[ Upstream commit 6214894f49a967c749ee6c07cb00f9cede748df4 ]

The hvc machinery registers both a console and a tty device based on
the hv ops provided by the specific implementation.  Those two
interfaces however have different locks, and there's no single locks
that's shared between the tty and the console implementations, hence
the driver needs to protect itself against concurrent accesses.
Otherwise concurrent calls using the split interfaces are likely to
corrupt the ring indexes, leaving the console unusable.

Introduce a lock to xencons_info to serialize accesses to the shared
ring.  This is only required when using the shared memory console,
concurrent accesses to the hypercall based console implementation are
not an issue.

Note the conditional logic in domU_read_console() is slightly modified
so the notify_daemon() call can be done outside of the locked region:
it's an hypercall and there's no need for it to be done with the lock
held.

Fixes: b536b4b96230 ('xen: use the hvc console infrastructure for Xen console')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20221130150919.13935-1-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Pull xen fixes from Juergen Gross:

 - two cleanup patches

 - a fix of a memory leak in the Xen pvfront driver

 - a fix of a locking issue in the Xen hypervisor console driver

* tag 'for-linus-6.2-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/pvcalls: free active map buffer on pvcalls_front_free_map
  hvc/xen: lock console list traversal
  x86/xen: Remove the unused function p2m_index()
  xen: make remove callback of xen driver void returned

The currently lockless access to the xen console list in
vtermno_to_xencons() is incorrect, as additions and removals from the
list can happen anytime, and as such the traversal of the list to get
the private console data for a given termno needs to happen with the
lock held.  Note users that modify the list already do so with the
lock taken.

Adjust current lock takers to use the _irq{save,restore} helpers,
since the context in which vtermno_to_xencons() is called can have
interrupts disabled.  Use the _irq{save,restore} set of helpers to
switch the current callers to disable interrupts in the locked region.
I haven't checked if existing users could instead use the _irq
variant, as I think it's safer to use _irq{save,restore} upfront.

While there switch from using list_for_each_entry_safe to
list_for_each_entry: the current entry cursor won't be removed as
part of the code in the loop body, so using the _safe variant is
pointless.

Fixes: 02e19f9c7cac ('hvc_xen: implement multiconsole support')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20221130163611.14686-1-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>

Pull tty/serial driver updates from Greg KH:
 "Here is the "big" set of tty/serial driver changes for 6.2-rc1.

  As in previous kernel releases, nothing big here at all, just some
  small incremental serial/tty layer cleanups and some individual driver
  additions and fixes. Highlights are:

   - serial helper macros from Jiri Slaby to reduce the amount of
     duplicated code in serial drivers

   - api cleanups and consolidations from Ilpo Järvinen in lots of
     serial drivers

   - the usual set of n_gsm fixes from Daniel Starke as that code gets
     exercised more

   - TIOCSTI is finally able to be disabled if requested (security
     hardening feature from Kees Cook)

   - fsl_lpuart driver fixes and features added

   - other small serial driver additions and fixes

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

* tag 'tty-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (97 commits)
  serial: atmel: don't stop the transmitter when doing PIO
  serial: atmel: cleanup atmel_start+stop_tx()
  tty: serial: fsl_lpuart: switch to new dmaengine_terminate_* API
  serial: sunsab: Fix error handling in sunsab_init()
  serial: altera_uart: fix locking in polling mode
  serial: pch: Fix PCI device refcount leak in pch_request_dma()
  tty: serial: fsl_lpuart: Use pm_ptr() to avoid need to make pm __maybe_unused
  tty: serial: fsl_lpuart: Add runtime pm support
  tty: serial: fsl_lpuart: enable wakeup source for lpuart
  serdev: Replace poll loop by readx_poll_timeout() macro
  tty: synclink_gt: unwind actions in error path of net device open
  serial: stm32: move dma_request_chan() before clk_prepare_enable()
  dt-bindings: serial: xlnx,opb-uartlite: Drop 'contains' from 'xlnx,use-parity'
  serial: pl011: Do not clear RX FIFO & RX interrupt in unthrottle.
  serial: amba-pl011: avoid SBSA UART accessing DMACR register
  tty: serial: altera_jtaguart: remove struct altera_jtaguart
  tty: serial: altera_jtaguart: use uart_port::read_status_mask
  tty: serial: altera_jtaguart: remove unused altera_jtaguart::sigs
  tty: serial: altera_jtaguart: remove flag from altera_jtaguart_rx_chars()
  n_tty: Rename tail to old_tail in n_tty_read()
  ...

Since commit fc7a6209d571 ("bus: Make remove callback return void")
forces bus_type::remove be void-returned, it doesn't make much sense for
any bus based driver implementing remove callbalk to return non-void to
its caller.

This change is for xen bus based drivers.

Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Link: https://lore.kernel.org/r/TYCP286MB23238119AB4DF190997075C9CAE39@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Juergen Gross <jgross@suse.com>

It is not reliable to check for CON_ENABLED in order to identify if a
console is registered. Use console_is_registered() instead.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20221116162152.193147-26-john.ogness@linutronix.de

The symbol is not used outside of the file, so mark it static.

Fixes the following warning:

drivers/tty/hvc/hvc_rtas.c:29:19: warning: symbol 'hvc_rtas_dev' was
not declared. Should it be static?

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: ruanjinjie <ruanjinjie@huawei.com>
Link: https://lore.kernel.org/r/20221019064412.3759874-1-ruanjinjie@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

According to Greg, in the context of magic numbers as defined in
magic-number.rst, "the tty layer should not need this and I'll gladly
take patches"

This stretches that definition slightly, since it multiplexes it with
the terminal number as a constant offset, but is equivalent

Acked-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Ref: https://lore.kernel.org/linux-doc/YyMlovoskUcHLEb7@kroah.com/
Link: https://lore.kernel.org/r/8c8a2c9dfc1bfbe6ef3f3237368e483865fc1c29.1663288066.git.nabijaczleweli@nabijaczleweli.xyz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

* new header (linut/termios_internal.h), pulled by the users of those
suckers
* defaults for INIT_C_CC and externs for conversion helpers moved over
there
* remove termios-base.h (empty now)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/YxDmptU7dNGZ+/Hn@ZenIV
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20220818210113.7469-1-wsa+renesas@sang-engineering.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>