Pull tty and serial updates from Greg KH:
"Here is the big set of tty/serial driver changes for 6.7-rc1. Included
in here are:
- console/vgacon cleanups and removals from Arnd
- tty core and n_tty cleanups from Jiri
- lots of 8250 driver updates and cleanups
- sc16is7xx serial driver updates
- dt binding updates
- first set of port lock wrapers from Thomas for the printk fixes
coming in future releases
- other small serial and tty core cleanups and updates
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (193 commits)
serdev: Replace custom code with device_match_acpi_handle()
serdev: Simplify devm_serdev_device_open() function
serdev: Make use of device_set_node()
tty: n_gsm: add copyright Siemens Mobility GmbH
tty: n_gsm: fix race condition in status line change on dead connections
serial: core: Fix runtime PM handling for pending tx
vgacon: fix mips/sibyte build regression
dt-bindings: serial: drop unsupported samsung bindings
tty: serial: samsung: drop earlycon support for unsupported platforms
tty: 8250: Add note for PX-835
tty: 8250: Fix IS-200 PCI ID comment
tty: 8250: Add Brainboxes Oxford Semiconductor-based quirks
tty: 8250: Add support for Intashield IX cards
tty: 8250: Add support for additional Brainboxes PX cards
tty: 8250: Fix up PX-803/PX-857
tty: 8250: Fix port count of PX-257
tty: 8250: Add support for Intashield IS-100
tty: 8250: Add support for Brainboxes UP cards
tty: 8250: Add support for additional Brainboxes UC cards
tty: 8250: Remove UC-257 and UC-431
...
On unplug of a Xen console, xencons_disconnect_backend() unconditionally
calls free_irq() via unbind_from_irqhandler(), causing a warning of
freeing an already-free IRQ:
(qemu) device_del con1
[ 32.050919] ------------[ cut here ]------------
[ 32.050942] Trying to free already-free IRQ 33
[ 32.050990] WARNING: CPU: 0 PID: 51 at kernel/irq/manage.c:1895 __free_irq+0x1d4/0x330
It should be using evtchn_put() to tear down the event channel binding,
and let the Linux IRQ side of it be handled by notifier_del_irq() through
the HVC code.
On which topic... xencons_disconnect_backend() should call hvc_remove()
*first*, rather than tearing down the event channel and grant mapping
while they are in use. And then the IRQ is guaranteed to be freed by
the time it's torn down by evtchn_put().
Since evtchn_put() also closes the actual event channel, avoid calling
xenbus_free_evtchn() except in the failure path where the IRQ was not
successfully set up.
However, calling hvc_remove() at the start of xencons_disconnect_backend()
still isn't early enough. An unplug request is indicated by the backend
setting its state to XenbusStateClosing, which triggers a notification
to xencons_backend_changed(), which... does nothing except set its own
frontend state directly to XenbusStateClosed without *actually* tearing
down the HVC device or, you know, making sure it isn't actively in use.
So the backend sees the guest frontend set its state to XenbusStateClosed
and stops servicing the interrupt... and the guest spins for ever in the
domU_write_console() function waiting for the ring to drain.
Fix that one by calling hvc_remove() from xencons_backend_changed() before
signalling to the backend that it's OK to proceed with the removal.
Tested with 'dd if=/dev/zero of=/dev/hvc1' while telling Qemu to remove
the console device.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231020161529.355083-4-dwmw2@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The xencons_connect_backend() function allocates a local interdomain
event channel with xenbus_alloc_evtchn(), then calls
bind_interdomain_evtchn_to_irq_lateeoi() to bind to that port# on the
*remote* domain.
That doesn't work very well:
(qemu) device_add xen-console,id=con1,chardev=pty0
[ 44.323872] xenconsole console-1: 2 xenbus_dev_probe on device/console/1
[ 44.323995] xenconsole: probe of console-1 failed with error -2
Fix it to use bind_evtchn_to_irq_lateeoi(), which does the right thing
by just binding that *local* event channel to an irq. The backend will
do the interdomain binding.
This didn't affect the primary console because the setup for that is
special — the toolstack allocates the guest event channel and the guest
discovers it with HVMOP_get_param.
Fixes: fe415186b4 ("xen/console: harden hvc_xen against event channel storms")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231020161529.355083-2-dwmw2@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # for imx
Link: https://lore.kernel.org/r/20230724205440.767071-1-robh@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull xen fixes from Juergen Gross:
- fix build warning
- avoid concurrent accesses to the Xen PV console ring page
* tag 'for-linus-6.3-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/PVH: avoid 32-bit build warning when obtaining VGA console info
hvc/xen: prevent concurrent accesses to the shared ring
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: b536b4b962 ('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>
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: 02e19f9c7c ('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()
...
Pull more xen updates from Juergen Gross:
"Two cleanup patches for Xen related code and (more important) an
update of MAINTAINERS for Xen, as Boris Ostrovsky decided to step
down"
* tag 'for-linus-5.19-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: replace xen_remap() with memremap()
MAINTAINERS: Update Xen maintainership
xen: switch gnttab_end_foreign_access() to take a struct page pointer
xen_remap() is used to establish mappings for frames not under direct
control of the kernel: for Xenstore and console ring pages, and for
grant pages of non-PV guests.
Today xen_remap() is defined to use ioremap() on x86 (doing uncached
mappings), and ioremap_cache() on Arm (doing cached mappings).
Uncached mappings for those use cases are bad for performance, so they
should be avoided if possible. As all use cases of xen_remap() don't
require uncached mappings (the mapped area is always physical RAM),
a mapping using the standard WB cache mode is fine.
As sparse is flagging some of the xen_remap() use cases to be not
appropriate for iomem(), as the result is not annotated with the
__iomem modifier, eliminate xen_remap() completely and replace all
use cases with memremap() specifying the MEMREMAP_WB caching mode.
xen_unmap() can be replaced with memunmap().
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20220530082634.6339-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Some external debuggers do not handle reads/writes from/to DCC
on secondary cores. Each core has its own DCC device registers,
so when a core reads or writes from/to DCC, it only accesses
its own DCC device. Since kernel code can run on any core,
every time the kernel wants to write to the console, it might
write to a different DCC.
In SMP mode, external debugger creates multiple windows, and
each window shows the DCC output only from that core's DCC.
The result is that console output is either lost or scattered
across windows.
Selecting this debug option will enable code that serializes all
console input and output to core 0. The DCC driver will create
input and output FIFOs that all cores will use. Reads and writes
from/to DCC are handled by a workqueue that runs only core 0.
This is a debug feature to be used only in early stage development
where debug serial console support would not be present. It disables
PM feature like CPU hotplug and is not suitable for production
environment.
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Acked-by: Adam Wallis <awallis@codeaurora.org>
Signed-off-by: Timur Tabi <timur@codeaurora.org>
Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Signed-off-by: Sai Prakash Ranjan <quic_saipraka@quicinc.com>
Link: https://lore.kernel.org/r/20220428090858.14489-1-quic_saipraka@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Xen console driver is still vulnerable for an attack via excessive
number of events sent by the backend. Fix that by using a lateeoi event
channel.
For the normal domU initial console this requires the introduction of
bind_evtchn_to_irq_lateeoi() as there is no xenbus device available
at the time the event channel is bound to the irq.
As the decision whether an interrupt was spurious or not requires to
test for bytes having been read from the backend, move sending the
event into the if statement, as sending an event without having found
any bytes to be read is making no sense at all.
This is part of XSA-391
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
V2:
- slightly adapt spurious irq detection (Jan Beulich)
V3:
- fix spurious irq detection (Jan Beulich)
As well known, hvc backend can register its opertions to hvc backend.
the operations contain put_chars(), get_chars() and so on.
Some hvc backend may do dma in its operations. eg, put_chars() of
virtio-console. But in the code of hvc framework, it may pass DMA
incapable memory to put_chars() under a specific configuration, which
is explained in commit c4baad5029(virtio-console: avoid DMA from stack):
1, c[] is on stack,
hvc_console_print():
char c[N_OUTBUF] __ALIGNED__;
cons_ops[index]->put_chars(vtermnos[index], c, i);
2, ch is on stack,
static void hvc_poll_put_char(,,char ch)
{
struct tty_struct *tty = driver->ttys[0];
struct hvc_struct *hp = tty->driver_data;
int n;
do {
n = hp->ops->put_chars(hp->vtermno, &ch, 1);
} while (n <= 0);
}
Commit c4baad5029 is just the fix to avoid DMA from stack memory, which
is passed to virtio-console by hvc framework in above code. But I think
the fix is aggressive, it directly uses kmemdup() to alloc new buffer
from kmalloc area and do memcpy no matter the memory is in kmalloc area
or not. But most importantly, it should better be fixed in the hvc
framework, by changing it to never pass stack memory to the put_chars()
function in the first place. Otherwise, we still face the same issue if
a new hvc backend using dma added in the furture.
In this patch, add 'char cons_outbuf[]' as part of 'struct hvc_struct',
so hp->cons_outbuf is no longer the stack memory, we can use it in above
cases safely. We also add lock to protect cons_outbuf instead of using
the global lock of hvc.
Introduce another array(cons_hvcs[]) for hvc pointers next to the
cons_ops[] and vtermnos[] arrays. With the array, we can easily find
hvc's cons_outbuf and its lock.
With the patch, we can revert the fix c4baad5029.
Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211015024658.1353987-3-xianting.tian@linux.alibaba.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull xen fixes from Juergen Gross:
- fix two minor issues in the Xen privcmd driver plus a cleanup patch
for that driver
- fix multiple issues related to running as PVH guest and some related
earlyprintk fixes for other Xen guest types
- fix an issue introduced in 5.15 the Xen balloon driver
* tag 'for-linus-5.15b-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/balloon: fix cancelled balloon action
xen/x86: adjust data placement
x86/PVH: adjust function/data placement
xen/x86: hook up xen_banner() also for PVH
xen/x86: generalize preferred console model from PV to PVH Dom0
xen/x86: make "earlyprintk=xen" work for HVM/PVH DomU
xen/x86: allow "earlyprintk=xen" to work for PV Dom0
xen/x86: make "earlyprintk=xen" work better for PVH Dom0
xen/x86: allow PVH Dom0 without XEN_PV=y
xen/x86: prevent PVH type from getting clobbered
xen/privcmd: drop "pages" parameter from xen_remap_pfn()
xen/privcmd: fix error handling in mmap-resource processing
xen/privcmd: replace kcalloc() by kvcalloc() when allocating empty pages
The xen_hvm_early_write() path better wouldn't be taken in this case;
while port 0xE9 can be used, the hypercall path is quite a bit more
efficient. Put that first, as it may also work for DomU-s (see also
xen_raw_console_write()).
While there also bail from the function when the first
domU_write_console() failed - later ones aren't going to succeed.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/4fd89dcb-cfc5-c740-2e94-bb271e432d3e@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
The alloc_tty_driver failure is handled gracefully in hvsi_init. But
tty_register_driver is not. panic is called if that one fails.
So handle the failure of tty_register_driver gracefully too. This will
keep at least the console functional as it was enabled earlier by
console_initcall in hvsi_console_init. Instead of shooting down the
whole system.
This means, we disable interrupts and restore hvsi_wait back to
poll_for_state().
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723074317.32690-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
