By the spec, fork() copies only the thread which executes it.
So it may happen, what while one thread is doing a fork,
another thread is holding `clone_lock` mutex
(e.g. doing a `fork()` or `exit()`).
So the child process is born with the mutex being held,
and there are nobody to release it.
As the thread executing do_syscall() is not considered running,
start_exclusive() does not protect us from the case.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3226
Signed-off-by: Aleksandr Sergeev <sergeev0xef@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20260126151612.2176451-1-sergeev0xef@gmail.com>
This commit adds support for the `prctl(PR_SET_SYSCALL_USER_DISPATCH)`
function in the Linux userspace emulator.
It is implemented as a fully host-independent function, by forcing
a SIGSYS early during syscall handling, if the PC is outside the
allowed range.
Since disabled SUD is indistinguishable from enabled SUD with
always-allowed region length == ~0, this encoding is used
instead of introducing a new flag.
Tested on [uglendix][1], will probably also apply to software like
tiny-wine, rpcsx, limbo, lazypoline, vicar, sysfail and endokernel,
to name a few.
[1]: https://sr.ht/~arusekk/uglendix
Signed-off-by: Arusekk <floss@arusekk.pl>
Message-ID: <20250711225226.14652-1-floss@arusekk.pl>
[rth: Split out is_vdso_sigreturn region matching and other minor tweaks.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Round-robin TCG is calling into cpu_exit() directly. In preparation
for making cpu_exit() usable from all accelerators, define a generic
thread-kick function for TCG which is used directly in the multi-threaded
case, and through CPU_FOREACH in the round-robin case.
Use it also for user-mode emulation, and take the occasion to move
the implementation to accel/tcg/user-exec.c.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
All targets have been converted, so we can call init_main_thread
directly. Remove do_init_main_thread and HAVE_INIT_MAIN_THREAD.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Provide a unified function to initialize the main thread.
Keep target_pt_regs isolated to this function.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Rename from cpu_get_model to emphasize that this is an elf-specific
function. Declare the function once in loader.h.
This frees up target_elf.h for other uses.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Remove GUEST_ADDR_MAX and add guest_addr_max.
Initialize it in *-user/main.c, after reserved_va.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Allow debugging individual processes in multi-process applications by
starting them with export QEMU_GDB=/tmp/qemu-%d.sock,suspend=n.
Currently one would have to attach to every process to ensure the app
makes progress.
In case suspend=n is not specified, the flow remains unchanged. If it
is specified, then accepting the client connection is delegated to a
thread. In the future this machinery may be reused for handling
reconnections and interruptions.
On accepting a connection, the thread schedules gdb_handlesig() on the
first CPU and wakes it up with host_interrupt_signal. Note that the
result of this gdb_handlesig() invocation is handled, as opposed to
many other existing call sites. These other call sites probably need to
be fixed separately.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20250117001542.8290-7-iii@linux.ibm.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20250207153112.3939799-16-alex.bennee@linaro.org>
This started as a clean-up to properly pass a Error handler to the
gdbserver_start so we could do the right thing for command line and
HMP invocations.
Now that we have cleaned up foreach_device_config_or_exit() in earlier
patches we can further simplify by it by passing &error_fatal instead
of checking the return value. Having a return value is still useful
for HMP though so tweak the return to use a simple bool instead.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20250116160306.1709518-11-alex.bennee@linaro.org>
"linux-user/cpu_loop-common.h" is generic enough to be used by
bsd-user, so rename it as "user/cpu_loop.h".
Mechanical change running:
$ sed -i -e 's,cpu_loop-common.h,user/cpu_loop.h,' \
$(git grep -l cpu_loop-common.h)
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20241212185341.2857-17-philmd@linaro.org>
Some applications want to use low priority realtime signals (e.g.,
SIGRTMAX). Currently QEMU cannot map all target realtime signals to
host realtime signals, and chooses to sacrifice the end of the target
realtime signal range.
Allow users to choose how to map target realtime signals to host
realtime signals using the new -t option, the new QEMU_RTSIG_MAP
environment variable, and the new -Drtsig_map=\"...\" meson flag.
To simplify things, the meson flag is not per-target, because the
intended use case is app-specific qemu-user builds.
The mapping is specified using the "tsig hsig count[,...]" syntax.
Target realtime signals [tsig,tsig+count) are mapped to host realtime
signals [hsig,hsig+count). Care is taken to avoid double and
out-of-range mappings.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20241029232211.206766-2-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
For arm32 host and arm64 guest we get
.../main.c:851:32: error: result of comparison of constant 70368744177664 with expression of type 'unsigned long' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
if (TASK_UNMAPPED_BASE < reserved_va) {
~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~
We already disable -Wtype-limits here, for this exact comparison, but
that is not enough for clang. Disable -Wtautological-compare as well,
which is a superset. GCC ignores the unknown warning flag.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20240630190050.160642-15-richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240705084047.857176-20-alex.bennee@linaro.org>
If the user didn't specify reserved_va, there's an else for 64-bit host
32-bit (or fewer) target to reserve 32-bits of address space. Update the
comments to reflect this, and rejustify comment to 80 columns.
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Declare 'have_guest_base' in "user/guest-base.h".
Very few files require this header, so explicitly include
it there instead of "exec/cpu-all.h" which is used in many
source files.
Assert this user-specific header is only included from user
emulation.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20231211212003.21686-23-philmd@linaro.org>
Reviewed-by: Anton Johansson <anjo@rev.ng>
This option controls the host page size. From the mis-usage in
our own testsuite, this is easily confused with guest page size.
The only thing that occurs when changing the host page size is
that stuff breaks, because one cannot actually change the host
page size. Therefore reject all but the no-op setting as part
of the deprecation process.
Reviewed-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Helge Deller <deller@gmx.de>
Message-Id: <20240102015808.132373-27-richard.henderson@linaro.org>
Fix:
hw/core/machine.c:1302:22: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
const CPUArchId *cpus = possible_cpus->cpus;
^
hw/core/numa.c:69:17: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
uint16List *cpus = NULL;
^
hw/acpi/aml-build.c:2005:20: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
CPUArchIdList *cpus = ms->possible_cpus;
^
hw/core/machine-smp.c:77:14: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
unsigned cpus = config->has_cpus ? config->cpus : 0;
^
include/hw/core/cpu.h:589:17: note: previous declaration is here
extern CPUTailQ cpus;
^
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Message-Id: <20231010115048.11856-2-philmd@linaro.org>
The tcg/tcg.h header is a big bucket, containing stuff related to
the translators and the JIT backend. The places that initialize
tcg or create new threads do not need all of that, so split out
these three functions to a new header.
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Copy each guest kernel's default value, then bound it
against reserved_va or the host address space.
Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Ensure that the chosen values for mmap_next_start and
task_unmapped_base are within the guest address space.
Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Do not reverse the order of environment variables in the target environ
array relative to the incoming environ order. Some testsuites depend on a
specific order, even though it is not defined by any standard.
Signed-off-by: Andreas Schwab <schwab@suse.de>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <mvmlejfsivd.fsf@suse.de>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
The '-singlestep' option is confusing, because it doesn't actually
have anything to do with single-stepping the CPU. What it does do
is force TCG emulation to put one guest instruction in each TB,
which can be useful in some situations.
Create a new command line argument -one-insn-per-tb, so we can
document that -singlestep is just a deprecated synonym for it,
and eventually perhaps drop it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230417164041.684562-5-peter.maydell@linaro.org
The only place left that looks at the old 'singlestep' global
variable is the TCG curr_cflags() function. Replace the old global
with a new 'one_insn_per_tb' which is defined in tcg-all.c and
declared in accel/tcg/internal.h. This keeps it restricted to the
TCG code, unlike 'singlestep' which was available to every file in
the system and defined in multiple different places for softmmu vs
linux-user vs bsd-user.
While we're making this change, use qatomic_read() and qatomic_set()
on the accesses to the new global, because TCG will read it without
holding a lock.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230417164041.684562-4-peter.maydell@linaro.org
This commit adds 'one-insn-per-tb' as a property on the TCG
accelerator object, so you can enable it with
-accel tcg,one-insn-per-tb=on
It has the same behaviour as the existing '-singlestep' command line
option. We use a different name because 'singlestep' has always been
a confusing choice, because it doesn't have anything to do with
single-stepping the CPU. What it does do is force TCG emulation to
put one guest instruction in each TB, which can be useful in some
situations (such as analysing debug logs).
The existing '-singlestep' commandline options are decoupled from the
global 'singlestep' variable and instead now are syntactic sugar for
setting the accel property. (These can then go away after a
deprecation period.)
The global variable remains for the moment as:
* what the TCG code looks at to change its behaviour
* what HMP and QMP use to query and set the behaviour
In the following commits we'll clean those up to not directly
look at the global variable.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230417164041.684562-2-peter.maydell@linaro.org
Change the semantics to be the last byte of the guest va, rather
than the following byte. This avoids some overflow conditions.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
