserver.

Unlike previous commits which were mostly refactoring, this commit is
the first that makes a real change, though that change should mostly
be for gdbserver; I've largely adopted the "GDB" way of doing things
for gdbserver, and this fixes a real gdbserver bug.

On a x86-64 Linux target, running the test:

  gdb.server/connect-with-no-symbol-file.exp

results in two core files being created.  Both of these core files are
from the inferior process, created after gdbserver has detached.

In this test a gdbserver process is started and then, after gdbserver
has started, but before GDB attaches, we either delete the inferior
executable, or change its permissions so it can't be read.  Only after
doing this do we attempt to connect with GDB.

As GDB connects to gdbserver, gdbserver attempts to figure out the
target description so that it can send the description to GDB, this
involves a call to x86_linux_read_description.

In x86_linux_read_description one of the first things we do is try to
figure out if the process is 32-bit or 64-bit.  To do this we look up
the executable via the thread-id, and then attempt to read the
architecture size from the executable.  This isn't going to work if
the executable has been deleted, or is no longer readable.

And so, as we can't read the executable, we default to an i386 target
and use an i386 target description.

A consequence of using an i386 target description is that addresses
are assumed to be 32-bits.  Here's an example session that shows the
problems this causes.  This is run on an x86-64 machine, and the test
binary (xx.x) is a standard 64-bit x86-64 binary:

  shell_1$ gdbserver --once localhost :54321 /tmp/xx.x

  shell_2$ gdb -q
  (gdb) set sysroot
  (gdb) shell chmod 000 /tmp/xx.x
  (gdb) target remote :54321
  Remote debugging using :54321
  warning: /tmp/xx.x: Permission denied.
  0xf7fd3110 in ?? ()
  (gdb) show architecture
  The target architecture is set to "auto" (currently "i386").
  (gdb) p/x $pc
  $1 = 0xf7fd3110
  (gdb) info proc mappings
  process 2412639
  Mapped address spaces:

  	Start Addr   End Addr       Size     Offset  Perms   objfile
  	  0x400000   0x401000     0x1000        0x0  r--p   /tmp/xx.x
  	  0x401000   0x402000     0x1000     0x1000  r-xp   /tmp/xx.x
  	  0x402000   0x403000     0x1000     0x2000  r--p   /tmp/xx.x
  	  0x403000   0x405000     0x2000     0x2000  rw-p   /tmp/xx.x
  	0xf7fcb000 0xf7fcf000     0x4000        0x0  r--p   [vvar]
  	0xf7fcf000 0xf7fd1000     0x2000        0x0  r-xp   [vdso]
  	0xf7fd1000 0xf7fd3000     0x2000        0x0  r--p   /usr/lib64/ld-2.30.so
  	0xf7fd3000 0xf7ff3000    0x20000     0x2000  r-xp   /usr/lib64/ld-2.30.so
  	0xf7ff3000 0xf7ffb000     0x8000    0x22000  r--p   /usr/lib64/ld-2.30.so
  	0xf7ffc000 0xf7ffe000     0x2000    0x2a000  rw-p   /usr/lib64/ld-2.30.so
  	0xf7ffe000 0xf7fff000     0x1000        0x0  rw-p
  	0xfffda000 0xfffff000    0x25000        0x0  rw-p   [stack]
  	0xff600000 0xff601000     0x1000        0x0  r-xp   [vsyscall]
  (gdb) info inferiors
    Num  Description       Connection           Executable
  * 1    process 2412639   1 (remote :54321)
  (gdb) shell cat /proc/2412639/maps
  00400000-00401000 r--p 00000000 fd:03 45907133           /tmp/xx.x
  00401000-00402000 r-xp 00001000 fd:03 45907133           /tmp/xx.x
  00402000-00403000 r--p 00002000 fd:03 45907133           /tmp/xx.x
  00403000-00405000 rw-p 00002000 fd:03 45907133           /tmp/xx.x
  7ffff7fcb000-7ffff7fcf000 r--p 00000000 00:00 0          [vvar]
  7ffff7fcf000-7ffff7fd1000 r-xp 00000000 00:00 0          [vdso]
  7ffff7fd1000-7ffff7fd3000 r--p 00000000 fd:00 143904     /usr/lib64/ld-2.30.so
  7ffff7fd3000-7ffff7ff3000 r-xp 00002000 fd:00 143904     /usr/lib64/ld-2.30.so
  7ffff7ff3000-7ffff7ffb000 r--p 00022000 fd:00 143904     /usr/lib64/ld-2.30.so
  7ffff7ffc000-7ffff7ffe000 rw-p 0002a000 fd:00 143904     /usr/lib64/ld-2.30.so
  7ffff7ffe000-7ffff7fff000 rw-p 00000000 00:00 0
  7ffffffda000-7ffffffff000 rw-p 00000000 00:00 0          [stack]
  ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0  [vsyscall]
  (gdb)

Notice the difference between the mappings reported via GDB and those
reported directly from the kernel via /proc/PID/maps, the addresses of
every mapping is clamped to 32-bits for GDB, while the kernel reports
real 64-bit addresses.

Notice also that the $pc value is a 32-bit value.  It appears to be
within one of the mappings reported by GDB, but is outside any of the
mappings reported from the kernel.

And this is where the problem arises.  When gdbserver detaches from
the inferior we pass the inferior the address from which it should
resume.  Due to the 32/64 bit confusion we tell the inferior to resume
from the 32-bit $pc value, which is not within any valid mapping, and
so, as soon as the inferior resumes, it segfaults.

If we look at how GDB (not gdbserver) figures out its target
description then we see an interesting difference.  GDB doesn't try to
read the executable.  Instead GDB uses ptrace to query the thread's
state, and uses this to figure out the if the thread is 32 or 64 bit.

If we update gdbserver to do it the "GDB" way then the above problem
is resolved, gdbserver now sees the process as 64-bit, and when we
detach from the inferior we give it the correct 64-bit address, and
the inferior no longer segfaults.

Now, I could just update the gdbserver code, but better, I think, to
share one copy of the code between GDB and gdbserver in gdb/nat/.
That is what this commit does.

The cores of x86_linux_read_description from gdbserver and
x86_linux_nat_target::read_description from GDB are moved into a new
file gdb/nat/x86-linux-tdesc.c and combined into a single function
x86_linux_tdesc_for_tid which is called from each location.

This new function does things the GDB way, the only changes are to
allow for the sharing; we now have a callback function to call the
first time that the xcr0 state is read, this allows for GDB and
gdbserver to perform their own initialisation as needed, and
additionally, the new function takes a pointer for where to cache the
xcr0 value, this isn't needed for this commit, but will be useful in a
later commit where gdbserver will want to read this cached xcr0
value.

Another thing to note about this commit is how the functions
i386_linux_read_description and amd64_linux_read_description are
handled.  For now I've left these function as implemented separately
in GDB and gdbserver.  I've moved the declarations of these functions
into gdb/nat/x86-linux-tdesc.h, but the implementations are left as
separate.

A later commit in this series will make these functions shared too,
but doing this is not trivial, so I've left that for a separate
commit.  Merging the declarations as I've done here ensures that
everyone implements the function to the same API, and once these
functions are shared (in a later commit) we'll want a shared
declaration anyway.

Approved-By: John Baldwin <jhb@FreeBSD.org>
2024-03-25 17:14:19 +00:00
Andrew Burgess
7816b81e9b gdb/gdbserver: share I386_LINUX_XSAVE_XCR0_OFFSET definition
Share the definition of I386_LINUX_XSAVE_XCR0_OFFSET between GDB and
gdbserver.

This commit is part of a series that aims to share more of the x86
target description creation code between GDB and gdbserver.  The
I386_LINUX_XSAVE_XCR0_OFFSET #define is used as part of the target
description creation, and I noticed that this constant is defined
separately for GDB and gdbserver.

This commit moves the definition into gdb/nat/x86-linux.h, which
allows the #define to be shared.

There should be no user visible changes after this commit.

Approved-By: John Baldwin <jhb@FreeBSD.org>
2024-03-25 17:14:19 +00:00
Andrew Burgess
0a7bb97ad2 gdbserver/x86: move no-xml code earlier in x86_linux_read_description
This commit is part of a series that aims to share more of the x86
target description reading/generation code between GDB and gdbserver.

There are a huge number of similarities between the code in
gdbserver's x86_linux_read_description function and GDB's
x86_linux_nat_target::read_description function, and it is this
similarity that I plan, in a later commit, to share between GDB and
gdbserver.

However, one thing that is different in x86_linux_read_description is
the code inside the '!use_xml' block.  This is the code that handles
the case where gdbserver is not allowed to send an XML target
description back to GDB.  In this case gdbserver uses some predefined,
fixed, target descriptions.

First, it's worth noting that I suspect this code is not tested any
more.  I couldn't find anything in the testsuite that tries to disable
XML target description support.  And the idea of having a single
"fixed" target description really doesn't work well when we think
about all the various x86 extensions that exist.  Part of me would
like to rip out the no-xml support in gdbserver (at least for x86),
and if a GDB connects that doesn't support XML target descriptions,
gdbserver can just give an error and drop the connection.  GDB has
supported XML target descriptions for 16 years now, I think it would
be reasonable for our shipped gdbserver to drop support for the old
way of doing things.

Anyway.... this commit doesn't do that.

What I did notice was that, over time, the '!use_xml' block appears to
have "drifted" within the x86_linux_read_description function; it's
now not the first check we do.  Instead we make some ptrace calls and
return a target description generated based on the result of these
ptrace calls.  Surely it only makes sense to generate variable target
descriptions if we can send these back to GDB?

So in this commit I propose to move the '!use_xml' block earlier in
the x86_linux_read_description function.

The benefit of this is that this leaves the later half of
x86_linux_read_description much more similar to the GDB function
x86_linux_nat_target::read_description and sets us up for potentially
sharing code between GDB and gdbserver in a later commit.

Approved-By: John Baldwin <jhb@FreeBSD.org>
2024-03-25 17:14:18 +00:00
Andrew Burgess
5920765d75 gdbserver: convert have_ptrace_getregset to a tribool
Convert the have_ptrace_getregset global within gdbserver to a
tribool.  This brings the flag into alignment with the corresponding
flag in GDB.

The gdbserver have_ptrace_getregset variable is already used as a
tribool, it just doesn't have the tribool type.

In a future commit I plan to share more code between GDB and
gdbserver, and having this variable be the same type in both code
bases will make the sharing much easier.

There should be no user visible changes after this commit.

Approved-By: John Baldwin <jhb@FreeBSD.org>
2024-03-25 17:14:18 +00:00
H.J. Lu
4bb20a6244 gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32
Since MPX isn't available for x32, we should clear X86_XSTATE_MPX bits
on x32.

	PR server/31511
	* linux-x86-low.cc (x86_linux_read_description): Clear
	X86_XSTATE_MPX bits in xcr0 on x32.
Reviewed-by: Felix Willgerodt <felix.willgerodt@intel.com>
2024-03-21 12:44:40 -07:00
Simon Marchi
da48217f31 gdbserver/linux: probe for libiconv in configure
Make gdbserver's build system locate libiconv when building for Linux.

Commit 07b3255c3b ("Filter invalid encodings from Linux thread names")
make libiconv madantory for building gdbserver on Linux.

While trying to cross-compile gdb for xtensa-fsf-linux-uclibc (with a
toolchain generated with crosstool-ng), I got:

    /home/smarchi/src/binutils-gdb/gdbserver/linux-low.cc:48:10: fatal error: iconv.h: No such file or directory
       48 | #include <iconv.h>
          |          ^~~~~~~~~

I downloaded GNU libiconv, built it for that host, and installed it in
an arbitrary directory.  I had to modify the gdbserver build system to
locate libiconv and use it, the result is this patch.

I eventually found that crosstool-ng has a config option to make uclibc
provide an implementation of iconv, which is of course much easier.  But
given that this patch is now written, I think it would be worth merging
it, it could help some people who do not have iconv built-in their libc
in the future (and may not have the luxury of rebuilding their libc like
I do).

Using AM_ICONV in configure.ac adds these options for configure (the
same we have for gdb):

    --with-libiconv-prefix[=DIR]  search for libiconv in DIR/include and DIR/lib
    --without-libiconv-prefix     don't search for libiconv in includedir and libdir
    --with-libiconv-type=TYPE     type of library to search for (auto/static/shared)

It sets the `LIBICONV` variable with whatever is needed to link with
libiconv, and adds the necessary `-I` flag to `CPPFLAGS`.

To avoid unnecessarily linking against libiconv on hosts that don't need
it, set `MAYBE_LIBICONV` with the contents of `LIBICONV` only if the
host is Linux, and use `MAYBE_LIBICONV` in `Makefile.in`.

Since libiconv is a hard requirement for Linux hosts, error out if it is
not found.

The bits in acinclude.m4 are similar to what we have in
gdb/acinclude.m4.

Update the top-level build system to support building against an in-tree
libiconv (I did not test this part though).  Something tells me that the
all-gdbserver dependency on all-libiconv is unnecessary, since there is
already a dependency of configure-gdbserver on all-libiconv (and
all-gdbserver surely depends on configure-gdbserver).  I just copied
what's done for GDB though.

ChangeLog:

	* Makefile.def: Add configure-gdbserver and all-gdbserver
	dependencies on all-libiconv.
	* Makefile.in: Re-generate.

Change-Id: I90f8ef88dd4917df5a68b45550d93622fc9cfed4
Approved-By: Tom Tromey <tom@tromey.com>
2024-03-14 13:40:08 -04:00
Thiago Jung Bauermann
bbb12eb9c8 gdb/arm: Remove tpidruro register from non-FreeBSD target descriptions
Commit 92d48a1e4e ("Add an arm-tls feature which includes the tpidruro
register from CP15.") introduced the org.gnu.gdb.arm.tls feature, which
adds the tpidruro register, and unconditionally enabled it in
aarch32_create_target_description.

In Linux, the tpidruro register isn't available via ptrace in the 32-bit
kernel but it is available for an aarch32 program running under an arm64
kernel via the ptrace compat interface.  This isn't currently implemented
however, which causes GDB on arm-linux with 64-bit kernel to list the
register but show it as unavailable, as reported by Tom de Vries:

  $ gdb -q -batch a.out -ex start -ex 'p $tpidruro'
  Temporary breakpoint 1 at 0x512

  Temporary breakpoint 1, 0xaaaaa512 in main ()
  $1 = <unavailable>

Simon Marchi then clarified:

> The only time we should be seeing some "unavailable" registers or memory
> is in the context of tracepoints, for things that are not collected.
> Seeing an unavailable register here is a sign that something is not
> right.

Therefore, disable the TLS feature in aarch32 target descriptions for Linux
and NetBSD targets (the latter also doesn't seem to support accessing
tpidruro either, based on a quick look at arm-netbsd-nat.c).

This patch fixes the following tests:

Running gdb.base/inline-frame-cycle-unwind.exp ...
FAIL: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 3: backtrace when the unwind is broken at frame 3
FAIL: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 5: backtrace when the unwind is broken at frame 5
FAIL: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 1: backtrace when the unwind is broken at frame 1

Tested with Ubuntu 22.04.3 on armv8l-linux-gnueabihf in native,
native-gdbserver and native-extended-gdbserver targets with no regressions.

PR tdep/31418
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31418

Approved-By: John Baldwin <jhb@FreeBSD.org>
2024-02-29 12:27:27 -03:00
Tiezhu Yang
4a4fd10d17 gdb: Modify the output of "info breakpoints" and "delete breakpoints"
The output of "info breakpoints" includes breakpoint, watchpoint,
tracepoint, and catchpoint if they are created, so it should show
all the four types are deleted in the output of "info breakpoints"
to report empty list after "delete breakpoints".

It should also change the output of "delete breakpoints" to make it
clear that watchpoints, tracepoints, and catchpoints are also being
deleted. This is suggested by Guinevere Larsen, thank you.

$ make check-gdb TESTS="gdb.base/access-mem-running.exp"
$ gdb/gdb gdb/testsuite/outputs/gdb.base/access-mem-running/access-mem-running
[...]
(gdb) break main
Breakpoint 1 at 0x12000073c: file /home/loongson/gdb.git/gdb/testsuite/gdb.base/access-mem-running.c, line 32.
(gdb) watch global_counter
Hardware watchpoint 2: global_counter
(gdb) trace maybe_stop_here
Tracepoint 3 at 0x12000071c: file /home/loongson/gdb.git/gdb/testsuite/gdb.base/access-mem-running.c, line 27.
(gdb) catch fork
Catchpoint 4 (fork)
(gdb) info breakpoints
Num     Type           Disp Enb Address            What
1       breakpoint     keep y   0x000000012000073c in main at /home/loongson/gdb.git/gdb/testsuite/gdb.base/access-mem-running.c:32
2       hw watchpoint  keep y                      global_counter
3       tracepoint     keep y   0x000000012000071c in maybe_stop_here at /home/loongson/gdb.git/gdb/testsuite/gdb.base/access-mem-running.c:27
	not installed on target
4       catchpoint     keep y                      fork

Without this patch:

(gdb) delete breakpoints
Delete all breakpoints? (y or n) y
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) info breakpoints 3
No breakpoint or watchpoint matching '3'.

With this patch:

(gdb) delete breakpoints
Delete all breakpoints, watchpoints, tracepoints, and catchpoints? (y or n) y
(gdb) info breakpoints
No breakpoints, watchpoints, tracepoints, or catchpoints.
(gdb) info breakpoints 3
No breakpoint, watchpoint, tracepoint, or catchpoint matching '3'.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Approved-by: Kevin Buettner <kevinb@redhat.com>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
2024-02-26 19:19:58 +08:00
Simon Marchi
aca8a74923 gdb: remove some GCC version checks
Since we now require C++17, and therefore gcc >= 9, it's no longer
useful to have gcc version checks for older gcc version.

Change-Id: I3a87baa03c475f2b847b422b16b69c5ff7215b54
Reviewed-by: Kevin Buettner <kevinb@redhat.com>
Approved-By: Pedro Alves <pedro@palves.net>
2024-02-21 13:30:17 -05:00
Pedro Alves
38065394e9 Fix crash in aarch64-linux gdbserver
Since commit 393a6b5947 ("Thread options & clone events (Linux
GDBserver)"), aarch64-linux gdbserver crashes when the inferior
vforks.  This happens in aarch64_get_debug_reg_state:

  struct process_info *proc = find_process_pid (pid);

  return &proc->priv->arch_private->debug_reg_state;

Here, find_process_pid returns nullptr -- the new inferior hasn't yet
been created in linux_process_target::handle_extended_wait.

This patch fixes the problem by having
linux_process_target::handle_extended_wait create the child process
earlier, before the child LWP is created.  This is what the function
did before it was reorganized by the commit referred above.

Change-Id: Ib8b3a2e6048c3ad2b91a92ea4430da507db03c50
Co-Authored-By: Tom Tromey <tromey@adacore.com>
2024-02-09 11:58:40 +00:00
Feiyang Chen
e4d74c01e7 gdb: LoongArch: Add LBT extension support
Loongson Binary Translation (LBT) is used to accelerate binary
translation, which contains 4 scratch registers (scr0 to scr3),
x86/ARM eflags (eflags) and x87 fpu stack pointer (ftop). This
patch support gdb to fetch/store these registers.

Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn> #  Framework
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>   #  Detail Optimizes
Signed-off-by: Hui Li <lihui@loongson.cn>             #  Error Fixes
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
2024-02-06 18:40:19 +08:00
Hui Li
1e9569f383 gdb: LoongArch: Add vector extensions support
Add LoongArch's vector extensions support, which including
128bit LSX (i.e., Loongson SIMD eXtension) and 256bit LASX
(i.e., Loongson Advanced SIMD eXtension). This patch support
gdb to fetch/store vector registers.

Signed-off-by: Hui Li <lihui@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
2024-02-06 18:40:02 +08:00
Tom Tromey
a197d5f7eb Really fix Windows gdbserver segment registers
My earlier attempt to mask the segment registers in gdbserver for
Windows introduced some bugs.  That patch is here:

https://sourceware.org/pipermail/gdb-patches/2023-December/205306.html

The problem turned out to be that these fields in the Windows
'CONTEXT' type are just 16 bits, so while masking the values on read
is fine, writing the truncated values back then causes zeros to be
written to some subsequent field.

This patch cleans this up by arranging never to write too much data to
a field.

I also noticed that two register numbers here were never updated for
the 64-bit port.  This patch fixes this as well, and renames the "FCS"
register to follow gdb.

Finally, this patch applies the same treatment to windows-nat.c.

Reviewed-by: John Baldwin <jhb@FreeBSD.org>
2024-01-30 10:18:38 -07:00
Andrew Burgess
1d506c26d9 Update copyright year range in header of all files managed by GDB
This commit is the result of the following actions:

  - Running gdb/copyright.py to update all of the copyright headers to
    include 2024,

  - Manually updating a few files the copyright.py script told me to
    update, these files had copyright headers embedded within the
    file,

  - Regenerating gdbsupport/Makefile.in to refresh it's copyright
    date,

  - Using grep to find other files that still mentioned 2023.  If
    these files were updated last year from 2022 to 2023 then I've
    updated them this year to 2024.

I'm sure I've probably missed some dates.  Feel free to fix them up as
you spot them.
2024-01-12 15:49:57 +00:00
Mike Frysinger
761ed61e7b gdbsupport: tighten up libiberty code a bit with dnl
No functional change here, just touch up generated output slightly.

Approved-By: Tom Tromey <tom@tromey.com>
2024-01-10 19:53:14 -05:00
Mike Frysinger
908ff469f5 gdb: libiberty: switch to AC_CHECK_DECLS_ONCE
Only check these decls once in case other m4 macros also look for them.

Approved-By: Tom Tromey <tom@tromey.com>
2024-01-10 19:53:05 -05:00
Mike Frysinger
3f258212a8 gdb: move libiberty.m4 to gdbsupport
This is used by gdb, gdbsupport, and gdbserver.  We want to use it
in the sim tree too.  Move it to gdbsupport which is meant as the
common sharing space for these projects.

Approved-By: Tom Tromey <tom@tromey.com>
2024-01-10 19:52:52 -05:00
Tom Tromey
862180a2d1 Fix two bugs in gdbserver thread name handling
Simon pointed out that my earlier patch to gdbserver's thread name
code:

    commit 07b3255c3b
    Author: Tom Tromey <tom@tromey.com>
    Date:   Thu Jul 13 17:28:48 2023 -0600

	Filter invalid encodings from Linux thread names

... introduced a regression.  This bug was that the iconv output was
not \0-terminated.

Looking at it, I found another bug as well -- replace_non_ascii would
not \0-terminate, and also would return the wrong pointer

This patch fixes both of them.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31153
2024-01-09 07:07:41 -07:00
Simon Marchi
51e6b8cfd6 gdb: change regcache interface to use array_view
Change most of regcache (and base classes) to use array_view when
possible, instead of raw pointers.  By propagating the use of array_view
further, it enables having some runtime checks to make sure the what we
read from or write to regcaches has the expected length (such as the one
in the `copy(array_view, array_view)` function.  It also integrates well
when connecting with other APIs already using gdb::array_view.

Add some overloads of the methods using raw pointers to avoid having to
change all call sites at once (which is both a lot of work and risky).

I tried to do this change in small increments, but since many of these
functions use each other, it ended up simpler to do it in one shot than
having a lot of intermediary / transient changes.

This change extends into gdbserver as well, because there is some part
of the regcache interface that is shared.

Changing the reg_buffer_common interface to use array_view caused some
build failures in nat/aarch64-scalable-linux-ptrace.c.  That file
currently "takes advantage" of the fact that
reg_buffer_common::{raw_supply,raw_collect} operates on `void *`, which
IMO is dangerous.  It uses raw_supply/raw_collect directly on
uint64_t's, which I guess is fine because it is expected that native
code will have the same endianness as the debugged process.  To
accomodate that, add some overloads of raw_collect and raw_supply that
work on uint64_t.

This file also uses raw_collect and raw_supply on `char` pointers.
Change it to use `gdb_byte` pointers instead.  Add overloads of
raw_collect and raw_supply that work on `gdb_byte *` and make an
array_view on the fly using the register's size.  Those call sites could
be converted to use array_view with not much work, in which case these
overloads could be removed, but I didn't want to do it in this patch, to
avoid starting to dig in arch-specific code.

During development, I inadvertently changed reg_buffer::raw_compare's
behavior to not accept an offset equal to the register size.  This
behavior (effectively comparing 0 bytes, returning true) change was
caught by the AArch64 SME core tests.  Add a selftest to make sure that
this raw_compare behavior is preserved in the future.

Change-Id: I9005f04114543ddff738949e12d85a31855304c2
Reviewed-By: John Baldwin <jhb@FreeBSD.org>
2023-12-14 16:04:49 +00:00
Simon Marchi
e4e20d4511 gdb: use reg_buffer_common throughout gdbsupport/common-regcache.h
Right now, gdbsupport/common-regcache.h contains two abstractons for a
regcache.  An opaque type `regcache` (gdb and gdbserver both have their
own regcache that is the concrete version of this) and an abstract base
class `reg_buffer_common`, that is the base of regcaches on both sides.
These abstractions allow code to be written for both gdb and gdbserver,
for instance in the gdb/arch sub-directory.

However, having two
different abstractions is impractical.  If some common code has a regcache,
and wants to use an operation defined on reg_buffer_common, it can't.
It would be better to have just one.  Change all instances of `regcache
*` in gdbsupport/common-regcache.h to be `reg_buffer_common *`, then fix
fallouts.

Implementations in gdb and gdbserver now need to down-cast (using
gdb::checked_static_cast) from reg_buffer_common to their concrete
regcache type.  Some of them could be avoided by changing free functions
(like regcache_register_size) to be virtual methods on
reg_buffer_common.  I tried it, it seems to work, but I did not include
it in this series to avoid adding unnecessary changes.

Change-Id: Ia5503adb6b5509a0f4604bd2a68b4642cc5283fd
Reviewed-by: John Baldwin <jhb@FreeBSD.org>
2023-12-14 16:04:49 +00:00
Stefano Moioli
fa659800b0 gdbserver/win32: fix crash on detach
this patch fixes a crash in gdbserver whenever a process is detached.
the crash is caused by `detach` calling `remove_process` before `win32_clear_inferiors`

error message:

Detaching from process 184
../../gdbserver/inferiors.cc:160: A problem internal to GDBserver has been detec
ted.
remove_process: Assertion `find_thread_process (process) == NULL' failed.

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

Approved-By: Tom Tromey <tom@tromey.com>
2023-12-12 13:19:30 -07:00
Andrew Burgess
8fd5a6058f gdbserver: allow for general 'monitor set debug COMPONENT VALUE' use
Building on the last commit, which added a general --debug=COMPONENT
option to the gdbserver command line, this commit updates the monitor
command to allow for general:

  (gdb) monitor set debug COMPONENT off|on

style commands.  Just like with the previous commit, the COMPONENT can
be any one of all, threads, remote, event-loop, and correspond to the
same set of global debug flags.

While on the command line it is possible to do:

  --debug=remote,event-loop,threads

the components have to be entered one at a time with the monitor
command.  I guess there's no reason why we couldn't allow component
grouping within the monitor command, but (to me) what I have here
seemed more in the spirit of GDB's existing 'set debug ...' commands.
If people want it then we can always add component grouping later.

Notice in the above that I use 'off' and 'on' instead of '0' and '1',
which is what the 'monitor set debug' command used to use.  The 0/1
can still be used, but I now advertise off/on in all the docs and help
text, again, this feels more inline with GDB's existing boolean
settings.

I have removed the two existing monitor commands:

  monitor set remote-debug 0|1
  monitor set event-loop-debug 0|1

These are replaced by:

  monitor set debug remote off|on
  monitor set debug event-loop off|on

respectively.

Approved-By: Tom Tromey <tom@tromey.com>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
2023-12-08 17:52:00 +00:00
Andrew Burgess
3bf9e166ca gdbserver: allow the --debug command line option to take a value
Currently, gdbserver has the following command line options related to
debugging output:

  --debug
  --remote-debug
  --event-loop-debug

This doesn't scale well.  If I want an extra debug component I need to
add another command line flag.

This commit changes --debug to take a list of components.

The currently supported components are: all, threads, remote, and
event-loop.  The 'threads' component represents the debug we currently
get from the --debug option.  And if --debug is used without a
component list then the threads component is assumed as the default.

Currently the threads component actually includes a lot of output that
is not really threads related.  In the future I'd like to split this
up into some new, separate components.  But that is not part of this
commit, or even this series.

The special component 'all' does what you'd expect: enables debug
output from all supported components.

The component list is parsed left to write, and you can prefix a
component with '-' to disable that component, so I can write:

  target> gdbserver --debug=all,-event-loop

to get debug for all components except the event-loop component.

I've removed the existing --remote-debug and --event-loop-debug
command line options, these are equivalent to --debug=remote and
--debug=event-loop respectively, or --debug=remote,event-loop to
enable both components.

In this commit I've only update the command line options, in the next
commit I'll update the monitor commands to support a similar
interface.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
2023-12-08 17:52:00 +00:00
Tom Tromey
74bbf9359a Update fall-through comment in gdbserver
I noticed that gdbserver/win32-low.cc has a fall-through comment that
should have been converted to use the annotation instead.

This patch makes the change.
2023-12-04 08:23:34 -07:00
Tom Tromey
c6f7f9c80c Bail out of "attach" if a thread cannot be traced
On Linux, threads are treated much like separate processes by the
kernel.  In particular, it's possible to ptrace just a single thread.
If gdb tries to attach to a multi-threaded inferior, where a non-main
thread is already being traced (e.g., by strace), then gdb will get
into an infinite loop attempting to attach.

This patch fixes this problem by having the attach fail if ptrace
fails to attach to any thread of the inferior.
2023-12-01 10:36:00 -07:00
Tom Tromey
69f6730df3 Remove gdb_static_assert
C++17 makes the second parameter to static_assert optional, so we can
remove gdb_static_assert now.
2023-11-29 14:29:44 -07:00
Tom Tromey
d57f38ec74 Switch to -Wimplicit-fallthrough=5
This changes the various gdb-related directories to use
-Wimplicit-fallthrough=5, meaning that only the fallthrough attribute
can be used in switches -- special 'fallthrough' comments will no
longer be usable.

Approved-By: Pedro Alves <pedro@palves.net>
2023-11-29 14:29:43 -07:00
Tom Tromey
d182e39881 Use C++17 [[fallthrough]] attribute
This changes gdb to use the C++17 [[fallthrough]] attribute rather
than special comments.

This was mostly done by script, but I neglected a few spellings and so
also fixed it up by hand.

I suspect this fixes the bug mentioned below, by switching to a
standard approach that, presumably, clang supports.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=23159
Approved-By: John Baldwin <jhb@FreeBSD.org>
Approved-By: Luis Machado <luis.machado@arm.com>
Approved-By: Pedro Alves <pedro@palves.net>
2023-11-29 14:29:43 -07:00
Tom Tromey
602971b386 Introduce throw_winerror_with_name
This introduces throw_winerror_with_name, a Windows analog of
perror_with_name, and changes various places in gdb to call it.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30770
2023-11-27 12:55:14 -07:00
Andrew Burgess
27365c5189 gdbserver: cleanup monitor_show_help
After this commit:

  commit 0b04e52316
  Date:   Sun Jan 19 14:33:37 2014 -0700

      link gdbserver against libiberty

we can cleanup how the help text is generated in monitor_show_help.
This doesn't change the output that the user will see -- it just folds
multiple monitor_output calls into one.

There should be no user visible change after this commit.
2023-11-22 15:20:31 +00:00
Lancelot Six
6b09f1342c gdb: Replace gdb::optional with std::optional
Since GDB now requires C++17, we don't need the internally maintained
gdb::optional implementation.  This patch does the following replacing:
  - gdb::optional -> std::optional
  - gdb::in_place -> std::in_place
  - #include "gdbsupport/gdb_optional.h" -> #include <optional>

This change has mostly been done automatically.  One exception is
gdbsupport/thread-pool.* which did not use the gdb:: prefix as it
already lives in the gdb namespace.

Change-Id: I19a92fa03e89637bab136c72e34fd351524f65e9
Approved-By: Tom Tromey <tom@tromey.com>
Approved-By: Pedro Alves <pedro@palves.net>
2023-11-21 11:52:35 +00:00
Sam James
9e11e7460d Finalized intl-update patches (deux)
Doing this on behalf of Arsen as obvious.

* gdb: Regenerate.
* gdbserver: Regenerate.
* gprofng: Regenerate.
2023-11-15 13:47:03 +00:00
Tom Tromey
07b3255c3b Filter invalid encodings from Linux thread names
On Linux, a thread can only be 16 bytes (including the trailing \0).
A user sent in a test case where this causes a truncated UTF-8
sequence, causing gdbserver to create invalid XML.

I went back and forth about different ways to solve this, and in the
end decided to fix it in gdbserver, with the reason being that it
seems important to generate correct XML for the <thread> response.

I am not totally sure whether the call to setlocale could have
unplanned consequences.  This is needed, though, for nl_langinfo to
return the correct result.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30618
2023-11-14 09:02:46 -07:00
Pedro Alves
e8a625d126 Report thread exit event for leader if reporting thread exit events
If GDB sets the GDB_THREAD_OPTION_EXIT option on a thread, then if the
thread disappears from the thread list, GDB expects to shortly see a
thread exit event for it.  See e.g., here, in
remote_target::update_thread_list():

    /* Do not remove the thread if we've requested to be
       notified of its exit.  For example, the thread may be
       displaced stepping, infrun will need to handle the
       exit event, and displaced stepping info is recorded
       in the thread object.  If we deleted the thread now,
       we'd lose that info.  */
    if ((tp->thread_options () & GDB_THREAD_OPTION_EXIT) != 0)
      continue;

There's one scenario that is deleting a thread from the
remote/gdbserver thread list without ever reporting a corresponding
thread exit event though -- check_zombie_leaders.  This can lead to
GDB getting confused.  For example, with a following patch that
enables GDB_THREAD_OPTION_EXIT whenever schedlock is enabled, we'd see
this regression:

 $ make check RUNTESTFLAGS="--target_board=native-extended-gdbserver" TESTS="gdb.threads/no-unwaited-for-left.exp"
 ...
 Running src/gdb/testsuite/gdb.threads/no-unwaited-for-left.exp ...
 FAIL: gdb.threads/no-unwaited-for-left.exp: continue stops when the main thread exits (timeout)
 ... some more cascading FAILs ...

gdb.log shows:

 (gdb) continue
 Continuing.
 FAIL: gdb.threads/no-unwaited-for-left.exp: continue stops when the main thread exits (timeout)

A passing run would have resulted in:

 (gdb) continue
 Continuing.
 No unwaited-for children left.
 (gdb) PASS: gdb.threads/no-unwaited-for-left.exp: continue stops when the main thread exits

note how the leader thread is not listed in the remote-reported XML
thread list below:

 (gdb) set debug remote 1
 (gdb) set debug infrun 1
 (gdb) info threads
   Id   Target Id                                Frame
 * 1    Thread 1163850.1163850 "no-unwaited-for" main () at /home/pedro/rocm/gdb/build/gdb/testsuite/../../../src/gdb/testsuite/gdb.threads/no-unwaited-for-left.c:65
   3    Thread 1163850.1164130 "no-unwaited-for" [remote] Sending packet: $Hgp11c24a.11c362#39
 (gdb) c
 Continuing.
 [infrun] clear_proceed_status_thread: 1163850.1163850.0
 ...
     [infrun] resume_1: step=1, signal=GDB_SIGNAL_0, trap_expected=1, current thread [1163850.1163850.0] at 0x55555555534f
     [remote] Sending packet: $QPassSignals:#f3
     [remote] Packet received: OK
     [remote] Sending packet: $QThreadOptions;3:p11c24a.11c24a#f3
     [remote] Packet received: OK
 ...
     [infrun] target_set_thread_options: [options for Thread 1163850.1163850 are now 0x3]
 ...
   [infrun] do_target_resume: resume_ptid=1163850.1163850.0, step=0, sig=GDB_SIGNAL_0
   [remote] Sending packet: $vCont;c:p11c24a.11c24a#98
   [infrun] prepare_to_wait: prepare_to_wait
   [infrun] reset: reason=handling event
   [infrun] maybe_set_commit_resumed_all_targets: enabling commit-resumed for target extended-remote
   [infrun] maybe_call_commit_resumed_all_targets: calling commit_resumed for target extended-remote
 [infrun] fetch_inferior_event: exit
 [infrun] fetch_inferior_event: enter
   [infrun] scoped_disable_commit_resumed: reason=handling event
   [infrun] random_pending_event_thread: None found.
   [remote] wait: enter
     [remote] Packet received: N
   [remote] wait: exit
   [infrun] print_target_wait_results: target_wait (-1.0.0 [process -1], status) =
   [infrun] print_target_wait_results:   -1.0.0 [process -1],
   [infrun] print_target_wait_results:   status->kind = NO_RESUMED
   [infrun] handle_inferior_event: status->kind = NO_RESUMED
   [remote] Sending packet: $Hgp0.0#ad
   [remote] Packet received: OK
   [remote] Sending packet: $qXfer:threads:read::0,1000#92
   [remote] Packet received: l<threads>\n<thread id="p11c24a.11c362" core="0" name="no-unwaited-for" handle="0097d8f7ff7f0000"/>\n</threads>\n
   [infrun] handle_no_resumed: TARGET_WAITKIND_NO_RESUMED (ignoring: found resumed)
 ...

... however, infrun decided there was a resumed thread still, so
ignored the TARGET_WAITKIND_NO_RESUMED event.  Debugging GDB, we see
that the "found resumed" thread that GDB finds, is the leader thread.
Even though that thread is not on the remote-reported thread list, it
is still on the GDB thread list, due to the special case in remote.c
mentioned above.

This commit addresses the issue by fixing GDBserver to report a thread
exit event for the zombie leader too, i.e., making GDBserver respect
the "if thread has GDB_THREAD_OPTION_EXIT set, report a thread exit"
invariant.  To do that, it takes a bit more code than one would
imagine off hand, due to the fact that we currently always report LWP
exit pending events as TARGET_WAITKIND_EXITED, and then decide whether
to convert it to TARGET_WAITKIND_THREAD_EXITED just before reporting
the event to GDBserver core.  For the zombie leader scenario
described, we need to record early on that we want to report a
THREAD_EXITED event, and then make sure that decision isn't lost along
the way to reporting the event to GDBserver core.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I1e68fccdbc9534434dee07163d3fd19744c8403b
2023-11-13 14:16:11 +00:00
Pedro Alves
ef980d654b gdbserver: Queue no-resumed event after thread exit
Normally, if the last resumed thread on the target exits, the server
sends a no-resumed event to GDB.  If however, GDB enables the
GDB_THREAD_OPTION_EXIT option on a thread, and, that thread exits, the
server sends a thread exit event for that thread instead.

In all-stop RSP mode, since events can only be forwarded to GDB one at
a time, and the whole target stops whenever an event is reported, GDB
resumes the target again after getting a THREAD_EXITED event, and then
the server finally reports back a no-resumed event if/when
appropriate.

For non-stop RSP though, events are asynchronous, and if the server
sends a thread-exit event for the last resumed thread, the no-resumed
event is never sent.  This patch makes sure that in non-stop mode, the
server queues a no-resumed event after the thread-exit event if it was
the last resumed thread that exited.

Without this, we'd see failures in step-over-thread-exit testcases
added later in the series, like so:

   continue
   Continuing.
 - No unwaited-for children left.
 - (gdb) PASS: gdb.threads/step-over-thread-exit.exp: displaced-stepping=off: non-stop=on: target-non-stop=on: schedlock=off: ns_stop_all=1: continue stops when thread exits
 + FAIL: gdb.threads/step-over-thread-exit.exp: displaced-stepping=off: non-stop=on: target-non-stop=on: schedlock=off: ns_stop_all=1: continue stops when thread exits (timeout)

(and other similar ones)

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I927d78b30f88236dbd5634b051a716f72420e7c7
2023-11-13 14:16:11 +00:00
Pedro Alves
4898949800 Implement GDB_THREAD_OPTION_EXIT support for Linux GDBserver
This implements support for the new GDB_THREAD_OPTION_EXIT thread
option for Linux GDBserver.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I96b719fdf7fee94709e98bb3a90751d8134f3a38
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338
2023-11-13 14:16:10 +00:00
Pedro Alves
ad320fbf91 gdbserver/linux-low.cc: Ignore event_ptid if TARGET_WAITKIND_IGNORE
gdbserver's linux_process_target::wait loops if:

 - called in sync mode, and,
 - wait_1 returns TARGET_WAITKIND_IGNORE, _and_,
 - wait_1 also returns null_ptid.

The null_ptid check fails however when this path is taken:

   ptid_t
   linux_process_target::filter_exit_event (lwp_info *event_child,
					    target_waitstatus *ourstatus)
   {
   ...
     if (!is_leader (thread))
       {
	 if (report_exit_events_for (thread))
	   ourstatus->set_thread_exited (0);
	 else
	   ourstatus->set_ignore ();            <<<<<<<

	 delete_lwp (event_child);
       }
     return ptid;
   }

This makes linux_process_target::wait return TARGET_WAITKIND_IGNORE in
sync mode, which is unexpected by the core and fails an assertion.

This commit fixes it by just making linux_process_target::wait loop if
it got a TARGET_WAITKIND_IGNORE, irrespective of event_ptid.

Change-Id: I39776908a6c75cbd68aa04139ffcf7be334868cf
2023-11-13 14:16:10 +00:00
Pedro Alves
00b0dc819d all-stop/synchronous RSP support thread-exit events
Currently, GDB does not understand the THREAD_EXITED stop reply in
remote all-stop mode.  There's no good reason for this, it just
happened that THREAD_EXITED was only ever reported in non-stop mode so
far.  This patch teaches GDB to parse that event in all-stop RSP too.
There is no need to add a qSupported feature for this, because the
server won't send a THREAD_EXITED event unless GDB explicitly asks for
it, with QThreadEvents, or with the GDB_THREAD_OPTION_EXIT
QThreadOptions option added in the next patch.

Change-Id: Ide5d12391adf432779fe4c79526801c4a5630966
2023-11-13 14:16:10 +00:00