On the i386 architecture, the processor only saves the current value
of `%esp' on stack if a privilege switch is necessary when entering
the interrupt handler. Thus, `frame->tf_esp' is only valid for
an entry from user mode. For interrupts taken in kernel mode, we
need to determine the top-of-stack for the interrupted kernel
procedure by adding the appropriate offset to the current frame
pointer.
Reported by: kris, Fabien Thomas
Tested by: Fabien Thomas <fabien.thomas at netasq dot com>
code. We only attempt a single reset using this method (a "hard" reset),
and we use two writes to ensure there is a 0 -> 1 transition in bit 2 to
force a reset.
MFC after: 1 week
memory-mapped config access. Add a workaround for these systems by
checking the first function of each slot on bus 0 using both the
memory-mapped config access and the older type 1 I/O port config access.
If we find a slot that is only visible via the type 1 I/O port config
access, we flag that slot. Future PCI config transactions to flagged
slots on bus 0 use type 1 I/O port config access rather than memory mapped
config access.
location in GDT where the segment descriptor from pcb_gs32sd is
copied, and the location is in GDT local to CPU.
Noted and reviewed by: peter
MFC after: 1 week
l_ucontext. To restore the registers content, trampoline needs to
dereference uc_mcontext instead of taking some undefined values from
l_ucontext.
Submitted by: Dmitry Chagin <dchagin@>
MFC after: 1 week
processes, clear PCB_32BIT and PCB_GS32BIT bits [1].
- Reread the fs and gs bases from the msr unconditionally, not believing
the values in pcb_fsbase and pcb_gsbase, since usermode may reload
segment registers, invalidating the cache. [2].
Both problems resulted in the wrong fs base, causing wrong tls pointer
be dereferenced in the usermode.
Reported and tested by: Vyacheslav Bocharov <adeepv at gmail com> [1]
Reported by: Bernd Walter <ticsoat cicely7 cicely de>,
Artem Belevich <fbsdlist at src cx>[2]
Reviewed by: peter
MFC after: 3 days
timer. Previously, the various divisors were fixed which meant that while
it gave somewhat reasonable stathz, etc. at hz=1000, it went off the rails
with any other hz value. With these changes, we now pick a lapic timer hz
based on the value of hz. If hz is >= 1500, then the lapic timer runs at
hz. If 1500 hz >= 750, we run the lapic timer at hz * 2. If hz < 750, we
run at hz * 4. We compute a divider at runtime to make stathz run as close
to 128 as we can since stathz really wants to be run at something close to
that frequency. Profiling just runs on every clock tick. So some examples:
With hz = 100, the lapic timer now runs at 400 instead of 2000. stathz
will be 133, and profhz = 400. With hz = 1000 (default), the lapic timer
is still at 2000 (as it is now), stathz is at 133 (as it is now), and
profhz will be 2000 (previously 666).
MFC after: 2 weeks
- Rename pciereg_cfgopen() to pcie_cfgregopen() and expose it to the
rest of the kernel. It now also accepts parameters via function
arguments rather than global variables.
- Add a notion of minimum and maximum bus numbers and reject requests for
an out of range bus.
- Add more range checks on slot/func/reg/bytes parameters to the cfg reg
read/write routines. Don't panic on any invalid parameters, just fail
the request (writes do nothing, reads return -1). This matches the
behavior of the other cfg mechanisms.
- Port the memory mapped configuration space access to amd64. On amd64
we simply use the direct map (via pmap_mapdev()) for the memory mapped
window.
- During acpi_attach() just after loading the ACPI tables, check for a
MCFG table. If it exists, call pciereg_cfgopen() on each subtable
(memory mapped window). For now we only support windows for domain 0
that start with bus 0. This removes the need for more chipset-specific
quirks in the MD code.
- Remove the chipset-specific quirks for the Intel 5000P/V/Z chipsets
since these machines should all have MCFG tables via ACPI.
- Updated pci_cfgregopen() to DTRT if ACPI had invoked pcie_cfgregopen()
earlier.
MFC after: 2 weeks
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
kernel gs base, because %rip is adjusted only on kernel-mode trap caused
by iretq execution. On the other hand, the stack contains (hardware
part of) trap frame from the usermode. As a consequence, checking for
frame mode and doing swapgs causes the kernel to enter trap() with
usermode gs base.
Remove the check for mode and conditional swapgs, we already have right
gs base in the MSR.
Submitted by: Nate Eldredge <neldredge math ucsd edu>
MFC after: 3 days
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
more mappings to the same physical page have different memory types, i.e.,
PAT settings. Consequently, if pmap_change_attr() is applied to a virtual
address range within the kernel map, then the corresponding ranges of the
direct map also need to be changed. Enhance pmap_change_attr() to handle
this case automatically.
Add a comment describing what pmap_change_attr() does.
Discussed with: jhb
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).
pmap_change_attr() in order to use the direct map for any cache mode, not
just write-back mode.
It is worth noting that this change also eliminates a situation in which we
have two mappings to the same physical memory with different cache modes.
Submitted by: Magesh Dhasayyan (with some changes by me)
Discussed with: jhb
mode changes, and cache and TLB invalidation when some or all of the
specified range is already mapped with the specified cache mode.
Submitted by: Magesh Dhasayyan
the 32bit images on amd64.
Change the semantic of the PCB_32BIT pcb flag to request the context
switch code to operate on the segment registers. Its previous meaning
of saving or restoring the %gs base offset is assigned to the new
PCB_GS32BIT flag.
FreeBSD 32bit image activator sets the PCB_32BIT flag, while Linux 32bit
emulation sets PCB_32BIT | PCB_GS32BIT.
Reviewed by: peter
MFC after: 2 weeks
mapping to 4KB page mappings when the specified attribute change only
applies to a portion of the 2MB page. Previously, in such cases,
pmap_change_attr() gave up and returned an error.
Submitted by: Magesh Dhasayyan
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
Initialize %ds, %es, and %fs during CPU startup. Otherwise a garbage
value could leak to a 32-bit process if a process migrated to a different
CPU after exec and the new CPU had never exec'd a 32-bit process.
A more complete fix is needed, but this mitigates the most frequent
manifestations.
Obtained from: ups
