Atomics are used for page busy and valid state when the shared busy is
held. The details of the locking protocol and valid and dirty
synchronization are in the updated vm_page.h comments.
Reviewed by: kib, markj
Tested by: pho
Sponsored by: Netflix, Intel
Differential Revision: https://reviews.freebsd.org/D21594
In case the implementation ever changes from using a chain of next pointers,
then changing the macro definition will be necessary, but changing all the
files that iterate over vm_map entries will not.
Drop a counter in vm_object.c that would have an effect only if the
vm_map entry count was wrong.
Discussed with: alc
Reviewed by: markj
Tested by: pho (earlier version)
Differential Revision: https://reviews.freebsd.org/D21882
Add an atomic shm rename operation, similar in spirit to a file
rename. Atomically unlink an shm from a source path and link it to a
destination path. If an existing shm is linked at the destination
path, unlink it as part of the same atomic operation. The caller needs
the same permissions as shm_unlink to the shm being renamed, and the
same permissions for the shm at the destination which is being
unlinked, if it exists. If those fail, EACCES is returned, as with the
other shm_* syscalls.
truss support is included; audit support will come later.
This commit includes only the implementation; the sysent-generated
bits will come in a follow-on commit.
Submitted by: Matthew Bryan <matthew.bryan@isilon.com>
Reviewed by: jilles (earlier revision)
Reviewed by: brueffer (manpages, earlier revision)
Relnotes: yes
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D21423
shm_open2 allows a little more flexibility than the original shm_open.
shm_open2 doesn't enforce CLOEXEC on its callers, and it has a separate
shmflag argument that can be expanded later. Currently the only shmflag is
to allow file sealing on the returned fd.
shm_open and memfd_create will both be implemented in libc to use this new
syscall.
__FreeBSD_version is bumped to indicate the presence.
Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D21393
Now that flags may be set on posixshm, add an argument to kern_shm_open()
for the initial seals. To maintain past behavior where callers of
shm_open(2) are guaranteed to not have any seals applied to the fd they're
given, apply F_SEAL_SEAL for existing callers of kern_shm_open. A special
flag could be opened later for shm_open(2) to indicate that sealing should
be allowed.
We currently restrict initial seals to F_SEAL_SEAL. We cannot error out if
F_SEAL_SEAL is re-applied, as this would easily break shm_open() twice to a
shmfd that already existed. A note's been added about the assumptions we've
made here as a hint towards anyone wanting to allow other seals to be
applied at creation.
Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D21392
Just return EINVAL if flags != 0. The Linux man page documents one
case of EINVAL as "The filesystem does not support one of the flags in
flags."
After r351723 userland binaries will try using new system calls.
Reported by: mjg
Reviewed by: mjg, trasz
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21590
A work callback may restart itself. Loop in the drain function to see if the
work has been rescheduled and stop the subsequent reschedules, if any.
MFC after: 1 week
Sponsored by: Mellanox Technologies
- VM_ALLOC_NOCREAT will grab without creating a page.
- vm_page_grab_valid() will grab and page in if necessary.
- vm_page_busy_acquire() automates some busy acquire loops.
Discussed with: alc, kib, markj
Tested by: pho (part of larger branch)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21546
There are several mechanisms by which a vm_page reference is held,
preventing the page from being freed back to the page allocator. In
particular, holding the page's object lock is sufficient to prevent the
page from being freed; holding the busy lock or a wiring is sufficent as
well. These references are protected by the page lock, which must
therefore be acquired for many per-page operations. This results in
false sharing since the page locks are external to the vm_page
structures themselves and each lock protects multiple structures.
Transition to using an atomically updated per-page reference counter.
The object's reference is counted using a flag bit in the counter. A
second flag bit is used to atomically block new references via
pmap_extract_and_hold() while removing managed mappings of a page.
Thus, the reference count of a page is guaranteed not to increase if the
page is unbusied, unmapped, and the object's write lock is held. As
a consequence of this, the page lock no longer protects a page's
identity; operations which move pages between objects are now
synchronized solely by the objects' locks.
The vm_page_wire() and vm_page_unwire() KPIs are changed. The former
requires that either the object lock or the busy lock is held. The
latter no longer has a return value and may free the page if it releases
the last reference to that page. vm_page_unwire_noq() behaves the same
as before; the caller is responsible for checking its return value and
freeing or enqueuing the page as appropriate. vm_page_wire_mapped() is
introduced for use in pmap_extract_and_hold(). It fails if the page is
concurrently being unmapped, typically triggering a fallback to the
fault handler. vm_page_wire() no longer requires the page lock and
vm_page_unwire() now internally acquires the page lock when releasing
the last wiring of a page (since the page lock still protects a page's
queue state). In particular, synchronization details are no longer
leaked into the caller.
The change excises the page lock from several frequently executed code
paths. In particular, vm_object_terminate() no longer bounces between
page locks as it releases an object's pages, and direct I/O and
sendfile(SF_NOCACHE) completions no longer require the page lock. In
these latter cases we now get linear scalability in the common scenario
where different threads are operating on different files.
__FreeBSD_version is bumped. The DRM ports have been updated to
accomodate the KPI changes.
Reviewed by: jeff (earlier version)
Tested by: gallatin (earlier version), pho
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20486
It allows a process to request that stack gap was not applied to its
stacks, retroactively. Also it is possible to control the gaps in the
process after exec.
PR: 239894
Reviewed by: alc
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21352
Previously userspace would issue one syscall to resolve the sysctl and then
another one to actually use it. Do it all in one trip.
Fallback is provided in case newer libc happens to be running on an older
kernel.
Submitted by: Pawel Biernacki
Reported by: kib, brooks
Differential Revision: https://reviews.freebsd.org/D17282
glibc 2.24 and up (eg Ubuntu 19.04) fail with "FATAL: kernel too old".
This alone is not enough to make newer binaries actually work;
fix/hack/workaround is pending review at https://reviews.freebsd.org/D20687.
Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20757
'compat.linux.osrelease=3.10.0-957.12.1.el7.x86_64', which
corresponds to CentOS 7.
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20685
Require the vnode to be locked for the VOP_UNSET_TEXT() call. This
will be used by the following bug fix for a tmpfs issue.
Tested by: sbruno, pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
This patch makes the DRM graphics driver in ports usable on aarch64.
Submitted by: Greg V <greg@unrelenting.technology>
Differential Revision: https://reviews.freebsd.org/D21008
MFC after: 1 week
Sponsored by: Mellanox Technologies
The DRM drivers use the lockdep assertion macros with spinlock_t locks
which are backed by mutexes, not sx locks. This causes compile
failures since you can't use sx_assert with a mutex. Instead, change
the lockdep macros to use lock_class methods. This works by assuming
that each LinuxKPI locking primitive embeds a FreeBSD lock as its
first structure and uses a cast to get to the underlying 'struct
lock_object'.
Reviewed by: hselasky
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20992
PowerPC, and possibly other architectures, use different address ranges for
PCI space vs physical address space, which is only mapped at resource
activation time, when the BAR gets written. The DRM kernel modules do not
activate the rman resources, soas not to waste KVA, instead only mapping
parts of the PCI memory at a time. This introduces a
BUS_TRANSLATE_RESOURCE() method, implemented in the Open Firmware/FDT PCI
driver, to perform this necessary translation without activating the
resource.
In addition to system KPI changes, LinuxKPI is updated to handle a
big-endian host, by adding proper endian swaps to the I/O functions.
Submitted by: mmacy
Reported by: hselasky
Differential Revision: https://reviews.freebsd.org/D21096
This effectively makes the stack base on the csu _start entry
randomized.
The gap is enabled if ASLR is for the ABI is enabled, and then
kern.elf{64,32}.aslr.stack_gap specify the max percentage of the
initial stack size that can be wasted for gap. Setting it to zero
disables the gap, and max is capped at 50%.
Only amd64 for now.
Reviewed by: cem, markj
Discussed with: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21081
The motivation for this change is to allow wrappers around shm to be written
that don't set CLOEXEC. kern_shm_open currently accepts O_CLOEXEC but sets
it unconditionally. kern_shm_open is used by the shm_open(2) syscall, which
is mandated by POSIX to set CLOEXEC, and CloudABI's sys_fd_create1().
Presumably O_CLOEXEC is intended in the latter caller, but it's unclear from
the context.
sys_shm_open() now unconditionally sets O_CLOEXEC to meet POSIX
requirements, and a comment has been dropped in to kern_fd_open() to explain
the situation and add a pointer to where O_CLOEXEC setting is maintained for
shm_open(2) correctness. CloudABI's sys_fd_create1() also unconditionally
sets O_CLOEXEC to match previous behavior.
This also has the side-effect of making flags correctly reflect the
O_CLOEXEC status on this fd for the rest of kern_shm_open(), but a
glance-over leads me to believe that it didn't really matter.
Reviewed by: kib, markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D21119
After r349240 kern_mprotect returns EINVAL for unsupported bits in the prot
argument. Linux rtld uses PROT_GROWSDOWN and PROT_GROWS_UP when marking the
stack executable. Mask these bits like kern_mprotect used to do. For other
unsupported bits EINVAL is returned like Linux does.
Reviewed by: trasz, brooks
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20864
The hold_count and wire_count fields of struct vm_page are separate
reference counters with similar semantics. The remaining essential
differences are that holds are not counted as a reference with respect
to LRU, and holds have an implicit free-on-last unhold semantic whereas
vm_page_unwire() callers must explicitly determine whether to free the
page once the last reference to the page is released.
This change removes the KPIs which directly manipulate hold_count.
Functions such as vm_fault_quick_hold_pages() now return wired pages
instead. Since r328977 the overhead of maintaining LRU for wired pages
is lower, and in many cases vm_fault_quick_hold_pages() callers would
swap holds for wirings on the returned pages anyway, so with this change
we remove a number of page lock acquisitions.
No functional change is intended. __FreeBSD_version is bumped.
Reviewed by: alc, kib
Discussed with: jeff
Discussed with: jhb, np (cxgbe)
Tested by: pho (previous version)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D19247
New system calls between 2.6.32 and 2.6.26 are already implemented.
This should be mostly NFC as far as contemporary Linux applications are
concerned though, as Linux kernel 3.2 is the oldest supported by a
number of popular distros today; work is in progress by others to enable
support for those applications.
Discussed with: trasz
MFC after: 1 month
Linux man(1) calls it for no good reason; this avoids the console spam
(eg '(man): ioctl fd=4, cmd=0x660b ('f',11) is not implemented').
Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20690
return something reasonable, and helps linux binaries which attempt
to close all the files, eg apt(8).
Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20692
LINUXKPI_VERSION macro is not defined for any compiled LinuxKPI code
which basically means __GFP_NOTWIRED is never checked when allocating
pages. This should work fine with the existing external DRM code as
long as the page wiring and unwiring is balanced.
MFC after: 3 days
Sponsored by: Mellanox Technologies
This was added for emulation of Linux's CDROMSUBCHNL, but allows
users with read access to a cd(4) device to overwrite kernel memory
provided that the driver detects some media present.
Reimplement CDROMSUBCHNL by bouncing the data from CDIOCREADSUBCHANNEL
through the linux_cdrom_subchnl structure passed from userspace.
admbugs: 768
Reported by: Alex Fortune
Security: CVE-2019-5602
Security: FreeBSD-SA-19:11.cd_ioctl
feature bit.
In particular, allocate the bit to opt-out the image from implicit
PROTMAX enablement. Provide procctl(2) verbs to set and query
implicit PROTMAX handling. The knobs mimic the same per-image flag
and per-process controls for ASLR.
Reviewed by: emaste, markj (previous version)
Discussed with: brooks
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D20795
- Add rcu list functions.
- Make rcu hlist's foreach macro use rcu calls instead of the non-rcu macro.
- Bump FreeBSD version so we have a checkpoint for the vboxvideo drm driver.
Reviewed by: hps
Approved by: imp (mentor), hps
MFC after: 1 week
Differential Revision: D20719
These calls are not the same in general: the former will dequeue the
page if it is enqueued, while the latter will just leave it alone. But,
all existing uses of the former apply to unmanaged pages, which are
never enqueued in the first place. No functional change intended.
Reviewed by: kib
MFC after: 1 week
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20470
Previously it did this only on platforms without a direct map. This
also more closely matches Linux's semantics.
Since some DRM v5.0 code assumes the old behaviour, use a
LINUXKPI_VERSION guard to preserve that until the out-of-tree module
is updated.
Reviewed by: hselasky, kib (earlier versions), johalun
MFC after: 1 week
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20502
syscalls.conf is included using "." which per the Open Group:
If file does not contain a <slash>, the shell shall use the search
path specified by PATH to find the directory containing file.
POSIX shells don't fall back to the current working directory.
Submitted by: Nathaniel Wesley Filardo <nwf20@cl.cam.ac.uk>
Reviewed by: bdrewery
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D20476
struct xucred. Do not bump XUCRED_VERSION as struct layout is not changed.
PR: 215202
Reviewed by: tijl
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D20415
This was enumerated with exhaustive search for sys/eventhandler.h includes,
cross-referenced against EVENTHANDLER_* usage with the comm(1) utility. Manual
checking was performed to avoid redundant includes in some drivers where a
common os_bsd.h (for example) included sys/eventhandler.h indirectly, but it is
possible some of these are redundant with driver-specific headers in ways I
didn't notice.
(These CUs did not show up as missing eventhandler.h in tinderbox.)
X-MFC-With: r347984
The source file was moved to base earlier and also improved upon,
but never compiled in. This patch will:
- Make a module in sys/modules
- Make lindebugfs depend on linuxkpi (for seq_file)
- Check if read/write functions are set before calling, DRM drivers
don't always set both of them.
Reviewed by: hps
Approved by: imp (mentor), hps
MFC after: 1 week
socket is non-blocking and connect() is not finished yet.
Initial patch developed by Steven Hartland in 2008 and adopted by me.
PR: 129169
Reported by: smh@
MFC after: 2 weeks
seq_file.h and linux_seq_file.c was imported form ports earlier but
linux_seq_file.c was never compiled in with the module. With this
commit base seq_file will replace ports seq_file and it required a
few modifications to not break functionality and build.
Reviewed by: hps
Approved by: imp (mentor), hps
MFC after: 1 week
DRM drivers expect tasklets to have a counter for enable/disable calls.
Also, add a few more tasklet locking functions.
This patch is part of D19565
Reviewed by: hps
Approved by: imp (mentor), hps
MFC after: 1 week
Assign self as group leader at creation to act as the only member of a
new process group.
This patch is part of D19565
Reviewed by: hps
Approved by: imp (mentor), hps
MFC after: 1 week
Check LINUXKPI_VERSION macro for backwards compatibility.
It's recommended to update any drivers that depend on the older KPI
so we can deprecate < 5.0 code as we update to newer Linux version.
This patch is part of D19565
Reviewed by: hps
Approved by: imp (mentor), hps
MFC after: 1 week
Check the new LINUXKPI_VERSION macro for backwards compatibility.
This patch is part of D19565
Reviewed by: hps
Approved by: imp (mentor), hps
MFC after: 1 week
Also, make ktime_get_raw call getnanouptime instead of getnanotime
to match (the correct) ktime_get_raw_ns.
This patch is part of D19565
Reviewed by: hps
Approved by: imp (mentor), hps
MFC after: 1 week
of them listed in opt_global.h which is not generated while building
modules outside of a kernel and such modules never match real cofigured
kernel.
So, we should prevent our users from building obviously defective modules.
Therefore, remove the root cause of the building of modules outside of a
kernel - the possibility of building modules with DEBUG or KTR flags.
And remove all of DEBUG printfs as it is incomplete and in threaded
programms not informative, also a half of system call does not have DEBUG
printf. For debuging Linux programms we have dtrace, ktr and ktrace ability.
PR: 222861
Reviewed by: trasz
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20178
alter the userspace sockaddr to convert the format between linux and BSD versions.
That's the minimum 3 of copyin/copyout operations for one syscall.
Also some syscall uses linux_sa_put() and linux_getsockaddr() when load
sockaddr to userspace or from userspace accordingly.
To avoid this chaos, especially converting sockaddr in the userspace,
rewrite these 4 functions to convert sockaddr only in kernel and leave
only 2 of this functions.
Also in order to reduce duplication between MD parts of the Linuxulator put
struct sockaddr conversion functions that are MI out into linux_common module.
PR: 232920
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20157
Add support for DIM based on Linux,
with some minor adaptions specific to FreeBSD.
Linux commit
f97c3dc3c0e8d23a5c4357d182afeef4c67f5c33
MFC after: 3 days
Sponsored by: Mellanox Technologies
Only two interfaces are created eth0 and lo and they expose
the following properties:
address, addr_len, flags, ifindex, mty, tx_queue_len and type.
Initial patch developed by Carlos Neira in 2017 and finished by me.
PR: 223722
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D13656
a final revision.
Fix style issues and change bool-like variables from int to bool.
Reviewed by: emaste
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20141
As Linux comment for this function point:
Signal to the system that the PCI device is not in use by the system
anymore. This only involves disabling PCI bus-mastering, if active.
Build tested drm-current-kmod prior to commit.
MFC after: 1 week
Submitted by: slavash@
Sponsored by: Mellanox Technologies
Turning on pr_debug at compile time make it non-optional at runtime.
This often means that the amount of the debugging is unbearable.
Allow developer to turn on pr_debug output only when needed.
Build tested drm-current-kmod prior to commit.
MFC after: 1 week
Submitted by: kib@
Sponsored by: Mellanox Technologies
kern_execve() locks text vnode exclusive to be able to set and clear
VV_TEXT flag. VV_TEXT is mutually exclusive with the v_writecount > 0
condition.
The change removes VV_TEXT, replacing it with the condition
v_writecount <= -1, and puts v_writecount under the vnode interlock.
Each text reference decrements v_writecount. To clear the text
reference when the segment is unmapped, it is recorded in the
vm_map_entry backed by the text file as MAP_ENTRY_VN_TEXT flag, and
v_writecount is incremented on the map entry removal
The operations like VOP_ADD_WRITECOUNT() and VOP_SET_TEXT() check that
v_writecount does not contradict the desired change. vn_writecheck()
is now racy and its use was eliminated everywhere except access.
Atomic check for writeability and increment of v_writecount is
performed by the VOP. vn_truncate() now increments v_writecount
around VOP_SETATTR() call, lack of which is arguably a bug on its own.
nullfs bypasses v_writecount to the lower vnode always, so nullfs
vnode has its own v_writecount correct, and lower vnode gets all
references, since object->handle is always lower vnode.
On the text vnode' vm object dealloc, the v_writecount value is reset
to zero, and deadfs vop_unset_text short-circuit the operation.
Reclamation of lowervp always reclaims all nullfs vnodes referencing
lowervp first, so no stray references are left.
Reviewed by: markj, trasz
Tested by: mjg, pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
Differential revision: https://reviews.freebsd.org/D19923
The S/G list must be mapped AS-IS without any optimisations.
This also implies that sg_dma_len() must be equal to sg->length.
Many Linux drivers assume this and this fixes some DRM issues.
Put the BUS DMA map pointer into the scatter-gather list to
allow multiple mappings on the same physical memory address.
The FreeBSD version has been bumped to force recompilation of
external kernel modules.
Sponsored by: Mellanox Technologies
move bits that are MI out into the headers in compat/linux.
For that remove bogus _packed attribute from struct l_sockaddr
and use MI types for struct members.
And continue to move into the linux_common module a code that is
intended for both Linuxulator modules (both instruction set - 32 & 64 bit)
or for external modules like linsysfs or linprocfs.
To avoid header pollution introduce new sys/compat/linux_common.h header.
Reviewed by: emaste
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20137
That makes Linux lscpu(1) work.
Reviewed by: dchagin
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20131
Make function macro wrappers for locking and unlocking to ease readability.
No functional change.
Discussed with: kib@, tychon@ and zeising@
Sponsored by: Mellanox Technologies
The <sys/pctrie.h> APIs expect a 64-bit DMA key.
This is fine as long as the DMA is less than or equal to 64 bits, which
is currently the case.
Sponsored by: Mellanox Technologies
r176215 corrected readlink(2)'s return type and the type of the last
argument. readlink(2) was introduced in r177788 after being developed
as part of Google Summer of Code 2007; it appears to have inherited the
wrong return type.
Man pages and header files were already ssize_t; update syscalls.master
to match.
PR: 197915
Submitted by: Henning Petersen <henning.petersen@t-online.de>
MFC after: 2 weeks
the file associated with the given file descriptor.
Reviewed by: kib, asomers
Reviewed by: cem, jilles, brooks (they reviewed previous version)
Discussed with: pjd, and many others
Differential Revision: https://reviews.freebsd.org/D14567
Each control message region must be aligned on a 4-byte boundary on 32-bit
architectures. The 32-bit compat shim for recvmsg() gets the actual layout
right, but doesn't pad the payload length when computing msg_controllen for
the output message header. If a control message contains an unaligned
payload, such as the 1-byte TTL field in the example attached to PR 236737,
this can produce control message payload boundaries that extend beyond
the boundary reported by msg_controllen.
PR: 236737
Reported by: Yuval Pavel Zholkover <paulzhol@gmail.com>
Reviewed by: markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D19768
For 32-bit Linuxulator, ipc() syscall was historically
the entry point for the IPC API. Starting in Linux 4.18, direct
syscalls are provided for the IPC. Enable it.
MFC after: 1 month
Add the infrastructure to allow MD procctl(2) commands, and use it to
introduce amd64 PTI control and reporting. PTI mode cannot be
modified for existing pmap, the knob controls PTI of the new vmspace
created on exec.
Requested by: jhb
Reviewed by: jhb, markj (previous version)
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D19514
Fix some style while at it.
Submitted by: Johannes Lundberg <johalun0@gmail.com>
MFC after: 1 week
Sponsored by: Limelight Networks
Sponsored by: Mellanox Technologies
Research Unix, 7th Edition introduced TIMEZONE and DSTFLAG
compile-time constants in sys/param.h to communicate these values for
the machine. 4.2BSD moved from the compile-time to run-time and
introduced these variables and used for localtime() to return the
right offset from UTC (sometimes referred to as GMT, for this purpose
is the same). 4.4BSD migrated to using the tzdata code/database and
these variables were basically unused.
FreeBSD removed the real need for these with adjkerntz in
1995. However, some RTC clocks continued to use these variables,
though they were largely unused otherwise. Later, phk centeralized
most of the uses in utc_offset, but left it using both tz_minuteswest
and adjkerntz.
POSIX (IEEE Std 1003.1-2017) states in the gettimeofday specification
"If tzp is not a null pointer, the behavior is unspecified" so there's
no standards reason to retain it anymore. In fact, gettimeofday has
been marked as obsolecent, meaning it could be removed from a future
release of the standard. It is the only interface defined in POSIX
that references these two values. All other references come from the
tzdata database via tzset().
These were used to more faithfully implement early unix ABIs which
have been removed from FreeBSD. NetBSD has completely eliminated
these variables years ago. Linux has migrated to tzdata as well,
though these variables technically still exist for compatibility
with unspecified older programs.
So, there's no real reason to have them these days. They are a
historical vestige that's no longer used in any meaningful way.
Reviewed By: jhb@, brooks@
Differential Revision: https://reviews.freebsd.org/D19550
In all of the architectures we have today, we always use PAGE_SIZE.
While in theory one could define different things, none of the
current architectures do, even the ones that have transitioned from
32-bit to 64-bit like i386 and arm. Some ancient mips binaries on
other systems used 8k instead of 4k, but we don't support running
those and likely never will due to their age and obscurity.
Reviewed by: imp (who also contributed the commit message)
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D19280
