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In the future we would like to disable power management on the serial devices
used as kernel consoles to avoid weird behaviour in some cases. However,
disabling PM may prevent system to go to deep sleep states, which in its turn
leads to the higher power consumption.
Tony Lindgren proposed a work around, i.e. allow user to detach such consoles
to make PM working again. In case user wants to see what's going on, it also
provides a mechanism to attach console back.
Link: https://lists.openwall.net/linux-kernel/2018/09/29/65
Suggested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200217114016.49856-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 175b558d0efb8b4f33aa7bd2c1b5389b912d3019.
When the user configures a kernel without support for Samsung SoCs, it
makes no sense to ask the user about enabling "Samsung SoC serial
support", as Samsung serial ports can only be found on Samsung SoCs.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200306102301.16870-1-geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We should validate if the 'sup' is NULL or not before freeing DMA
memory, to fix below warning.
"drivers/tty/serial/sprd_serial.c:1141 sprd_remove()
error: we previously assumed 'sup' could be null (see line 1132)"
Fixes: f4487db58eb7 ("serial: sprd: Add DMA mode support")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Lanqing Liu <liuhhome@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/e2bd92691538e95b04a2c2a728f3292e1617018f.1584325957.git.liuhhome@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The function sprd_console_setup() would be called from .probe() which can
be called after freeing __init functions, for example the .probe() would
return -EPROBE_DEFER since it depends on clock modules.
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Link: https://lore.kernel.org/r/20200316101930.9962-3-zhang.lyra@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The SPRD serial driver need to know which serial port would be used as
console in an early period during initialization, the purpose is to
keep the console port alive as possible even if there's some error
caused by no clock configured under serial devicetree nodes. But with
the patch [1], the console port couldn't be identified if missing
console command line.
So this patch adds using another interface to do check by reading
stdout-path.
[1] https://lore.kernel.org/lkml/20190826072929.7696-4-zhang.lyra@gmail.com/
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Link: https://lore.kernel.org/r/20200316101930.9962-2-zhang.lyra@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Shift cases one level left. This makes the code more readable and some
lines need not wrap anymore.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200316065911.11024-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We have a helper called rounddown for these modulo computations. So use
it.
No functional change intended and "objdump -d" proves that.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200316065911.11024-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Instead of awkward ternary operator with comparison, use simple min()
for blankinterval and vesa_off_interval.
No functional change intended and "objdump -d" proves that.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200316065911.11024-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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As Joe suggests, dynamic debug can print module name and line number
along with message. So remove __FILE__ and __LINE__ from all those
pr_debug calls.
Out of curiosity, I measured the savings, 200 bytes of code are gone.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Suggested-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/20200316064910.4941-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The merge commit cb05c6c82fb0 (Merge 5.6-rc5 into tty-next) introduced a
double lock to set_selection_kernel. vc_sel.lock is locked both in
set_selection_kernel and its callee __set_selection_kernel now.
Remove the latter.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/r/20200316064544.4799-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The geni serial driver's shutdown code had a special case to call
console_stop(). Grepping through the code, it was the only serial
driver doing something like this (the only other caller of
console_stop() was in serial_core.c).
As far as I can tell there's no reason to call console_stop() in the
geni code. ...and a good reason _not_ to call it. Specifically if
you have an agetty running on the same serial port as the console then
killing the agetty kills your console and if you start the agetty
again the console doesn't come back.
Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200313134635.2.I3648fac6c98b887742934146ac2729ecb7232eb1@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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On a board using qcom_geni_serial I found that I could no longer
interact with kdb if I got a crash after the "agetty" running on the
same serial port was killed. This meant that various classes of
crashes that happened at reboot time were undebuggable.
Reading through the code, I couldn't figure out why qcom_geni_serial
felt the need to run so much code at port shutdown time. All we need
to do is disable the interrupt.
After I make this change then a hardcoded kgdb_breakpoint in some late
shutdown code now allows me to interact with the debugger. I also
could freely close / re-open the port without problems.
Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200313134635.1.Icf54c533065306b02b880c46dfd401d8db34e213@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The vc_cons_allocated() checks in vt_ioctl() and vt_compat_ioctl() are
unnecessary because they can only be reached by calling ioctl() on an
open tty, which implies the corresponding virtual console is allocated.
And even if the virtual console *could* be freed concurrently, then
these checks would be broken since they aren't done under console_lock,
and the vc_data is dereferenced before them anyway.
So, remove these unneeded checks to avoid confusion.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200224080326.295046-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The might_sleep() in do_con_write() is redundant because console_lock()
already contains might_sleep(). Remove it.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200224073450.292892-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Refactor uart_unlock_and_check_sysrq() to:
- explicitly show that we release a port lock which makes
static analyzers happy:
CHECK drivers/tty/serial/serial_core.c
.../serial_core.c:3290:17: warning: context imbalance in 'uart_unlock_and_check_sysrq' - unexpected unlock
- use flags instead of irqflags to avoid confusion with IRQ flags
- provide one return point
- be more compact
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Link: https://lore.kernel.org/r/20200310174337.74109-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Use uart_console() helper in SysRq code instead of open coded variant.
This eliminates the conditional entirely for SERIAL_CORE_CONSOLE=n case.
While here, refactor the conditional to be more compact.
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200310174337.74109-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It is useful to see on the serial console the magic sequence itself
to enable SysRq without rummaging source code.
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200310174337.74109-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Compiler is not happy about using ARRAY_SIZE() in comparison to smaller type:
CC drivers/tty/serial/serial_core.o
.../serial_core.c: In function ‘uart_try_toggle_sysrq’:
.../serial_core.c:3222:24: warning: comparison is always false due to limited range of data type [-Wtype-limits]
3222 | if (++port->sysrq_seq < (ARRAY_SIZE(sysrq_toggle_seq) - 1)) {
| ^
Looking at the code it appears that there is an additional weirdness,
i.e. use ARRAY_SIZE() against simple string literal. Yes, the idea probably
was to allow '\0' in the sequence, but it's impractical: kernel configuration
won't accept it to begin with followed by a comment about '\0' before
comparison in question.
Drop all these by switching to strlen() and convert code accordingly.
Note, GCC seems clever enough to calculate string length at compile time.
Fixes: 68af43173d3f ("serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE")
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200310174337.74109-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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To fix the RX cancel command failure, rx_fifo buffer needs to be
flushed in stop_rx() by calling handle_rx().In handle_rx() the data
in rx_fifo buffer is read and then dropped, not sent to upper layers.
If set_termios is called before startup, by this time memory is not
allocated to port->rx_fifo buffer, which leads to a NULL pointer
dereference.
To avoid this NULL pointer dereference allocate memory to port->rx_fifo
in probe itself.
Signed-off-by: satya priya <skakit@codeaurora.org>
Reported-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/1583477228-32231-2-git-send-email-skakit@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This driver for the Intel MID never seems to have been properly
integrated upstream: the platform data in <linux/spi/ifx_modem.h>
is not used anywhere in the kernel and haven't been since it was
merged into the kernel in 2010.
There might be out-of-tree users, so I don't want to delete the
driver, but I will refactor it to use GPIO descriptors, which
means that out-of-tree users will need to adapt.
There are several examples in the kernel of how to provide the
resources necessary for using GPIO descriptors to pass in the
GPIO lines, for the MID platform in particular, it will suffice
to inspect the code in files like:
arch/x86/platform/intel-mid/device_libs/platform_bt.c
This refactoring transfers all GPIOs in the driver, including
a hard-coded "PMU reset" in the driver to use GPIO descriptors
instead.
The following named GPIO descriptors need to be supplied:
- reset
- power
- mrdy
- srdy
- rst_out
- pmu_reset
Cc: Russ Gorby <russ.gorby@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200311083131.693908-2-linus.walleij@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The &spi->dev is used so many times that the code gets
visibly better by introducing a simple dev helper variable.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200311083131.693908-1-linus.walleij@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The LS1028A has six LPUART controllers. Add the nodes.
This was tested on a custom board.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200307091302.14881-2-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add the LS1028A SoC compatibility string to the lpuart devicetree
bindings documentation.
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200307091302.14881-1-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add a early_console_setup() for the LS1028A SoC with 32bit, little
endian access. If the bootloader does a fixup of the clock-frequency
node the baudrate divisor register will automatically be set.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-5-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The LS1028A uses little endian register access and has a different FIFO
size encoding.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-4-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Use the correct device to request the DMA mapping. Otherwise the IOMMU
doesn't get the mapping and it will generate a page fault.
The error messages look like:
[ 19.012140] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xbbfff800, fsynr=0x3e0021, cbfrsynra=0x828, cb=9
[ 19.023593] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xbbfff800, fsynr=0x3e0021, cbfrsynra=0x828, cb=9
This was tested on a custom board with a LS1028A SoC.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-3-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The DMA channel might not be available at probe time. This is esp. the
case if the DMA controller has an IOMMU mapping.
There is also another caveat. If there is no DMA controller at all,
dma_request_chan() will also return -EPROBE_DEFER. Thus we cannot test
for -EPROBE_DEFER in probe(). Otherwise the lpuart driver will fail to
probe if, for example, the DMA driver is not enabled in the kernel
configuration.
To workaround this, we request the DMA channel in _startup(). Other
serial drivers do it the same way.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-2-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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To make it more obvious what almost everyone wants to set here.
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vasiliy Khoruzhick <vasilykh@arista.com>
Cc: linux-serial@vger.kernel.org
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200306153156.579921-1-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Use uart_console() helper in instead of open coded variant.
Note, SERIAL_CORE_CONSOLE is selected by SERIAL_ATMEL_CONSOLE,
thus no functional changes expected.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Link: https://lore.kernel.org/r/20200310133057.86840-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Use uart_console() helper in instead of open coded variant.
Note, SERIAL_CORE_CONSOLE is selected by SERIAL_PIC32_CONSOLE,
thus no functional changes expected.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200311090027.64441-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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SiFive's UART has a software controller clock divider that produces the
final baud rate clock. Whenever the clock that drives the UART is
changed this divider must be updated accordingly, and given that these
two events are controlled by software they cannot be done atomically.
During the period between updating the UART's driving clock and internal
divider the UART will transmit a different baud rate than what the user
has configured, which will probably result in a corrupted transmission
stream.
The SiFive UART has a FIFO, but due to an issue with the programming
interface there is no way to directly determine when the UART has
finished transmitting. We're essentially restricted to dead reckoning
in order to figure that out: we can use the FIFO's TX busy register to
figure out when the last frame has begun transmission and just delay for
a long enough that the last frame is guaranteed to get out.
As far as the actual implementation goes: I've modified the existing
existing clock notifier function to drain both the FIFO and the shift
register in on PRE_RATE_CHANGE. As far as I know there is no hardware
flow control in this UART, so there's no good way to ask the other end
to stop transmission while we can't receive (inserting software flow
control messages seems like a bad idea here).
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Tested-by: Yash Shah <yash.shah@sifive.com>
Link: https://lore.kernel.org/r/20200307042637.83728-1-palmer@dabbelt.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There is a recipe to deadlock the kernel: submit a timeout sqe with a
linked_timeout (e.g. test_single_link_timeout_ception() from liburing),
and SIGKILL the process.
Then, io_kill_timeouts() takes @ctx->completion_lock, but the timeout
isn't flagged with REQ_F_COMP_LOCKED, and will try to double grab it
during io_put_free() to cancel the linked timeout. Probably, the same
can happen with another io_kill_timeout() call site, that is
io_commit_cqring().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Mark mips_ejtag_fdc_encode() methods switch-case-4 as expecting to
fall through.
This patch fixes the following warning:
drivers/tty/mips_ejtag_fdc.c: In function ‘mips_ejtag_fdc_encode’:
drivers/tty/mips_ejtag_fdc.c:245:13: warning: this statement may fall through [-Wimplicit-fallthrough=]
word.word &= 0x00ffffff;
~~~~~~~~~~^~~~~~~~~~~~~
drivers/tty/mips_ejtag_fdc.c:246:2: note: here
case 3:
^~~~
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Link: https://lore.kernel.org/r/20200306124913.151A68030792@mail.baikalelectronics.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Many embedded boards have a disconnected TTL level serial which can
generate some garbage that can lead to spurious false sysrq detects.
Currently, sysrq can be either completely disabled for serial console
or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since
commit 732dbf3a6104 ("serial: do not accept sysrq characters via serial port")
At Arista, we have such boards that can generate BREAK and random
garbage. While disabling sysrq for serial console would solve
the problem with spurious false sysrq triggers, it's also desirable
to have a way to enable sysrq back.
As a measure of balance between on and off options, add
MAGIC_SYSRQ_SERIAL_SEQUENCE which is a string sequence that can enable
sysrq if it follows BREAK on a serial line. The longer the string - the
less likely it may be in the garbage.
Having the way to enable sysrq was beneficial to debug lockups with
a manual investigation in field and on the other side preventing false
sysrq detections.
Based-on-patch-by: Vasiliy Khoruzhick <vasilykh@arista.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200302175135.269397-3-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Many embedded boards have a disconnected TTL level serial which can
generate some garbage that can lead to spurious false sysrq detects.
Currently, sysrq can be either completely disabled for serial console
or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since
commit 732dbf3a6104 ("serial: do not accept sysrq characters via serial port")
At Arista, we have such boards that can generate BREAK and random
garbage. While disabling sysrq for serial console would solve
the problem with spurious false sysrq triggers, it's also desirable
to have a way to enable sysrq back.
Having the way to enable sysrq was beneficial to debug lockups with
a manual investigation in field and on the other side preventing false
sysrq detections.
As a preparation to add sysrq_toggle_support() call into uart,
remove a private copy of sysrq_enabled from sysctl - it should reflect
the actual status of sysrq.
Furthermore, the private copy isn't correct already in case
sysrq_always_enabled is true. So, remove __sysrq_enabled and use a
getter-helper sysrq_mask() to check sysrq_key_op enabled status.
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200302175135.269397-2-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
introduced support to use RTS as an rs485 Transmit Enable signal if data
is transmitted through the tty layer.
Console messages bypass the tty layer and instead are emitted via
serial8250_console_write(). Amend that function to drive RTS as well,
allowing for a console on rs485 ports.
Note that serial8250_console_write() may be called concurrently to the
tty layer accessing the port. The two protect their accesses with the
port lock, but serial8250_console_write() may find RTS still being
asserted by the tty layer, in which case it shouldn't be deasserted
after the console message has been printed. Recognize such situations
by checking the em485->tx_stopped flag.
If a delay_rts_before_send or delay_rts_after_send has been specified,
serial8250_console_write() busy-waits for its duration. Optimizations
for those wait times are conceivable: E.g. if RTS is already asserted,
we could check whether em485->start_tx_timer is active and wait only
for the remaining expire time. But this would require calling into
the hrtimer infrastructure, which involves acquiring locks and
potentially reprogramming timer hardware. Such operations seem too
risky in the context of console printout, which needs to work even when
the kernel has crashed and emits a BUG splat. So I've gone with a
simplistic solution which just always waits for the full delay.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/65edffce4670a19e598015c03cbe46f1ffd93e43.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Amend 8250_bcm2835aux.c to support rs485 as introduced for 8250_omap.c
by commit e490c9144cfa ("tty: Add software emulated RS485 support for
8250").
The bcm2835aux differs from omap chips by inverting the meaning of RTS
in the MCR register: If the bit is clear, RTS is high. With omap, it's
apparently the other way round.
Moreover, omap achieves half-duplex mode by disabling the UART_IER_RDI
interrupt and clearing the RX FIFO when TX stops. This approach doesn't
work on bcm2835aux because the UART_LSR_DR bit is set even when
UART_IER_RDI is disabled. Consequently, serial8250_handle_irq() invokes
serial8250_rx_chars() to empty the FIFO and characters are received even
though the user requested half-duplex. Solve by disabling the receiver
using the non-standard CNTL register.
Cache that register in the driver's private data for performance. Set
the private data pointer before calling serial8250_register_8250_port()
to prevent a null pointer deref in case one of the rs485 callbacks is
invoked immediately after port registration.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/dd86460e20a8f979b7272a0bde73640312b902b1.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
introduced support to use RTS as an rs485 Transmit Enable signal.
So far the only drivers taking advantage of it are 8250_omap.c and
8250_of.c.
We're about to make use of the feature in 8250_bcm2835aux.c as well.
The bcm2835aux differs from omap chips by inverting the meaning of RTS
in the MCR register. Moreover, omap achieves half-duplex mode by
disabling the RX interrupt and clearing the RX FIFO when TX stops.
The bcm2835aux requires disabling the receiver instead.
Support these behavioral differences by generalizing the rs485 emulation:
Introduce ->rs485_start_tx() and ->rs485_stop_tx() callbacks in struct
uart_8250_port, provide generic implementations containing the existing
code and use them as callbacks in 8250_omap.c and 8250_of.c.
start_tx_rs485() is idempotent in that it recognizes whether RTS is
already asserted. Achieve the same by introducing a tx_stopped flag in
struct uart_8250_em485. This may even perform a little better on arches
where memory access is faster than mmio access.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/5ac0464ae4414708e723a1e0d52b0c1b2bd41b9b.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When rs485 transmission over an 8250 port stops, __stop_tx() assigns
active_timer = NULL before calling __stop_tx_rs485().
That function in turn either assigns active_timer = stop_tx_timer and
rearms the timer (in case a delay_rts_after_send needs to be observed)
or directly calls __do_stop_tx_rs485().
Move the assignment active_timer = NULL to __stop_tx_rs485() into the
branch which directly calls __do_stop_tx_rs485(), thereby avoiding a
duplicate assignment and simplifying the code.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/bca638405550eaf92f0c6060b553b687f35885e0.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Amend the generic ->rs485_config() callback to sanitize RTS polarity and
zero-fill the padding (in addition to the existing sanitization of the
RTS delays).
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/ff833721bc372d38678f289eb2a44dbf016d5203.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
introduced support to use RTS as an rs485 Transmit Enable signal.
Drivers opt in to the feature by calling serial8250_em485_init() from
their ->rs485_config() callback.
So far there are two drivers doing that, 8250_omap.c and 8250_of.c.
Both use an identical callback. We're about to add a third user of that
callback, therefore deduplicate it and move it to 8250_port.c.
Drivers now opt in to rs485 software emulation by assigning the generic
serial8250_rs485_config() callback introduced herein to their
.rs485_config struct member. This change allows unexporting
serial8250_em485_init() and declaring it static.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Cc: Heiko Schocher <hs@denx.de>
Link: https://lore.kernel.org/r/fcef63642dc4eae41ae7842d23747b2bf5d40285.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Retrieve rs485 devicetree properties on registration of 8250 ports in
case they are attached to an rs485 transceiver.
If the property "linux,rs485-enabled-at-boot-time" is present, invoke
the ->rs485_config() callback to immediately deassert RTS, thereby
ceasing control of the bus.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Giulio Benetti <giulio.benetti@micronovasrl.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/5908ea89b7f9da54872d6634b606d83db032297a.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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serial8250_do_set_mctrl() currently allows modifying the RTS modem
control line even when RTS is used as an rs485 Transmit Enable signal.
It is thus possible for user space to interfere with rs485 communication
by invoking a TIOCMSET ioctl().
Ignore such change requests and retain the current RTS polarity when in
rs485 mode. Note that serial8250_set_mctrl() is always called with
port->lock held, so there's no risk that RTS is changed concurrently.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/b1ce34ca9bc4d7bdc6e9852fcf30b1f4e37c8a80.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If a driver exposes early consoles with EARLYCON_DECLARE() and
OF_EARLYCON_DECLARE(), pefer the non-OF variant if the user specifies it
by
earlycon=<driver>,<options>
The rationale behind this is that some drivers register multiple setup
functions under the same driver name. Eg.
OF_EARLYCON_DECLARE(lpuart, "fsl,vf610-lpuart", lpuart_early_console_setup);
OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1021a-lpuart", lpuart32_early_console_setup);
OF_EARLYCON_DECLARE(lpuart32, "fsl,imx7ulp-lpuart", lpuart32_imx_early_console_setup);
EARLYCON_DECLARE(lpuart, lpuart_early_console_setup);
EARLYCON_DECLARE(lpuart32, lpuart32_early_console_setup);
It depends on the order of the entries which console_setup() actually
gets called. To make things worse, I guess it also depends on the
compiler how these are ordered. Thus always prefer the EARLYCON_DECLARE()
ones.
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200220174607.24285-1-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This patch corrects the SPDX License Identifier style in
header files related to tty serial drivers.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).
Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Link: https://lore.kernel.org/r/20200301204517.GA10368@nishad
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This makes the script more convenient to run.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When syzkaller tests, there is a UAF:
BUG: KASan: use after free in vgacon_invert_region+0x9d/0x110 at addr
ffff880000100000
Read of size 2 by task syz-executor.1/16489
page:ffffea0000004000 count:0 mapcount:-127 mapping: (null)
index:0x0
page flags: 0xfffff00000000()
page dumped because: kasan: bad access detected
CPU: 1 PID: 16489 Comm: syz-executor.1 Not tainted
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
Call Trace:
[<ffffffffb119f309>] dump_stack+0x1e/0x20
[<ffffffffb04af957>] kasan_report+0x577/0x950
[<ffffffffb04ae652>] __asan_load2+0x62/0x80
[<ffffffffb090f26d>] vgacon_invert_region+0x9d/0x110
[<ffffffffb0a39d95>] invert_screen+0xe5/0x470
[<ffffffffb0a21dcb>] set_selection+0x44b/0x12f0
[<ffffffffb0a3bfae>] tioclinux+0xee/0x490
[<ffffffffb0a1d114>] vt_ioctl+0xff4/0x2670
[<ffffffffb0a0089a>] tty_ioctl+0x46a/0x1a10
[<ffffffffb052db3d>] do_vfs_ioctl+0x5bd/0xc40
[<ffffffffb052e2f2>] SyS_ioctl+0x132/0x170
[<ffffffffb11c9b1b>] system_call_fastpath+0x22/0x27
Memory state around the buggy address:
ffff8800000fff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00
ffff8800000fff80: 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00
>ffff880000100000: ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff ff
It can be reproduce in the linux mainline by the program:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <linux/vt.h>
struct tiocl_selection {
unsigned short xs; /* X start */
unsigned short ys; /* Y start */
unsigned short xe; /* X end */
unsigned short ye; /* Y end */
unsigned short sel_mode; /* selection mode */
};
#define TIOCL_SETSEL 2
struct tiocl {
unsigned char type;
unsigned char pad;
struct tiocl_selection sel;
};
int main()
{
int fd = 0;
const char *dev = "/dev/char/4:1";
struct vt_consize v = {0};
struct tiocl tioc = {0};
fd = open(dev, O_RDWR, 0);
v.v_rows = 3346;
ioctl(fd, VT_RESIZEX, &v);
tioc.type = TIOCL_SETSEL;
ioctl(fd, TIOCLINUX, &tioc);
return 0;
}
When resize the screen, update the 'vc->vc_size_row' to the new_row_size,
but when 'set_origin' in 'vgacon_set_origin', vgacon use 'vga_vram_base'
for 'vc_origin' and 'vc_visible_origin', not 'vc_screenbuf'. It maybe
smaller than 'vc_screenbuf'. When TIOCLINUX, use the new_row_size to calc
the offset, it maybe larger than the vga_vram_size in vgacon driver, then
bad access.
Also, if set an larger screenbuf firstly, then set an more larger
screenbuf, when copy old_origin to new_origin, a bad access may happen.
So, If the screen size larger than vga_vram, resize screen should be
failed. This alse fix CVE-2020-8649 and CVE-2020-8647.
Linus pointed out that overflow checking seems absent. We're saved by
the existing bounds checks in vc_do_resize() with rather strict
limits:
if (cols > VC_RESIZE_MAXCOL || lines > VC_RESIZE_MAXROW)
return -EINVAL;
Fixes: 0aec4867dca14 ("[PATCH] SVGATextMode fix")
Reference: CVE-2020-8647 and CVE-2020-8649
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
[danvet: augment commit message to point out overflow safety]
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200304022429.37738-1-zhangxiaoxu5@huawei.com
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The hierarchical topology with power-domain should be described through
child nodes, rather than as currently described in the PSCI root node. Fix
this by adding a patternProperties with a corresponding reference to the
power-domain DT binding.
Additionally, update the example to conform to the new pattern, but also to
the adjusted domain-idle-state DT binding.
Fixes: a3f048b5424e ("dt: psci: Update DT bindings to support hierarchical PSCI states")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[robh: Add missing allOf, tweak power-domain node name]
Signed-off-by: Rob Herring <robh@kernel.org>
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The existing binding requires the nodename to have a '@', which is a bit
limiting for the wider use case. Therefore, let's extend the pattern to
allow either '@' or '-'.
Fixes: a3f048b5424e ("dt: psci: Update DT bindings to support hierarchical PSCI states")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[robh: drop example change]
Signed-off-by: Rob Herring <robh@kernel.org>
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Andy Shevchenko
Geert Uytterhoeven
Lanqing Liu
Chunyan Zhang
Jiri Slaby
Douglas Anderson
Eric Biggers
satya priya
Linus Walleij
Michael Walle
Dmitry Safonov
Palmer Dabbelt
Linus Torvalds
Pavel Begunkov
Serge Semin
Lukas Wunner
Nishad Kamdar
Jonathan Neuschäfer
Zhang Xiaoxu
Ulf Hansson