- Revert the change for seed(0) in r300384. I misunderstood the standard
and while our random() implementation in libkern may be improved, it
handles the seed(0) case fine.
Pointed out by: bde, ache
- Revert r300377: The implementation claims to return a value
within the range. [1]
- Adjust the value for the case of a zero seed, whihc according
to standards should be equivalent to a seed of value 1.
Pointed out by: cem
This is a long standing problem: our random() function returns an
unsigned integer but the rand provided by ndis(4) returns an int.
Scale it down.
MFC after: 2 weeks
In ndis(4) we expose a rand() function that was constantly reseeding
with a time depending function every time it was called. This
essentially broke the reasoning behind seeding, and rendered srand()
a no-op.
Keep it simple, just use random() and srandom() as it's meant to work.
It would have been tempting to just go for arc4random() but we
want to mimic Microsoft, and we don't need crypto-grade randomness
here.
PR: 209616
MFC after: 2 weeks
intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013.
A robust mutex is guaranteed to be cleared by the system upon either
thread or process owner termination while the mutex is held. The next
mutex locker is then notified about inconsistent mutex state and can
execute (or abandon) corrective actions.
The patch mostly consists of small changes here and there, adding
neccessary checks for the inconsistent and abandoned conditions into
existing paths. Additionally, the thread exit handler was extended to
iterate over the userspace-maintained list of owned robust mutexes,
unlocking and marking as terminated each of them.
The list of owned robust mutexes cannot be maintained atomically
synchronous with the mutex lock state (it is possible in kernel, but
is too expensive). Instead, for the duration of lock or unlock
operation, the current mutex is remembered in a special slot that is
also checked by the kernel at thread termination.
Kernel must be aware about the per-thread location of the heads of
robust mutex lists and the current active mutex slot. When a thread
touches a robust mutex for the first time, a new umtx op syscall is
issued which informs about location of lists heads.
The umtx sleep queues for PP and PI mutexes are split between
non-robust and robust.
Somewhat unrelated changes in the patch:
1. Style.
2. The fix for proper tdfind() call use in umtxq_sleep_pi() for shared
pi mutexes.
3. Removal of the userspace struct pthread_mutex m_owner field.
4. The sysctl kern.ipc.umtx_vnode_persistent is added, which controls
the lifetime of the shared mutex associated with a vnode' page.
Reviewed by: jilles (previous version, supposedly the objection was fixed)
Discussed with: brooks, Martin Simmons <martin@lispworks.com> (some aspects)
Tested by: pho
Sponsored by: The FreeBSD Foundation
at it use NULL for some pointer checks.
Bump the FreeBSD version to force recompilation of all kernel modules
due to a structure size change.
Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies
streamline the rest of the xxx_to_jiffies() functions to have a
constant 64-bit argument and use identical range checks for the
result.
Specifically preserve msecs_to_jiffies(0) returning 0. See r282743 for
further details.
MFC after: 1 week
Sponsored by: Mellanox Technologies
error code checks might fail. ERESTART is in the BSD world defined as
-1. While at it add more Linux error codes.
Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies
Linux requires that all IOCTL data resides in userspace. FreeBSD
always moves the main IOCTL structure into a kernel buffer before
invoking the IOCTL handler and then copies it back into userspace,
before returning. Hide this difference in the "linux_copyin()" and
"linux_copyout()" functions by remapping userspace addresses in the
range from 0x10000 to 0x20000, to the kernel IOCTL data buffer.
It is assumed that the userspace code, data and stack segments starts
no lower than memory address 0x400000, which is also stated by "man 1
ld", which means any valid userspace pointer can be passed to regular
LinuxKPI handled IOCTLs.
Bump the FreeBSD version to force recompilation of all kernel modules.
Discussed with: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies
"current" inside all LinuxKPI file operation callbacks. The "current"
is frequently used for various debug prints, printing the thread name
and thread ID for example.
Obtained from: kmacy @
MFC after: 1 week
Sponsored by: Mellanox Technologies
