This makes the simulator work the same regardless of the target (bare
metal m32r-elf or Linux m32r-linux-gnu) by unifying the traps code.
It was mostly already the same with the only difference being support
for trap #2 reserved for Linux syscalls. We can move that logic to
runtime by checking the current environment operating mode instead.
This improves the logic a bit by making the host<->target translations
a bit more clear. The structs still bleed way too much between the two
worlds, but let's fix one thing at a time.
We don't want to handle Linux syscalls when in the virtual environment,
just the user environment, so adjust the Linux traps logic to check for
that specifically (instead of just skipping the operating environment).
Also tweak some testcases to explicitly specify the environment they run
under rather than relying on the default matching their needs. This gets
the tests passing for all m32r targets.
The use of __NR_ defines in here conflicts a lot with the standard
host syscalls, sometimes leading to build errors (when the numbers
happen to be the same we get duplicate case handlers), and other
times leading to misbehavior (where the m32r syscall # is not what
is actually checked).
Namespace these using the standard that we already use: change the
__NR_ to TARGET_LINUX_SYS_ with a simple `sed`.
Also add a few missing includes so the code at least compiles.
This makes it easier to override to point to an older version of guile.
The current cgen code doesn't work with guile-2, so need to point to an
older guile-1.8.
For the variables that don't need to be exported, mark them static.
For the ones shared between modules, add a "nds32_" prefix to avoid
collisions with these common variable names.
This is exporting the variable "opcodes" as a large writable blob.
This is not a namespace friendly name, so add a "microblaze" prefix,
and then sprinkle const over its definition & use.
Currently, on GNU/Linux, if you try to access memory and you have a
running thread selected, GDB fails the memory accesses, like:
(gdb) c&
Continuing.
(gdb) p global_var
Cannot access memory at address 0x555555558010
Or:
(gdb) b main
Breakpoint 2 at 0x55555555524d: file access-mem-running.c, line 59.
Warning:
Cannot insert breakpoint 2.
Cannot access memory at address 0x55555555524d
This patch removes this limitation. It teaches the native Linux
target to read/write memory even if the target is running. And it
does this without temporarily stopping threads. We now get:
(gdb) c&
Continuing.
(gdb) p global_var
$1 = 123
(gdb) b main
Breakpoint 2 at 0x555555555259: file access-mem-running.c, line 62.
(The scenarios above work correctly with current GDBserver, because
GDBserver temporarily stops all threads in the process whenever GDB
wants to access memory (see prepare_to_access_memory /
done_accessing_memory). Freezing the whole process makes sense when
we need to be sure that we have a consistent view of memory and don't
race with the inferior changing it at the same time as GDB is
accessing it. But I think that's a too-heavy hammer for the default
behavior. I think that ideally, whether to stop all threads or not
should be policy decided by gdb core, probably best implemented by
exposing something like gdbserver's prepare_to_access_memory /
done_accessing_memory to gdb core.)
Currently, if we're accessing (reading/writing) just a few bytes, then
the Linux native backend does not try accessing memory via
/proc/<pid>/mem and goes straight to ptrace
PTRACE_PEEKTEXT/PTRACE_POKETEXT. However, ptrace always fails when
the ptracee is running. So the first step is to prefer
/proc/<pid>/mem even for small accesses. Without further changes
however, that may cause a performance regression, due to constantly
opening and closing /proc/<pid>/mem for each memory access. So the
next step is to keep the /proc/<pid>/mem file open across memory
accesses. If we have this, then it doesn't make sense anymore to even
have the ptrace fallback, so the patch disables it.
I've made it such that GDB only ever has one /proc/<pid>/mem file open
at any time. As long as a memory access hits the same inferior
process as the previous access, then we reuse the previously open
file. If however, we access memory of a different process, then we
close the previous file and open a new one for the new process.
If we wanted, we could keep one /proc/<pid>/mem file open per
inferior, and never close them (unless the inferior exits or execs).
However, having seen bfd patches recently about hitting too many open
file descriptors, I kept the logic to have only one file open tops.
Also, we need to handle memory accesses for processes for which we
don't have an inferior object, for when we need to detach a
fork-child, and we'd probaly want to handle caching the open file for
that scenario (no inferior for process) too, which would probably end
up meaning caching for last non-inferior process, which is very much
what I'm proposing anyhow. So always having one file open likely ends
up a smaller patch.
The next step is handling the case of GDB reading/writing memory
through a thread that is running and exits. The access should not
result in a user-visible failure if the inferior/process is still
alive.
Once we manage to open a /proc/<lwpid>/mem file, then that file is
usable for memory accesses even if the corresponding lwp exits and is
reaped. I double checked that trying to open the same
/proc/<lwpid>/mem path again fails because the lwp is really gone so
there's no /proc/<lwpid>/ entry on the filesystem anymore, but the
previously open file remains usable. It's only when the whole process
execs that we need to reopen a new file.
When the kernel destroys the whole address space, i.e., when the
process exits or execs, the reads/writes fail with 0 aka EOF, in which
case there's nothing else to do than returning a memory access
failure. Note this means that when we get an exec event, we need to
reopen the file, to access the process's new address space.
If we need to open (or reopen) the /proc/<pid>/mem file, and the LWP
we're opening it for exits before we open it and before we reap the
LWP (i.e., the LWP is zombie), the open fails with EACCES. The patch
handles this by just looking for another thread until it finds one
that we can open a /proc/<pid>/mem successfully for.
If we need to open (or reopen) the /proc/<pid>/mem file, and the LWP
we're opening has exited and we already reaped it, which is the case
if the selected thread is in THREAD_EXIT state, the open fails with
ENOENT. The patch handles this the same way as a zombie race
(EACCES), instead of checking upfront whether we're accessing a
known-exited thread, because that would result in more complicated
code, because we also need to handle accessing lwps that are not
listed in the core thread list, and it's the core thread list that
records the THREAD_EXIT state.
The patch includes two testcases:
#1 - gdb.base/access-mem-running.exp
This is the conceptually simplest - it is single-threaded, and has
GDB read and write memory while the program is running. It also
tests setting a breakpoint while the program is running, and checks
that the breakpoint is hit immediately.
#2 - gdb.threads/access-mem-running-thread-exit.exp
This one is more elaborate, as it continuously spawns short-lived
threads in order to exercise accessing memory just while threads are
exiting. It also spawns two different processes and alternates
accessing memory between the two processes to exercise the reopening
the /proc file frequently. This also ends up exercising GDB reading
from an exited thread frequently. I confirmed by putting abort()
calls in the EACCES/ENOENT paths added by the patch that we do hit
all of them frequently with the testcase. It also exits the
process's main thread (i.e., the main thread becomes zombie), to
make sure accessing memory in such a corner-case scenario works now
and in the future.
The tests fail on GNU/Linux native before the code changes, and pass
after. They pass against current GDBserver, again because GDBserver
supports memory access even if all threads are running, by
transparently pausing the whole process.
gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
PR mi/15729
PR gdb/13463
* linux-nat.c (linux_nat_target::detach): Close the
/proc/<pid>/mem file if it was open for this process.
(linux_handle_extended_wait) <PTRACE_EVENT_EXEC>: Close the
/proc/<pid>/mem file if it was open for this process.
(linux_nat_target::mourn_inferior): Close the /proc/<pid>/mem file
if it was open for this process.
(linux_nat_target::xfer_partial): Adjust. Do not fall back to
inf_ptrace_target::xfer_partial for memory accesses.
(last_proc_mem_file): New.
(maybe_close_proc_mem_file): New.
(linux_proc_xfer_memory_partial_pid): New, with bits factored out
from linux_proc_xfer_partial.
(linux_proc_xfer_partial): Delete.
(linux_proc_xfer_memory_partial): New.
gdb/testsuite/ChangeLog
yyyy-mm-dd Pedro Alves <pedro@palves.net>
PR mi/15729
PR gdb/13463
* gdb.base/access-mem-running.c: New.
* gdb.base/access-mem-running.exp: New.
* gdb.threads/access-mem-running-thread-exit.c: New.
* gdb.threads/access-mem-running-thread-exit.exp: New.
Change-Id: Ib3c082528872662a3fc0ca9b31c34d4876c874c9
* readelf.c (process_archive): Reset file position to the
beginning when calling process_object for thin archive members.
* testsuite/binutils-all/readelf.exp: Add test.
* testsuite/binutils-all/readelf.h.thin: New file.
Although the XScale and its iwMMX extensions are implemented in the
Arm co-processor space, they are not considered to be part of the FPU
specification. In particular, they cannot be enabled or disabled via
a .fpu directive. It's therefore incorrect to strip these properties
when a new .fpu directive is encountered.
Note that the legacy Maverick co-processor is considered to be a FPU
and it is possible to control this via the .fpu directive.
include:
PR gas/28031
* opcode/arm.h (FPU_ANY): Exclude XScale-related features.
Copy most of the common build warning logic over from the common
code to help keep code behavior a bit consistent, and turn them
on by default. We disable a few flags for now until we can clean
the code up.
Now that the scache logic has been migrated into the common code,
there's nothing specific in these configure scripts, so merge them
into the common one.
The frv unique logic can be moved to a dedicated include and merged
in the common configure since the flag has been scoped to the arch.
The cgen scache module is enabled by every cgen port, and with the
same default value of 16k (which matches the common default value).
Let's pull this option out of the individual ports (via CPPFLAGS)
and into the common code (via config.h).
The object itself is compiled only for cgen ports atm, so that part
doesn't change. The scache code is initialized dynamically via the
modules.c logic. That's why the profile code needs an additional
CGEN_ARCH check.
This will allow us to collapse arch configure files more. Merging
the source files will require more future work, but integrating the
cgen & non-cgen worlds itself will take a lot.
These were never fully migrated from the psim to common code, and since
we've finished moving the logic into the runtime sim state, we won't ever
need these. So punt them.
This kills off another compile-time option by moving the setting to
the individual arch runtimes. This will allow dynamic selection by
the arch when doing a single build with multiple arches.
The sim_model_init rework is a little funky. In the past it was
disabled entirely if no default model was set. We maintain the
spirit of the logic by gating the fallback logic on whether the
port has defined any models.
We want to do a single build with all arches in one binary which means
we need to namespace sim_machs on a per-arch basis. Move it from a
global variable to the sim description structure so it can be setup at
runtime.
Changing the SIM_MODEL->num from an enum to an int is unfortunate, but
we specifically don't want to maintain a centralized list anymore, and
this was never used directly in common code, just passed to per-arch
callbacks.
The $(arch) variable is only setup for cgen ports, so calculate this
value dynamically. We also need to generate multiple inputs in order
to properly recreate the subdir Makefile, so list them all.
We have some code tripping this warning, but it depends on the gcc
version & optimization levels. We've added some hints to the code
so some versions of gcc work better, but still not all. Let's just
disable the warning like gdb does.
I wrote this while debugging a problem where the expected unwinder for a
frame wasn't used. It adds messages to show which unwinders are
considered for a frame, why they are not selected (if an exception is
thrown), and finally which unwinder is selected in the end.
To be able to show a meaningful, human-readable name for the unwinders,
add a "name" field to struct frame_unwind, and update all instances to
include a name.
Here's an example of the output:
[frame] frame_unwind_find_by_frame: this_frame=0
[frame] frame_unwind_try_unwinder: trying unwinder "dummy"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "dwarf2 tailcall"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "inline"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "jit"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "python"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "amd64 epilogue"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "i386 epilogue"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "dwarf2"
[frame] frame_unwind_try_unwinder: yes
gdb/ChangeLog:
* frame-unwind.h (struct frame_unwind) <name>: New. Update
instances everywhere to include this field.
* frame-unwind.c (frame_unwind_try_unwinder,
frame_unwind_find_by_frame): Add debug messages.
Change-Id: I813f17777422425f0d08b22499817b23922e8ddb
Introduce frame_debug_printf, to convert the "frame" debug messages to
the new system. Replace fprint_frame with a frame_info::to_string
method that returns a string, like what was done with
frame_id::to_string. This makes it easier to use with
frame_debug_printf.
gdb/ChangeLog:
* frame.h (frame_debug_printf): New.
* frame.c: Use frame_debug_printf throughout when printing frame
debug messages.
* amd64-windows-tdep.c: Likewise.
* value.c: Likewise.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-reg-undefined.exp: Update regexp.
Change-Id: I3c230b0814ea81c23af3e1aca1aac8d4ba91d726
gdb/ChangeLog:
* frame.h (frame_debug): Change type to bool.
* frame.c (frame_debug): Change type to bool.
(_initialize_frame): Adjust.
Change-Id: I27b5359a25ad53ac42618b5708a025c348a1eeda
There are two declarations of 'find_thread_ptid' in gdbthread.h
with the same signature:
/* Find (non-exited) thread PTID of inferior INF. */
extern thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
and
/* Search function to lookup a (non-exited) thread by 'ptid'. Only
searches in threads of INF. */
extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
Retain the former, remove the latter. Tested by rebuilding.
gdb/ChangeLog:
2021-06-29 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdbthread.h (find_thread_ptid): Remove the duplicate declaration.
This helps these funcs get printf format checking coverage.
The sim-io.c hack as a result is a bit unfortunate, but the compiler
throws warnings when printing with empty strings. In this one case,
we actually want that due to the side-effect of the callback halting
execution for us.
These cover functions aren't used anywhere, so drop them. There was
one caller, but it's old DOS code that most likely hasn't been tested
in years, so just delete that too.
