Fix the following sparse warning:
drivers/hwtracing/coresight/coresight-etb10.c:720:30: warning: symbol
'coresight_etb_groups' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-12-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix the following sparse warning:
drivers/hwtracing/coresight/coresight-cti.c:22:1: warning: symbol
'ect_net' was not declared. Should it be static?
drivers/hwtracing/coresight/coresight-cti.c:625:32: warning: symbol
'cti_ops_ect' was not declared. Should it be static?
drivers/hwtracing/coresight/coresight-cti.c:630:28: warning: symbol
'cti_ops' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-11-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Replace the AMBA ETM PIDs with UCI IDs to avoid future
conflicts when adding the CTI support for QCOM Kryo385
CPU cores.
Fixes: 17b4add0d4 ("coresight: etm4x: Add ETM PIDs for SDM845 and MSM8996")
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-10-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add ETM UCI IDs for Qualcomm SC7180 SoC. It has 2
big CPU cores based on Cortex-A76 and 6 LITTLE CPU
cores based on Cortex-A55.
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Tested-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-9-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Update the CoreSight documents to describe the new connections directory
and the links between CoreSight devices in this directory.
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-7-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adds in sysfs links for connections where the connected device is another
coresight device. This allows examination of the coresight topology.
Non-coresight connections remain just as a reference name.
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-6-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Coresight device connections are a bit complicated and is not
exposed currently to the user. One has to look at the platform
descriptions (DT bindings or ACPI bindings) to make an understanding.
Given the new naming scheme, it will be helpful to have this information
to choose the appropriate devices for tracing. This patch exposes
the device connections via links in the sysfs directories.
e.g, for a connection devA[OutputPort_X] -> devB[InputPort_Y]
is represented as two symlinks:
/sys/bus/coresight/.../devA/out:X -> /sys/bus/coresight/.../devB
/sys/bus/coresight/.../devB/in:Y -> /sys/bus/coresight/.../devA
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
[Revised to use the generic sysfs links functions & link structures.
Provides a connections sysfs group in each device to hold the links.]
Co-developed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-5-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To allow the connections between coresight components to be represented
in sysfs, generic methods for creating sysfs links between two coresight
devices are added.
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-4-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Handle failures in fixing up connections for a newly registered
device. This will be useful to handle cases where we fail to expose
the links via sysfs for the connections.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-3-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As we prepare to expose the links between the devices in
sysfs, pass the coresight_device instance to the
coresight_release_platform_data in order to free up the connections
when the device is removed.
No functional changes as such in this patch.
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-2-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When we look at i915_request_is_started() we must be careful in case we
are using a request that does not have the initial-breadcrumb and
instead the is-started is being compared against the end of the previous
request. This will make wait_for_submit() declare that a request has
been already submitted too early.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200519063123.20673-4-chris@chris-wilson.co.uk
We recorded the execlists->queue_priority_hint update for the inflight
request without kicking the tasklet. The next submitted request then
failed to be scheduled as it had a lower priority than the hint, leaving
the HW running with only the inflight request.
Fixes: 6cebcf746f ("drm/i915: Tweak scheduler's kick_submission()")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200519063123.20673-1-chris@chris-wilson.co.uk
A useful metric of the system's health is how fast we can tell the GPU
to do various actions, so measure our latency.
v2: Refactor all the instruction building into emitters.
v3: Mark the error handling if not perfect, at least consistent.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200519130802.4067-1-chris@chris-wilson.co.uk
- GAUDI ASIC support. The tag contains code and header files needed to
initialize the GAUDI ASIC and run workloads on it. There are changes to
the common code that are needed for GAUDI and there is the addition of
new ASIC-dependent code of GAUDI.
- Add new feature of signal/wait command submissions. This is relevant to
GAUDI only and allows the user to sync between streams (queues) inside
the device.
- Allow user to retrieve the device time alongside the host time, to allow
a user application to synchronize device time together with host
time during profiling.
- Change ASIC's CPU initialization by loading its boot loader code from the
Host memory (instead of it being programmed on the on-board FLASH).
- Expose more attributes through HWMON.
- Move the ASIC event handling code to be "common code". This will be
shared between GAUDI and future ASICs. Goya will still use its own code.
- Fix bug in command submission parsing in Goya.
- Small fixes to security configuration (open up some registers for user
access).
- Improvements to ASIC reset code.
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Merge tag 'misc-habanalabs-next-2020-05-19' of git://people.freedesktop.org/~gabbayo/linux into char-misc-next
Oded writes:
This tag contains the following changes for kernel 5.8:
- GAUDI ASIC support. The tag contains code and header files needed to
initialize the GAUDI ASIC and run workloads on it. There are changes to
the common code that are needed for GAUDI and there is the addition of
new ASIC-dependent code of GAUDI.
- Add new feature of signal/wait command submissions. This is relevant to
GAUDI only and allows the user to sync between streams (queues) inside
the device.
- Allow user to retrieve the device time alongside the host time, to allow
a user application to synchronize device time together with host
time during profiling.
- Change ASIC's CPU initialization by loading its boot loader code from the
Host memory (instead of it being programmed on the on-board FLASH).
- Expose more attributes through HWMON.
- Move the ASIC event handling code to be "common code". This will be
shared between GAUDI and future ASICs. Goya will still use its own code.
- Fix bug in command submission parsing in Goya.
- Small fixes to security configuration (open up some registers for user
access).
- Improvements to ASIC reset code.
* tag 'misc-habanalabs-next-2020-05-19' of git://people.freedesktop.org/~gabbayo/linux: (38 commits)
habanalabs: update patched_cb_size for Wreg32
habanalabs: move event handling to common firmware file
habanalabs: enable gaudi code in driver
habanalabs: add gaudi profiler module
habanalabs: add gaudi security module
habanalabs: add hwmgr module for gaudi
habanalabs: add gaudi asic-dependent code
uapi: habanalabs: add gaudi defines
habanalabs: add gaudi asic registers header files
habanalabs: get card type, location from F/W
habanalabs: support clock gating enable/disable
habanalabs: set PM profile to auto only for goya
habanalabs: add dedicated define for hard reset
habanalabs: check if CoreSight is supported
habanalabs: add signal/wait to CS IOCTL operations
habanalabs: handle the h/w sync object
habanalabs: define ASIC-dependent interface for signal/wait
uapi: habanalabs: add signal/wait operations
habanalabs: add missing MODULE_DEVICE_TABLE
habanalabs: print all CB handles as hex numbers
...
When submitting the previous fix "tty: n_gsm: Fix waking up upper tty
layer when room available". It was suggested to switch from a while to
a for loop, but when doing it, there was a remaining bogus i++.
This patch removes this i++ and also reorganizes the code making it more
compact.
Fixes: e1eaea46bb ("tty: n_gsm line discipline")
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20200518084517.2173242-3-gregory.clement@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the length is zero then the print_hex_dump_bytes won't output
anything, so testing the length before the call is unnecessary.
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20200518084517.2173242-2-gregory.clement@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a key/keyring change notification facility whereby notifications about
changes in key and keyring content and attributes can be received.
Firstly, an event queue needs to be created:
pipe2(fds, O_NOTIFICATION_PIPE);
ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, 256);
then a notification can be set up to report notifications via that queue:
struct watch_notification_filter filter = {
.nr_filters = 1,
.filters = {
[0] = {
.type = WATCH_TYPE_KEY_NOTIFY,
.subtype_filter[0] = UINT_MAX,
},
},
};
ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter);
keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01);
After that, records will be placed into the queue when events occur in
which keys are changed in some way. Records are of the following format:
struct key_notification {
struct watch_notification watch;
__u32 key_id;
__u32 aux;
} *n;
Where:
n->watch.type will be WATCH_TYPE_KEY_NOTIFY.
n->watch.subtype will indicate the type of event, such as
NOTIFY_KEY_REVOKED.
n->watch.info & WATCH_INFO_LENGTH will indicate the length of the
record.
n->watch.info & WATCH_INFO_ID will be the second argument to
keyctl_watch_key(), shifted.
n->key will be the ID of the affected key.
n->aux will hold subtype-dependent information, such as the key
being linked into the keyring specified by n->key in the case of
NOTIFY_KEY_LINKED.
Note that it is permissible for event records to be of variable length -
or, at least, the length may be dependent on the subtype. Note also that
the queue can be shared between multiple notifications of various types.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Use usb_anchor to track tx submitted urbs and initialize the
urb as needed in vnt_tx_context.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/077f42f8-4f7f-adc4-5a14-955165cef9f1@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Create room for vnt_tx_short_buf_head in sk_buff and vnt_tx_usb_header.
The struct ieee80211_mgmt is not longer in the header and is at
the initial skb->data point.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/5f00d319-9242-65b2-d100-dcfe9b0e32be@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mac80211 can provide space for the driver to put a tx header on
the skb buffer instead coping the entire frame on to a local
buffer with the header.
To use this extra_tx_headroom must be set in mac80211 with the largest
possible header which is struct vnt_tx_buffer.
The driver has 8 possible combinations of tx header size which
are found in vnt_get_hdr_size replacing vnt_mac_hdr_pos.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/7b967bfc-1d4b-4b45-efab-d54f16cca226@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add security hooks that will allow an LSM to rule on whether or not a watch
may be set. More than one hook is required as the watches watch different
types of object.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jamorris@linux.microsoft.com>
cc: Casey Schaufler <casey@schaufler-ca.com>
cc: Stephen Smalley <sds@tycho.nsa.gov>
cc: linux-security-module@vger.kernel.org
fix below issue reported by checkpatch:
CHECK: Using comparison to true is error prone
CHECK: Using comparison to false is error prone
Signed-off-by: John Oldman <john.oldman@polehill.co.uk>
Link: https://lore.kernel.org/r/20200516163327.9197-1-john.oldman@polehill.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fix below issue reported by checkpatch
CHECK: Using comparison to true is error prone
CHECK: Using comparison to false is error prone
Signed-off-by: John Oldman <john.oldman@polehill.co.uk>
Link: https://lore.kernel.org/r/20200515173108.14739-1-john.oldman@polehill.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Coding style issues:
This patch clears the checkpatch.pl "braces {} are not necessary for
single statement blocks" and "else_should_follow_close_brace"
warnings.
Signed-off-by: John Oldman <john.oldman@polehill.co.uk>
Link: https://lore.kernel.org/r/20200515165646.12867-1-john.oldman@polehill.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make it possible to have a general notification queue built on top of a
standard pipe. Notifications are 'spliced' into the pipe and then read
out. splice(), vmsplice() and sendfile() are forbidden on pipes used for
notifications as post_one_notification() cannot take pipe->mutex. This
means that notifications could be posted in between individual pipe
buffers, making iov_iter_revert() difficult to effect.
The way the notification queue is used is:
(1) An application opens a pipe with a special flag and indicates the
number of messages it wishes to be able to queue at once (this can
only be set once):
pipe2(fds, O_NOTIFICATION_PIPE);
ioctl(fds[0], IOC_WATCH_QUEUE_SET_SIZE, queue_depth);
(2) The application then uses poll() and read() as normal to extract data
from the pipe. read() will return multiple notifications if the
buffer is big enough, but it will not split a notification across
buffers - rather it will return a short read or EMSGSIZE.
Notification messages include a length in the header so that the
caller can split them up.
Each message has a header that describes it:
struct watch_notification {
__u32 type:24;
__u32 subtype:8;
__u32 info;
};
The type indicates the source (eg. mount tree changes, superblock events,
keyring changes, block layer events) and the subtype indicates the event
type (eg. mount, unmount; EIO, EDQUOT; link, unlink). The info field
indicates a number of things, including the entry length, an ID assigned to
a watchpoint contributing to this buffer and type-specific flags.
Supplementary data, such as the key ID that generated an event, can be
attached in additional slots. The maximum message size is 127 bytes.
Messages may not be padded or aligned, so there is no guarantee, for
example, that the notification type will be on a 4-byte bounary.
Signed-off-by: David Howells <dhowells@redhat.com>
Add an O_NOTIFICATION_PIPE flag that can be passed to pipe2() to indicate
that the pipe being created is going to be used for notifications. This
suppresses the use of splice(), vmsplice(), tee() and sendfile() on the
pipe as calling iov_iter_revert() on a pipe when a kernel notification
message has been inserted into the middle of a multi-buffer splice will be
messy.
The flag is given the same value as O_EXCL as it seems unlikely that
this flag will ever be applicable to pipes and I don't want to use up
another O_* bit unnecessarily. An alternative could be to add a pipe3()
system call.
Signed-off-by: David Howells <dhowells@redhat.com>
Add a security hook that allows an LSM to rule on whether a notification
message is allowed to be inserted into a particular watch queue.
The hook is given the following information:
(1) The credentials of the triggerer (which may be init_cred for a system
notification, eg. a hardware error).
(2) The credentials of the whoever set the watch.
(3) The notification message.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jamorris@linux.microsoft.com>
cc: Casey Schaufler <casey@schaufler-ca.com>
cc: Stephen Smalley <sds@tycho.nsa.gov>
cc: linux-security-module@vger.kernel.org
Add UAPI definitions for the general notification queue, including the
following pieces:
(*) struct watch_notification.
This is the metadata header for notification messages. It includes a
type and subtype that indicate the source of the message
(eg. WATCH_TYPE_MOUNT_NOTIFY) and the kind of the message
(eg. NOTIFY_MOUNT_NEW_MOUNT).
The header also contains an information field that conveys the
following information:
- WATCH_INFO_LENGTH. The size of the entry (entries are variable
length).
- WATCH_INFO_ID. The watch ID specified when the watchpoint was
set.
- WATCH_INFO_TYPE_INFO. (Sub)type-specific information.
- WATCH_INFO_FLAG_*. Flag bits overlain on the type-specific
information. For use by the type.
All the information in the header can be used in filtering messages at
the point of writing into the buffer.
(*) struct watch_notification_removal
This is an extended watch-removal notification record that includes an
'id' field that can indicate the identifier of the object being
removed if available (for instance, a keyring serial number).
Signed-off-by: David Howells <dhowells@redhat.com>
Instrumentation is forbidden in the .noinstr.text section. Make kprobes
respect this.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20200505134100.179862032@linutronix.de
The async page fault injection into kernel space creates more problems than
it solves. The host has absolutely no knowledge about the state of the
guest if the fault happens in CPL0. The only restriction for the host is
interrupt disabled state. If interrupts are enabled in the guest then the
exception can hit arbitrary code. The HALT based wait in non-preemotible
code is a hacky replacement for a proper hypercall.
For the ongoing work to restrict instrumentation and make the RCU idle
interaction well defined the required extra work for supporting async
pagefault in CPL0 is just not justified and creates complexity for a
dubious benefit.
The CPL3 injection is well defined and does not cause any issues as it is
more or less the same as a regular page fault from CPL3.
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.369802541@linutronix.de
While working on the entry consolidation I stumbled over the KVM async page
fault handler and kvm_async_pf_task_wait() in particular. It took me a
while to realize that the randomly sprinkled around rcu_irq_enter()/exit()
invocations are just cargo cult programming. Several patches "fixed" RCU
splats by curing the symptoms without noticing that the code is flawed
from a design perspective.
The main problem is that this async injection is not based on a proper
handshake mechanism and only respects the minimal requirement, i.e. the
guest is not in a state where it has interrupts disabled.
Aside of that the actual code is a convoluted one fits it all swiss army
knife. It is invoked from different places with different RCU constraints:
1) Host side:
vcpu_enter_guest()
kvm_x86_ops->handle_exit()
kvm_handle_page_fault()
kvm_async_pf_task_wait()
The invocation happens from fully preemptible context.
2) Guest side:
The async page fault interrupted:
a) user space
b) preemptible kernel code which is not in a RCU read side
critical section
c) non-preemtible kernel code or a RCU read side critical section
or kernel code with CONFIG_PREEMPTION=n which allows not to
differentiate between #2b and #2c.
RCU is watching for:
#1 The vCPU exited and current is definitely not the idle task
#2a The #PF entry code on the guest went through enter_from_user_mode()
which reactivates RCU
#2b There is no preemptible, interrupts enabled code in the kernel
which can run with RCU looking away. (The idle task is always
non preemptible).
I.e. all schedulable states (#1, #2a, #2b) do not need any of this RCU
voodoo at all.
In #2c RCU is eventually not watching, but as that state cannot schedule
anyway there is no point to worry about it so it has to invoke
rcu_irq_enter() before running that code. This can be optimized, but this
will be done as an extra step in course of the entry code consolidation
work.
So the proper solution for this is to:
- Split kvm_async_pf_task_wait() into schedule and halt based waiting
interfaces which share the enqueueing code.
- Add comments (condensed form of this changelog) to spare others the
time waste and pain of reverse engineering all of this with the help of
uncomprehensible changelogs and code history.
- Invoke kvm_async_pf_task_wait_schedule() from kvm_handle_page_fault(),
user mode and schedulable kernel side async page faults (#1, #2a, #2b)
- Invoke kvm_async_pf_task_wait_halt() for the non schedulable kernel
case (#2c).
For this case also remove the rcu_irq_exit()/enter() pair around the
halt as it is just a pointless exercise:
- vCPUs can VMEXIT at any random point and can be scheduled out for
an arbitrary amount of time by the host and this is not any
different except that it voluntary triggers the exit via halt.
- The interrupted context could have RCU watching already. So the
rcu_irq_exit() before the halt is not gaining anything aside of
confusing the reader. Claiming that this might prevent RCU stalls
is just an illusion.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.262701431@linutronix.de
KVM overloads #PF to indicate two types of not-actually-page-fault
events. Right now, the KVM guest code intercepts them by modifying
the IDT and hooking the #PF vector. This makes the already fragile
fault code even harder to understand, and it also pollutes call
traces with async_page_fault and do_async_page_fault for normal page
faults.
Clean it up by moving the logic into do_page_fault() using a static
branch. This gets rid of the platform trap_init override mechanism
completely.
[ tglx: Fixed up 32bit, removed error code from the async functions and
massaged coding style ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.169270470@linutronix.de
In order to display console messages in low power mode, console pins
must be kept active after suspend call.
Initial patch "serial: stm32: add support for no_console_suspend" was part
of "STM32 usart power improvement" series, but as dependancy to
console_suspend pinctl state has been removed to fit with Rob comment [1],
this patch has no more dependancy with any other patch of this series.
[1] https://lkml.org/lkml/2019/7/9/451
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Link: https://lore.kernel.org/r/20200519094104.27082-1-erwan.leray@st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Same as rcu_is_watching() but without the preempt_disable/enable() pair
inside the function. It is merked noinstr so it ends up in the
non-instrumentable text section.
This is useful for non-preemptible code especially in the low level entry
section. Using rcu_is_watching() there results in a call to the
preempt_schedule_notrace() thunk which triggers noinstr section warnings in
objtool.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200512213810.518709291@linutronix.de
Interrupts and exceptions invoke rcu_irq_enter() on entry and need to
invoke rcu_irq_exit() before they either return to the interrupted code or
invoke the scheduler due to preemption.
The general assumption is that RCU idle code has to have preemption
disabled so that a return from interrupt cannot schedule. So the return
from interrupt code invokes rcu_irq_exit() and preempt_schedule_irq().
If there is any imbalance in the rcu_irq/nmi* invocations or RCU idle code
had preemption enabled then this goes unnoticed until the CPU goes idle or
some other RCU check is executed.
Provide rcu_irq_exit_preempt() which can be invoked from the
interrupt/exception return code in case that preemption is enabled. It
invokes rcu_irq_exit() and contains a few sanity checks in case that
CONFIG_PROVE_RCU is enabled to catch such issues directly.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134904.364456424@linutronix.de
The rcu_nmi_enter_common() and rcu_nmi_exit_common() functions take an
"irq" parameter that indicates whether these functions have been invoked from
an irq handler (irq==true) or an NMI handler (irq==false).
However, recent changes have applied notrace to a few critical functions
such that rcu_nmi_enter_common() and rcu_nmi_exit_common() many now rely on
in_nmi(). Note that in_nmi() works no differently than before, but rather
that tracing is now prohibited in code regions where in_nmi() would
incorrectly report NMI state.
Therefore remove the "irq" parameter and inline rcu_nmi_enter_common() and
rcu_nmi_exit_common() into rcu_nmi_enter() and rcu_nmi_exit(),
respectively.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134101.617130349@linutronix.de
These functions are invoked from context tracking and other places in the
low level entry code. Move them into the .noinstr.text section to exclude
them from instrumentation.
Mark the places which are safe to invoke traceable functions with
instrumentation_begin/end() so objtool won't complain.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/20200505134100.575356107@linutronix.de
A few exceptions (like #DB and #BP) can happen at any location in the code,
this then means that tracers should treat events from these exceptions as
NMI-like. The interrupted context could be holding locks with interrupts
disabled for instance.
Similarly, #MC is an actual NMI-like exception.
All of them use ist_enter() which only concerns itself with RCU, but does
not do any of the other setup that NMIs need. This means things like:
printk()
raw_spin_lock_irq(&logbuf_lock);
<#DB/#BP/#MC>
printk()
raw_spin_lock_irq(&logbuf_lock);
are entirely possible (well, not really since printk tries hard to
play nice, but the concept stands).
So replace ist_enter() with nmi_enter(). Also observe that any nmi_enter()
caller must be both notrace and NOKPROBE, or in the noinstr text section.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134101.525508608@linutronix.de
Convert #MC over to using task_work_add(); it will run the same code
slightly later, on the return to user path of the same exception.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134100.957390899@linutronix.de
This is completely overengineered and definitely not an interface which
should be made available to anything else than this particular MCE case.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.462640294@linutronix.de
If a tracer is invoked before in_nmi() becomes true, the tracer can no
longer detect it is called from NMI context and behave correctly.
Therefore change nmi_{enter,exit}() to use __preempt_count_{add,sub}()
as the normal preempt_count_{add,sub}() have a (desired) function
trace entry.
This fixes a potential issue with the current code; when the function-tracer
has stack-tracing enabled __trace_stack() will malfunction when it hits the
preempt_count_add() function entry from NMI context.
Suggested-by: Steven Rostedt (VMware) <rosted@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134101.434193525@linutronix.de
SuperH is the last remaining user of arch_ftrace_nmi_{enter,exit}(),
remove it from the generic code and into the SuperH code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200505134101.248881738@linutronix.de
These functions are called {early,late} in nmi_{enter,exit} and should
not be traced or probed. They are also puny, so 'inline' them.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134101.048523500@linutronix.de
