qemu-user can hang in a multi-threaded fork. One common
reason is that when creating a TB, between fork and exec
we manipulate a GTree whose memory allocator (GSlice) is
not fork-safe.
Although POSIX does not mandate it, the system's allocator
(e.g. tcmalloc, libc malloc) is probably fork-safe.
Fix some of these hangs by using QTree, which uses the system's
allocator regardless of the Glib version that we used at
configuration time.
Tested with the test program in the original bug report, i.e.:
```
void garble() {
int pid = fork();
if (pid == 0) {
exit(0);
} else {
int wstatus;
waitpid(pid, &wstatus, 0);
}
}
void supragarble(unsigned depth) {
if (depth == 0)
return ;
std::thread a(supragarble, depth-1);
std::thread b(supragarble, depth-1);
garble();
a.join();
b.join();
}
int main() {
supragarble(10);
}
```
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/285
Reported-by: Valentin David <me@valentindavid.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Emilio Cota <cota@braap.org>
Message-Id: <20230205163758.416992-3-cota@braap.org>
[rth: Add QEMU_DISABLE_CFI for all callback using functions.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This fixes a bug in POSIX-compliant environments. Since we had allocated
a buffer named 'tcg-jit' with read-write access protections we need a int
type to combine these access flags and return it, whereas we had inexplicably
return a bool type. It may cause an unnecessary protection change in
tcg_region_init().
Cc: qemu-stable@nongnu.org
Fixes: 7be9ebcf92 ("tcg: Return the map protection from alloc_code_gen_buffer")
Signed-off-by: Shaobo Song <shnusongshaobo@gmail.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220624150216.3627-1-shnusongshaobo@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Replace the global variables with inlined helper functions. getpagesize() is very
likely annotated with a "const" function attribute (at least with glibc), and thus
optimization should apply even better.
This avoids the need for a constructor initialization too.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220323155743.1585078-12-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the various memalign-related functions out of osdep.h and into
their own header, which we include only where they are used.
While we're doing this, add some brief documentation comments.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20220226180723.1706285-10-peter.maydell@linaro.org
The qemu_icache_linesize, qemu_icache_linesize_log,
qemu_dcache_linesize, and qemu_dcache_linesize_log variables are not
used in many files. Move them out of osdep.h to a new
qemu/cacheinfo.h, and document them.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220208200856.3558249-5-peter.maydell@linaro.org
The qemu_mprotect_*() family of functions are used in very few files;
move them from osdep.h to a new qemu/mprotect.h.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220208200856.3558249-3-peter.maydell@linaro.org
The function qemu_madvise() and the QEMU_MADV_* constants associated
with it are used in only 10 files. Move them out of osdep.h to a new
qemu/madvise.h header that is included where it is needed.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220208200856.3558249-2-peter.maydell@linaro.org
We can call do_tb_phys_invalidate from an iocontext, which has
no per-thread tcg_ctx. Move this to tb_ctx, which is global.
The actual update still takes place with a lock held, so only
an atomic set is required, not an atomic increment.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/457
Tested-by: Viktor Ashirov <vashirov@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The function is called only at tcg_gen_code() when duplicated TBs
are translated by different threads, and when the tcg_region_tree
is reset. Bake it into the underlying GTree as its value destroy
function to unite these situations.
Also remove tcg_region_tree_traverse() which now becomes useless.
Signed-off-by: Liren Wei <lrwei@bupt.edu.cn>
Message-Id: <8dc352f08d038c4e7a1f5f56962398cdc700c3aa.1625404483.git.lrwei@bupt.edu.cn>
[rth: Name the new tb_tc_cmp parameter correctly.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
There's a change in mprotect() behaviour [1] in the latest macOS
on M1 and it's not yet clear if it's going to be fixed by Apple.
In this case, instead of changing permissions of N guard pages,
we change permissions of N rwx regions. The same number of
syscalls are required either way.
[1] https://gist.github.com/hikalium/75ae822466ee4da13cbbe486498a191f
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Do not handle protections on a case-by-case basis in the
various alloc_code_gen_buffer instances; do it within a
single loop in tcg_region_init.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
If qemu_get_host_physmem returns an odd number of pages,
then physmem / 8 will not be a multiple of the page size.
The following was observed on a gitlab runner:
ERROR qtest-arm/boot-serial-test - Bail out!
ERROR:../util/osdep.c:80:qemu_mprotect__osdep: \
assertion failed: (!(size & ~qemu_real_host_page_mask))
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Move the call out of the N versions of alloc_code_gen_buffer
and into tcg_region_init.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Change the interface from a boolean error indication to a
negative error vs a non-negative protection. For the moment
this is only interface change, not making use of the new data.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Do not mess around with setting values within tcg_init_ctx.
Put the values into 'region' directly, which is where they
will live for the lifetime of the program.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Shortly, the full code_gen_buffer will only be visible
to region.c, so move in_code_gen_buffer out-of-line.
Move the debugging versions of tcg_splitwx_to_{rx,rw}
to region.c as well, so that the compiler gets to see
the implementation of in_code_gen_buffer.
This leaves exactly one use of in_code_gen_buffer outside
of region.c, in cpu_restore_state. Which, being on the
exception path, is not performance critical.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Return output buffer and size via output pointer arguments,
rather than returning size via tcg_ctx->code_gen_buffer_size.
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Compute the value using straight division and bounds,
rather than a loop. Pass in tb_size rather than reading
from tcg_init_ctx.code_gen_buffer_size,
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Give the field a name reflecting its actual meaning.
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
A size is easier to work with than an end point,
particularly during initial buffer allocation.
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Remove the ifdef ladder and move each define into the
appropriate header file.
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Finish the divorce of tcg/ from hw/, and do not take
the max cpu value from MachineState; just remember what
we were passed in tcg_init.
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Start removing the include of hw/boards.h from tcg/.
Pass down the max_cpus value from tcg_init_machine,
where we have the MachineState already.
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Buffer management is integral to tcg. Do not leave the allocation
to code outside of tcg/. This is code movement, with further
cleanups to follow.
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
