3ec7e1695c
When pmap operates in PTI mode, we must reload %cr3 on return to userspace. In non-PCID mode the reload always flushes all non-global TLB entries and we take advantage of it by only invalidating the KPT TLB entries (there is no cached UPT entries at all). In PCID mode, we flush both KPT and UPT TLB explicitly, but we can take advantage of the fact that PCID mode command to reload %cr3 includes a flag to flush/not flush target TLB. In particular, we can avoid the flush for UPT, instead record that load of pc_ucr3 into %cr3 on return to usermode should be flushing. This is done by providing either all-1s or ~CR3_PCID_MASK in pc_ucr3_load_mask. The mask is automatically reset to all-1s on return to usermode. Similarly, we can avoid flushing UPT TLB on context switch, replacing it by setting pc_ucr3_load_mask. This unifies INVPCID and non-INVPCID PTI ifunc, leaving only 4 cases instead of 6. This trick is also applicable both to the TLB shootdown IPI handlers, since handlers interrupt the target thread. But then we need to check pc_curpmap in handlers, and this would reopen the same race for INVPCID machines as was fixed in r306350 for non-INVPCID. To not introduce the same bug, unconditionally do spinlock_enter() in pmap_activate(). Reviewed by: alc, markj Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 3 weeks Differential revision: https://reviews.freebsd.org/D25483 |
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bin | ||
cddl | ||
contrib | ||
crypto | ||
etc | ||
gnu | ||
include | ||
kerberos5 | ||
lib | ||
libexec | ||
release | ||
rescue | ||
sbin | ||
secure | ||
share | ||
stand | ||
sys | ||
targets | ||
tests | ||
tools | ||
usr.bin | ||
usr.sbin | ||
.arcconfig | ||
.arclint | ||
.cirrus.yml | ||
.clang-format | ||
.gitattributes | ||
.gitignore | ||
COPYRIGHT | ||
LOCKS | ||
MAINTAINERS | ||
Makefile | ||
Makefile.inc1 | ||
Makefile.libcompat | ||
Makefile.sys.inc | ||
ObsoleteFiles.inc | ||
README | ||
README.md | ||
RELNOTES | ||
UPDATING |
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
FreeBSD
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
For copyright information, please see the file COPYRIGHT in this directory. Additional copyright information also exists for some sources in this tree - please see the specific source directories for more information.
The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7), config(8), https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information, including setting make(1) variables.
Source Roadmap:
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cddl Various commands and libraries under the Common Development
and Distribution License.
contrib Packages contributed by 3rd parties.
crypto Cryptography stuff (see crypto/README).
etc Template files for /etc.
gnu Various commands and libraries under the GNU Public License.
Please see gnu/COPYING* for more information.
include System include files.
kerberos5 Kerberos5 (Heimdal) package.
lib System libraries.
libexec System daemons.
release Release building Makefile & associated tools.
rescue Build system for statically linked /rescue utilities.
sbin System commands.
secure Cryptographic libraries and commands.
share Shared resources.
stand Boot loader sources.
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used in release builds. NOTES contains documentation of
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tools Utilities for regression testing and miscellaneous tasks.
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