The recent patch ("kgdboc: Add kgdboc_earlycon to support early kgdb
using boot consoles") adds a new kernel command line parameter.
Document it.

Note that the patch adding the feature does some comparing/contrasting
of "kgdboc_earlycon" vs. the existing "ekgdboc".  See that patch for
more details, but briefly "ekgdboc" can be used _instead_ of "kgdboc"
and just makes "kgdboc" do its normal initialization early (only works
if your tty driver is already ready).  The new "kgdboc_earlycon" works
in combination with "kgdboc" and is backed by boot consoles.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.9.I7d5eb42c6180c831d47aef1af44d0b8be3fac559@changeidSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

When I combined kgdboc_earlycon with an inflight patch titled ("soc:
qcom-geni-se: Add interconnect support to fix earlycon crash") [1]
things went boom.  Specifically I got a crash during the transition
between kgdboc_earlycon and the main kgdboc that looked like this:

Call trace:
 __schedule_bug+0x68/0x6c
 __schedule+0x75c/0x924
 schedule+0x8c/0xbc
 schedule_timeout+0x9c/0xfc
 do_wait_for_common+0xd0/0x160
 wait_for_completion_timeout+0x54/0x74
 rpmh_write_batch+0x1fc/0x23c
 qcom_icc_bcm_voter_commit+0x1b4/0x388
 qcom_icc_set+0x2c/0x3c
 apply_constraints+0x5c/0x98
 icc_set_bw+0x204/0x3bc
 icc_put+0x30/0xf8
 geni_remove_earlycon_icc_vote+0x6c/0x9c
 qcom_geni_serial_earlycon_exit+0x10/0x1c
 kgdboc_earlycon_deinit+0x38/0x58
 kgdb_register_io_module+0x11c/0x194
 configure_kgdboc+0x108/0x174
 kgdboc_probe+0x38/0x60
 platform_drv_probe+0x90/0xb0
 really_probe+0x130/0x2fc
 ...

The problem was that we were holding the "kgdb_registration_lock"
while calling into code that didn't expect to be called in spinlock
context.

Let's slightly defer when we call the deinit code so that it's not
done under spinlock.

NOTE: this does mean that the "deinit" call of the old kgdb IO module
is now made _after_ the init of the new IO module, but presumably
that's OK.

[1] https://lkml.kernel.org/r/1588919619-21355-3-git-send-email-akashast@codeaurora.org

Fixes: 22099562 ("kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200526142001.1.I523dc33f96589cb9956f5679976d402c8cda36fa@changeid
[daniel.thompson@linaro.org: Resolved merge issues by hand]
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>

When kgdboc is compiled as a module all of the "ekgdboc" and
"kgdb_earlycon" code isn't useful and, in fact, breaks compilation.
This is because early_param() isn't defined for modules and that's how
this code gets configured.

It turns out that this was broken by commit eae3e19c ("kgdboc:
Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc") and then
made worse by commit 22099562 ("kgdboc: Add kgdboc_earlycon to
support early kgdb using boot consoles").  I guess the #ifdef wasn't
so useless, even if it wasn't obvious why it was useful.  When kgdboc
was compiled as a module only "CONFIG_KGDB_SERIAL_CONSOLE_MODULE" was
defined, not "CONFIG_KGDB_SERIAL_CONSOLE".  That meant that the old
module.

Let's basically do the same thing that the old code (pre-removal of
the #ifdef) did but use "IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE)" to
make it more obvious what the point of the check is.  We'll fix
kgdboc_earlycon in a similar way.

Fixes: 22099562 ("kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles")
Fixes: eae3e19c ("kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200519084345.1.I91670accc8a5ddabab227eb63bb4ad3e2e9d2b58@changeidSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

We want to enable kgdb to debug the early parts of the kernel.
Unfortunately kgdb normally is a client of the tty API in the kernel
and serial drivers don't register to the tty layer until fairly late
in the boot process.

Serial drivers do, however, commonly register a boot console.  Let's
enable the kgdboc driver to work with boot consoles to provide early
debugging.

This change co-opts the existing read() function pointer that's part
of "struct console".  It's assumed that if a boot console (with the
flag CON_BOOT) has implemented read() that both the read() and write()
function are polling functions.  That means they work without
interrupts and read() will return immediately (with 0 bytes read) if
there's nothing to read.  This should be a safe assumption since it
appears that no current boot consoles implement read() right now and
there seems no reason to do so unless they wanted to support
"kgdboc_earlycon".

The normal/expected way to make all this work is to use
"kgdboc_earlycon" and "kgdboc" together.  You should point them both
to the same physical serial connection.  At boot time, as the system
transitions from the boot console to the normal console (and registers
a tty), kgdb will switch over.

One awkward part of all this, though, is that there can be a window
where the boot console goes away and we can't quite transtion over to
the main kgdboc that uses the tty layer.  There are two main problems:

1. The act of registering the tty doesn't cause any call into kgdboc
   so there is a window of time when the tty is there but kgdboc's
   init code hasn't been called so we can't transition to it.

2. On some serial drivers the normal console inits (and replaces the
   boot console) quite early in the system.  Presumably these drivers
   were coded up before earlycon worked as well as it does today and
   probably they don't need to do this anymore, but it causes us
   problems nontheless.

Problem #1 is not too big of a deal somewhat due to the luck of probe
ordering.  kgdboc is last in the tty/serial/Makefile so its probe gets
right after all other tty devices.  It's not fun to rely on this, but
it does work for the most part.

Problem #2 is a big deal, but only for some serial drivers.  Other
serial drivers end up registering the console (which gets rid of the
boot console) and tty at nearly the same time.

The way we'll deal with the window when the system has stopped using
the boot console and the time when we're setup using the tty is to
keep using the boot console.  This may sound surprising, but it has
been found to work well in practice.  If it doesn't work, it shouldn't
be too hard for a given serial driver to make it keep working.
Specifically, it's expected that the read()/write() function provided
in the boot console should be the same (or nearly the same) as the
normal kgdb polling functions.  That means continuing to use them
should work just fine.  To make things even more likely to work work
we'll also trap the recently added exit() function in the boot console
we're using and delay any calls to it until we're all done with the
boot console.

NOTE: there could be ways to use all this in weird / unexpected ways.
If you do something like this, it's a bit of a buyer beware situation.
Specifically:
- If you specify only "kgdboc_earlycon" but not "kgdboc" then
  (depending on your serial driver) things will probably work OK, but
  you'll get a warning printed the first time you use kgdb after the
  boot console is gone.  You'd only be able to do this, of course, if
  the serial driver you're running atop provided an early boot console.
- If your "kgdboc_earlycon" and "kgdboc" devices are not the same
  device things should work OK, but it'll be your job to switch over
  which device you're monitoring (including figuring out how to switch
  over gdb in-flight if you're using it).

When trying to enable "kgdboc_earlycon" it should be noted that the
names that are registered through the boot console layer and the tty
layer are not the same for the same port.  For example when debugging
on one board I'd need to pass "kgdboc_earlycon=qcom_geni
kgdboc=ttyMSM0" to enable things properly.  Since digging up the boot
console name is a pain and there will rarely be more than one boot
console enabled, you can provide the "kgdboc_earlycon" parameter
without specifying the name of the boot console.  In this case we'll
just pick the first boot that implements read() that we find.

This new "kgdboc_earlycon" parameter should be contrasted to the
existing "ekgdboc" parameter.  While both provide a way to debug very
early, the usage and mechanisms are quite different.  Specifically
"kgdboc_earlycon" is meant to be used in tandem with "kgdboc" and
there is a transition from one to the other.  The "ekgdboc" parameter,
on the other hand, replaces the "kgdboc" parameter.  It runs the same
logic as the "kgdboc" parameter but just relies on your TTY driver
being present super early.  The only known usage of the old "ekgdboc"
parameter is documented as "ekgdboc=kbd earlyprintk=vga".  It should
be noted that "kbd" has special treatment allowing it to init early as
a tty device.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.8.I8fba5961bf452ab92350654aa61957f23ecf0100@changeidSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

This file is only ever compiled if that config is on since the
Makefile says:

  obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o

Let's get rid of the useless #ifdef.
Reported-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200507130644.v4.7.Icb528f03d0026d957e60f537aa711ada6fd219dc@changeidSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

If we detect that we recursively entered the debugger we should hack
our I/O ops to NULL so that the panic() in the next line won't
actually cause another recursion into the debugger.  The first line of
kgdb_panic() will check this and return.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.6.I89de39f68736c9de610e6f241e68d8dbc44bc266@changeidSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

Using kgdb requires at least some level of architecture-level
initialization.  If nothing else, it relies on the architecture to
pass breakpoints / crashes onto kgdb.

On some architectures this all works super early, specifically it
starts working at some point in time before Linux parses
early_params's.  On other architectures it doesn't.  A survey of a few
platforms:

a) x86: Presumably it all works early since "ekgdboc" is documented to
   work here.
b) arm64: Catching crashes works; with a simple patch breakpoints can
   also be made to work.
c) arm: Nothing in kgdb works until
   paging_init() -> devicemaps_init() -> early_trap_init()

Let's be conservative and, by default, process "kgdbwait" (which tells
the kernel to drop into the debugger ASAP at boot) a bit later at
dbg_late_init() time.  If an architecture has tested it and wants to
re-enable super early debugging, they can select the
ARCH_HAS_EARLY_DEBUG KConfig option.  We'll do this for x86 to start.
It should be noted that dbg_late_init() is still called quite early in
the system.

Note that this patch doesn't affect when kgdb runs its init.  If kgdb
is set to initialize early it will still initialize when parsing
early_param's.  This patch _only_ inhibits the initial breakpoint from
"kgdbwait".  This means:

* Without any extra patches arm64 platforms will at least catch
  crashes after kgdb inits.
* arm platforms will catch crashes (and could handle a hardcoded
  kgdb_breakpoint()) any time after early_trap_init() runs, even
  before dbg_late_init().
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200507130644.v4.4.I3113aea1b08d8ce36dc3720209392ae8b815201b@changeidSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

If you build CONFIG_KGDB_SERIAL_CONSOLE into the kernel then you
should be able to have KGDB init itself at bootup by specifying the
"kgdboc=..." kernel command line parameter.  This has worked OK for me
for many years, but on a new device I switched to it stopped working.

The problem is that on this new device the serial driver gets its
probe deferred.  Now when kgdb initializes it can't find the tty
driver and when it gives up it never tries again.

We could try to find ways to move up the initialization of the serial
driver and such a thing might be worthwhile, but it's nice to be
robust against serial drivers that load late.  We could move kgdb to
init itself later but that penalizes our ability to debug early boot
code on systems where the driver inits early.  We could roll our own
system of detecting when new tty drivers get loaded and then use that
to figure out when kgdb can init, but that's ugly.

Instead, let's jump on the -EPROBE_DEFER bandwagon.  We'll create a
singleton instance of a "kgdboc" platform device.  If we can't find
our tty device when the singleton "kgdboc" probes we'll return
-EPROBE_DEFER which means that the system will call us back later to
try again when the tty device might be there.

We won't fully transition all of the kgdboc to a platform device
because early kgdb initialization (via the "ekgdboc" kernel command
line parameter) still runs before the platform device has been
created.  The kgdb platform device is merely used as a convenient way
to hook into the system's normal probe deferral mechanisms.

As part of this, we'll ever-so-slightly change how the "kgdboc=..."
kernel command line parameter works.  Previously if you booted up and
kgdb couldn't find the tty driver then later reading
'/sys/module/kgdboc/parameters/kgdboc' would return a blank string.
Now kgdb will keep track of the string that came as part of the
command line and give it back to you.  It's expected that this should
be an OK change.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.3.I4a493cfb0f9f740ce8fd2ab58e62dc92d18fed30@changeid
[daniel.thompson@linaro.org: Make config_mutex static]
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>

This reverts commit 81eaadca.

Commit 81eaadca ("kgdboc: disable the console lock when in kgdb")
is no longer needed now that we have the patch ("kgdb: Disable
WARN_CONSOLE_UNLOCKED for all kgdb").  Revert it.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.2.I02258eee1497e55bcbe8dc477de90369c7c7c2c5@changeidSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

In commit 81eaadca ("kgdboc: disable the console lock when in
kgdb") we avoided the WARN_CONSOLE_UNLOCKED() yell when we were in
kgdboc.  That still works fine, but it turns out that we get a similar
yell when using other I/O drivers.  One example is the "I/O driver"
for the kgdb test suite (kgdbts).  When I enabled that I again got the
same yells.

Even though "kgdbts" doesn't actually interact with the user over the
console, using it still causes kgdb to print to the consoles.  That
trips the same warning:
  con_is_visible+0x60/0x68
  con_scroll+0x110/0x1b8
  lf+0x4c/0xc8
  vt_console_print+0x1b8/0x348
  vkdb_printf+0x320/0x89c
  kdb_printf+0x68/0x90
  kdb_main_loop+0x190/0x860
  kdb_stub+0x2cc/0x3ec
  kgdb_cpu_enter+0x268/0x744
  kgdb_handle_exception+0x1a4/0x200
  kgdb_compiled_brk_fn+0x34/0x44
  brk_handler+0x7c/0xb8
  do_debug_exception+0x1b4/0x228

Let's increment/decrement the "ignore_console_lock_warning" variable
all the time when we enter the debugger.

This will allow us to later revert commit 81eaadca ("kgdboc:
disable the console lock when in kgdb").
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.1.Ied2b058357152ebcc8bf68edd6f20a11d98d7d4e@changeidSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

Fix the following coccicheck warning:

include/linux/kgdb.h:301:54-55: WARNING: return of 0/1 in function
'kgdb_nmi_poll_knock' with return type bool
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Link: https://lore.kernel.org/r/20200507110649.37426-1-yanaijie@huawei.comSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

Kernel doc does not understand POD variables to be referred to.

.../debug_core.c:73: warning: cannot understand function prototype:
'int                             kgdb_connected; '

Convert kernel doc to pure comment.

Fixes: dc7d5527 ("kgdb: core")
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>

Currently there is a small window where a badly timed migration could
cause in_dbg_master() to spuriously return true. Specifically if we
migrate to a new core after reading the processor id and the previous
core takes a breakpoint then we will evaluate true if we read
kgdb_active before we get the IPI to bring us to halt.

Fix this by checking irqs_disabled() first. Interrupts are always
disabled when we are executing the kgdb trap so this is an acceptable
prerequisite. This also allows us to replace raw_smp_processor_id()
with smp_processor_id() since the short circuit logic will prevent
warnings from PREEMPT_DEBUG.

Fixes: dcc78711 ("kgdb: core changes to support kdb")
Suggested-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200506164223.2875760-1-daniel.thompson@linaro.orgReviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>

Pull cifs fixes from Steve French:
 "Five cifs/smb3 fixes:two for DFS reconnect failover, one lease fix for
  stable and the others to fix a missing spinlock during reconnect"

* tag '5.7-rc2-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix uninitialised lease_key in open_shroot()
  cifs: ensure correct super block for DFS reconnect
  cifs: do not share tcons with DFS
  cifs: minor update to comments around the cifs_tcp_ses_lock mutex
  cifs: protect updating server->dstaddr with a spinlock

Pull USB fixes from Greg KH:
 "Here are a number of USB driver fixes for 5.7-rc3.

  Nothing huge, just the usual collection of:

   - xhci fixes

   - gadget driver fixes

   - syzkaller fuzzing fixes

   - new device ids and DT bindings

   - new quirks added for broken devices

  A few of the gadget driver fixes show up twice here as they were
  applied to my branch, and also by Felipe to his branch which I then
  pulled in as we got out of sync a bit.

  All of these have been in linux-next with no reported issues"

* tag 'usb-5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (33 commits)
  USB: sisusbvga: Change port variable from signed to unsigned
  usb-storage: Add unusual_devs entry for JMicron JMS566
  USB: hub: Revert commit bd0e6c96 ("usb: hub: try old enumeration scheme first for high speed devices")
  USB: hub: Fix handling of connect changes during sleep
  usb: typec: altmode: Fix typec_altmode_get_partner sometimes returning an invalid pointer
  xhci: Don't clear hub TT buffer on ep0 protocol stall
  xhci: prevent bus suspend if a roothub port detected a over-current condition
  xhci: Fix handling halted endpoint even if endpoint ring appears empty
  usb: raw-gadget: Fix copy_to/from_user() checks
  usb: raw-gadget: fix raw_event_queue_fetch locking
  usb: gadget: udc: atmel: Fix vbus disconnect handling
  usb: dwc3: gadget: Fix request completion check
  USB: Add USB_QUIRK_DELAY_CTRL_MSG and USB_QUIRK_DELAY_INIT for Corsair K70 RGB RAPIDFIRE
  phy: tegra: Select USB_COMMON for usb_get_maximum_speed()
  usb: typec: tcpm: Ignore CC and vbus changes in PORT_RESET change
  usb: f_fs: Clear OS Extended descriptor counts to zero in ffs_data_reset()
  cdc-acm: introduce a cool down
  cdc-acm: close race betrween suspend() and acm_softint
  UAS: fix deadlock in error handling and PM flushing work
  UAS: no use logging any details in case of ENODEV
  ...

Pull tty/serial fixes from Greg KH:
 "Here are some tty and serial driver fixes for 5.7-rc3.

  The "largest" in here are a number of reverts for previous changes to
  the uartps serial driver that turned out to not be a good idea at all.

  The others are just small fixes found by people and tools. Included in
  here is a much-reported symbol export needed by previous changes that
  happened in 5.7-rc1. All of these have been in linux-next for a while
  with no reported issues"

* tag 'tty-5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: hvc: fix buffer overflow during hvc_alloc().
  tty: rocket, avoid OOB access
  tty: serial: bcm63xx: fix missing clk_put() in bcm63xx_uart
  vt: don't hardcode the mem allocation upper bound
  tty: serial: owl: add "much needed" clk_prepare_enable()
  vt: don't use kmalloc() for the unicode screen buffer
  tty/sysrq: Export sysrq_mask(), sysrq_toggle_support()
  serial: sh-sci: Make sure status register SCxSR is read in correct sequence
  serial: sunhv: Initialize lock for non-registered console
  Revert "serial: uartps: Register own uart console and driver structures"
  Revert "serial: uartps: Move Port ID to device data structure"
  Revert "serial: uartps: Change uart ID port allocation"
  Revert "serial: uartps: Do not allow use aliases >= MAX_UART_INSTANCES"
  Revert "serial: uartps: Fix error path when alloc failed"
  Revert "serial: uartps: Use the same dynamic major number for all ports"
  Revert "serial: uartps: Fix uartps_major handling"

Pull char/misc driver fixes from Greg KH:
 "Here are 4 small misc driver fixes for 5.7-rc3:

   - mei driver fix

   - interconnect driver fix

   - two fpga driver fixes

  All have been in linux-next with no reported issues"

* tag 'char-misc-5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  interconnect: qcom: Fix uninitialized tcs_cmd::wait
  mei: me: fix irq number stored in hw struct
  fpga: dfl: pci: fix return value of cci_pci_sriov_configure
  fpga: zynq: Remove clk_get error message for probe defer

Pull staging/IIO driver fixes from Greg KH:
 "Here are some small staging and IIO driver fixes for 5.7-rc3

  Lots of tiny things for reported issues in staging and IIO drivers,
  including a counter driver fix as well (the iio drivers seem to be
  tied to those). Full details of the fixes are in the shortlog.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (27 commits)
  staging: vt6656: Fix calling conditions of vnt_set_bss_mode
  staging: comedi: Fix comedi_device refcnt leak in comedi_open
  staging: vt6656: Fix pairwise key entry save.
  staging: vt6656: Fix drivers TBTT timing counter.
  staging: vt6656: Don't set RCR_MULTICAST or RCR_BROADCAST by default.
  MAINTAINERS: remove Stefan Popa's email
  iio: adc: ad7192: fix null pointer de-reference crash during probe
  iio: core: remove extra semi-colon from devm_iio_device_register() macro
  iio: adc: ti-ads8344: properly byte swap value
  iio: imu: inv_mpu6050: fix suspend/resume with runtime power
  iio: st_sensors: rely on odr mask to know if odr can be set
  iio: xilinx-xadc: Make sure not exceed maximum samplerate
  iio: xilinx-xadc: Fix sequencer configuration for aux channels in simultaneous mode
  iio: xilinx-xadc: Fix clearing interrupt when enabling trigger
  iio: xilinx-xadc: Fix ADC-B powerdown
  iio: dac: ad5770r: fix off-by-one check on maximum number of channels
  iio: imu: st_lsm6dsx: flush hw FIFO before resetting the device
  iio: core: Fix handling of 'dB'
  dt-bindings: iio: adc: stm32-adc: fix id relative path
  counter: 104-quad-8: Add lock guards - generic interface
  ...

Pull driver core fixes from Greg KH:
 "Here are some small firmware/driver core/debugfs fixes for 5.7-rc3.

  The debugfs change is now possible as now the last users of
  debugfs_create_u32() have been fixed up in the different trees that
  got merged into 5.7-rc1, and I don't want it creeping back in.

  The firmware changes did cause a regression in linux-next, so the
  final patch here reverts part of that, re-exporting the symbol to
  resolve that issue. All of these patches, with the exception of the
  final one, have been in linux-next with only that one reported issue"

* tag 'driver-core-5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  firmware_loader: revert removal of the fw_fallback_config export
  debugfs: remove return value of debugfs_create_u32()
  firmware_loader: remove unused exports
  firmware: imx: fix compile-testing

Pull s390 fixes from Vasily Gorbik:

 - Add a few notrace annotations to avoid potential crashes when
   switching ftrace tracers.

 - Avoid setting affinity for floating irqs in pci code.

 - Fix build issue found by kbuild test robot.

* tag 's390-5.7-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/protvirt: fix compilation issue
  s390/pci: do not set affinity for floating irqs
  s390/ftrace: fix potential crashes when switching tracers

Pull powerpc fixes from Michael Ellerman:

 - One important fix for a bug in the way we find the cache-line size
   from the device tree, which was leading to the wrong size being
   reported to userspace on some platforms.

 - A fix for 8xx STRICT_KERNEL_RWX which was leaving TLB entries around
   leading to a window at boot when the strict mapping wasn't enforced.

 - A fix to enable our KUAP (kernel user access prevention) debugging on
   PPC32.

 - A build fix for clang in lib/mpi.

Thanks to: Chris Packham, Christophe Leroy, Nathan Chancellor, Qian Cai.

* tag 'powerpc-5.7-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  lib/mpi: Fix building for powerpc with clang
  powerpc/mm: Fix CONFIG_PPC_KUAP_DEBUG on PPC32
  powerpc/8xx: Fix STRICT_KERNEL_RWX startup test failure
  powerpc/setup_64: Set cache-line-size based on cache-block-size

Pull more Devicetree fixes from Rob Herring:
 "A couple of schema and kbuild fixes"

* tag 'devicetree-fixes-for-5.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  dt-bindings: phy: qcom-qusb2: Fix defaults
  dt-bindings: Fix erroneous 'additionalProperties'
  dt-bindings: Fix command line length limit calling dt-mk-schema
  dt-bindings: Re-enable core schemas for dtbs_check

Christoph's patch removed two unsused exported symbols, however, one
symbol is used by the firmware_loader itself.  If CONFIG_FW_LOADER=m so
the firmware_loader is modular but CONFIG_FW_LOADER_USER_HELPER=y we fail
the build at mostpost.

ERROR: modpost: "fw_fallback_config" [drivers/base/firmware_loader/firmware_class.ko] undefined!

This happens because the variable fw_fallback_config is built into the
kernel if CONFIG_FW_LOADER_USER_HELPER=y always, so we need to grant
access to the firmware loader module by exporting it.

Revert only one hunk from his patch.

Fixes: 73960473 ("firmware_loader: remove unused exports")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20200424184916.22843-1-mcgrof@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull pid leak fix from Eric Biederman:
 "Oleg noticed that put_pid(thread_pid) was not getting called when proc
  was not compiled in.

  Let's get that fixed before 5.7 is released and causes problems for
  anyone"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  proc: Put thread_pid in release_task not proc_flush_pid

Pull timer fixlet from Ingo Molnar:
 "A single fix for a comment that may show up in DocBook output"

* tag 'timers-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  vdso/datapage: Use correct clock mode name in comment

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes:

   - an uclamp accounting fix

   - three frequency invariance fixes and a readability improvement"

* tag 'sched-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Fix reset-on-fork from RT with uclamp
  x86, sched: Move check for CPU type to caller function
  x86, sched: Don't enable static key when starting secondary CPUs
  x86, sched: Account for CPUs with less than 4 cores in freq. invariance
  x86, sched: Bail out of frequency invariance if base frequency is unknown

Pull perf fixes from Ingo Molnar:
 "Two changes:

   - fix exit event records

   - extend x86 PMU driver enumeration to add Intel Jasper Lake CPU
     support"

* tag 'perf-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: fix parent pid/tid in task exit events
  perf/x86/cstate: Add Jasper Lake CPU support

Pull objtool fixes from Ingo Molnar:
 "Two fixes: fix an off-by-one bug, and fix 32-bit builds on 64-bit
  systems"

* tag 'objtool-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix off-by-one in symbol_by_offset()
  objtool: Fix 32bit cross builds

The kernel fails to compile with CONFIG_PROTECTED_VIRTUALIZATION_GUEST
set but CONFIG_KVM unset.

This patch fixes the issue by making the needed variable always available.

Link: https://lkml.kernel.org/r/20200423120114.2027410-1-imbrenda@linux.ibm.com
Fixes: a0f60f84 ("s390/protvirt: Add sysfs firmware interface for Ultravisor information")
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Philipp Rudo <prudo@linux.ibm.com>
Suggested-by: Philipp Rudo <prudo@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Pull networking fixes from David Miller:

 1) Fix memory leak in netfilter flowtable, from Roi Dayan.

 2) Ref-count leaks in netrom and tipc, from Xiyu Yang.

 3) Fix warning when mptcp socket is never accepted before close, from
    Florian Westphal.

 4) Missed locking in ovs_ct_exit(), from Tonghao Zhang.

 5) Fix large delays during PTP synchornization in cxgb4, from Rahul
    Lakkireddy.

 6) team_mode_get() can hang, from Taehee Yoo.

 7) Need to use kvzalloc() when allocating fw tracer in mlx5 driver,
    from Niklas Schnelle.

 8) Fix handling of bpf XADD on BTF memory, from Jann Horn.

 9) Fix BPF_STX/BPF_B encoding in x86 bpf jit, from Luke Nelson.

10) Missing queue memory release in iwlwifi pcie code, from Johannes
    Berg.

11) Fix NULL deref in macvlan device event, from Taehee Yoo.

12) Initialize lan87xx phy correctly, from Yuiko Oshino.

13) Fix looping between VRF and XFRM lookups, from David Ahern.

14) etf packet scheduler assumes all sockets are full sockets, which is
    not necessarily true. From Eric Dumazet.

15) Fix mptcp data_fin handling in RX path, from Paolo Abeni.

16) fib_select_default() needs to handle nexthop objects, from David
    Ahern.

17) Use GFP_ATOMIC under spinlock in mac80211_hwsim, from Wei Yongjun.

18) vxlan and geneve use wrong nlattr array, from Sabrina Dubroca.

19) Correct rx/tx stats in bcmgenet driver, from Doug Berger.

20) BPF_LDX zero-extension is encoded improperly in x86_32 bpf jit, fix
    from Luke Nelson.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (100 commits)
  selftests/bpf: Fix a couple of broken test_btf cases
  tools/runqslower: Ensure own vmlinux.h is picked up first
  bpf: Make bpf_link_fops static
  bpftool: Respect the -d option in struct_ops cmd
  selftests/bpf: Add test for freplace program with expected_attach_type
  bpf: Propagate expected_attach_type when verifying freplace programs
  bpf: Fix leak in LINK_UPDATE and enforce empty old_prog_fd
  bpf, x86_32: Fix logic error in BPF_LDX zero-extension
  bpf, x86_32: Fix clobbering of dst for BPF_JSET
  bpf, x86_32: Fix incorrect encoding in BPF_LDX zero-extension
  bpf: Fix reStructuredText markup
  net: systemport: suppress warnings on failed Rx SKB allocations
  net: bcmgenet: suppress warnings on failed Rx SKB allocations
  macsec: avoid to set wrong mtu
  mac80211: sta_info: Add lockdep condition for RCU list usage
  mac80211: populate debugfs only after cfg80211 init
  net: bcmgenet: correct per TX/RX ring statistics
  net: meth: remove spurious copyright text
  net: phy: bcm84881: clear settings on link down
  chcr: Fix CPU hard lockup
  ...

Alexei Starovoitov says:

====================
pull-request: bpf 2020-04-24

The following pull-request contains BPF updates for your *net* tree.

We've added 17 non-merge commits during the last 5 day(s) which contain
a total of 19 files changed, 203 insertions(+), 85 deletions(-).

The main changes are:

1) link_update fix, from Andrii.

2) libbpf get_xdp_id fix, from David.

3) xadd verifier fix, from Jann.

4) x86-32 JIT fixes, from Luke and Wang.

5) test_btf fix, from Stanislav.

6) freplace verifier fix, from Toke.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 51c39bb1 ("bpf: Introduce function-by-function verification")
introduced function linkage flag and changed the error message from
"vlen != 0" to "Invalid func linkage" and broke some fake BPF programs.

Adjust the test accordingly.

AFACT, the programs don't really need any arguments and only look
at BTF for maps, so let's drop the args altogether.

Before:
BTF raw test[103] (func (Non zero vlen)): do_test_raw:3703:FAIL expected
err_str:vlen != 0
magic: 0xeb9f
version: 1
flags: 0x0
hdr_len: 24
type_off: 0
type_len: 72
str_off: 72
str_len: 10
btf_total_size: 106
[1] INT (anon) size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
[2] INT (anon) size=4 bits_offset=0 nr_bits=32 encoding=(none)
[3] FUNC_PROTO (anon) return=0 args=(1 a, 2 b)
[4] FUNC func type_id=3 Invalid func linkage

BTF libbpf test[1] (test_btf_haskv.o): libbpf: load bpf program failed:
Invalid argument
libbpf: -- BEGIN DUMP LOG ---
libbpf:
Validating test_long_fname_2() func#1...
Arg#0 type PTR in test_long_fname_2() is not supported yet.
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0
peak_states 0 mark_read 0

libbpf: -- END LOG --
libbpf: failed to load program 'dummy_tracepoint'
libbpf: failed to load object 'test_btf_haskv.o'
do_test_file:4201:FAIL bpf_object__load: -4007
BTF libbpf test[2] (test_btf_newkv.o): libbpf: load bpf program failed:
Invalid argument
libbpf: -- BEGIN DUMP LOG ---
libbpf:
Validating test_long_fname_2() func#1...
Arg#0 type PTR in test_long_fname_2() is not supported yet.
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0
peak_states 0 mark_read 0

libbpf: -- END LOG --
libbpf: failed to load program 'dummy_tracepoint'
libbpf: failed to load object 'test_btf_newkv.o'
do_test_file:4201:FAIL bpf_object__load: -4007
BTF libbpf test[3] (test_btf_nokv.o): libbpf: load bpf program failed:
Invalid argument
libbpf: -- BEGIN DUMP LOG ---
libbpf:
Validating test_long_fname_2() func#1...
Arg#0 type PTR in test_long_fname_2() is not supported yet.
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0
peak_states 0 mark_read 0

libbpf: -- END LOG --
libbpf: failed to load program 'dummy_tracepoint'
libbpf: failed to load object 'test_btf_nokv.o'
do_test_file:4201:FAIL bpf_object__load: -4007

Fixes: 51c39bb1 ("bpf: Introduce function-by-function verification")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200422003753.124921-1-sdf@google.com

Reorder include paths to ensure that runqslower sources are picking up
vmlinux.h, generated by runqslower's own Makefile. When runqslower is built
from selftests/bpf, due to current -I$(BPF_INCLUDE) -I$(OUTPUT) ordering, it
might pick up not-yet-complete vmlinux.h, generated by selftests Makefile,
which could lead to compilation errors like [0]. So ensure that -I$(OUTPUT)
goes first and rely on runqslower's Makefile own dependency chain to ensure
vmlinux.h is properly completed before source code relying on it is compiled.

  [0] https://travis-ci.org/github/libbpf/libbpf/jobs/677905925Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200422012407.176303-1-andriin@fb.com

Fix the following sparse warning:

kernel/bpf/syscall.c:2289:30: warning: symbol 'bpf_link_fops' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/1587609160-117806-1-git-send-email-zou_wei@huawei.com

In the prog cmd, the "-d" option turns on the verifier log.
This is missed in the "struct_ops" cmd and this patch fixes it.

Fixes: 65c93628 ("bpftool: Add struct_ops support")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200424182911.1259355-1-kafai@fb.com

This adds a new selftest that tests the ability to attach an freplace
program to a program type that relies on the expected_attach_type of the
target program to pass verification.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/158773526831.293902.16011743438619684815.stgit@toke.dk

For some program types, the verifier relies on the expected_attach_type of
the program being verified in the verification process. However, for
freplace programs, the attach type was not propagated along with the
verifier ops, so the expected_attach_type would always be zero for freplace
programs.

This in turn caused the verifier to sometimes make the wrong call for
freplace programs. For all existing uses of expected_attach_type for this
purpose, the result of this was only false negatives (i.e., freplace
functions would be rejected by the verifier even though they were valid
programs for the target they were replacing). However, should a false
positive be introduced, this can lead to out-of-bounds accesses and/or
crashes.

The fix introduced in this patch is to propagate the expected_attach_type
to the freplace program during verification, and reset it after that is
done.

Fixes: be8704ff ("bpf: Introduce dynamic program extensions")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/158773526726.293902.13257293296560360508.stgit@toke.dk

Fix bug of not putting bpf_link in LINK_UPDATE command.
Also enforce zeroed old_prog_fd if no BPF_F_REPLACE flag is specified.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200424052045.4002963-1-andriin@fb.com

When verifier_zext is true, we don't need to emit code
for zero-extension.

Fixes: 836256bf ("x32: bpf: eliminate zero extension code-gen")
Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200423050637.GA4029@udknight