Without the lock page mapping and buffer eviction can run in parallel
which may cause following race:

page mapper thread               thread calling arc_evict()
map_addr() {
  page = arc_get_page();
  add_mapping(page, ptep);
                                  evict(page) {
                                    ptep = get_mapping(page);
                                    ptep.write(0);
                                    free(page);
                                  }

  ptep.write(page);
}

ARC code has no well defined order for taking its mutexes. It uses trylock()
and skips a buffer if required locks cannot be acquired. This patch uses
same approach for vma_list_mutex: if evicted buffer is shared try to
lock vma_list_mutex and skip the buffer if this fails.

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

thread_list was populated with references to sched::thread* rather
than sched::thread. The commands were assuming the latter. As a result
the commands were printing and comparing not against sched::thread
address but against address of the pointer to sched::thread in
sched::thread_map.

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

Looks like gdb.Value() cannot be implicitly converted to int
by range() on GDB with python3:

    for qidx in range(0, vb['_num_queues']):
  TypeError: 'gdb.Value' object cannot be interpreted as an integer
  Error occurred in Python command: 'gdb.Value' object cannot be interpreted as an integer

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

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

Reviewed-by: Tomasz Grabiec <tgrabiec@gmail.com>
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Reviewed-by: Tomasz Grabiec <tgrabiec@gmail.com>
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

For a long time we've had the bug summarized in issue #178, where very
rarely but consistently, in various runs such as Cassandra, Netperf and
tst-queue-mpsc.so, we saw OSv crashing because of some corruption in the
timer list, such as arming an already armed timer, or canceling and already
canceled timer.

It turns out the problem was the schedule() function, which basically did
cpu::current()->schedule(). The problem is that if we're unlucky enough,
the thread can be migrated right after calling cpu::current(), but before
the irq disable in schedule(), which causes us to do a rescheduling for
one CPU on a different CPU, which is a big faux pas. This can cause us,
for example, to mess with one CPU's preemption_timer from a different CPU,
causing the timer-related races and crashes we've seen in issue #178.

Clearly, we shouldn't at all have a *method* cpu->schedule() which can
operate on any cpu. Rather, we should have only a *function* (class-static)
cpu::schedule() which operates on the current cpu - and makes sure we find
that current CPU within the IRQ lock to ensure (among other things) the
thread cannot get migrated.

Another benefit of this patch is that it actually simplifies the code,
with one less function called "schedule".

Fixes #178.

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

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

Changes:

commit 29ae2430f0e2b538477b49b4b9f8432780ddf60e
Author: Tomasz Grabiec <tgrabiec@cloudius-systems.com>

    httpserver: add missing module.py

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

This also bumps up mgmt submodule HEAD to the version which has
httpserver as separate module.

Specific output:

Reading directory entries at /proc...
dentry name: .
dentry name: ..
dentry name: self
Reading directory entries at /proc/self...
dentry name: .
dentry name: ..
dentry name: maps

Signed-off-by: Raphael S. Carvalho <raphaelsc@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

This patch fixes applications that read directory entries of a procfs,
e.g. ls /proc.
Modeled after ramfs.

Closes #243

Signed-off-by: Raphael S. Carvalho <raphaelsc@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Currently, "mgmt.httpserver" pulls the entire OpenJDK which is not what
we want for osv-base image which is supposed to be around 10 MB.

Switch to "empty" image configuration until the problem is resolved.

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

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

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

"This is v3 of the patch series that enables first stubbed support
for AArch64."

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

Conflicts:
	bsd/porting/mmu.cc
	build.mk
	fs/vfs/vfs_fops.cc

get the command line and elf header start, then try to
stay clear of apparent random limitations during boot
early stage with the model, and set up vectors as soon
as possible, to enable some minimal post-mortem info.

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

This should build and reach end of premain.

See PORTING for some initial build instructions.

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>

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

include/api/x64/atomic.h is not used anywhere.

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

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

implementation includes only for the few rels that are actually
encountered during elf::get_init().

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

protect x64 machine code in #ifdef __x86_64__

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

stub console_init for AArch64.

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

the functions debug_early, debug_early_u64 and
debug_early_entry can be used very early, before premain.

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

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>

rename processor::halt_no_interrupts to cli_hlt, which
logically matches existing processor::sti_hlt.

Make use of arch::halt_no_interrupts in core/power.cc,
enclose x64-specific code in ifdefs, as well as putting
code on AArch64.

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

virt_to_phys just returns the virtual address again
for AArch64 for now, while mmu_unmap will abort.

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

use %wn when referring to the non-extended register n,
and %n when referring to the extended register n,
emit the right memory barrier instructions, get the
semantics of atomic_store_rel hopefully right.

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

this contains still prototyped code, which if reached either
hangs (setjmp, longjmp), aborts (all that requires mmu::),
or implements differently (allocating with malloc instead of mmap)
This is enough libc AArch64 support for reaching the end of premain.

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

"
This is write page cache implemented on top of ARC read cache. On a
read fault pages are initially mapped from ARC directly, but they are
marked as RO in a page table. On a write fault pages are copied into
small write page cache for shared mapping, or into anonymous page for
private mappings.  Pages are removed from write cache and written back
into a file in a FIFO order.

This passes "make check", misc-mmap-big-file modified to do write in
addition to read and "cassandra-stress -d".
"

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

This reverts commit 64889277.

The structure is not longer used.

Signed-off-by: Gleb Natapov <gleb@cloudius-systems.com>

This patch adds write page cache implementation. On a read fault pages
are initially mapped from ARC directly, but they are marked as RO in a
page table. On a write fault pages are copied into small write page
cache for shared mapping, or into anonymous page for private mappings.
Pages are removed from write cache and written back into a file in FIFO
order.

Signed-off-by: Gleb Natapov <gleb@cloudius-systems.com>

File page allocator needs to know fault type (read/write) and mapping
type (shared/private) to handle page allocation correctly. It also needs
a way to communicate to a caller that some pages need to be mapped RO
for COW. This patch adds required functionality without using it yet.

Signed-off-by: Gleb Natapov <gleb@cloudius-systems.com>

It holds offset into file, not mapping. Also to be consistent with
map_file_page_read.

Signed-off-by: Gleb Natapov <gleb@cloudius-systems.com>