Merge tag 'char-misc-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc driver updates from Greg KH:
 "Here is the large set of char/misc/whatever driver subsystem updates
  for 5.12-rc1. Over time it seems like this tree is collecting more and
  more tiny driver subsystems in one place, making it easier for those
  maintainers, which is why this is getting larger.

  Included in here are:

   - coresight driver updates

   - habannalabs driver updates

   - virtual acrn driver addition (proper acks from the x86 maintainers)

   - broadcom misc driver addition

   - speakup driver updates

   - soundwire driver updates

   - fpga driver updates

   - amba driver updates

   - mei driver updates

   - vfio driver updates

   - greybus driver updates

   - nvmeem driver updates

   - phy driver updates

   - mhi driver updates

   - interconnect driver udpates

   - fsl-mc bus driver updates

   - random driver fix

   - some small misc driver updates (rtsx, pvpanic, etc.)

  All of these have been in linux-next for a while, with the only
  reported issue being a merge conflict due to the dfl_device_id
  addition from the fpga subsystem in here"

* tag 'char-misc-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (311 commits)
  spmi: spmi-pmic-arb: Fix hw_irq overflow
  Documentation: coresight: Add PID tracing description
  coresight: etm-perf: Support PID tracing for kernel at EL2
  coresight: etm-perf: Clarify comment on perf options
  ACRN: update MAINTAINERS: mailing list is subscribers-only
  regmap: sdw-mbq: use MODULE_LICENSE("GPL")
  regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ
  regmap: sdw: use _no_pm functions in regmap_read/write
  soundwire: intel: fix possible crash when no device is detected
  MAINTAINERS: replace my with email with replacements
  mhi: Fix double dma free
  uapi: map_to_7segment: Update example in documentation
  uio: uio_pci_generic: don't fail probe if pdev->irq equals to IRQ_NOTCONNECTED
  drivers/misc/vmw_vmci: restrict too big queue size in qp_host_alloc_queue
  firewire: replace tricky statement by two simple ones
  vme: make remove callback return void
  firmware: google: make coreboot driver's remove callback return void
  firmware: xilinx: Use explicit values for all enum values
  sample/acrn: Introduce a sample of HSM ioctl interface usage
  virt: acrn: Introduce an interface for Service VM to control vCPU
  ...

1 files changed, 32 insertions, 0 deletions

diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst
index 0b73acb44efa..169749efd8d1 100644
--- a/Documentation/trace/coresight/coresight.rst
+++ b/Documentation/trace/coresight/coresight.rst
@@ -512,6 +512,38 @@ The --itrace option controls the type and frequency of synthesized events
 Note that only 64-bit programs are currently supported - further work is
 required to support instruction decode of 32-bit Arm programs.
 
+2.2) Tracing PID
+
+The kernel can be built to write the PID value into the PE ContextID registers.
+For a kernel running at EL1, the PID is stored in CONTEXTIDR_EL1.  A PE may
+implement Arm Virtualization Host Extensions (VHE), which the kernel can
+run at EL2 as a virtualisation host; in this case, the PID value is stored in
+CONTEXTIDR_EL2.
+
+perf provides PMU formats that program the ETM to insert these values into the
+trace data; the PMU formats are defined as below:
+
+  "contextid1": Available on both EL1 kernel and EL2 kernel.  When the
+                kernel is running at EL1, "contextid1" enables the PID
+                tracing; when the kernel is running at EL2, this enables
+                tracing the PID of guest applications.
+
+  "contextid2": Only usable when the kernel is running at EL2.  When
+                selected, enables PID tracing on EL2 kernel.
+
+  "contextid":  Will be an alias for the option that enables PID
+                tracing.  I.e,
+                contextid == contextid1, on EL1 kernel.
+                contextid == contextid2, on EL2 kernel.
+
+perf will always enable PID tracing at the relevant EL, this is accomplished by
+automatically enable the "contextid" config - but for EL2 it is possible to make
+specific adjustments using configs "contextid1" and "contextid2", E.g. if a user
+wants to trace PIDs for both host and guest, the two configs "contextid1" and
+"contextid2" can be set at the same time:
+
+  perf record -e cs_etm/contextid1,contextid2/u -- vm
+
 
 Generating coverage files for Feedback Directed Optimization: AutoFDO
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