Fix duplicate TLB entries issue during section promotion/demotion.
Such situation is defined as UNPREDICTABLE by arm arm manual.
This patch fixes all explicit TLB fetches which could cause this issue
and speculative TLB fetches for sections mapped in user address space.
Speculative TLB fetches for sections mapped in kernel address space are
not fixed yet as the break-before-make approach must be implemented for
kernel mappings too. This means that promoted/demoted section will be
unmapped for a while. Either kernel stack the promotion/demotion is
being done on or L1 page table(s) which must be modified may be mapped
by this section. Thus the fix will not be so simple like for userland
mappings.
The issue was detectable only on Cortex-A8 platforms and only very
rarely. It was reported few times. First, it was by Mikael Urankar
in June 2015. He helped to identify the mechanism of this issue, but
we were not sure how to fix it correctly until now.
PR: 208381
Reported by: Mikael Urankar (mikael.urankar at gmail.com)
Reviewed by: kib
Don't use atomic operations for page table entries and handle access
and R/W emulation aborts under pmap lock.
There were two reasons for using of atomic operations:
(1) the pmap code is based on i386 one where they are used,
(2) there was an idea that access and R/W emulation aborts should be
handled as quick as possible, without pmap locking.
However, the atomic operations in i386 pmap code are used only because
page table entries may be modified by hardware. At the beginning, we
were not sure that it's the only reason. So even if arm hardware does
not modify them, we did not risk to not use them at that time. Further,
it turns out after some testing that using of pmap lock for access and
R/W emulation aborts does not bring any extra cost and there was no
measurable difference. Thus, we have decided finally to use pmap lock
for all operations on page table entries and so, there is no reason for
atomic operations on them. This makes the code cleaner and safer.
This decision introduce a question if it's safe to use pmap lock for
access and R/W emulation aborts. Anyhow, there may happen two cases in
general:
(A) Aborts while the pmap lock is locked already - this should not
happen as pmap lock is not recursive. However, under pmap lock only
internal kernel data should be accessed and such data should be mapped
with A bit set and NM bit cleared. If double abort happens, then
a mapping of data which has caused it must be fixed.
(B) Aborts while another lock(s) is/are locked - this already can
happen. There is no difference here if it's either access or R/W
emulation abort, or if it's some other abort.
Add four functions which check a virtual address for stage 1 privileged
(PL1) and unprivileged (PL0) read/write access. As cp15 virtual to
physical address translation operations are used, interrupts must be
disabled to get consistent result when they are called.
These functions should be used only in very specific occasions like
during abort handling or kernel debugging. One of them is going to be
used in pmap_fault(). However, complete function set is added. It cost
nothing, as they are inlined.
Enji Cooper [Fri, 22 Apr 2016 05:24:15 +0000 (05:24 +0000)]
Simplify always evaluated branch (`e != NULL`)
- xalloc(..) ensures that e will be non-null via malloc + err.
- `e` is already dereferenced above, so logically it's impossible
to hit the lower test without crashing if it was indeed NULL.
Submitted by: Jun Su <junsu microsoft com>
Reviewed by: sephe, Dexuan Cui <decui microsoft com>
MFC after: 1 week
Sponsored by: Microsoft OSTC
Differential Revision: https://reviews.freebsd.org/D5957
Pedro F. Giffuni [Thu, 21 Apr 2016 19:57:40 +0000 (19:57 +0000)]
sys: use our roundup2/rounddown2() macros when param.h is available.
rounddown2 tends to produce longer lines than the original code
and when the code has a high indentation level it was not really
advantageous to do the replacement.
This tries to strike a balance between readability using the macros
and flexibility of having the expressions, so not everything is
converted.
John Baldwin [Thu, 21 Apr 2016 18:37:36 +0000 (18:37 +0000)]
Adjust the fdc worker thread startup to work when APs are started earlier.
- Enable the commented out locking in fd_probe(). The worker thread
should not be running yet (even after these changes), but better to be
safe than sorry.
- Defer starting the worker thread until after the child drives have been
probed. The worker thread startup is moved into a fdc_start_worker()
thread that the various front ends call at the end of attach. As a
side effect this fixes a few edge cases that weren't shutting down the
worker thread if attach encountered a late failure.
- When executing the initial reset requested by attach in the worker
thread, use DELAY() instead of a tsleep() if cold is set.
Tested by: Howard Su <howard0su@gmail.com>
Sponsored by: Netflix
John Baldwin [Thu, 21 Apr 2016 18:27:05 +0000 (18:27 +0000)]
Queue the CPU-probing task after all acpi_cpu devices are attached.
Eventually with earlier AP startup this code will change to call the
startup function synchronously instead of queueing the task. Moving
the time we queue the task should be a no-op since taskqueue threads
don't start executing tasks until much later, but this reduces the diff
with the earlier AP startup patches.
IPv6 addresses has a scope ID which sometimes is stored in the
"sin6_scope_id" field of "struct sockaddr_in6" and sometimes as part
of the IPv6 address itself depending on the context. If the scope ID
is not in the expected location, the IPv6 address lookups in the
so-called GID table will fail. Some code factoring has been made to
achieve a clean exit of the "addr_resolve" function via a common
"done" label.
Get rid of rctl_lock; use racct_lock where appropriate. The fast paths
already required both of them, so having a separate rctl_lock didn't
buy us anything.
Reviewed by: mjg@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D5914
Prevent underflows in tp->snd_wnd if the remote side ACKs more than
tp->snd_wnd. This can happen, for example, when the remote side responds to
a window probe by ACKing the one byte it contains.
ascii.c was removed during r290494 but this introduced an issue with ASCII that
has been fixed in r290618 and lead to a rewrite of ascii.c based on none.c.
ascii.c was wrongly reintroduced in r290620 without proper svn operation which
lost the history.
net80211: enable promiscuous mode state change for non-monitor/ahdemo modes
- Allow to enable/disable promiscuous mode when:
* interface is not a member of bridge, or;
* request was issued by user (ifconfig wlan0 promisc), or;
* interface is in MONITOR or AHDEMO mode.
- Drop local workarounds in mwl(4) and malo(4).
Bring a little more compability with GNU units 2.12
- notionally support a 'history file' flag. This doesn't do much now,
but is there to prevent scripts written against GNU units from
breaking
- correctly gracefully quit rather than exit (this will make it easier
to support a history file in the future)
- remove the "t" flag from fopen which was there to support windows. We
have not supported windows since at the latest, the introduction of
capsicum.
dhclient: Log a warning instead of bailing upon "illegal" options
In Azure, the DHCP servers add private option (id 0xf5), which contains
binary form of an IPv4 address. Once this option is converted to string
form, it could contain '$', e.g.
dhclient bails upon "illegal" options like the above example, thus the
VM bring-up will fail.
Also as a side note, this "illegal" option detection was added in
OpenBSD ~11years ago:
http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sbin/dhclient/dhclient.c?rev=1.50&content-type=text/x-cvsweb-markup
And it was removed along with the removal of script support in OpenBSD
~3years ago:
http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sbin/dhclient/dhclient.c?rev=1.159&content-type=text/x-cvsweb-markup
Reported by: Hongxiong Xian <v-hoxian microsoft com>
Reviewed by: jhb, Dexuan Cui <decui microsoft com>
Tested by: Hongxiong Xian <v-hoxian microsoft com>
Analyzed by: Dong Liu <doliu microsoft com>
MFC after: 1 week
Sponsored by: Microsoft OSTC
Differential Revision: https://reviews.freebsd.org/D5853
Force framebuffer virtual viewport to be the same as physical
VideoCore reports garbage in viewport geometry fields unless
viewport was set previously by earlier stage boot loader. So
when booting FreeBSD kernel directly from VideoCore's start.elf
framebuffer intialization fails due to invalid vxres, vyres
values. Make sure we request viewport to be equal to physical
resolution
John Baldwin [Wed, 20 Apr 2016 20:55:58 +0000 (20:55 +0000)]
Add a wrapper for evaluating _OSC methods.
This wrapper does not translate errors in the first word to ACPI
error status returns. Use this wrapper in the acpi_cpu(4) driver in
place of the existing _OSC code. While here, fix a bug where the wrong
count of words was passed when invoking _OSC.
Wojciech Macek [Wed, 20 Apr 2016 17:58:13 +0000 (17:58 +0000)]
Fix KGDB backtrace on ARM
Modify trapframe decoding to properly analyze trapframe.
Provide method for fixup_pc. It happens, that in some kernel
functions, the GDB stack frame decoder cannot determine both
func name and frame size. This is because these functions
either contain invalid instruction, or their format does
not match standard schema. Detect that scenarios and move
PC accordingly to jump into known function schema, which
GDB is able to parse.
projects / FreeBSD / FreeBSD.git / log