memory_order_acquire does not prevent previous stores from moving past
the barrier so if the _migration_lock_counter incrementation is split
into two accesses, this is eligible:

tmp = _migration_lock_counter;
atomic_signal_fence(std::memory_order_acquire); // load-load, load-store
<critical instructions here>
_migration_lock_counter = tmp + 1; // was moved past the barrier

To prevent this, we need to order previous stores with future
loads and stores, which is given only by std::memory_order_seq_cst.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Take the migration lock for pinned threads instead of a separate
check whether they are pinned or not.

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

Instead of forcing a reload (and a flush) of all variables in memory,
use the minimum required barrier via std::atomic_signal_fence().

Reviewed-by: Tomasz Grabiec <tgrabiec@gmail.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

Proper memory ordering should be implied to loads and stores of _begin
field. Otherwise they may be reordered with the appropriate stores and
loads to/from the _ring array and in a corner case when the ring is full
it may lead to ring data corruption.

Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Reported-by: Nadav Har'el <nyh@cloudius-systems.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

Signed-off-by: Jani Kokkonen <jani.kokkonen@huawei.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

These functions are used to demark a critical section and should
follow a contract which says that no operation inside the critical
section should be moved before migrate_disable() and after
migrate_enable(). These functions are declared inline and the compiler
could theoretically move instructions across these.

Spotted during code contemplation.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

The lock has been pushed down to a helper class and cannot be accessed here,
so remove the assert.

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

revert to a simple implementation which is just atomic,
adding a barrier for the compiler.
The store release is used without load acquire.

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

we start with only a tst-hello.so.

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

move driver setup and console creation to arch-setup,
and ioapic init for x64 to smp_launch, so that we
can remove ifdefs and increase the amount of common code.

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>
Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>

allow execution to flow until main_cont
so we can reach the backtrace.

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

we need to move one instruction back from the return address
to get the address we want to show. Also format the pointers
as long.

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

Signed-off-by: Jani Kokkonen <jani.kokkonen@huawei.com>

[claudio: renamed fixup.hh to fault-fixup.hh]
Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

implement fixup fault and the backtrace functionality which is
its first simple user.

Signed-off-by: Jani Kokkonen <jani.kokkonen@huawei.com>

[claudio: added elf changes to allow lookup and demangling to work]

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

Signed-off-by: Jani Kokkonen <jani.kokkonen@huawei.com>
Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

generate exception frame

Signed-off-by: Jani Kokkonen <jani.kokkonen@huawei.com>
Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

arch::init_on_cpu should initialize the gic cpu interface,
but not for the boot CPU, for which this has already been
done.

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

we need to do that because load/store instructions
behave differently with Device-nGnRnE memory.

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

Signed-off-by: Claudio Fontana <claudio.fontana@huawei.com>

Add qemu command path argument to test different versions of qemu.

Signed-off-by: Takuya ASADA <syuu@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

thread::current()->thread_clock() returns the CPU time consumed by this
thread. A thread that wishes to measure the amount of CPU time consumed
by some short section of code will want this clock to have high resolution,
but in the existing code it was only updated on context switches, so shorter
durations could not be measured with it.

This patch fixes thread_clock() to also add the time that passed since
the the time slice started.

When running thread_clock() on *another* thread (not thread::current()),
we still return a cpu time snapshot from the last context switch - even
if the thread happens to be running now (on another CPU). Fixing that case
is quite difficult (and will probably require additional memory-ordering
guarantees), and anyway not very important: Usually we don't need a
high-resolution estimate of a different thread's cpu time.

Fixes #302.

Reviewed-by: Gleb Natapov <gleb@cloudius-systems.com>
Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Again, we are currently calling a function everytime we disable/enable preemption
(actually a pair of functions), where simple mov instructions would do.

Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

We are heavily using this function to grab the address of the current thread.
That means a function call will be issued every time that is done, where a
simple mov instruction would do.

For objects outside the main ELF, we don't want that to be inlined, since that
would mean the resolution would have to go through an expensive __tls_get_addr.
So what we do is that we don't present the symbol as inline for them, and make
sure the symbol is always generated.

Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

It is sometimes useful to programatically learn if something will end up
in the main ELF or in a shared library. This is the function usually
performed by _KERNEL. However, using that proved quite difficult when
Asias was trying to conditionally compile some zfs tools.  This is
because a lot of our headers expect _KERNEL to be defined and they are
also included in the tools build. Too messy, unfortunately.

Because of that, I am defining a new constant that will be available for
every object that will end up in the main ELF, but won't be defined
otherwise.

Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Remove the unnecessary default vnc :1 argument during make.
It also does not allow make to proceed if another vm is already using :1

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Jaspal Singh Dhillon <jaspal.iiith@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

$ ./scripts/run.py -e 'zpool.so list'
OSv v0.08-81-gc3422a7
eth0: 192.168.122.15
NAME   SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
osv   9.94G   148M  9.79G     1%  1.00x  ONLINE  -

$ ./scripts/run.py -e 'zfs.so list'
OSv v0.08-81-gc3422a7
eth0: 192.168.122.15
NAME      USED  AVAIL  REFER  MOUNTPOINT
osv       148M  9.64G    32K  /
osv/zfs   148M  9.64G   148M  /zfs

Enable it by compiling the missing functions.

Reviewed-by: Glauber Costa <glommer@cloudius-systems.com>
Signed-off-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Signed-off-by: KANATSU Minoru <icc.pot.tyew272@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

add symbol for porting CRuby
this function is depend on execv()

Signed-off-by: KANATSU Minoru <icc.pot.tyew272@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

add symbol for porting CRuby

Signed-off-by: KANATSU Minoru <icc.pot.tyew272@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

The version built on muninn does not have the leading
'tracepoint_base::log_backtrace(trace_record*, unsigned char*&)'
frame.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

They are important in some cases so we should not hide them. Lambda
functions are reported like that.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Our "Makefile" runs build.mk with "make -r", to disable all the default
rules. This flag is saved by make in the MAKEFLAGS variable, which is
passed on to child processes. Unfortunately, it is also passed to the
makefiles of individual modules (apps/*) when we build specific modules.
These makefiles are completely stand-alone, and are normally written to
assume that the default rules (e.g., .c->.o) do exist. They will fail when
run with MAKEFLAGS=r.

We recently noticed both redis-memonly and memcached to exhibit this problem
and committed workarounds (see 914bef6f75d9f3e7f268aecdb00a023b86439b85 and
e2f7ba1b1d80bb5e89d7fca71b4994c7de15ed4e in apps.git).

However, the right fix is for our build.mk to acknowledge that the modules'
makefiles are stand-alone, and must not inherit our prefered flags like
"-r". So this patch clears the MAKEFLAGS variable when calling module.py
(module.py will later invoke "make module" in the module's directory).

Reviewed-by: Tomasz Grabiec <tgrabiec@gmail.com>
Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Signed-off-by: Takuya ASADA <syuu@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

RX descriptor length is 14 bit field, we overflow it
by allocating 16K buffers and device treats RX descriptor
buffer length as zero.

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>