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This is the 4.18.45 stable release
# gpg: Signature made Sat 21 Sep 2019 12:20:15 PM EDT
# gpg: using RSA key EBCE84042C07D1D6
# gpg: Can't check signature: No public key
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commit 4c92057661a3412f547ede95715641d7ee16ddac upstream.
Add documentation to the Spectre document about the new swapgs variant of
Spectre v1.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit a2059825986a1c8143fd6698774fa9d83733bb11 upstream.
The previous commit added macro calls in the entry code which mitigate the
Spectre v1 swapgs issue if the X86_FEATURE_FENCE_SWAPGS_* features are
enabled. Enable those features where applicable.
The mitigations may be disabled with "nospectre_v1" or "mitigations=off".
There are different features which can affect the risk of attack:
- When FSGSBASE is enabled, unprivileged users are able to place any
value in GS, using the wrgsbase instruction. This means they can
write a GS value which points to any value in kernel space, which can
be useful with the following gadget in an interrupt/exception/NMI
handler:
if (coming from user space)
swapgs
mov %gs:<percpu_offset>, %reg1
// dependent load or store based on the value of %reg
// for example: mov %(reg1), %reg2
If an interrupt is coming from user space, and the entry code
speculatively skips the swapgs (due to user branch mistraining), it
may speculatively execute the GS-based load and a subsequent dependent
load or store, exposing the kernel data to an L1 side channel leak.
Note that, on Intel, a similar attack exists in the above gadget when
coming from kernel space, if the swapgs gets speculatively executed to
switch back to the user GS. On AMD, this variant isn't possible
because swapgs is serializing with respect to future GS-based
accesses.
NOTE: The FSGSBASE patch set hasn't been merged yet, so the above case
doesn't exist quite yet.
- When FSGSBASE is disabled, the issue is mitigated somewhat because
unprivileged users must use prctl(ARCH_SET_GS) to set GS, which
restricts GS values to user space addresses only. That means the
gadget would need an additional step, since the target kernel address
needs to be read from user space first. Something like:
if (coming from user space)
swapgs
mov %gs:<percpu_offset>, %reg1
mov (%reg1), %reg2
// dependent load or store based on the value of %reg2
// for example: mov %(reg2), %reg3
It's difficult to audit for this gadget in all the handlers, so while
there are no known instances of it, it's entirely possible that it
exists somewhere (or could be introduced in the future). Without
tooling to analyze all such code paths, consider it vulnerable.
Effects of SMAP on the !FSGSBASE case:
- If SMAP is enabled, and the CPU reports RDCL_NO (i.e., not
susceptible to Meltdown), the kernel is prevented from speculatively
reading user space memory, even L1 cached values. This effectively
disables the !FSGSBASE attack vector.
- If SMAP is enabled, but the CPU *is* susceptible to Meltdown, SMAP
still prevents the kernel from speculatively reading user space
memory. But it does *not* prevent the kernel from reading the
user value from L1, if it has already been cached. This is probably
only a small hurdle for an attacker to overcome.
Thanks to Dave Hansen for contributing the speculative_smap() function.
Thanks to Andrew Cooper for providing the inside scoop on whether swapgs
is serializing on AMD.
[ tglx: Fixed the USER fence decision and polished the comment as suggested
by Dave Hansen ]
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 6e88559470f581741bcd0f2794f9054814ac9740 upstream.
Add documentation for Spectre vulnerability and the mitigation mechanisms:
- Explain the problem and risks
- Document the mitigation mechanisms
- Document the command line controls
- Document the sysfs files
Co-developed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Co-developed-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 26cb1f36c43ee6e89d2a9f48a5a7500d5248f836 upstream.
Currently only supported on powerpc.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.41 stable release
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commit 5f3e2bf008c2221478101ee72f5cb4654b9fc363 upstream.
Some TCP peers announce a very small MSS option in their SYN and/or
SYN/ACK messages.
This forces the stack to send packets with a very high network/cpu
overhead.
Linux has enforced a minimal value of 48. Since this value includes
the size of TCP options, and that the options can consume up to 40
bytes, this means that each segment can include only 8 bytes of payload.
In some cases, it can be useful to increase the minimal value
to a saner value.
We still let the default to 48 (TCP_MIN_SND_MSS), for compatibility
reasons.
Note that TCP_MAXSEG socket option enforces a minimal value
of (TCP_MIN_MSS). David Miller increased this minimal value
in commit c39508d6f118 ("tcp: Make TCP_MAXSEG minimum more correct.")
from 64 to 88.
We might in the future merge TCP_MIN_SND_MSS and TCP_MIN_MSS.
CVE-2019-11479 -- tcp mss hardcoded to 48
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Jonathan Looney <jtl@netflix.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Bruce Curtis <brucec@netflix.com>
Cc: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit ede95a63b5e84ddeea6b0c473b36ab8bfd8c6ce3 upstream.
Rick reported that the BPF JIT could potentially fill the entire module
space with BPF programs from unprivileged users which would prevent later
attempts to load normal kernel modules or privileged BPF programs, for
example. If JIT was enabled but unsuccessful to generate the image, then
before commit 290af86629b2 ("bpf: introduce BPF_JIT_ALWAYS_ON config")
we would always fall back to the BPF interpreter. Nowadays in the case
where the CONFIG_BPF_JIT_ALWAYS_ON could be set, then the load will abort
with a failure since the BPF interpreter was compiled out.
Add a global limit and enforce it for unprivileged users such that in case
of BPF interpreter compiled out we fail once the limit has been reached
or we fall back to BPF interpreter earlier w/o using module mem if latter
was compiled in. In a next step, fair share among unprivileged users can
be resolved in particular for the case where we would fail hard once limit
is reached.
Fixes: 290af86629b2 ("bpf: introduce BPF_JIT_ALWAYS_ON config")
Fixes: 0a14842f5a3c ("net: filter: Just In Time compiler for x86-64")
Co-Developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 5467a68cbf6884c9a9d91e2a89140afb1839c835 upstream.
For lockless accesses to dentries we don't have pinned we rely
(among other things) upon having an RCU delay between dropping
the last reference and actually freeing the memory.
On the other hand, for things like pipes and sockets we neither
do that kind of lockless access, nor want to deal with the
overhead of an RCU delay every time a socket gets closed.
So delay was made optional - setting DCACHE_RCUACCESS in ->d_flags
made sure it would happen. We tried to avoid setting it unless
we knew we need it. Unfortunately, that had led to recurring
class of bugs, in which we missed the need to set it.
We only really need it for dentries that are created by
d_alloc_pseudo(), so let's not bother with trying to be smart -
just make having an RCU delay the default. The ones that do
*not* get it set the replacement flag (DCACHE_NORCU) and we'd
better use that sparingly. d_alloc_pseudo() is the only
such user right now.
FWIW, the race that finally prompted that switch had been
between __lock_parent() of immediate subdirectory of what's
currently the root of a disconnected tree (e.g. from
open-by-handle in progress) racing with d_splice_alias()
elsewhere picking another alias for the same inode, either
on outright corrupted fs image, or (in case of open-by-handle
on NFS) that subdirectory having been just moved on server.
It's not easy to hit, so the sky is not falling, but that's
not the first race on similar missed cases and the logics
for settinf DCACHE_RCUACCESS has gotten ridiculously
convoluted.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.40 stable release
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commit 9d8d0294e78a164d407133dea05caf4b84247d6a upstream.
On x86_64, all returns to usermode go through
prepare_exit_to_usermode(), with the sole exception of do_nmi().
This even includes machine checks -- this was added several years
ago to support MCE recovery. Update the documentation.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jon Masters <jcm@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: 04dcbdb80578 ("x86/speculation/mds: Clear CPU buffers on exit to user")
Link: http://lkml.kernel.org/r/999fa9e126ba6a48e9d214d2f18dbde5c62ac55c.1557865329.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 88640e1dcd089879530a49a8d212d1814678dfe7 upstream.
The double fault ESPFIX path doesn't return to user mode at all --
it returns back to the kernel by simulating a #GP fault.
prepare_exit_to_usermode() will run on the way out of
general_protection before running user code.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jon Masters <jcm@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: 04dcbdb80578 ("x86/speculation/mds: Clear CPU buffers on exit to user")
Link: http://lkml.kernel.org/r/ac97612445c0a44ee10374f6ea79c222fe22a5c4.1557865329.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.39 stable release
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commit c2b71462d294cf517a0bc6e4fd6424d7cee5596f upstream.
The syzkaller fuzzer reported a bug in the USB hub driver which turned
out to be caused by a negative runtime-PM usage counter. This allowed
a hub to be runtime suspended at a time when the driver did not expect
it. The symptom is a WARNING issued because the hub's status URB is
submitted while it is already active:
URB 0000000031fb463e submitted while active
WARNING: CPU: 0 PID: 2917 at drivers/usb/core/urb.c:363
The negative runtime-PM usage count was caused by an unfortunate
design decision made when runtime PM was first implemented for USB.
At that time, USB class drivers were allowed to unbind from their
interfaces without balancing the usage counter (i.e., leaving it with
a positive count). The core code would take care of setting the
counter back to 0 before allowing another driver to bind to the
interface.
Later on when runtime PM was implemented for the entire kernel, the
opposite decision was made: Drivers were required to balance their
runtime-PM get and put calls. In order to maintain backward
compatibility, however, the USB subsystem adapted to the new
implementation by keeping an independent usage counter for each
interface and using it to automatically adjust the normal usage
counter back to 0 whenever a driver was unbound.
This approach involves duplicating information, but what is worse, it
doesn't work properly in cases where a USB class driver delays
decrementing the usage counter until after the driver's disconnect()
routine has returned and the counter has been adjusted back to 0.
Doing so would cause the usage counter to become negative. There's
even a warning about this in the USB power management documentation!
As it happens, this is exactly what the hub driver does. The
kick_hub_wq() routine increments the runtime-PM usage counter, and the
corresponding decrement is carried out by hub_event() in the context
of the hub_wq work-queue thread. This work routine may sometimes run
after the driver has been unbound from its interface, and when it does
it causes the usage counter to go negative.
It is not possible for hub_disconnect() to wait for a pending
hub_event() call to finish, because hub_disconnect() is called with
the device lock held and hub_event() acquires that lock. The only
feasible fix is to reverse the original design decision: remove the
duplicate interface-specific usage counter and require USB drivers to
balance their runtime PM gets and puts. As far as I know, all
existing drivers currently do this.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.38 stable release
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This is the 4.18.37 stable release
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commit 3ec25826ae33618a03c28235af8d62e8a7f7f15f upstream.
In commit b1fca27d384e ("kernel debug: support resetting WARN*_ONCE")
we got the opportunity to reset state on the one shot messages,
without having to reboot.
However printk_once (printk_deferred_once) live in a different file
and didn't get the same kind of update/conversion, so they remain
unconditionally one shot, until the system is rebooted.
For example, we currently have:
sched/rt.c: printk_deferred_once("sched: RT throttling activated\n");
..which could reasonably be tripped as someone is testing and tuning
a new system/workload and their task placements. For consistency, and
to avoid reboots in the same vein as the original commit, we make these
two instances of _once the same as the WARN*_ONCE instances are.
Link: http://lkml.kernel.org/r/1555121491-31213-1-git-send-email-paul.gortmaker@windriver.com
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit e59f5bd759b7dee57593c5b6c0441609bda5d530 upstream.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 19fad20d15a6494f47f85d869f00b11343ee5c78 upstream.
There is a UBSAN report as below:
UBSAN: Undefined behaviour in net/ipv4/tcp_input.c:2877:56
signed integer overflow:
2147483647 * 1000 cannot be represented in type 'int'
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.1.0-rc4-00058-g582549e #1
Call Trace:
<IRQ>
dump_stack+0x8c/0xba
ubsan_epilogue+0x11/0x60
handle_overflow+0x12d/0x170
? ttwu_do_wakeup+0x21/0x320
__ubsan_handle_mul_overflow+0x12/0x20
tcp_ack_update_rtt+0x76c/0x780
tcp_clean_rtx_queue+0x499/0x14d0
tcp_ack+0x69e/0x1240
? __wake_up_sync_key+0x2c/0x50
? update_group_capacity+0x50/0x680
tcp_rcv_established+0x4e2/0xe10
tcp_v4_do_rcv+0x22b/0x420
tcp_v4_rcv+0xfe8/0x1190
ip_protocol_deliver_rcu+0x36/0x180
ip_local_deliver+0x15b/0x1a0
ip_rcv+0xac/0xd0
__netif_receive_skb_one_core+0x7f/0xb0
__netif_receive_skb+0x33/0xc0
netif_receive_skb_internal+0x84/0x1c0
napi_gro_receive+0x2a0/0x300
receive_buf+0x3d4/0x2350
? detach_buf_split+0x159/0x390
virtnet_poll+0x198/0x840
? reweight_entity+0x243/0x4b0
net_rx_action+0x25c/0x770
__do_softirq+0x19b/0x66d
irq_exit+0x1eb/0x230
do_IRQ+0x7a/0x150
common_interrupt+0xf/0xf
</IRQ>
It can be reproduced by:
echo 2147483647 > /proc/sys/net/ipv4/tcp_min_rtt_wlen
Fixes: f672258391b42 ("tcp: track min RTT using windowed min-filter")
Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 95310e348a321b45fb746c176961d4da72344282 upstream
Fix a minor typo in the MDS documentation: "eanbled" -> "enabled".
Reported-by: Jeff Bastian <jbastian@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit ea01668f9f43021b28b3f4d5ffad50106a1e1301 upstream
Adjust the last two rows in the table that display possible values when
MDS mitigation is enabled. They both were slightly innacurate.
In addition, convert the table of possible values and their descriptions
to a list-table. The simple table format uses the top border of equals
signs to determine cell width which resulted in the first column being
far too wide in comparison to the second column that contained the
majority of the text.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit e672f8bf71c66253197e503f75c771dd28ada4a0 upstream
Updated the documentation for a new CVE-2019-11091 Microarchitectural Data
Sampling Uncacheable Memory (MDSUM) which is a variant of
Microarchitectural Data Sampling (MDS). MDS is a family of side channel
attacks on internal buffers in Intel CPUs.
MDSUM is a special case of MSBDS, MFBDS and MLPDS. An uncacheable load from
memory that takes a fault or assist can leave data in a microarchitectural
structure that may later be observed using one of the same methods used by
MSBDS, MFBDS or MLPDS. There are no new code changes expected for MDSUM.
The existing mitigation for MDS applies to MDSUM as well.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 5c14068f87d04adc73ba3f41c2a303d3c3d1fa12 upstream
Add MDS to the new 'mitigations=' cmdline option.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 0336e04a6520bdaefdb0769d2a70084fa52e81ed upstream
Configure s390 runtime CPU speculation bug mitigations in accordance
with the 'mitigations=' cmdline option. This affects Spectre v1 and
Spectre v2.
The default behavior is unchanged.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/e4a161805458a5ec88812aac0307ae3908a030fc.1555085500.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[PG: align with the 4.14.119 stable version of this change.]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 782e69efb3dfed6e8360bc612e8c7827a901a8f9 upstream
Configure powerpc CPU runtime speculation bug mitigations in accordance
with the 'mitigations=' cmdline option. This affects Meltdown, Spectre
v1, Spectre v2, and Speculative Store Bypass.
The default behavior is unchanged.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/245a606e1a42a558a310220312d9b6adb9159df6.1555085500.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
|
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commit d68be4c4d31295ff6ae34a8ddfaa4c1a8ff42812 upstream
Configure x86 runtime CPU speculation bug mitigations in accordance with
the 'mitigations=' cmdline option. This affects Meltdown, Spectre v2,
Speculative Store Bypass, and L1TF.
The default behavior is unchanged.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/6616d0ae169308516cfdf5216bedd169f8a8291b.1555085500.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 98af8452945c55652de68536afdde3b520fec429 upstream
Keeping track of the number of mitigations for all the CPU speculation
bugs has become overwhelming for many users. It's getting more and more
complicated to decide which mitigations are needed for a given
architecture. Complicating matters is the fact that each arch tends to
have its own custom way to mitigate the same vulnerability.
Most users fall into a few basic categories:
a) they want all mitigations off;
b) they want all reasonable mitigations on, with SMT enabled even if
it's vulnerable; or
c) they want all reasonable mitigations on, with SMT disabled if
vulnerable.
Define a set of curated, arch-independent options, each of which is an
aggregation of existing options:
- mitigations=off: Disable all mitigations.
- mitigations=auto: [default] Enable all the default mitigations, but
leave SMT enabled, even if it's vulnerable.
- mitigations=auto,nosmt: Enable all the default mitigations, disabling
SMT if needed by a mitigation.
Currently, these options are placeholders which don't actually do
anything. They will be fleshed out in upcoming patches.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/b07a8ef9b7c5055c3a4637c87d07c296d5016fe0.1555085500.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit d71eb0ce109a124b0fa714832823b9452f2762cf upstream
Add the mds=full,nosmt cmdline option. This is like mds=full, but with
SMT disabled if the CPU is vulnerable.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 5999bbe7a6ea3c62029532ec84dc06003a1fa258 upstream
Add the initial MDS vulnerability documentation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 65fd4cb65b2dad97feb8330b6690445910b56d6a upstream
Move L!TF to a separate directory so the MDS stuff can be added at the
side. Otherwise the all hardware vulnerabilites have their own top level
entry. Should have done that right away.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 22dd8365088b6403630b82423cf906491859b65e upstream
In virtualized environments it can happen that the host has the microcode
update which utilizes the VERW instruction to clear CPU buffers, but the
hypervisor is not yet updated to expose the X86_FEATURE_MD_CLEAR CPUID bit
to guests.
Introduce an internal mitigation mode VMWERV which enables the invocation
of the CPU buffer clearing even if X86_FEATURE_MD_CLEAR is not set. If the
system has no updated microcode this results in a pointless execution of
the VERW instruction wasting a few CPU cycles. If the microcode is updated,
but not exposed to a guest then the CPU buffers will be cleared.
That said: Virtual Machines Will Eventually Receive Vaccine
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 8a4b06d391b0a42a373808979b5028f5c84d9c6a upstream
Add the sysfs reporting file for MDS. It exposes the vulnerability and
mitigation state similar to the existing files for the other speculative
hardware vulnerabilities.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit bc1241700acd82ec69fde98c5763ce51086269f8 upstream
Now that the mitigations are in place, add a command line parameter to
control the mitigation, a mitigation selector function and a SMT update
mechanism.
This is the minimal straight forward initial implementation which just
provides an always on/off mode. The command line parameter is:
mds=[full|off]
This is consistent with the existing mitigations for other speculative
hardware vulnerabilities.
The idle invocation is dynamically updated according to the SMT state of
the system similar to the dynamic update of the STIBP mitigation. The idle
mitigation is limited to CPUs which are only affected by MSBDS and not any
other variant, because the other variants cannot be mitigated on SMT
enabled systems.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 07f07f55a29cb705e221eda7894dd67ab81ef343 upstream
Add a static key which controls the invocation of the CPU buffer clear
mechanism on idle entry. This is independent of other MDS mitigations
because the idle entry invocation to mitigate the potential leakage due to
store buffer repartitioning is only necessary on SMT systems.
Add the actual invocations to the different halt/mwait variants which
covers all usage sites. mwaitx is not patched as it's not available on
Intel CPUs.
The buffer clear is only invoked before entering the C-State to prevent
that stale data from the idling CPU is spilled to the Hyper-Thread sibling
after the Store buffer got repartitioned and all entries are available to
the non idle sibling.
When coming out of idle the store buffer is partitioned again so each
sibling has half of it available. Now CPU which returned from idle could be
speculatively exposed to contents of the sibling, but the buffers are
flushed either on exit to user space or on VMENTER.
When later on conditional buffer clearing is implemented on top of this,
then there is no action required either because before returning to user
space the context switch will set the condition flag which causes a flush
on the return to user path.
Note, that the buffer clearing on idle is only sensible on CPUs which are
solely affected by MSBDS and not any other variant of MDS because the other
MDS variants cannot be mitigated when SMT is enabled, so the buffer
clearing on idle would be a window dressing exercise.
This intentionally does not handle the case in the acpi/processor_idle
driver which uses the legacy IO port interface for C-State transitions for
two reasons:
- The acpi/processor_idle driver was replaced by the intel_idle driver
almost a decade ago. Anything Nehalem upwards supports it and defaults
to that new driver.
- The legacy IO port interface is likely to be used on older and therefore
unaffected CPUs or on systems which do not receive microcode updates
anymore, so there is no point in adding that.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 04dcbdb8057827b043b3c71aa397c4c63e67d086 upstream
Add a static key which controls the invocation of the CPU buffer clear
mechanism on exit to user space and add the call into
prepare_exit_to_usermode() and do_nmi() right before actually returning.
Add documentation which kernel to user space transition this covers and
explain why some corner cases are not mitigated.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 6a9e529272517755904b7afa639f6db59ddb793e upstream
The Microarchitectural Data Sampling (MDS) vulernabilities are mitigated by
clearing the affected CPU buffers. The mechanism for clearing the buffers
uses the unused and obsolete VERW instruction in combination with a
microcode update which triggers a CPU buffer clear when VERW is executed.
Provide a inline function with the assembly magic. The argument of the VERW
instruction must be a memory operand as documented:
"MD_CLEAR enumerates that the memory-operand variant of VERW (for
example, VERW m16) has been extended to also overwrite buffers affected
by MDS. This buffer overwriting functionality is not guaranteed for the
register operand variant of VERW."
Documentation also recommends to use a writable data segment selector:
"The buffer overwriting occurs regardless of the result of the VERW
permission check, as well as when the selector is null or causes a
descriptor load segment violation. However, for lowest latency we
recommend using a selector that indicates a valid writable data
segment."
Add x86 specific documentation about MDS and the internal workings of the
mitigation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Jon Masters <jcm@redhat.com>
Tested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 60ca05c3b44566b70d64fbb8e87a6e0c67725468 upstream
Fix small typo (wiil -> will) in the "3.4. Nested virtual machines"
section.
Fixes: 5b76a3cff011 ("KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry")
Cc: linux-kernel@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-doc@vger.kernel.org
Cc: trivial@kernel.org
Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.35 stable release
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commit de9c0d49d85dc563549972edc5589d195cd5e859 upstream.
While building arm32 allyesconfig, I ran into the following errors:
arch/arm/lib/xor-neon.c:17:2: error: You should compile this file with
'-mfloat-abi=softfp -mfpu=neon'
In file included from lib/raid6/neon1.c:27:
/home/nathan/cbl/prebuilt/lib/clang/8.0.0/include/arm_neon.h:28:2:
error: "NEON support not enabled"
Building V=1 showed NEON_FLAGS getting passed along to Clang but
__ARM_NEON__ was not getting defined. Ultimately, it boils down to Clang
only defining __ARM_NEON__ when targeting armv7, rather than armv6k,
which is the '-march' value for allyesconfig.
>From lib/Basic/Targets/ARM.cpp in the Clang source:
// This only gets set when Neon instructions are actually available, unlike
// the VFP define, hence the soft float and arch check. This is subtly
// different from gcc, we follow the intent which was that it should be set
// when Neon instructions are actually available.
if ((FPU & NeonFPU) && !SoftFloat && ArchVersion >= 7) {
Builder.defineMacro("__ARM_NEON", "1");
Builder.defineMacro("__ARM_NEON__");
// current AArch32 NEON implementations do not support double-precision
// floating-point even when it is present in VFP.
Builder.defineMacro("__ARM_NEON_FP",
"0x" + Twine::utohexstr(HW_FP & ~HW_FP_DP));
}
Ard Biesheuvel recommended explicitly adding '-march=armv7-a' at the
beginning of the NEON_FLAGS definitions so that __ARM_NEON__ always gets
definined by Clang. This doesn't functionally change anything because
that code will only run where NEON is supported, which is implicitly
armv7.
Link: https://github.com/ClangBuiltLinux/linux/issues/287
Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit ad8c0eaa0a418ae8ef3f9217638bb86439399eac upstream.
Add the ISO7816 ioctl and associated accessors and data structure.
Drivers can then use this common implementation to handle ISO7816
(smart cards).
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
[ludovic.desroches@microchip.com: squash and rebase, removal of gpios, checkpatch fixes]
Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.34 stable release
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commit ddba91801aeb5c160b660caed1800eb3aef403f8 upstream.
KVM's API requires thats ioctls must be issued from the same process
that created the VM. In other words, userspace can play games with a
VM's file descriptors, e.g. fork(), SCM_RIGHTS, etc..., but only the
creator can do anything useful. Explicitly reject device ioctls that
are issued by a process other than the VM's creator, and update KVM's
API documentation to extend its requirements to device ioctls.
Fixes: 852b6d57dc7f ("kvm: add device control API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.33 stable release
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commit a41e8f25fa8f8f67360d88eb0eebbabe95a64bdf upstream.
The networking maintainer keeps a public list of the patches being
queued up for the next round of stable releases. Be sure to check there
before asking for a patch to be applied so that you do not waste
people's time.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit c950ca8c35eeb32224a63adc47e12f9e226da241 upstream.
The Allwinner A64 SoC is known[1] to have an unstable architectural
timer, which manifests itself most obviously in the time jumping forward
a multiple of 95 years[2][3]. This coincides with 2^56 cycles at a
timer frequency of 24 MHz, implying that the time went slightly backward
(and this was interpreted by the kernel as it jumping forward and
wrapping around past the epoch).
Investigation revealed instability in the low bits of CNTVCT at the
point a high bit rolls over. This leads to power-of-two cycle forward
and backward jumps. (Testing shows that forward jumps are about twice as
likely as backward jumps.) Since the counter value returns to normal
after an indeterminate read, each "jump" really consists of both a
forward and backward jump from the software perspective.
Unless the kernel is trapping CNTVCT reads, a userspace program is able
to read the register in a loop faster than it changes. A test program
running on all 4 CPU cores that reported jumps larger than 100 ms was
run for 13.6 hours and reported the following:
Count | Event
-------+---------------------------
9940 | jumped backward 699ms
268 | jumped backward 1398ms
1 | jumped backward 2097ms
16020 | jumped forward 175ms
6443 | jumped forward 699ms
2976 | jumped forward 1398ms
9 | jumped forward 356516ms
9 | jumped forward 357215ms
4 | jumped forward 714430ms
1 | jumped forward 3578440ms
This works out to a jump larger than 100 ms about every 5.5 seconds on
each CPU core.
The largest jump (almost an hour!) was the following sequence of reads:
0x0000007fffffffff → 0x00000093feffffff → 0x0000008000000000
Note that the middle bits don't necessarily all read as all zeroes or
all ones during the anomalous behavior; however the low 10 bits checked
by the function in this patch have never been observed with any other
value.
Also note that smaller jumps are much more common, with backward jumps
of 2048 (2^11) cycles observed over 400 times per second on each core.
(Of course, this is partially explained by lower bits rolling over more
frequently.) Any one of these could have caused the 95 year time skip.
Similar anomalies were observed while reading CNTPCT (after patching the
kernel to allow reads from userspace). However, the CNTPCT jumps are
much less frequent, and only small jumps were observed. The same program
as before (except now reading CNTPCT) observed after 72 hours:
Count | Event
-------+---------------------------
17 | jumped backward 699ms
52 | jumped forward 175ms
2831 | jumped forward 699ms
5 | jumped forward 1398ms
Further investigation showed that the instability in CNTPCT/CNTVCT also
affected the respective timer's TVAL register. The following values were
observed immediately after writing CNVT_TVAL to 0x10000000:
CNTVCT | CNTV_TVAL | CNTV_CVAL | CNTV_TVAL Error
--------------------+------------+--------------------+-----------------
0x000000d4a2d8bfff | 0x10003fff | 0x000000d4b2d8bfff | +0x00004000
0x000000d4a2d94000 | 0x0fffffff | 0x000000d4b2d97fff | -0x00004000
0x000000d4a2d97fff | 0x10003fff | 0x000000d4b2d97fff | +0x00004000
0x000000d4a2d9c000 | 0x0fffffff | 0x000000d4b2d9ffff | -0x00004000
The pattern of errors in CNTV_TVAL seemed to depend on exactly which
value was written to it. For example, after writing 0x10101010:
CNTVCT | CNTV_TVAL | CNTV_CVAL | CNTV_TVAL Error
--------------------+------------+--------------------+-----------------
0x000001ac3effffff | 0x1110100f | 0x000001ac4f10100f | +0x1000000
0x000001ac40000000 | 0x1010100f | 0x000001ac5110100f | -0x1000000
0x000001ac58ffffff | 0x1110100f | 0x000001ac6910100f | +0x1000000
0x000001ac66000000 | 0x1010100f | 0x000001ac7710100f | -0x1000000
0x000001ac6affffff | 0x1110100f | 0x000001ac7b10100f | +0x1000000
0x000001ac6e000000 | 0x1010100f | 0x000001ac7f10100f | -0x1000000
I was also twice able to reproduce the issue covered by Allwinner's
workaround[4], that writing to TVAL sometimes fails, and both CVAL and
TVAL are left with entirely bogus values. One was the following values:
CNTVCT | CNTV_TVAL | CNTV_CVAL
--------------------+------------+--------------------------------------
0x000000d4a2d6014c | 0x8fbd5721 | 0x000000d132935fff (615s in the past)
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
========================================================================
Because the CPU can read the CNTPCT/CNTVCT registers faster than they
change, performing two reads of the register and comparing the high bits
(like other workarounds) is not a workable solution. And because the
timer can jump both forward and backward, no pair of reads can
distinguish a good value from a bad one. The only way to guarantee a
good value from consecutive reads would be to read _three_ times, and
take the middle value only if the three values are 1) each unique and
2) increasing. This takes at minimum 3 counter cycles (125 ns), or more
if an anomaly is detected.
However, since there is a distinct pattern to the bad values, we can
optimize the common case (1022/1024 of the time) to a single read by
simply ignoring values that match the error pattern. This still takes no
more than 3 cycles in the worst case, and requires much less code. As an
additional safety check, we still limit the loop iteration to the number
of max-frequency (1.2 GHz) CPU cycles in three 24 MHz counter periods.
For the TVAL registers, the simple solution is to not use them. Instead,
read or write the CVAL and calculate the TVAL value in software.
Although the manufacturer is aware of at least part of the erratum[4],
there is no official name for it. For now, use the kernel-internal name
"UNKNOWN1".
[1]: https://github.com/armbian/build/commit/a08cd6fe7ae9
[2]: https://forum.armbian.com/topic/3458-a64-datetime-clock-issue/
[3]: https://irclog.whitequark.org/linux-sunxi/2018-01-26
[4]: https://github.com/Allwinner-Homlet/H6-BSP4.9-linux/blob/master/drivers/clocksource/arm_arch_timer.c#L272
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.30 stable release
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commit 6c0c5dc33ff42af49243e94842d0ebdb153189ea upstream.
Add new compatible to the device tree bindings.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.27 stable release
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commit 7550c6079846a24f30d15ac75a941c8515dbedfb upstream.
Patch series "THP eligibility reporting via proc".
This series of three patches aims at making THP eligibility reporting much
more robust and long term sustainable. The trigger for the change is a
regression report [2] and the long follow up discussion. In short the
specific application didn't have good API to query whether a particular
mapping can be backed by THP so it has used VMA flags to workaround that.
These flags represent a deep internal state of VMAs and as such they
should be used by userspace with a great deal of caution.
A similar has happened for [3] when users complained that VM_MIXEDMAP is
no longer set on DAX mappings. Again a lack of a proper API led to an
abuse.
The first patch in the series tries to emphasise that that the semantic of
flags might change and any application consuming those should be really
careful.
The remaining two patches provide a more suitable interface to address [2]
and provide a consistent API to query the THP status both for each VMA and
process wide as well. [1]
http://lkml.kernel.org/r/20181120103515.25280-1-mhocko@kernel.org [2]
http://lkml.kernel.org/r/http://lkml.kernel.org/r/alpine.DEB.2.21.1809241054050.224429@chino.kir.corp.google.com
[3] http://lkml.kernel.org/r/20181002100531.GC4135@quack2.suse.cz
This patch (of 3):
Even though vma flags exported via /proc/<pid>/smaps are explicitly
documented to be not guaranteed for future compatibility the warning
doesn't go far enough because it doesn't mention semantic changes to those
flags. And they are important as well because these flags are a deep
implementation internal to the MM code and the semantic might change at
any time.
Let's consider two recent examples:
http://lkml.kernel.org/r/20181002100531.GC4135@quack2.suse.cz
: commit e1fb4a086495 "dax: remove VM_MIXEDMAP for fsdax and device dax" has
: removed VM_MIXEDMAP flag from DAX VMAs. Now our testing shows that in the
: mean time certain customer of ours started poking into /proc/<pid>/smaps
: and looks at VMA flags there and if VM_MIXEDMAP is missing among the VMA
: flags, the application just fails to start complaining that DAX support is
: missing in the kernel.
http://lkml.kernel.org/r/alpine.DEB.2.21.1809241054050.224429@chino.kir.corp.google.com
: Commit 1860033237d4 ("mm: make PR_SET_THP_DISABLE immediately active")
: introduced a regression in that userspace cannot always determine the set
: of vmas where thp is ineligible.
: Userspace relies on the "nh" flag being emitted as part of /proc/pid/smaps
: to determine if a vma is eligible to be backed by hugepages.
: Previous to this commit, prctl(PR_SET_THP_DISABLE, 1) would cause thp to
: be disabled and emit "nh" as a flag for the corresponding vmas as part of
: /proc/pid/smaps. After the commit, thp is disabled by means of an mm
: flag and "nh" is not emitted.
: This causes smaps parsing libraries to assume a vma is eligible for thp
: and ends up puzzling the user on why its memory is not backed by thp.
In both cases userspace was relying on a semantic of a specific VMA flag.
The primary reason why that happened is a lack of a proper interface.
While this has been worked on and it will be fixed properly, it seems that
our wording could see some refinement and be more vocal about semantic
aspect of these flags as well.
Link: http://lkml.kernel.org/r/20181211143641.3503-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Paul Oppenheimer <bepvte@gmail.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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This is the 4.18.22 stable release
# gpg: Signature made Sun 16 Dec 2018 09:34:14 PM EST using RSA key ID 2C07D1D6
# gpg: Can't check signature: public key not found
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Bruce Ashfield
Josh Poimboeuf
Tim Chen
Diana Craciun
Eric Dumazet
Daniel Borkmann
Al Viro
Andy Lutomirski
Alan Stern
Paul Gortmaker
ZhangXiaoxu
Tyler Hicks
speck for Pawan Gupta
Thomas Gleixner
Salvatore Bonaccorso
Nathan Chancellor
Nicolas Ferre
Sean Christopherson
Greg Kroah-Hartman
Samuel Holland
Adrian Bunk
Michal Hocko
Bruce Ashfield