private area called PRDA that remains unshared. We implement this by using
different vmspace for each share group member, and keeping the memory
appings in sync on each mmap/munmap/mprotect/break...
We use irix_saddr_sync_vmcmd and irix_saddr_sync_syscall to apply a
vmcmd or a syscall to all share group member, this makes the job a bit
easier.
Also implements {get|set}rlimit{64}.
- First implementation of procblk(). THis is supposed to suspend processes.
We emulate this by sending a SIGSTOP, which is not very accurate since
on IRIX, sending a SIGCONT to a process suspended by procblk() will not
resume it.
- support for shared groups
poll will return true until the semaphore is blocked again, but before the
semaphore is blocked, poll returns false.
We do this by maintaining another queue of "released" processes in
struct irix_usema_rec. Unblocking causes the waiting process record to be
moved to the released queue, and poll check for the process in this released
queue.
a SIGSEGV when sigaction(2) is used before a fork(2) and a signal is received
in the child.
- we now nearly correctly emulate PR_TERMCHILD in prctl(2). (the perfect
emulation would not send a SIGHUP if the parent is killed)
return the number of processes waiting on the semaphore. We now maintiain
a count of waiting processes.
- Blocked processes are unblocked "first in, first out". We now have a
queue of waiting processes on a asemaphores, so that we can wakeup the
first blocked process.
Problems:
- We now have a lot of dynamic memory allocation, it may be a bit slow.
- Nothing is SMP safe for now. We need to add locks.
- On close, we forget about a semaphore, which is incorrect. One process
can close its fd attached on a semaphore, but other processes would carry
on using it. Since any process can join a shared arena, this is not an
easy thing to solve.
- A lot of usema/usync functionnalities are still to be discovered.
successfully emulates a few test program that use poll semaphores,
including the attach-to-file-descriptor-and-select feature.
There are a few issues:
1) at least one ioctl need to set retval. We handle this in irix_sys_ioctl()
by replacing the data argument by a pointer to a strucutre in the stackgap
that carries the real data and retval. The underlying ioctl methods can
therefore retreive both data and retval.
2) usemaclone is a cloning device: each time it is open, it creates a new
context, and ioctl operation on each open file descriptor will lead to
different behavior. This functionnality is available in NetBSD through the
devvp branch. This first implementation does not use devvp yet, but this
should be done later. Currently, we create a new vnode, and we provide our
own vnode operations. Some operation are applied to the cloned vnode, others
are applied to the original vnode. The v_data field is used to hold a
reference to the original vnode so that we can work on it.
3) at least the setattr vnode operation needs some customisation: IRIX
libc relies on the fact that fchmod on /dev/usema will return 0 in case
of failure.
- initial support for MAP_AUTOGROW flag. When mapping beyond the end of file is
requested with MAP_AUTOGROW, if pages beyond the end of file are touched, the
file should be resized. We are not able to emulate this yet, so we immediatly
resize the file to fit the whole mapping.
- implements mmap64
address 0x200000 (disasembling usinit shows that this address is hardcoded in
libc). It uses it for locks and semaphres.
We therefore allocate this page of memory, to prevent IRIX process from
faulting when thay call usinit(3).
- the signal trampoline address is given to the kernel by a sigaction()
fourth argument
- we introduce an irix_emuldata structure to keep track of the signal
trampoline address
- we don't support per-sigaction signal trampolines, we only do per-process
- now that we use the IRIX libc signal trampoline, we do not have to handle
the errno update from the signal trampoline
- it is possible that IRIX 5 signal delivery works too, since theses binaries
will come with their own signal trampoline
when SA_SIGINFO is used. The IRIX process will hence find the expected
information using the third argument of the signal handler.
We do not provide code and siginfo yet.
swapent, or as seen in userland, is dbtob(1), which turns to be 512 for all
arch for now.
In struct swapdev, there is another field for block size. This value is private
to uvm_swap.c and is only used for swap I/O on regular files. It is equal to
the underlying device block size and it is not necessarily 512.
- Added two more swapctl commands: GETFREESWAP and GETSWAPVIRT.
There is a problem in the way swap block size are found here. See comment
in get_block_size().
