If MDS mitigation is enabled by the tunable but MDS microcode is not
early-loaded, software mitigation is selected. This causes
initializecpu() to try to allocate memory which makes boot process
very unhappy.
Create SYSINIT that runs sufficiently late to succeed.
Reported by: naddy
PR: 237968
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
This allows replacing "sys/eventfilter.h" includes with "sys/_eventfilter.h"
in other header files (e.g., sys/{bus,conf,cpu}.h) and reduces header
pollution substantially.
EVENTHANDLER_DECLARE and EVENTHANDLER_LIST_DECLAREs were moved out of .c
files into appropriate headers (e.g., sys/proc.h, powernv/opal.h).
As a side effect of reduced header pollution, many .c files and headers no
longer contain needed definitions. The remainder of the patch addresses
adding appropriate includes to fix those files.
LOCK_DEBUG and LOCK_FILE_LINE_ARG are moved to sys/_lock.h, as required by
sys/mutex.h since r326106 (but silently protected by header pollution prior
to this change).
No functional change (intended). Of course, any out of tree modules that
relied on header pollution for sys/eventhandler.h, sys/lock.h, or
sys/mutex.h inclusion need to be fixed. __FreeBSD_version has been bumped.
Submitted by: Patrick Mooney <pmooney@pfmooney.com>
Reviewed by: kib
Tested by: Patrick on SmartOS with Linux and Windows guests
Obtained from: Joyent
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D20296
Apparently, there is more code trying to call pmap_remove() early,
mostly to free preloaded memory. Instead of moving all deallocations
to the point where a scheduler is initialized, add missed setup of
thread0 di init at hammer_time().
The code in pmap_delayed_invl_start_u() is modified to not ever take
the thread lock if the thread priority is less or equal to PVM. Since
thread0 starts at priority 0, and then is reset to PVM at
proc0_init(), this eliminates taking the thread lock during early
boot.
While there, fix off by one in comparision of the base priority.
Reported and tested by: bcran (previous version)
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 29 days
In all practical situations, the resolver visibility is static.
Requested by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: so (emaste)
Differential revision: https://reviews.freebsd.org/D20281
This is done mostly for debugging in field. Also added the sysctl of
the same name to report used mode.
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
For machines having cmpxcgh16b instruction, i.e. everything but very
early Athlons, provide lockless implementation of delayed
invalidation.
The implementation maintains lock-less single-linked list with the
trick from the T.L. Harris article about volatile mark of the elements
being removed. Double-CAS is used to atomically update both link and
generation. New thread starting DI appends itself to the end of the
queue, setting the generation to the generation of the last element
+1. On DI finish, thread donates its generation to the previous
element. The generation of the fake head of the list is the last
passed DI generation. Basically, the implementation is a queued
spinlock but without spinlock.
Many thanks both to Peter Holm and Mark Johnson for keeping with me
while I produced intermediate versions of the patch.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
MFC note: td_md.md_invl_gen should go to the end of struct thread
Differential revision: https://reviews.freebsd.org/D19630
of the 'flags' argument to mmap(2) with Linux strace(1).
Reviewed by: dchagin
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20223
Microarchitectural buffers on some Intel processors utilizing
speculative execution may allow a local process to obtain a memory
disclosure. An attacker may be able to read secret data from the
kernel or from a process when executing untrusted code (for example,
in a web browser).
Reference: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00233.html
Security: CVE-2018-12126, CVE-2018-12127, CVE-2018-12130, CVE-2019-11091
Security: FreeBSD-SA-19:07.mds
Reviewed by: jhb
Tested by: emaste, lwhsu
Approved by: so (gtetlow)
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
Historically we have not distinguished between kernel wirings and user
wirings for accounting purposes. User wirings (via mlock(2)) were
subject to a global limit on the number of wired pages, so if large
swaths of physical memory were wired by the kernel, as happens with
the ZFS ARC among other things, the limit could be exceeded, causing
user wirings to fail.
The change adds a new counter, v_user_wire_count, which counts the
number of virtual pages wired by user processes via mlock(2) and
mlockall(2). Only user-wired pages are subject to the system-wide
limit which helps provide some safety against deadlocks. In
particular, while sources of kernel wirings typically support some
backpressure mechanism, there is no way to reclaim user-wired pages
shorting of killing the wiring process. The limit is exported as
vm.max_user_wired, renamed from vm.max_wired, and changed from u_int
to u_long.
The choice to count virtual user-wired pages rather than physical
pages was done for simplicity. There are mechanisms that can cause
user-wired mappings to be destroyed while maintaining a wiring of
the backing physical page; these make it difficult to accurately
track user wirings at the physical page layer.
The change also closes some holes which allowed user wirings to succeed
even when they would cause the system limit to be exceeded. For
instance, mmap() may now fail with ENOMEM in a process that has called
mlockall(MCL_FUTURE) if the new mapping would cause the user wiring
limit to be exceeded.
Note that bhyve -S is subject to the user wiring limit, which defaults
to 1/3 of physical RAM. Users that wish to exceed the limit must tune
vm.max_user_wired.
Reviewed by: kib, ngie (mlock() test changes)
Tested by: pho (earlier version)
MFC after: 45 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D19908
This gets rid of the global cpu_ipi_pending array.
While replace cmpset with fcmpset in the delivery code and opportunistically
check if given IPI is already pending.
Sponsored by: The FreeBSD Foundation
Having IPSEC compiled into the kernel imposes a non-trivial
performance penalty on multi-threaded workloads due to IPSEC
refcounting. In my benchmarks of multi-threaded UDP
transmit (connected sockets), I've seen a roughly 20% performance
penalty when the IPSEC option is included in the kernel (16.8Mpps
vs 13.8Mpps with 32 senders on a 14 core / 28 HTT Xeon
2697v3)). This is largely due to key_addref() incrementing and
decrementing an atomic reference count on the default
policy. This cause all CPUs to stall on the same cacheline, as it
bounces between different CPUs.
Given that relatively few users use ipsec, and that it can be
loaded as a module, it seems reasonable to ask those users to
load the ipsec module so as to avoid imposing this penalty on the
GENERIC kernel. Its my hope that this will make FreeBSD look
better in "out of the box" benchmark comparisons with other
operating systems.
Many thanks to ae for fixing auto-loading of ipsec.ko when
ifconfig tries to configure ipsec, and to cy for volunteering
to ensure the the racoon ports will load the ipsec.ko module
Reviewed by: cem, cy, delphij, gnn, jhb, jpaetzel
Differential Revision: https://reviews.freebsd.org/D20163
tun(4) and tap(4) share the same general management interface and have a lot
in common. Bugs exist in tap(4) that have been fixed in tun(4), and
vice-versa. Let's reduce the maintenance requirements by merging them
together and using flags to differentiate between the three interface types
(tun, tap, vmnet).
This fixes a couple of tap(4)/vmnet(4) issues right out of the gate:
- tap devices may no longer be destroyed while they're open [0]
- VIMAGE issues already addressed in tun by kp
[0] emaste had removed an easy-panic-button in r240938 due to devdrn
blocking. A naive glance over this leads me to believe that this isn't quite
complete -- destroy_devl will only block while executing d_* functions, but
doesn't block the device from being destroyed while a process has it open.
The latter is the intent of the condvar in tun, so this is "fixed" (for
certain definitions of the word -- it wasn't really broken in tap, it just
wasn't quite ideal).
ifconfig(8) also grew the ability to map an interface name to a kld, so
that `ifconfig {tun,tap}0` can continue to autoload the correct module, and
`ifconfig vmnet0 create` will now autoload the correct module. This is a
low overhead addition.
(MFC commentary)
This may get MFC'd if many bugs in tun(4)/tap(4) are discovered after this,
and how critical they are. Changes after this are likely easily MFC'd
without taking this merge, but the merge will be easier.
I have no plans to do this MFC as of now.
Reviewed by: bcr (manpages), tuexen (testing, syzkaller/packetdrill)
Input also from: melifaro
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D20044
While Linux strace(1) doesn't strictly require it - it has a fallback
to PTRACE_GETREGS - it's a newer interface, so we better support it
before the old one is deprecated.
Reviewed by: dchagin
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20152
IPI_STOP is used after panic or when ddb is entered manually. MONITOR/
MWAIT allows CPUs that support the feature to sleep in a low power way
instead of spinning. Something similar is already used at idle.
It is perhaps especially useful in oversubscribed VM environments, and is
safe to use even if the panic/ddb thread is not the BSP. (Except in the
presence of MWAIT errata, which are detected automatically on platforms with
known wakeup problems.)
It can be tuned/sysctled with "machdep.stop_mwait," which defaults to 0
(off). This commit also introduces the tunable
"machdep.mwait_cpustop_broken," which defaults to 0, unless the CPU has
known errata, but may be set to "1" in loader.conf to signal that mwait
wakeup is broken on CPUs FreeBSD does not yet know about.
Unfortunately, Bhyve doesn't yet support MONITOR extensions, so this doesn't
help bhyve hypervisors running FreeBSD guests.
Submitted by: Anton Rang <rang AT acm.org> (earlier version)
Reviewed by: kib
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D20135
Rather than just accessing it via pointer cast.
No functional change intended.
Discussed with: kib (earlier version)
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D20135
OVMF's flash variable storage is using add instructions when indexing
the variable store bootrom location.
Submitted by: D Scott Phillips <d.scott.phillips@intel.com>
Reviewed by: rgrimes
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D19975
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
Use it wherever COMPAT_FREEBSD11 is currently specified, like r309749.
Reviewed by: imp, jhb, markj
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D20120
Replace most VM_MAXCPU constant useses with an accessor function to
vm->maxcpus which for now is initialized and kept at the value of
VM_MAXCPUS.
This is a rework of Fabian Freyer (fabian.freyer_physik.tu-berlin.de)
work from D10070 to adjust it for the cpu topology changes that
occured in r332298
Submitted by: Fabian Freyer (fabian.freyer_physik.tu-berlin.de)
Reviewed by: Patrick Mooney <patrick.mooney@joyent.com>
Approved by: bde (mentor), jhb (maintainer)
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D18755
After the referenced commit, we did not set x87 and sse valid bits in
the xstate_bv bitmask for initial fpu state (stored in memory), when
using XSAVE.
The state is loaded into FPU register file to initialize the process
FPU state, and since both bits were clear, the default x87 and SSE
states were loaded. By chance, FreeBSD ABI SSE2 state is same as FPU
initial state, so the bug is not visible for 64bit processes. But on
i386, the precision control should be set to double (53bit mantissa),
instead of the default double extended (64bit mantissa). For 32bit
processes on amd64, kernel reloads control word with the right mask,
which only left native i386 and amd64 native but using x87 as
affected.
Fix it by setting minimal required xstate_bv mask.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Some early PCIe chipsets are explicitly listed in the white-list to
enable use of the MMIO config space accesses, perhaps because ACPI
tables were not reliable source of the base MCFG address at that time.
For that chipsets, MCFG base was read from the known chipset MCFGbase
config register.
During very early stage of boot, when access to the PCI config space
is performed (see e.g. pci_early_quirks.c), we cannot map 255MB of
registers because the method used with pre-boot pmap overflows initial
kernel page tables.
Move fallback to read MCFGbase to the attachment method of the
x86/legacy device, which removes code duplication, and results in the
use of io accesses until MCFG is parsed or legacy attach called.
For amd64, pre-initialize cfgmech with CFGMECH_1, right now we
dynamically assign CFGMECH_1 to it anyway, and remove checks for
CFGMECH_NONE.
There is a mention in the Intel documentation for corresponding
chipsets that OS must use either io port or MMIO access method, but we
already break this rule by reading MCFGbase register, so one more
access seems to be innocent.
Reported by: longwitz@incore.de
PR: 236838
Reviewed by: avg (other version), jhb
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D19833
For PCI device (i.e. child of a PCI bus), reset tries FLR if
implemented and worked, and falls to power reset otherwise.
For PCIe bus (child of a PCIe bridge or root port), reset
disables PCIe link and then re-trains it, performing what is known as
link-level reset.
Reviewed by: imp (previous version), jhb (previous version)
Sponsored by: Mellanox Technologies
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D19646
Remove redundant npxsave_core definition while here.
Suggested by: Anton Rang
Reviewed by: kib, Anton Rang <rang AT acm.org>
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D19665
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
AMD64_SET_**BASE expects a pointer to a pointer, we just passing in the pointer value itself.
Set PCB_FULL_IRET for doreti to restore %fs, %gs and its correspondig base.
PR: 225105
Reported by: trasz@
MFC after: 1 month
There are some unusual cases where a process may cause an mlock()ed
range of memory to be unmapped. If the application subsequently
faults on that region, the handler may attempt to create a superpage
mapping backed by the resident, wired pages. However, the pmap code
responsible for creating such a mapping (pmap_enter_pde() on i386
and amd64) does not ensure that a leaf page table page is available
if the superpage is later demoted; the demotion operation must therefore
perform a non-blocking page allocation and must unmap the entire
superpage if the allocation fails. The pmap layer ensures that this
can never happen for wired mappings, and so the case described above
breaks that invariant.
For now, simply ensure that the MI fault handler never attempts to
create a wired superpage except via promotion.
Reviewed by: kib
Reported by: syzbot+292d3b0416c27c131505@syzkaller.appspotmail.com
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19670
It may happen on some machines, that even if SGX is disabled
in firmware, the driver would still attach despite EPC base and
size equal zero. Such behaviour causes a kernel panic when the
module is unloaded. Add a simple check to make sure we
only attach when these values are correctly set.
Submitted by: Kornel Duleba <mindal@semihalf.com>
Reviewed by: br
Obtained from: Semihalf
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D19595
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
PTI mode for the process pmap on exec is activated iff P_MD_PTI is set.
On exec, the existing vmspace can be reused only if pti mode of the
pmap matches the P_MD_PTI flag of the process. Add MD
cpu_exec_vmspace_reuse() callback for exec_new_vmspace() which can
vetoed reuse of the existing vmspace.
MFC note: md_flags change struct proc KBI.
Reviewed by: jhb, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D19514
When the pmap with pti disabled (i.e. pm_ucr3 == PMAP_NO_CR3) is
activated, tss.rsp0 was not updated. Any interrupt that happen before
next context switch would use pti trampoline stack for hardware frame
but fault and interrupt handlers are not prepared to this. Correctly
update tss.rsp0 for both PMAP_NO_CR3 and pti pmaps.
Note that this case, pti = 1 but pmap->pm_ucr3 == PMAP_NO_CR3 is not
used at the moment.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D19514
and for %ecx after RDTSCP.
Initialize TSC_AUX MSR with CPUID. It allows for userspace to cheaply
identify CPU it was executed on some time ago, which is sometimes useful.
Note: The values returned might be changed in future.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
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
When a vCPU is HLTed, interrupts with a priority below the processor
priority (PPR) should not resume the vCPU while interrupts at or above
the PPR should. With posted interrupts, bhyve maintains a bitmap of
pending interrupts in PIR descriptor along with a single 'pending'
bit. This bit is checked by a CPU running in guest mode at various
places to determine if it should be checked. In addition, another CPU
can force a CPU in guest mode to check for pending interrupts by
sending an IPI to a special IDT vector reserved for this purpose.
bhyve had a bug in that it would only notify a guest vCPU of an
interrupt (e.g. by sending the special IPI or by resuming it if it was
idle due to HLT) if an interrupt arrived that was higher priority than
PPR and no interrupts were currently pending. This assumed that if
the 'pending' bit was set, any needed notification was already in
progress. However, if the first interrupt sent to a HLTed vCPU was
lower priority than PPR and the second was higher than PPR, the first
interrupt would set 'pending' but not notify the vCPU, and the second
interrupt would not notify the vCPU because 'pending' was already set.
To fix this, track the priority of pending interrupts in a separate
per-vCPU bitmask and notify a vCPU anytime an interrupt arrives that
is above PPR and higher than any previously-received interrupt.
This was found and debugged in the bhyve port to SmartOS maintained by
Joyent. Relevant SmartOS bugs with more background:
https://smartos.org/bugview/OS-6829https://smartos.org/bugview/OS-6930https://smartos.org/bugview/OS-7354
Submitted by: Patrick Mooney <pmooney@pfmooney.com>
Reviewed by: tychon, rgrimes
Obtained from: SmartOS / Joyent
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D19299
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
Skylake Xeons.
See SDM rev. 68 Vol 3 4.6.2 Protection Keys and the description of the
RDPKRU and WRPKRU instructions.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D18893
The pmap_works variable is always true for amd64. Remove it, the
branch in the initialization taken when false, and corresponding
sysctl.
Remove pat_table[] local array, work on pat_index[] directly.
Collapse whole initialization to not override already assigned values.
Add comment explaining the choice for PAT4 and PAT7.
Reviewed by: alc, markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
MFC note: Leave the sysctl around
Differential revision: https://reviews.freebsd.org/D19225
Some argument validation error paths would return without releasing the
file reference obtained at the beginning of the function.
While here, fix some style bugs and remove trivial debug prints.
Reviewed by: kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19214
With this change, randomization can be enabled for all non-fixed
mappings. It means that the base address for the mapping is selected
with a guaranteed amount of entropy (bits). If the mapping was
requested to be superpage aligned, the randomization honours the
superpage attributes.
Although the value of ASLR is diminshing over time as exploit authors
work out simple ASLR bypass techniques, it elimintates the trivial
exploitation of certain vulnerabilities, at least in theory. This
implementation is relatively small and happens at the correct
architectural level. Also, it is not expected to introduce
regressions in existing cases when turned off (default for now), or
cause any significant maintaince burden.
The randomization is done on a best-effort basis - that is, the
allocator falls back to a first fit strategy if fragmentation prevents
entropy injection. It is trivial to implement a strong mode where
failure to guarantee the requested amount of entropy results in
mapping request failure, but I do not consider that to be usable.
I have not fine-tuned the amount of entropy injected right now. It is
only a quantitive change that will not change the implementation. The
current amount is controlled by aslr_pages_rnd.
To not spoil coalescing optimizations, to reduce the page table
fragmentation inherent to ASLR, and to keep the transient superpage
promotion for the malloced memory, locality clustering is implemented
for anonymous private mappings, which are automatically grouped until
fragmentation kicks in. The initial location for the anon group range
is, of course, randomized. This is controlled by vm.cluster_anon,
enabled by default.
The default mode keeps the sbrk area unpopulated by other mappings,
but this can be turned off, which gives much more breathing bits on
architectures with small address space, such as i386. This is tied
with the question of following an application's hint about the mmap(2)
base address. Testing shows that ignoring the hint does not affect the
function of common applications, but I would expect more demanding
code could break. By default sbrk is preserved and mmap hints are
satisfied, which can be changed by using the
kern.elf{32,64}.aslr.honor_sbrk sysctl.
ASLR is enabled on per-ABI basis, and currently it is only allowed on
FreeBSD native i386 and amd64 (including compat 32bit) ABIs. Support
for additional architectures will be added after further testing.
Both per-process and per-image controls are implemented:
- procctl(2) adds PROC_ASLR_CTL/PROC_ASLR_STATUS;
- NT_FREEBSD_FCTL_ASLR_DISABLE feature control note bit makes it possible
to force ASLR off for the given binary. (A tool to edit the feature
control note is in development.)
Global controls are:
- kern.elf{32,64}.aslr.enable - for non-fixed mappings done by mmap(2);
- kern.elf{32,64}.aslr.pie_enable - for PIE image activation mappings;
- kern.elf{32,64}.aslr.honor_sbrk - allow to use sbrk area for mmap(2);
- vm.cluster_anon - enables anon mapping clustering.
PR: 208580 (exp runs)
Exp-runs done by: antoine
Reviewed by: markj (previous version)
Discussed with: emaste
Tested by: pho
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D5603
The COVERAGE option breaks xtoolchain-gcc GENERIC kernel early boot
extremely badly and hasn't been fixed for the ~week since it was committed.
Please enable for GENERIC only when it doesn't do that.
Related fallout reported by: lwhsu, tuexen (pr 235611)
%r8, %r10, and on non-KPTI configuration %r9 were not restored on fast
return from a syscall.
Reviewed by: markj
Approved by: so
Security: CVE-2019-5595
Sponsored by: The FreeBSD Foundation
MFC after: 0 minutes
This allows userspace to trace the kernel using the coverage sanitizer
found in clang. It will also allow other coverage tools to be built as
modules and attach into the same framework.
Sponsored by: DARPA, AFRL
iflib is already a module, but it is unconditionally compiled into the
kernel. There are drivers which do not need iflib(4), and there are
situations where somebody might not want iflib in kernel because of
using the corresponding driver as module.
Reviewed by: marius
Discussed with: erj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D19041
This will allow multiple consumers of the coverage data to be compiled
into the kernel together. The only requirement is only one can be
registered at a given point in time, however it is expected they will
only register when the coverage data is needed.
A new kernel conflig option COVERAGE is added. This will allow kcov to
become a module that can be loaded as needed, or compiled into the
kernel.
While here clean up the #include style a little.
Reviewed by: kib
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D18955
For parity with Intel hosts, which already mask out the CPUID feature
bits that indicate the presence of the SPEC_CTRL MSR, do the same on
AMD.
Eventually we may want to have a better support story for guests, but
for now, limit the damage of incorrectly indicating an MSR we do not yet
support.
Eventually, we may want a generic CPUID override system for
administrators, or for minimum supported feature set in heterogenous
environments with failover. That is a much larger scope effort than
this bug fix.
PR: 235010
Reported by: Rys Sommefeldt <rys AT sommefeldt.com>
Sponsored by: Dell EMC Isilon
vmm's CPUID emulation presented Intel topology information to the guest, but
disabled AMD topology information and in some cases passed through garbage.
I.e., CPUID leaves 0x8000_001[de] were passed through to the guest, but
guest CPUs can migrate between host threads, so the information presented
was not consistent. This could easily be observed with 'cpucontrol -i 0xfoo
/dev/cpuctl0'.
Slightly improve this situation by enabling the AMD topology feature flag
and presenting at least the CPUID fields used by FreeBSD itself to probe
topology on more modern AMD64 hardware (Family 15h+). Older stuff is
probably less interesting. I have not been able to empirically confirm it
is sufficient, but it should not regress anything either.
Reviewed by: araujo (previous version)
Relnotes: sure
When building with KCOV enabled the compiler will insert function calls
to probes allowing us to trace the execution of the kernel from userspace.
These probes are on function entry (trace-pc) and on comparison operations
(trace-cmp).
Userspace can enable the use of these probes on a single kernel thread with
an ioctl interface. It can allocate space for the probe with KIOSETBUFSIZE,
then mmap the allocated buffer and enable tracing with KIOENABLE, with the
trace mode being passed in as the int argument. When complete KIODISABLE
is used to disable tracing.
The first item in the buffer is the number of trace event that have
happened. Userspace can write 0 to this to reset the tracing, and is
expected to do so on first use.
The format of the buffer depends on the trace mode. When in PC tracing just
the return address of the probe is stored. Under comparison tracing the
comparison type, the two arguments, and the return address are traced. The
former method uses on entry per trace event, while the later uses 4. As
such they are incompatible so only a single mode may be enabled.
KCOV is expected to help fuzzing the kernel, and while in development has
already found a number of issues. It is required for the syzkaller system
call fuzzer [1]. Other kernel fuzzers could also make use of it, either
with the current interface, or by extending it with new modes.
A man page is currently being worked on and is expected to be committed
soon, however having the code in the kernel now is useful for other
developers to use.
[1] https://github.com/google/syzkaller
Submitted by: Mitchell Horne <mhorne063@gmail.com> (Earlier version)
Reviewed by: kib
Testing by: tuexen
Sponsored by: DARPA, AFRL
Sponsored by: The FreeBSD Foundation (Mitchell Horne)
Differential Revision: https://reviews.freebsd.org/D14599
It is useful for inspecting tlb shootdown hangs. The smp_tlb_generation value
is available using regular ddb data inspection commands.
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
This KPI may in principle be used to create kernel mappings, in which
case we certainly should not be setting PG_U. In any case, PG_U must be
set on all layers in the page tables to grant user mode access, and we
were only setting it on leaf entries. Thus, this change should have no
functional impact.
Reviewed by: kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Originally read value is still safely kept. Re-reading code was there
for previous iterations which were partially shared with i386.
Sponsored by: The FreeBSD Foundation
On some architectures, the structures returned by PT_GET*REGS were not
fully populated and could contain uninitialized stack memory. The same
issue existed with the register files in procfs.
Reported by: Thomas Barabosch, Fraunhofer FKIE
Reviewed by: kib
MFC after: 3 days
Security: kernel stack memory disclosure
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18421
See the review for sample test results.
Reviewed by: kib (kernel part)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18401
Handling sizes of > 32 backwards will be updated later.
Reviewed by: kib (kernel part)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18387
For non-ERMS case the code used handle possible trailing bytes with
movsb first and then followed it up with movsq. This also happened
to alter how calculations were done for other cases.
Handle the tail with regular movs, just like when copying forward.
Use leaq to calculate the right offset from the get go, instead of
doing separate add and sub.
This adjusts the offset for non-rep cases so that they can be used
to handle the tail.
The routine is still a work in progress.
Sponsored by: The FreeBSD Foundation
pmap_large_unmap() asserts that an unmapping request covers the
entirety of a 2M or 1G page. The logic in the asserts was out of date
with the loop logic. Correct the test to actually check that
destroying the current superpage mapping does not unmap addresses
beyond those requested by the caller.
Submitted by: D Scott Phillips <d.scott.phillips@intel.com>
Reviewed by: alc
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D18345
We zero the whole structure; we don't need to zero the __spare__ field again.
Remove trailing whitespace.
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
