Pull kgdb updates from Daniel Thompson:
"By far the biggest change in this cycle are the changes that allow
much earlier debug of systems that are hooked up via UART by taking
advantage of the earlycon framework to implement the kgdb I/O hooks
before handing over to the regular polling I/O drivers once they are
available. When discussing Doug's work we also found and fixed an
broken raw_smp_processor_id() sequence in in_dbg_master().
Also included are a collection of much smaller fixes and tweaks: a
couple of tweaks to ged rid of doc gen or coccicheck warnings, future
proof some internal calculations that made implicit power-of-2
assumptions and eliminate some rather weird handling of magic
environment variables in kdb"
* tag 'kgdb-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
kdb: Remove the misfeature 'KDBFLAGS'
kdb: Cleanup math with KDB_CMD_HISTORY_COUNT
serial: amba-pl011: Support kgdboc_earlycon
serial: 8250_early: Support kgdboc_earlycon
serial: qcom_geni_serial: Support kgdboc_earlycon
serial: kgdboc: Allow earlycon initialization to be deferred
Documentation: kgdboc: Document new kgdboc_earlycon parameter
kgdb: Don't call the deinit under spinlock
kgdboc: Disable all the early code when kgdboc is a module
kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles
kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc
kgdb: Prevent infinite recursive entries to the debugger
kgdb: Delay "kgdbwait" to dbg_late_init() by default
kgdboc: Use a platform device to handle tty drivers showing up late
Revert "kgdboc: disable the console lock when in kgdb"
kgdb: Disable WARN_CONSOLE_UNLOCKED for all kgdb
kgdb: Return true in kgdb_nmi_poll_knock()
kgdb: Drop malformed kernel doc comment
kgdb: Fix spurious true from in_dbg_master()
Currently there is no guarantee that an earlycon will be initialized
before kgdboc tries to adopt it. Almost the opposite: on systems
with ACPI then if earlycon has no arguments then it is guaranteed that
earlycon will not be initialized.
This patch mitigates the problem by giving kgdboc_earlycon a second
chance during console_init(). This isn't quite as good as stopping during
early parameter parsing but it is still early in the kernel boot.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200430161741.1832050-1-daniel.thompson@linaro.org
Reviewed-by: Douglas Anderson <dianders@chromium.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 eae3e19ca9 ("kgdboc:
Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc") and then
made worse by commit 220995622d ("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: 220995622d ("kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles")
Fixes: eae3e19ca9 ("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@changeid
Signed-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@changeid
Signed-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>
Pull tty/serial fixes from Greg KH:
"Here are three small TTY/Serial/VT fixes for 5.7-rc5:
- revert for the bcm63xx driver "fix" that was incorrect
- vt unicode console bugfix
- xilinx_uartps console driver fix
All of these have been in linux next with no reported issues"
* tag 'tty-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
tty: xilinx_uartps: Fix missing id assignment to the console
vt: fix unicode console freeing with a common interface
Revert "tty: serial: bcm63xx: fix missing clk_put() in bcm63xx_uart"
Pull RISC-V fixes from Palmer Dabbelt:
"A handful of fixes.
Specifically:
- fix linker argument to allow linking with lld
- build fix for configurations without a frame pointer
- a handful of build fixes related the SBI 0.1 vs 0.2 split
- remove STRICT_KERNEL_RWX for !MMU, which isn't useful"
* tag 'riscv-for-linus-5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: select ARCH_HAS_STRICT_KERNEL_RWX only if MMU
riscv: sbi: Fix undefined reference to sbi_shutdown
tty: riscv: Using RISCV_SBI_V01 instead of RISCV_SBI
riscv: sbi: Correct sbi_shutdown() and sbi_clear_ipi() export
riscv: fix vdso build with lld
RISC-V: stacktrace: Declare sp_in_global outside ifdef
commit 8ba92cf593 ("arm64: dts: actions: s700: Add Clock Management Unit")
breaks the UART on Cubieboard7-lite (based on S700 SoC), This is due to the
fact that generic clk routine clk_disable_unused() disables the gate clks,
and that in turns disables OWL UART (but UART driver never enables it). To
prove this theory, Andre suggested to use "clk_ignore_unused" in kernel
commnd line and it worked (Kernel happily lands into RAMFS world :)).
This commit fix this up by adding clk_prepare_enable().
Fixes: 8ba92cf593 ("arm64: dts: actions: s700: Add Clock Management Unit")
Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1587067917-1400-1-git-send-email-amittomer25@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As shown in SBI v0.2, the legacy console SBI functions (sbi_console_getchar()
and sbi_console_putchar()) are expected to be deprecated; they have no replacement.
Let's HVC_RISCV_SBI and SERIAL_EARLYCON_RISCV_SBI depends on RISCV_SBI_V01.
Fixes: efca139892 ("RISC-V: Introduce a new config for SBI v0.1")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
The commit a3cb39d258
("serial: core: Allow detach and attach serial device for console")
changed a bit logic behind lock initialization since for most of the console
driver it's supposed to have lock already initialized even if console is not
enabled. However, it's not the case for Sparc HV console.
Initialize lock explicitly in the ->probe().
Note, there is still an open question should or shouldn't not this driver
register console properly.
Fixes: a3cb39d258 ("serial: core: Allow detach and attach serial device for console")
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Anatoly Pugachev <matorola@gmail.com>
Link: https://lore.kernel.org/r/20200402172026.79478-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull char/misc driver updates from Greg KH:
"Here is the big set of char/misc/other driver patches for 5.7-rc1.
Lots of things in here, and it's later than expected due to some
reverts to resolve some reported issues. All is now clean with no
reported problems in linux-next.
Included in here is:
- interconnect updates
- mei driver updates
- uio updates
- nvmem driver updates
- soundwire updates
- binderfs updates
- coresight updates
- habanalabs updates
- mhi new bus type and core
- extcon driver updates
- some Kconfig cleanups
- other small misc driver cleanups and updates
As mentioned, all have been in linux-next for a while, and with the
last two reverts, all is calm and good"
* tag 'char-misc-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (174 commits)
Revert "driver core: platform: Initialize dma_parms for platform devices"
Revert "amba: Initialize dma_parms for amba devices"
amba: Initialize dma_parms for amba devices
driver core: platform: Initialize dma_parms for platform devices
bus: mhi: core: Drop the references to mhi_dev in mhi_destroy_device()
bus: mhi: core: Initialize bhie field in mhi_cntrl for RDDM capture
bus: mhi: core: Add support for reading MHI info from device
misc: rtsx: set correct pcr_ops for rts522A
speakup: misc: Use dynamic minor numbers for speakup devices
mei: me: add cedar fork device ids
coresight: do not use the BIT() macro in the UAPI header
Documentation: provide IBM contacts for embargoed hardware
nvmem: core: remove nvmem_sysfs_get_groups()
nvmem: core: use is_bin_visible for permissions
nvmem: core: use device_register and device_unregister
nvmem: core: add root_only member to nvmem device struct
extcon: axp288: Add wakeup support
extcon: Mark extcon_get_edev_name() function as exported symbol
extcon: palmas: Hide error messages if gpio returns -EPROBE_DEFER
dt-bindings: extcon: usbc-cros-ec: convert extcon-usbc-cros-ec.txt to yaml format
...
Pull tty/serial updates from Greg KH:
"Here is the big set of TTY / Serial patches for 5.7-rc1
Lots of console fixups and reworking in here, serial core tweaks
(doesn't that ever get old, why are we still creating new serial
devices?), serial driver updates, line-protocol driver updates, and
some vt cleanups and fixes included in here as well.
All have been in linux-next with no reported issues"
* tag 'tty-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (161 commits)
serial: 8250: Optimize irq enable after console write
serial: 8250: Fix rs485 delay after console write
vt: vt_ioctl: fix use-after-free in vt_in_use()
vt: vt_ioctl: fix VT_DISALLOCATE freeing in-use virtual console
tty: serial: make SERIAL_SPRD depend on COMMON_CLK
tty: serial: fsl_lpuart: fix return value checking
tty: serial: fsl_lpuart: move dma_request_chan()
ARM: dts: tango4: Make /serial compatible with ns16550a
ARM: dts: mmp*: Make the serial ports compatible with xscale-uart
ARM: dts: mmp*: Fix serial port names
ARM: dts: mmp2-brownstone: Don't redeclare phandle references
ARM: dts: pxa*: Make the serial ports compatible with xscale-uart
ARM: dts: pxa*: Fix serial port names
ARM: dts: pxa*: Don't redeclare phandle references
serial: omap: drop unused dt-bindings header
serial: 8250: 8250_omap: Add DMA support for UARTs on K3 SoCs
serial: 8250: 8250_omap: Work around errata causing spurious IRQs with DMA
serial: 8250: 8250_omap: Extend driver data to pass FIFO trigger info
serial: 8250: 8250_omap: Move locking out from __dma_rx_do_complete()
serial: 8250: 8250_omap: Account for data in flight during DMA teardown
...
Commit 7f9803072f ("serial: 8250: Support console on software emulated
rs485 ports") amended serial8250_console_write() with rs485 support, but
positioned the invocation of ->rs485_stop_tx() after re-enablement of
interrupts. The irq handler and ->console_write() are serialized with
the port spinlock, so no problem there, but due to the rs485 delay, the
irq handler may unnecessarily spin for a while. Avoid that by moving
->rs485_stop_tx() before re-enablement of interrupts, which also mirrors
the order at the beginning of serial8250_console_write().
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/019839cb1f61b01210b6ff9ac9f9079ca77f8411.1585319447.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kbuild-test reported an error:
config: mips-randconfig-a001-20200321 ...
>> drivers/tty/serial/sprd_serial.c:1175: undefined reference
to `clk_set_parent'
Because some mips Kconfig selects HAVE_CLK but not COMMON_CLK and no
clk_set_parent implemented, so the error was exposed. So adding
dependence on COMMON_CLK can fix this issue.
Fixes: 7ba87cfec7 ("tty: serial: make SERIAL_SPRD not depend on ARCH_SPRD")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20200325081427.20312-1-zhang.lyra@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As per Advisory 27 of AM437x Silicon errata document, Spurious UART
interrupts may occur when DMA mode (FCR.DMA_MODE) is enabled. The
Interrupt Controller flags that a UART interrupt has occurred; however,
the associated IT_PENDING bit remains set to 1, indicating that no
interrupt is pending. Acknowledge the spurious interrupts for every
occurrence as workaround.
Errata is applicable to all TI SoCs with this IP.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200319110344.21348-6-vigneshr@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Although same 8250 compliant UART IP is reused across different SoC,
their integration wrt DMA varies greatly across SoCs. Therefore,
different SoC may need to use different FIFO trigger level for DMA
event and DMA configuration parameters. Provide a way to pass this
information via driver data. This is required to support UART DMA on
AM654/J721e SoCs.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200319110344.21348-5-vigneshr@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Terminate and flush DMA internal buffers, before pushing RX data to
higher layer. Otherwise, this will lead to data corruption, as driver
would end up pushing stale buffer data to higher layer while actual data
is still stuck inside DMA hardware and has yet not arrived at the
memory.
While at that, replace deprecated dmaengine_terminate_all() with
dmaengine_terminate_async().
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200319110344.21348-2-vigneshr@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When port's throttle callback is called, it should stop pushing any more
data into TTY buffer to avoid buffer overflow. This means driver has to
stop HW from receiving more data and assert the HW flow control. For
UARTs with auto HW flow control (such as 8250_omap) manual assertion of
flow control line is not possible and only way is to allow RX FIFO to
fill up, thus trigger auto HW flow control logic.
Therefore make sure that 8250 generic IRQ handler does not drain data
when port is stopped (i.e UART_LSR_DR is unset in read_status_mask). Not
servicing, RX FIFO would trigger auto HW flow control when FIFO
occupancy reaches preset threshold, thus halting RX.
Since, error conditions in UART_LSR register are cleared just by reading
the register, data has to be drained in case there are FIFO errors, else
error information will lost.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200319103230.16867-2-vigneshr@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch simplifies the process of getting serial port number, with
this patch, serial devices must have aliases configured in devicetree.
The serial port searched out via sprd_port array maybe wrong if we don't
have serial alias defined in devicetree, and specify console with command
line, we would get the wrong port number if other serial ports probe
failed before console's. So using aliases is mandatory.
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20200318105049.19623-2-zhang.lyra@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
