The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:
- Improved driver model:
The old TTY layer has a driver model that is not abstract enough to
make it friendly to use. A good example is the output path, where the
device drivers directly access the output buffers. This means that an
in-kernel PPP implementation must always convert network buffers into
TTY buffers.
If a PPP implementation would be built on top of the new TTY layer
(still needs a hooks layer, though), it would allow the PPP
implementation to directly hand the data to the TTY driver.
- Improved hotplugging:
With the old TTY layer, it isn't entirely safe to destroy TTY's from
the system. This implementation has a two-step destructing design,
where the driver first abandons the TTY. After all threads have left
the TTY, the TTY layer calls a routine in the driver, which can be
used to free resources (unit numbers, etc).
The pts(4) driver also implements this feature, which means
posix_openpt() will now return PTY's that are created on the fly.
- Improved performance:
One of the major improvements is the per-TTY mutex, which is expected
to improve scalability when compared to the old Giant locking.
Another change is the unbuffered copying to userspace, which is both
used on TTY device nodes and PTY masters.
Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.
Obtained from: //depot/projects/mpsafetty/...
Approved by: philip (ex-mentor)
Discussed: on the lists, at BSDCan, at the DevSummit
Sponsored by: Snow B.V., the Netherlands
dcons(4) fixed by: kan
virtualization work done by Marko Zec (zec@).
This is the first in a series of commits over the course
of the next few weeks.
Mark all uses of global variables to be virtualized
with a V_ prefix.
Use macros to map them back to their global names for
now, so this is a NOP change only.
We hope to have caught at least 85-90% of what is needed
so we do not invalidate a lot of outstanding patches again.
Obtained from: //depot/projects/vimage-commit2/...
Reviewed by: brooks, des, ed, mav, julian,
jamie, kris, rwatson, zec, ...
(various people I forgot, different versions)
md5 (with a bit of help)
Sponsored by: NLnet Foundation, The FreeBSD Foundation
X-MFC after: never
V_Commit_Message_Reviewed_By: more people than the patch
priority of some of the drivers that manage the same state (e.g. ichss0
vs est0). Specifically, powernow, est, and p4tcc are added at order 10,
ichss at order 20, and smist at order 30. Previously, some laptops were
seeing both ichss0 and est0 attaching and stomping on each other.
XXX: This isn't quite ideal, but works with the existing hacks, I think
what we really want instead is a single "speedstep0" device for CPUs
that the ichss, est, and smist drivers probe (but with differing
priorities).
MFC after: 1 week
found in Soekris hardware, for instance). The hardware supports acceleration
of AES-128-CBC accessible through crypto(4) and supplies entropy to random(4).
TODO:
o Implement rndtest(4) support
o Performance enhancements
Submitted by: Patrick Lamaizière <patfbsd -at- davenulle.org>
Reviewed by: jhb, sam
MFC after: 1 week
features of CPUs like reading/writing machine-specific registers,
retrieving cpuid data, and updating microcode.
- Add cpucontrol(8) utility, that provides userland access to
the features of cpuctl(4).
- Add subsequent manpages.
The cpuctl(4) device operates as follows. The pseudo-device node cpuctlX
is created for each cpu present in the systems. The pseudo-device minor
number corresponds to the cpu number in the system. The cpuctl(4) pseudo-
device allows a number of ioctl to be preformed, namely RDMSR/WRMSR/CPUID
and UPDATE. The first pair alows the caller to read/write machine-specific
registers from the correspondent CPU. cpuid data could be retrieved using
the CPUID call, and microcode updates are applied via UPDATE.
The permissions are inforced based on the pseudo-device file permissions.
RDMSR/CPUID will be allowed when the caller has read access to the device
node, while WRMSR/UPDATE will be granted only when the node is opened
for writing. There're also a number of priv(9) checks.
The cpucontrol(8) utility is intened to provide userland access to
the cpuctl(4) device features. The utility also allows one to apply
cpu microcode updates.
Currently only Intel and AMD cpus are supported and were tested.
Approved by: kib
Reviewed by: rpaulo, cokane, Peter Jeremy
MFC after: 1 month
As clearly mentioned on the mailing lists, there is a list of drivers
that have not been ported to the MPSAFE TTY layer yet. Remove them from
the kernel configuration files. This means people can now still use
these drivers if they explicitly put them in their kernel configuration
file, which is good.
People should keep in mind that after August 10, these drivers will not
work anymore. Even though owners of the hardware are capable of getting
these drivers working again, I will see if I can at least get them to a
compilable state (if time permits).
when stack realignment is turned on (it is ALWAYS on for main), however
in a profiling build %ecx would be clobbered by mcount(), this would lead
to a segmentation fault when the code tries to reference any argument.
This fix changes mcount() to preserve %ecx.
PR: bin/119709
Reviewed by: bde
MFC after: 1 week
The uart(4) driver has the advantage of supporting a wider variety of
hardware on a greater amount of platforms. This driver has already been
the standard on platforms such as ia64, powerpc and sparc64.
I've decided not to change anything on pc98. I'd rather let people from
the pc98 team look at this.
Approved by: philip (mentor), marcel
to vm_page_alloc() instead of VM_ALLOC_SYSTEM. VM_ALLOC_SYSTEM was the
logical choice before FreeBSD 7.0 because VM_ALLOC_INTERRUPT could not
reclaim a cached page. Simply put, there was no ordering between
VM_ALLOC_INTERRUPT and VM_ALLOC_SYSTEM as to which "dug deeper" into the
cache and free queues. Now, there is; VM_ALLOC_INTERRUPT dominates
VM_ALLOC_SYSTEM.
While I'm here, teach pmap_growkernel() to request a prezeroed page.
MFC after: 1 week
to global hostname and domainname variables. Where necessary, copy
to or from a stack-local buffer before performing copyin() or
copyout(). A few uses, such as in cd9660 and daemon_saver, remain
under-synchronized and will require further updates.
Correct a bug in which a failed copyin() of domainname would leave
domainname potentially corrupted.
MFC after: 3 weeks
