con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-18-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-17-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-16-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-15-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-14-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-13-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-12-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-11-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-10-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-9-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-7-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-6-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-5-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

con_init in tty/vt.c will now set conswitchp to dummy_con if it's unset.
Drop it from arch setup code.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-4-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

If the arch setup code hasn't initialized conswitchp yet, set it to
dummy_con in con_init. This will allow us to drop the dummy_con
initialization that's done in almost every architecture.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-3-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit [1] consolidated console configuration in
drivers/video/console, DUMMY_CONSOLE has always been enabled, since the
dependency is always satisfied.

There is no point in trying to allow it to be configured out, since
(a) it's tiny, and (b) if VT_CONSOLE is enabled, we must have a working
console driver by the time con_init(vt.c) runs, and only dummycon is
guaranteed to work (vgacon may be configured in, but that doesn't mean
we have a VGA device).

So just remove the fake dependency.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit?id=31d2a7d36d6989c714b792ec00358ada24c039e7Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-2-nivedita@alum.mit.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Clang warns:

../drivers/tty/synclink_gt.c:1337:3: warning: misleading indentation;
statement is not part of the previous 'if' [-Wmisleading-indentation]
        if (C_CRTSCTS(tty)) {
        ^
../drivers/tty/synclink_gt.c:1335:2: note: previous statement is here
        if (I_IXOFF(tty))
        ^
../drivers/tty/synclink_gt.c:2563:3: warning: misleading indentation;
statement is not part of the previous 'if' [-Wmisleading-indentation]
        if (I_BRKINT(info->port.tty) || I_PARMRK(info->port.tty))
        ^
../drivers/tty/synclink_gt.c:2561:2: note: previous statement is here
        if (I_INPCK(info->port.tty))
        ^
../drivers/tty/synclink_gt.c:3221:3: warning: misleading indentation;
statement is not part of the previous 'else' [-Wmisleading-indentation]
        set_signals(info);
        ^
../drivers/tty/synclink_gt.c:3219:2: note: previous statement is here
        else
        ^
3 warnings generated.

The indentation on these lines is not at all consistent, tabs and spaces
are mixed together. Convert to just using tabs to be consistent with the
Linux kernel coding style and eliminate these warnings from clang.

Link: https://github.com/ClangBuiltLinux/linux/issues/822Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lore.kernel.org/r/20191218023912.13827-1-natechancellor@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Clang warns:

../drivers/tty/synclinkmp.c:1456:3: warning: misleading indentation;
statement is not part of the previous 'if' [-Wmisleading-indentation]
        if (C_CRTSCTS(tty)) {
        ^
../drivers/tty/synclinkmp.c:1453:2: note: previous statement is here
        if (I_IXOFF(tty))
        ^
../drivers/tty/synclinkmp.c:2473:8: warning: misleading indentation;
statement is not part of the previous 'if' [-Wmisleading-indentation]
                                                info->port.tty->hw_stopped = 0;
                                                ^
../drivers/tty/synclinkmp.c:2471:7: note: previous statement is here
                                                if ( debug_level >= DEBUG_LEVEL_ISR )
                                                ^
../drivers/tty/synclinkmp.c:2482:8: warning: misleading indentation;
statement is not part of the previous 'if' [-Wmisleading-indentation]
                                                info->port.tty->hw_stopped = 1;
                                                ^
../drivers/tty/synclinkmp.c:2480:7: note: previous statement is here
                                                if ( debug_level >= DEBUG_LEVEL_ISR )
                                                ^
../drivers/tty/synclinkmp.c:2809:3: warning: misleading indentation;
statement is not part of the previous 'if' [-Wmisleading-indentation]
        if (I_BRKINT(info->port.tty) || I_PARMRK(info->port.tty))
        ^
../drivers/tty/synclinkmp.c:2807:2: note: previous statement is here
        if (I_INPCK(info->port.tty))
        ^
../drivers/tty/synclinkmp.c:3246:3: warning: misleading indentation;
statement is not part of the previous 'else' [-Wmisleading-indentation]
        set_signals(info);
        ^
../drivers/tty/synclinkmp.c:3244:2: note: previous statement is here
        else
        ^
5 warnings generated.

The indentation on these lines is not at all consistent, tabs and spaces
are mixed together. Convert to just using tabs to be consistent with the
Linux kernel coding style and eliminate these warnings from clang.

Link: https://github.com/ClangBuiltLinux/linux/issues/823Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lore.kernel.org/r/20191218024720.3528-1-natechancellor@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tpk_write()/tpk_close() could be interrupted when holding a mutex, then
in timer handler tpk_write() may be called again trying to acquire same
mutex, lead to deadlock.

Google syzbot reported this issue with CONFIG_DEBUG_ATOMIC_SLEEP
enabled:

BUG: sleeping function called from invalid context at
kernel/locking/mutex.c:938
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/1
1 lock held by swapper/1/0:
...
Call Trace:
  <IRQ>
  dump_stack+0x197/0x210
  ___might_sleep.cold+0x1fb/0x23e
  __might_sleep+0x95/0x190
  __mutex_lock+0xc5/0x13c0
  mutex_lock_nested+0x16/0x20
  tpk_write+0x5d/0x340
  resync_tnc+0x1b6/0x320
  call_timer_fn+0x1ac/0x780
  run_timer_softirq+0x6c3/0x1790
  __do_softirq+0x262/0x98c
  irq_exit+0x19b/0x1e0
  smp_apic_timer_interrupt+0x1a3/0x610
  apic_timer_interrupt+0xf/0x20
  </IRQ>

See link https://syzkaller.appspot.com/bug?extid=2eeef62ee31f9460ad65 for
more details.

Fix it by using spinlock in process context instead of mutex and having
interrupt disabled in critical section.

Reported-by: syzbot+2eeef62ee31f9460ad65@syzkaller.appspotmail.com
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200113034842.435-1-zhenzhong.duan@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Michael Ellerman made a call for volunteers from NXP to maintain
this driver and I offered myself.
Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Acked-by: Timur Tabi <timur@kernel.org>
Link: https://lore.kernel.org/r/20200114110012.17351-1-laurentiu.tudor@nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

set_mctrl now sets RTS and DTR.
Signed-off-by: Maarten Brock <m.brock@vanmierlo.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/1574687731-21563-3-git-send-email-shubhrajyoti.datta@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Let set_termios enable/disable automatic flow control.
set_mctrl should not touch automatic flow control.
Signed-off-by: Maarten Brock <m.brock@vanmierlo.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/1574687731-21563-2-git-send-email-shubhrajyoti.datta@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Some of the applications like microcom do not work if
modem is disabled. To fix them we always return
TIOCM_CTS | TIOCM_DSR | TIOCM_CAR instead of 0 when
using cts_override. Make get_mctrl return actual status
when not using cts_override.
Signed-off-by: Maarten Brock <m.brock@vanmierlo.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/1574687731-21563-1-git-send-email-shubhrajyoti.datta@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixes coccicheck warning:

drivers/tty/serial/8250/8250_exar.c:189:6-17: WARNING: Assignment of 0/1 to bool variable
drivers/tty/serial/8250/8250_exar.c:197:3-14: WARNING: Assignment of 0/1 to bool variable
drivers/tty/serial/8250/8250_exar.c:199:3-14: WARNING: Assignment of 0/1 to bool variable
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Link: https://lore.kernel.org/r/1578881777-65475-5-git-send-email-zhengbin13@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixes coccicheck warning:

drivers/tty/serial/atmel_serial.c:1062:1-23: WARNING: Assignment of 0/1 to bool variable
drivers/tty/serial/atmel_serial.c:1261:1-23: WARNING: Assignment of 0/1 to bool variable
drivers/tty/serial/atmel_serial.c:1688:3-25: WARNING: Assignment of 0/1 to bool variable
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Link: https://lore.kernel.org/r/1578881777-65475-4-git-send-email-zhengbin13@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixes coccicheck warning:

drivers/tty/serial/kgdb_nmi.c:121:6-13: WARNING: Assignment of 0/1 to bool variable
drivers/tty/serial/kgdb_nmi.c:133:2-9: WARNING: Assignment of 0/1 to bool variable
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Link: https://lore.kernel.org/r/1578881777-65475-3-git-send-email-zhengbin13@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixes coccicheck warning:

drivers/tty/synclink_gt.c:2101:3-19: WARNING: Assignment of 0/1 to bool variable
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Link: https://lore.kernel.org/r/1578881777-65475-2-git-send-email-zhengbin13@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

During db410c stress test and when the system is low on memory,
the UART/console becomes unresponsive and never recover back.
This has been narrowed down to the msm_start_rx_dma which does
not manage error cases correctly (e.g. dma mapping failure),
indeed, when an error happens, dma transfer is simply discarded
and so never completed, leading to unconfigured RX path.

This patch fixes this issue by switching to SW/FIFO mode in case
of DMA issue. This mainly consists in resetting the receiver to
apply RX BAM/DMA disabling change and re-enabling the RX level
and stale interrupts (previously disabled for DMA transfers).

The DMA will be re-enabled once memory is available since the
SW/FIFO read function (msm_handle_rx_dm) retries to start dma
on completion.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Link: https://lore.kernel.org/r/1578646684-17379-1-git-send-email-loic.poulain@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The 8250 driver can probe for many variants of the venerable 16550A
serial port. Some of those probes involve long (20ms) mdelay calls,
which delay system boot. Modern systems and virtual machines don't have
those variants.

Provide a Kconfig option to disable probes for 16550A variants.
Disabling this speeds up the boot of a virtual machine with a serial
console by more than 20ms (a substantial fraction of the ~100ms needed
to boot a carefully configured VM).

Before:
[  +0.021919] 00:04: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
After:
[  +0.000097] 00:04: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Link: https://lore.kernel.org/r/20200111022513.GA166267@localhostSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Synchronize only the dirty part of DMA buffer in order to avoid
unnecessary overhead of syncing of the clean part, which is the case
of every serial DMA transfer in practice.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20200112180919.5194-3-digetx@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This allows DMA engine to go into runtime-suspended mode whenever there is
no data to receive, instead of keeping DMA active all the time while TTY
is opened (i.e. permanently active in practice, like in the case of UART
Bluetooth).
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20200112180919.5194-2-digetx@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We need the serial/tty fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull RISC-V fixes from Paul Walmsley:
 "Two fixes for RISC-V:

   - Clear FP registers during boot when FP support is present, rather
     than when they aren't present

   - Move the header files associated with the SiFive L2 cache
     controller to drivers/soc (where the code was recently moved)"

* tag 'riscv/for-v5.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: Fixup obvious bug for fp-regs reset
  riscv: move sifive_l2_cache.h to include/soc

CSR_MISA is defined in Privileged Architectures' spec: 3.1.1 Machine
ISA Register misa. Every bit:1 indicate a feature, so we should beqz
reset_done when there is no F/D bit in csr_misa register.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
[paul.walmsley@sifive.com: fix typo in commit message]
Fixes: 9e806356 ("riscv: clear the instruction cache and all registers when booting")
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>

The commit 9209fb51 ("riscv: move sifive_l2_cache.c to drivers/soc")
moves the sifive L2 cache driver to driver/soc. It did not move the
header file along with the driver. Therefore this patch moves the header
file to driver/soc
Signed-off-by: Yash Shah <yash.shah@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
[paul.walmsley@sifive.com: updated to fix the include guard]
Fixes: 9209fb51 ("riscv: move sifive_l2_cache.c to drivers/soc")
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>

Pull iommu fixes from Joerg Roedel:

 - Two fixes for VT-d and generic IOMMU code to fix teardown on error
   handling code paths.

 - Patch for the Intel VT-d driver to fix handling of non-PCI devices

 - Fix W=1 compile warning in dma-iommu code

* tag 'iommu-fixes-v5.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/dma: fix variable 'cookie' set but not used
  iommu/vt-d: Unlink device if failed to add to group
  iommu: Remove device link to group on failure
  iommu/vt-d: Fix adding non-PCI devices to Intel IOMMU

Pull i2c fixes from Wolfram Sang:
 "Two driver bugfixes, a documentation fix, and a removal of a spec
  violation for the bus recovery algorithm in the core"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: fix bus recovery stop mode timing
  i2c: bcm2835: Store pointer to bus clock
  dt-bindings: i2c: at91: fix i2c-sda-hold-time-ns documentation for sam9x60
  i2c: at91: fix clk_offset for sam9x60

Pull thread fixes from Christian Brauner:
 "This contains a series of patches to fix CLONE_SETTLS when used with
  clone3().

  The clone3() syscall passes the tls argument through struct clone_args
  instead of a register. This means, all architectures that do not
  implement copy_thread_tls() but still support CLONE_SETTLS via
  copy_thread() expecting the tls to be located in a register argument
  based on clone() are currently unfortunately broken. Their tls value
  will be garbage.

  The patch series fixes this on all architectures that currently define
  __ARCH_WANT_SYS_CLONE3. It also adds a compile-time check to ensure
  that any architecture that enables clone3() in the future is forced to
  also implement copy_thread_tls().

  My ultimate goal is to get rid of the copy_thread()/copy_thread_tls()
  split and just have copy_thread_tls() at some point in the not too
  distant future (Maybe even renaming copy_thread_tls() back to simply
  copy_thread() once the old function is ripped from all arches). This
  is dependent now on all arches supporting clone3().

  While all relevant arches do that now there are still four missing:
  ia64, m68k, sh and sparc. They have the system call reserved, but not
  implemented. Once they all implement clone3() we can get rid of
  ARCH_WANT_SYS_CLONE3 and HAVE_COPY_THREAD_TLS.

  This series also includes a minor fix for the arm64 uapi headers which
  caused __NR_clone3 to be missing from the exported user headers.

  Unfortunately the series came in a little late especially given that
  it touches a range of architectures. Due to the holidays not all arch
  maintainers responded in time probably due to their backlog. Will and
  Arnd have thankfully acked the arm specific changes.

  Given that the changes are straightforward and rather minimal combined
  with the fact the that clone3() with CLONE_SETTLS is broken I decided
  to send them post rc3 nonetheless"

* tag 'clone3-tls-v5.5-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  um: Implement copy_thread_tls
  clone3: ensure copy_thread_tls is implemented
  xtensa: Implement copy_thread_tls
  riscv: Implement copy_thread_tls
  parisc: Implement copy_thread_tls
  arm: Implement copy_thread_tls
  arm64: Implement copy_thread_tls
  arm64: Move __ARCH_WANT_SYS_CLONE3 definition to uapi headers

Pull HID fix from Jiri Kosina:
 "A regression fix for EPOLLOUT handling in hidraw and uhid"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid:
  HID: hidraw, uhid: Always report EPOLLOUT