linux-stable.git/drivers/tty/serial/sh-sci.c, branch v4.18.2

Merge tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

2018-06-06T23:04:55+00:00

Pull printk updates from Petr Mladek:

 - Help userspace log daemons to catch up with a flood of messages. They
   will get woken after each message even if the console is far behind
   and handled by another process.

 - Flush printk safe buffers safely even when panic() happens in the
   normal context.

 - Fix possible va_list reuse when race happened in printk_safe().

 - Remove %pCr printf format to prevent sleeping in the atomic context.

 - Misc vsprintf code cleanup.

* tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  printk: drop in_nmi check from printk_safe_flush_on_panic()
  lib/vsprintf: Remove atomic-unsafe support for %pCr
  serial: sh-sci: Stop using printk format %pCr
  thermal: bcm2835: Stop using printk format %pCr
  clk: renesas: cpg-mssr: Stop using printk format %pCr
  printk: fix possible reuse of va_list variable
  printk: wake up klogd in vprintk_emit
  vsprintf: Tweak pF/pf comment
  lib/vsprintf: Mark expected switch fall-through
  lib/vsprintf: Replace space with '_' before crng is ready
  lib/vsprintf: Deduplicate pointer_string()
  lib/vsprintf: Move pointer_string() upper
  lib/vsprintf: Make flag_spec global
  lib/vsprintf: Make strspec global
  lib/vsprintf: Make dec_spec global
  lib/test_printf: Mark big constant with UL

serial: sh-sci: Stop using printk format %pCr

2018-06-05T07:43:39+00:00

Printk format "%pCr" will be removed soon, as clk_get_rate() must not be
called in atomic context.

Replace it by open-coding the operation.  This is safe here, as the code
runs in task context.

Link: http://lkml.kernel.org/r/1527845302-12159-4-git-send-email-geert+renesas@glider.be
To: Jia-Ju Bai 
To: Jonathan Corbet 
To: Michael Turquette 
To: Stephen Boyd 
To: Zhang Rui 
To: Eduardo Valentin 
To: Eric Anholt 
To: Stefan Wahren 
To: Greg Kroah-Hartman 
Cc: Sergey Senozhatsky 
Cc: Petr Mladek 
Cc: Linus Torvalds 
Cc: Steven Rostedt 
Cc: linux-doc@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Geert Uytterhoeven 
Cc: stable@vger.kernel.org # 4.5+
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Petr Mladek

serial: sh-sci: Use spin_{try}lock_irqsave instead of open coding version

2018-05-14T11:51:11+00:00

Commit 40f70c03e33a ("serial: sh-sci: add locking to console write
function to avoid SMP lockup") copied the strategy to avoid locking
problems in conjuncture with the console from the UART8250
driver. Instead using directly spin_{try}lock_irqsave(),
local_irq_save() followed by spin_{try}lock() was used. While this is
correct on mainline, for -rt it is a problem. spin_{try}lock() will
check if it is running in a valid context. Since the local_irq_save()
has already been executed, the context has changed and
spin_{try}lock() will complain. The reason why spin_{try}lock()
complains is that on -rt the spin locks are turned into mutexes and
therefore can sleep. Sleeping with interrupts disabled is not valid.

BUG: sleeping function called from invalid context at /home/wagi/work/rt/v4.4-cip-rt/kernel/locking/rtmutex.c:995
in_atomic(): 0, irqs_disabled(): 128, pid: 778, name: irq/76-eth0
CPU: 0 PID: 778 Comm: irq/76-eth0 Not tainted 4.4.126-test-cip22-rt14-00403-gcd03665c8318 #12
Hardware name: Generic RZ/G1 (Flattened Device Tree)
Backtrace:
[] (dump_backtrace) from [] (show_stack+0x18/0x1c)
 r7:c06b01f0 r6:60010193 r5:00000000 r4:c06b01f0
[] (show_stack) from [] (dump_stack+0x78/0x94)
[] (dump_stack) from [] (___might_sleep+0x134/0x194)
 r7:60010113 r6:c06d3559 r5:00000000 r4:ffffe000
[] (___might_sleep) from [] (rt_spin_lock+0x20/0x74)
 r5:c06f4d60 r4:c06f4d60
[] (rt_spin_lock) from [] (serial_console_write+0x100/0x118)
 r5:c06f4d60 r4:c06f4d60
[] (serial_console_write) from [] (call_console_drivers.constprop.15+0x10c/0x124)
 r10:c06d2894 r9:c04e18b0 r8:00000028 r7:00000000 r6:c06d3559 r5:c06d2798
 r4:c06b9914 r3:c02576e4
[] (call_console_drivers.constprop.15) from [] (console_unlock+0x32c/0x430)
 r10:c06d30d8 r9:00000028 r8:c06dd518 r7:00000005 r6:00000000 r5:c06d2798
 r4:c06d2798 r3:00000028
[] (console_unlock) from [] (vprintk_emit+0x394/0x4f0)
 r10:c06d2798 r9:c06d30ee r8:00000006 r7:00000005 r6:c06a78fc r5:00000027
 r4:00000003
[] (vprintk_emit) from [] (vprintk+0x28/0x30)
 r10:c060bd46 r9:00001000 r8:c06b9a90 r7:c06b9a90 r6:c06b994c r5:c06b9a3c
 r4:c0062fa8
[] (vprintk) from [] (vprintk_default+0x10/0x14)
[] (vprintk_default) from [] (printk+0x78/0x84)
[] (printk) from [] (credit_entropy_bits+0x17c/0x2cc)
 r3:00000001 r2:decade60 r1:c061a5ee r0:c061a523
 r4:00000006
[] (credit_entropy_bits) from [] (add_interrupt_randomness+0x160/0x178)
 r10:466e7196 r9:1f536000 r8:fffeef74 r7:00000000 r6:c06b9a60 r5:c06b9a3c
 r4:dfbcf680
[] (add_interrupt_randomness) from [] (irq_thread+0x1e8/0x248)
 r10:c006537c r9:c06cdf21 r8:c0064fcc r7:df791c24 r6:df791c00 r5:ffffe000
 r4:df525180
[] (irq_thread) from [] (kthread+0x108/0x11c)
 r10:00000000 r9:00000000 r8:c0065184 r7:df791c00 r6:00000000 r5:df791d00
 r4:decac000
[] (kthread) from [] (ret_from_fork+0x14/0x3c)
 r8:00000000 r7:00000000 r6:00000000 r5:c003fa9c r4:df791d00

Cc: Sebastian Andrzej Siewior 
Signed-off-by: Daniel Wagner 
Reviewed-by: Geert Uytterhoeven 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Support for HSCIF RX sampling point adjustment

2018-04-23T08:08:18+00:00

HSCIF has facilities that allow moving the RX sampling point by between
-8 and 7 sampling cycles (one sampling cycles equals 1/15 of a bit
by default) to improve the error margin in case of slightly mismatched
bit rates between sender and receiver.

This patch tries to determine if shifting the sampling point can improve
the error margin and will enable it if so.

Signed-off-by: Ulrich Hecht 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Add support for dynamic instances

2018-04-23T08:08:18+00:00

On DT platforms, the sh-sci driver requires the presence of "serialN"
aliases in DT, from which instance IDs are derived.  If a DT alias is
missing, the drivers fails to probe the corresponding serial port.

This becomes cumbersome when considering DT overlays, as currently
there is no upstream support for dynamically updating the /aliases node
in DT.  Furthermore, even in the presence of such support, hardcoded
instance IDs in independent overlays are prone to conflicts.

Hence add support for dynamic instance IDs, to be used in the absence of
a DT alias.  This makes serial ports behave similar to I2C and SPI
buses, which already support dynamic instances.

Ports in use are tracked using a simple bitmask of type unsigned long,
which is sufficient to handle all current hardware (max. 18 ports).
The maximum number of serial ports is still fixed, and configurable
through Kconfig.  Range validation is done through both Kconfig and a
compile-time check.

Due to the fixed maximum number of serial ports, dynamic and static
instances share the same ID space.  Static instances added later are
rejected when conflicting with dynamic instances registered earlier.

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Greg Kroah-Hartman

Merge 4.16-rc6 into tty-next

2018-03-20T10:27:18+00:00

We want the serial/tty fixes in here as well.

Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: Fix out-of-bounds access through DT alias

2018-02-28T14:30:00+00:00

The sci_ports[] array is indexed using a value derived from the
"serialN" alias in DT, which may lead to an out-of-bounds access.

Fix this by adding a range check.

Note that the array size is defined by a Kconfig symbol
(CONFIG_SERIAL_SH_SCI_NR_UARTS), so this can even be triggered using a
legitimate DTB.

Fixes: 97ed9790c514066b ("serial: sh-sci: Remove unused platform data capabilities field")
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: prevent lockup on full TTY buffers

2018-02-28T12:48:21+00:00

When the TTY buffers fill up to the configured maximum, a system lockup
occurs:

[  598.820128] INFO: rcu_preempt detected stalls on CPUs/tasks:
[  598.825796]  0-...!: (1 GPs behind) idle=5a6/2/0 softirq=1974/1974 fqs=1
[  598.832577]  (detected by 3, t=62517 jiffies, g=296, c=295, q=126)
[  598.838755] Task dump for CPU 0:
[  598.841977] swapper/0       R  running task        0     0      0 0x00000022
[  598.849023] Call trace:
[  598.851476]  __switch_to+0x98/0xb0
[  598.854870]            (null)

This can be prevented by doing a dummy read of the RX data register.

This issue affects both HSCIF and SCIF ports. Reported for R-Car H3 ES2.0;
reproduced and fixed on H3 ES1.1. Probably affects other R-Car platforms
as well.

Reported-by: Yoshihiro Shimoda 
Signed-off-by: Ulrich Hecht 
Reviewed-by: Geert Uytterhoeven 
Cc: stable 
Tested-by: Nguyen Viet Dung 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: use hrtimer for receive timeout

2018-02-28T12:40:22+00:00

High latencies of classic timers cause performance issues for high-
speed serial transmissions. This patch transforms rx_timer into an
hrtimer to reduce the minimum latency.

Signed-off-by: Ulrich Hecht 
Signed-off-by: Greg Kroah-Hartman

treewide: Use DEVICE_ATTR_RW

2018-01-09T15:33:31+00:00

Convert DEVICE_ATTR uses to DEVICE_ATTR_RW where possible.

Done with perl script:

$ git grep -w --name-only DEVICE_ATTR | \
  xargs perl -i -e 'local $/; while (<>) { s/\bDEVICE_ATTR\s*\(\s*(\w+)\s*,\s*\(?(\s*S_IRUGO\s*\|\s*S_IWUSR|\s*S_IWUSR\s*\|\s*S_IRUGO\s*|\s*0644\s*)\)?\s*,\s*\1_show\s*,\s*\1_store\s*\)/DEVICE_ATTR_RW(\1)/g; print;}'

Signed-off-by: Joe Perches 
Acked-by: Felipe Balbi 
Acked-by: Andy Shevchenko 
Acked-by: Bartlomiej Zolnierkiewicz 
Acked-by: Zhang Rui 
Acked-by: Jarkko Nikula 
Acked-by: Jani Nikula 
Signed-off-by: Greg Kroah-Hartman