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95ee2897 |
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16-Aug-2023 |
Warner Losh <imp@FreeBSD.org> |
sys: Remove $FreeBSD$: two-line .h pattern Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/
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4d846d26 |
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10-May-2023 |
Warner Losh <imp@FreeBSD.org> |
spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch up to that fact and revert to their recommended match of BSD-2-Clause. Discussed with: pfg MFC After: 3 days Sponsored by: Netflix
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f8e8a06d |
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10-Oct-2020 |
Conrad Meyer <cem@FreeBSD.org> |
random(4) FenestrasX: Push root seed version to arc4random(3) Push the root seed version to userspace through the VDSO page, if the RANDOM_FENESTRASX algorithm is enabled. Otherwise, there is no functional change. The mechanism can be disabled with debug.fxrng_vdso_enable=0. arc4random(3) obtains a pointer to the root seed version published by the kernel in the shared page at allocation time. Like arc4random(9), it maintains its own per-process copy of the seed version corresponding to the root seed version at the time it last rekeyed. On read requests, the process seed version is compared with the version published in the shared page; if they do not match, arc4random(3) reseeds from the kernel before providing generated output. This change does not implement the FenestrasX concept of PCPU userspace generators seeded from a per-process base generator. That change is left for future discussion/work. Reviewed by: kib (previous version) Approved by: csprng (me -- only touching FXRNG here) Differential Revision: https://reviews.freebsd.org/D22839
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9464e1ef |
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07-Sep-2020 |
Brandon Bergren <bdragon@FreeBSD.org> |
Fix vdso compat32 timekeeping on !=x86. Since x86 is the only 32-bit arch that has a 32-bit time_t, adjust the private bintime32 struct in vdso to only use a 32 bit sec on amd64. This matches the existing behavior in the compat code. Noticed while implementing vdso timekeeping on powerpc. This should also theoretically fix vdso timekeeping for arm binaries on aarch64. See tools attached to https://reviews.freebsd.org/D26347 for testing. Reviewed by: kib (in irc) Sponsored by: Tag1 Consulting, Inc.
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c4e20cad |
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27-Nov-2017 |
Pedro F. Giffuni <pfg@FreeBSD.org> |
sys/sys: further adoption of SPDX licensing ID tags. Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts.
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fff5be0b |
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19-Dec-2016 |
Sepherosa Ziehau <sephe@FreeBSD.org> |
hyperv: Implement userspace gettimeofday(2) with Hyper-V reference TSC This 6 times gettimeofday performance, as measured by tools/tools/syscall_timing Reviewed by: kib MFC after: 1 week Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D8789
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16808549 |
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17-Aug-2016 |
Konstantin Belousov <kib@FreeBSD.org> |
Implement userspace gettimeofday(2) with HPET timecounter. Right now, userspace (fast) gettimeofday(2) on x86 only works for RDTSC. For older machines, like Core2, where RDTSC is not C2/C3 invariant, and which fall to HPET hardware, this means that the call has both the penalty of the syscall and of the uncached hw behind the QPI or PCIe connection to the sought bridge. Nothing can me done against the access latency, but the syscall overhead can be removed. System already provides mappable /dev/hpetX devices, which gives straight access to the HPET registers page. Add yet another algorithm to the x86 'vdso' timehands. Libc is updated to handle both RDTSC and HPET. For HPET, the index of the hpet device to mmap is passed from kernel to userspace, index might be changed and libc invalidates its mapping as needed. Remove cpu_fill_vdso_timehands() KPI, instead require that timecounters which can be used from userspace, to provide tc_fill_vdso_timehands{,32}() methods. Merge i386 and amd64 libc/<arch>/sys/__vdso_gettc.c into one source file in the new libc/x86/sys location. __vdso_gettc() internal interface is changed to move timecounter algorithm detection into the MD code. Measurements show that RDTSC even with the syscall overhead is faster than userspace HPET access. But still, userspace HPET is three-four times faster than syscall HPET on several Core2 and SandyBridge machines. Tested by: Howard Su <howard0su@gmail.com> Sponsored by: The FreeBSD Foundation MFC after: 1 month Differential revision: https://reviews.freebsd.org/D7473
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5e27d793 |
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23-Nov-2015 |
Konstantin Belousov <kib@FreeBSD.org> |
Split kerne timekeep ABI structure vdso_sv_tk out of the struct sysentvec. This allows the timekeep data to be shared between similar ABIs which cannot share sysentvec. Make the timekeep_push_vdso() tick callback to the timekeep structures instead of sysentvecs. If several sysentvec share the vdso_sv_tk structure, we would update the userspace data several times on each tick, without the change. Only allocate vdso_sv_tk in the exec_sysvec_init() sysinit when sysentvec is marked with the new SV_TIMEKEEP flag. This saves allocation and update of unneeded vdso_sv_tk for ABIs which do not provide userspace gettimeofday yet, which are PowerPCs arches right now. Make vdso_sv_tk allocator public, namely split out and export alloc_sv_tk() and alloc_sv_tk_compat32(). ABIs which share timekeep data now can allocate it manually and share as appropriate. Requested by: nwhitehorn Tested by: nwhitehorn, pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
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d1b1b600 |
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19-Jan-2015 |
Neel Natu <neel@FreeBSD.org> |
Update the vdso timehands only via tc_windup(). Prior to this change CLOCK_MONOTONIC could go backwards when the timecounter hardware was changed via 'sysctl kern.timecounter.hardware'. This happened because the vdso timehands update was missing the special treatment in tc_windup() when changing timecounters. Reviewed by: kib
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150facd2 |
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29-Jan-2013 |
Konstantin Belousov <kib@FreeBSD.org> |
Rework the __vdso_* symbols attributes to only make the symbols weak, but use normal references instead of weak. This makes the statically linked binaries to use fast gettimeofday(2) by forcing the linker to resolve references and providing the neccessary functions. Reported by: bde Tested by: marius (sparc64) MFC after: 2 weeks
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21c295ef |
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23-Jun-2012 |
Konstantin Belousov <kib@FreeBSD.org> |
Stop updating the struct vdso_timehands from even handler executed in the scheduled task from tc_windup(). Do it directly from tc_windup in interrupt context [1]. Establish the permanent mapping of the shared page into the kernel address space, avoiding the potential need to sleep waiting for allocation of sf buffer during vdso_timehands update. As a consequence, shared_page_write_start() and shared_page_write_end() functions are not needed anymore. Guess and memorize the pointers to native host and compat32 sysentvec during initialization, to avoid the need to get shared_page_alloc_sx lock during the update. In tc_fill_vdso_timehands(), do not loop waiting for timehands generation to stabilize, since vdso_timehands is written in the same interrupt context which wrote timehands. Requested by: mav [1] MFC after: 29 days
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aea81038 |
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22-Jun-2012 |
Konstantin Belousov <kib@FreeBSD.org> |
Implement mechanism to export some kernel timekeeping data to usermode, using shared page. The structures and functions have vdso prefix, to indicate the intended location of the code in some future. The versioned per-algorithm data is exported in the format of struct vdso_timehands, which mostly repeats the content of in-kernel struct timehands. Usermode reading of the structure can be lockless. Compatibility export for 32bit processes on 64bit host is also provided. Kernel also provides usermode with indication about currently used timecounter, so that libc can fall back to syscall if configured timecounter is unknown to usermode code. The shared data updates are initiated both from the tc_windup(), where a fast task is queued to do the update, and from sysctl handlers which change timecounter. A manual override switch kern.timecounter.fast_gettime allows to turn off the mechanism. Only x86 architectures export the real algorithm data, and there, only for tsc timecounter. HPET counters page could be exported as well, but I prefer to not further glue the kernel and libc ABI there until proper vdso-based solution is developed. Minimal stubs neccessary for non-x86 architectures to still compile are provided. Discussed with: bde Reviewed by: jhb Tested by: flo MFC after: 1 month
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