* [PATCH tty v1 61/74] serial: sifive: Use port lock wrappers
2023-09-14 18:37 [PATCH tty v1 00/74] serial: wrappers for uart port lock John Ogness
@ 2023-09-14 18:38 ` John Ogness
2023-09-14 19:01 ` [PATCH tty v1 00/74] serial: wrappers for uart port lock Maciej W. Rozycki
` (2 subsequent siblings)
3 siblings, 0 replies; 10+ messages in thread
From: John Ogness @ 2023-09-14 18:38 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Petr Mladek, Yangtao Li, Richard GENOUD, Ruan Jinjie,
linux-kernel, Nick Hu, Palmer Dabbelt, linux-serial,
Paul Walmsley, Thomas Gleixner, Jiri Slaby, linux-riscv
From: Thomas Gleixner <tglx@linutronix.de>
When a serial port is used for kernel console output, then all
modifications to the UART registers which are done from other contexts,
e.g. getty, termios, are interference points for the kernel console.
So far this has been ignored and the printk output is based on the
principle of hope. The rework of the console infrastructure which aims to
support threaded and atomic consoles, requires to mark sections which
modify the UART registers as unsafe. This allows the atomic write function
to make informed decisions and eventually to restore operational state. It
also allows to prevent the regular UART code from modifying UART registers
while printk output is in progress.
All modifications of UART registers are guarded by the UART port lock,
which provides an obvious synchronization point with the console
infrastructure.
To avoid adding this functionality to all UART drivers, wrap the
spin_[un]lock*() invocations for uart_port::lock into helper functions
which just contain the spin_[un]lock*() invocations for now. In a
subsequent step these helpers will gain the console synchronization
mechanisms.
Converted with coccinelle. No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
drivers/tty/serial/sifive.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index d195c5de52e7..b296e57a9dee 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -521,11 +521,11 @@ static irqreturn_t sifive_serial_irq(int irq, void *dev_id)
struct sifive_serial_port *ssp = dev_id;
u32 ip;
- spin_lock(&ssp->port.lock);
+ uart_port_lock(&ssp->port);
ip = __ssp_readl(ssp, SIFIVE_SERIAL_IP_OFFS);
if (!ip) {
- spin_unlock(&ssp->port.lock);
+ uart_port_unlock(&ssp->port);
return IRQ_NONE;
}
@@ -534,7 +534,7 @@ static irqreturn_t sifive_serial_irq(int irq, void *dev_id)
if (ip & SIFIVE_SERIAL_IP_TXWM_MASK)
__ssp_transmit_chars(ssp);
- spin_unlock(&ssp->port.lock);
+ uart_port_unlock(&ssp->port);
return IRQ_HANDLED;
}
@@ -653,7 +653,7 @@ static void sifive_serial_set_termios(struct uart_port *port,
ssp->port.uartclk / 16);
__ssp_update_baud_rate(ssp, rate);
- spin_lock_irqsave(&ssp->port.lock, flags);
+ uart_port_lock_irqsave(&ssp->port, &flags);
/* Update the per-port timeout */
uart_update_timeout(port, termios->c_cflag, rate);
@@ -670,7 +670,7 @@ static void sifive_serial_set_termios(struct uart_port *port,
if (v != old_v)
__ssp_writel(v, SIFIVE_SERIAL_RXCTRL_OFFS, ssp);
- spin_unlock_irqrestore(&ssp->port.lock, flags);
+ uart_port_unlock_irqrestore(&ssp->port, flags);
}
static void sifive_serial_release_port(struct uart_port *port)
@@ -795,9 +795,9 @@ static void sifive_serial_console_write(struct console *co, const char *s,
if (ssp->port.sysrq)
locked = 0;
else if (oops_in_progress)
- locked = spin_trylock(&ssp->port.lock);
+ locked = uart_port_trylock(&ssp->port);
else
- spin_lock(&ssp->port.lock);
+ uart_port_lock(&ssp->port);
ier = __ssp_readl(ssp, SIFIVE_SERIAL_IE_OFFS);
__ssp_writel(0, SIFIVE_SERIAL_IE_OFFS, ssp);
@@ -807,7 +807,7 @@ static void sifive_serial_console_write(struct console *co, const char *s,
__ssp_writel(ier, SIFIVE_SERIAL_IE_OFFS, ssp);
if (locked)
- spin_unlock(&ssp->port.lock);
+ uart_port_unlock(&ssp->port);
local_irq_restore(flags);
}
--
2.39.2
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^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock
2023-09-14 18:37 [PATCH tty v1 00/74] serial: wrappers for uart port lock John Ogness
2023-09-14 18:38 ` [PATCH tty v1 61/74] serial: sifive: Use port lock wrappers John Ogness
@ 2023-09-14 19:01 ` Maciej W. Rozycki
2023-09-15 12:04 ` Thomas Gleixner
2023-09-15 9:12 ` Ilpo Järvinen
2023-09-18 8:23 ` John Ogness
3 siblings, 1 reply; 10+ messages in thread
From: Maciej W. Rozycki @ 2023-09-14 19:01 UTC (permalink / raw)
To: John Ogness
Cc: Geert Uytterhoeven, Alim Akhtar, Peter Korsgaard, linux-stm32,
Karol Gugala, Jerome Brunet, linux-samsung-soc, Kevin Hilman,
Hugo Villeneuve, Christophe Leroy, Hammer Hsieh, Jiamei Xie,
NXP Linux Team, Vineet Gupta, Thierry Reding, Petr Mladek,
Arend van Spriel, Sascha Hauer, Nicholas Piggin, linux-unisoc,
Thomas Gleixner, Andrew Jeffery, Greg Kroah-Hartman, linux-kernel,
Richard Genoud, Pengutronix Kernel Team, Andrew Morton,
Alexandre Belloni, linux-aspeed, Laxman Dewangan, Dmitry Rokosov,
Xiongfeng Wang, Matthias Schiffer, delisun, Fabio Estevam,
Ruan Jinjie, Matthew Howell, Jonathan Hunter, Gabriel Somlo,
Hongyu Xie, Tobias Klauser, Yangtao Li, Martin Blumenstingl,
linux-arm-msm, linux-actions, Biju Das, linux-amlogic,
Michal Simek, Sherry Sun, Neil Armstrong, Chunyan Zhang,
David S. Miller, Kumaravel Thiagarajan, Lukas Wunner,
Sergey Organov, Mukesh Ojha, Maxime Coquelin, Michael Ellerman,
Pali Rohár, Lino Sanfilippo, Tom Rix, Lorenzo Pieralisi,
Al Cooper, Yuan Can, Isaac True, linux-tegra, Jiri Slaby,
Rob Herring, Florian Fainelli, Mateusz Holenko, Kevin Cernekee,
Andy Shevchenko, Shenwei Wang,
Broadcom internal kernel review list, Joel Stanley, Chen-Yu Tsai,
Ilpo Järvinen, linux-snps-arc, Patrice Chotard, Jacky Huang,
Arnd Bergmann, Uwe Kleine-König, Jonathan Neuschäfer,
Vladimir Zapolskiy, Baolin Wang, Orson Zhai, Tharun Kumar P,
Timur Tabi, Claudiu Beznea, Konrad Dybcio, Thierry Reding,
Sudeep Holla, Shawn Guo, Andreas Färber, Baruch Siach,
Valentin Caron, Tony Lindgren, Sebastian Andrzej Siewior,
Liviu Dudau, Alexandre Torgue, sparclinux, Shan-Chun Hung,
linux-riscv, Marek Vasut, Lech Perczak, Russell King, Nick Hu,
Andy Gross, linux-serial, Lukas Bulwahn, Manivannan Sadhasivam,
Johan Hovold, linux-mediatek, Paul Walmsley, Matthias Brugger,
Andy Shevchenko, AngeloGioacchino Del Regno, linux-arm-kernel,
Taichi Sugaya, Bjorn Andersson, Nicolas Ferre, Lucas Tanure,
Andrew Davis, Krzysztof Kozlowski, Palmer Dabbelt, Takao Orito,
linuxppc-dev
On Thu, 14 Sep 2023, John Ogness wrote:
> Patches 2-74 switch all uart port locking call sites to use the new
> wrappers. These patches were automatically generated using coccinelle.
Hmm, no need to do this for drivers/tty/serial/zs.c?
Maciej
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock
2023-09-14 19:01 ` [PATCH tty v1 00/74] serial: wrappers for uart port lock Maciej W. Rozycki
@ 2023-09-15 12:04 ` Thomas Gleixner
2023-09-15 17:23 ` Maciej W. Rozycki
0 siblings, 1 reply; 10+ messages in thread
From: Thomas Gleixner @ 2023-09-15 12:04 UTC (permalink / raw)
To: Maciej W. Rozycki, John Ogness
Cc: Geert Uytterhoeven, Alim Akhtar, Peter Korsgaard, linux-stm32,
Karol Gugala, Jerome Brunet, linux-samsung-soc, Michael Ellerman,
Hugo Villeneuve, Christophe Leroy, Hammer Hsieh, Jiamei Xie,
NXP Linux Team, Vineet Gupta, Thierry Reding, Petr Mladek,
Arend van Spriel, Sascha Hauer, Nicholas Piggin, linux-unisoc,
Andrew Jeffery, Greg Kroah-Hartman, linux-kernel, Richard Genoud,
Pengutronix Kernel Team, Andrew Morton, Alexandre Belloni,
linux-aspeed, Laxman Dewangan, Dmitry Rokosov, Xiongfeng Wang,
Matthias Schiffer, delisun, Fabio Estevam, Ruan Jinjie,
Matthew Howell, Jonathan Hunter, Gabriel Somlo, Hongyu Xie,
Tobias Klauser, Yangtao Li, Martin Blumenstingl, linux-arm-msm,
linux-actions, Biju Das, linux-amlogic, Michal Simek, Sherry Sun,
Neil Armstrong, Chunyan Zhang, David S. Miller,
Kumaravel Thiagarajan, Lukas Wunner, Sergey Organov, Mukesh Ojha,
Maxime Coquelin, Kevin Hilman, Pali Rohár, Lino Sanfilippo,
Tom Rix, Lorenzo Pieralisi, Al Cooper, Yuan Can, Isaac True,
linux-tegra, Jiri Slaby, Rob Herring, Florian Fainelli,
Mateusz Holenko, Kevin Cernekee, Andy Shevchenko, Shenwei Wang,
Broadcom internal kernel review list, Joel Stanley, Chen-Yu Tsai,
Ilpo Järvinen, linux-snps-arc, Patrice Chotard, Jacky Huang,
Arnd Bergmann, Uwe Kleine-König, Jonathan Neuschäfer,
Vladimir Zapolskiy, Baolin Wang, Orson Zhai, Tharun Kumar P,
Timur Tabi, Claudiu Beznea, Konrad Dybcio, Thierry Reding,
Sudeep Holla, Shawn Guo, Andreas Färber, Baruch Siach,
Valentin Caron, Tony Lindgren, Sebastian Andrzej Siewior,
Liviu Dudau, Alexandre Torgue, sparclinux, Shan-Chun Hung,
linux-riscv, Marek Vasut, Lech Perczak, Russell King, Nick Hu,
Andy Gross, linux-serial, Lukas Bulwahn, Manivannan Sadhasivam,
Johan Hovold, linux-mediatek, Paul Walmsley, Matthias Brugger,
Andy Shevchenko, AngeloGioacchino Del Regno, linux-arm-kernel,
Taichi Sugaya, Bjorn Andersson, Nicolas Ferre, Lucas Tanure,
Andrew Davis, Krzysztof Kozlowski, Palmer Dabbelt, Takao Orito,
linuxppc-dev
On Thu, Sep 14 2023 at 20:01, Maciej W. Rozycki wrote:
> On Thu, 14 Sep 2023, John Ogness wrote:
>
>> Patches 2-74 switch all uart port locking call sites to use the new
>> wrappers. These patches were automatically generated using coccinelle.
>
> Hmm, no need to do this for drivers/tty/serial/zs.c?
zs.c does not use port lock at all. It has like a couple of other
drivers a local homebrewn spinlock.
Thanks,
tglx
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^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock
2023-09-15 12:04 ` Thomas Gleixner
@ 2023-09-15 17:23 ` Maciej W. Rozycki
2023-09-16 19:24 ` John Ogness
0 siblings, 1 reply; 10+ messages in thread
From: Maciej W. Rozycki @ 2023-09-15 17:23 UTC (permalink / raw)
To: Thomas Gleixner
Cc: Geert Uytterhoeven, Alim Akhtar, linux-stm32, Karol Gugala,
Jerome Brunet, linux-samsung-soc, Kevin Hilman, Hugo Villeneuve,
Christophe Leroy, Hammer Hsieh, Jiamei Xie, NXP Linux Team,
Vineet Gupta, Thierry Reding, Petr Mladek, Arend van Spriel,
Sascha Hauer, Nicholas Piggin, linux-unisoc, Andrew Jeffery,
Greg Kroah-Hartman, linux-kernel, Richard Genoud,
Pengutronix Kernel Team, Andrew Morton, Alexandre Belloni,
linux-aspeed, Laxman Dewangan, Dmitry Rokosov, Xiongfeng Wang,
Matthias Schiffer, delisun, Fabio Estevam, Ruan Jinjie,
Matthew Howell, Jonathan Hunter, Gabriel Somlo, Hongyu Xie,
Tobias Klauser, John Ogness, Yangtao Li, Martin Blumenstingl,
linux-arm-msm, linux-actions, Biju Das, linux-amlogic,
Michal Simek, Sherry Sun, Neil Armstrong, Chunyan Zhang,
David S. Miller, Kumaravel Thiagarajan, Lukas Wunner,
Sergey Organov, Mukesh Ojha, Maxime Coquelin, Michael Ellerman,
Pali Rohár, Lino Sanfilippo, Tom Rix, Lorenzo Pieralisi,
Al Cooper, Yuan Can, Isaac True, linux-tegra, Jiri Slaby,
Rob Herring, Florian Fainelli, Mateusz Holenko, Kevin Cernekee,
Andy Shevchenko, Shenwei Wang,
Broadcom internal kernel review list, Joel Stanley, Chen-Yu Tsai,
Ilpo Järvinen, linux-snps-arc, Patrice Chotard, Jacky Huang,
Arnd Bergmann, Uwe Kleine-König, Jonathan Neuschäfer,
Vladimir Zapolskiy, Baolin Wang, Orson Zhai, Tharun Kumar P,
Timur Tabi, Claudiu Beznea, Konrad Dybcio, Thierry Reding,
Sudeep Holla, Shawn Guo, Andreas Färber, Baruch Siach,
Valentin Caron, Tony Lindgren, Sebastian Andrzej Siewior,
Liviu Dudau, Alexandre Torgue, sparclinux, Shan-Chun Hung,
linux-riscv, Marek Vasut, Lech Perczak, Russell King, Nick Hu,
Andy Gross, linux-serial, Lukas Bulwahn, Manivannan Sadhasivam,
Johan Hovold, linux-mediatek, Paul Walmsley, Matthias Brugger,
Andy Shevchenko, AngeloGioacchino Del Regno, linux-arm-kernel,
Taichi Sugaya, Bjorn Andersson, Nicolas Ferre, Lucas Tanure,
Andrew Davis, Krzysztof Kozlowski, Palmer Dabbelt, Takao Orito,
linuxppc-dev
On Fri, 15 Sep 2023, Thomas Gleixner wrote:
> >> Patches 2-74 switch all uart port locking call sites to use the new
> >> wrappers. These patches were automatically generated using coccinelle.
> >
> > Hmm, no need to do this for drivers/tty/serial/zs.c?
>
> zs.c does not use port lock at all. It has like a couple of other
> drivers a local homebrewn spinlock.
Ah, right, that's because there are registers shared between two ports
within one SCC, so the spinlock has to be shared as well.
This also indicates that dz.c is wrong and shouldn't be using a per-port
spinlock as the DZ has a shared register set between all the four ports
(it's a serial line multiplexer rather than a set discrete ports; up to 8
lines are architecturally supported, though we don't have support in Linux
for systems having those), e.g. there's only one 16-bit receiver buffer
register for all the four ports, supplying the 8-bit character received
along with the receive status and the number of the line this data arrived
on, and similarly there's only one transmit data register, which supplies
data to the next enabled line whose transmit buffer needs servicing, and
the chip routes the data itself. Therefore the driver ought to use a
shared spinlock too.
I guess it wasn't noticed so far because DZ devices aren't that common
(and my usual test machine is currently broken too, pending an SRAM chip
replacement, hopefully in the next few weeks) and then hardly ever more
than one serial line has been used at a time with these devices. It looks
like the first issue for me to look into once the machine has been fixed.
Maybe dz.c shouldn't be touched by this series then? (Though obviously
both drivers will have to be eventually adapted for the ultimate console
rework.)
Thanks for your input, as it turns out it has had an unexpected outcome.
Maciej
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock
2023-09-15 17:23 ` Maciej W. Rozycki
@ 2023-09-16 19:24 ` John Ogness
0 siblings, 0 replies; 10+ messages in thread
From: John Ogness @ 2023-09-16 19:24 UTC (permalink / raw)
To: Maciej W. Rozycki, Thomas Gleixner
Cc: Geert Uytterhoeven, Alim Akhtar, linux-stm32, Karol Gugala,
Jerome Brunet, linux-samsung-soc, Michael Ellerman,
Hugo Villeneuve, Christophe Leroy, Hammer Hsieh, Jiamei Xie,
NXP Linux Team, Vineet Gupta, Thierry Reding, Petr Mladek,
Arend van Spriel, Sascha Hauer, Nicholas Piggin, linux-unisoc,
Andrew Jeffery, Greg Kroah-Hartman, linux-kernel, Richard Genoud,
Pengutronix Kernel Team, Andrew Morton, Alexandre Belloni,
linux-aspeed, Laxman Dewangan, Dmitry Rokosov, Xiongfeng Wang,
Matthias Schiffer, delisun, Fabio Estevam, Ruan Jinjie,
Matthew Howell, Jonathan Hunter, Gabriel Somlo, Hongyu Xie,
Tobias Klauser, Yangtao Li, Martin Blumenstingl, linux-arm-msm,
linux-actions, Biju Das, linux-amlogic, Michal Simek, Sherry Sun,
Neil Armstrong, Chunyan Zhang, David S. Miller,
Kumaravel Thiagarajan, Lukas Wunner, Sergey Organov, Mukesh Ojha,
Maxime Coquelin, Kevin Hilman, Pali Rohár, Lino Sanfilippo,
Tom Rix, Lorenzo Pieralisi, Al Cooper, Yuan Can, Isaac True,
linux-tegra, Jiri Slaby, Rob Herring, Florian Fainelli,
Mateusz Holenko, Kevin Cernekee, Andy Shevchenko, Shenwei Wang,
Broadcom internal kernel review list, Joel Stanley, Chen-Yu Tsai,
Ilpo Järvinen, linux-snps-arc, Patrice Chotard, Jacky Huang,
Arnd Bergmann, Uwe Kleine-König, Jonathan Neuschäfer,
Vladimir Zapolskiy, Baolin Wang, Orson Zhai, Tharun Kumar P,
Timur Tabi, Claudiu Beznea, Konrad Dybcio, Thierry Reding,
Sudeep Holla, Shawn Guo, Andreas Färber, Baruch Siach,
Valentin Caron, Tony Lindgren, Sebastian Andrzej Siewior,
Liviu Dudau, Alexandre Torgue, sparclinux, Shan-Chun Hung,
linux-riscv, Marek Vasut, Lech Perczak, Russell King, Nick Hu,
Andy Gross, linux-serial, Lukas Bulwahn, Manivannan Sadhasivam,
Johan Hovold, linux-mediatek, Paul Walmsley, Matthias Brugger,
Andy Shevchenko, AngeloGioacchino Del Regno, linux-arm-kernel,
Taichi Sugaya, Bjorn Andersson, Nicolas Ferre, Lucas Tanure,
Andrew Davis, Krzysztof Kozlowski, Palmer Dabbelt, Takao Orito,
linuxppc-dev
On 2023-09-15, "Maciej W. Rozycki" <macro@orcam.me.uk> wrote:
> Maybe dz.c shouldn't be touched by this series then?
Correct. This series is only wrapping the uart port lock, which dz.c is
not using.
> Though obviously both drivers will have to be eventually adapted for
> the ultimate console rework.
Correct.
Thanks for clarifying how the hardware works.
John
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock
2023-09-14 18:37 [PATCH tty v1 00/74] serial: wrappers for uart port lock John Ogness
2023-09-14 18:38 ` [PATCH tty v1 61/74] serial: sifive: Use port lock wrappers John Ogness
2023-09-14 19:01 ` [PATCH tty v1 00/74] serial: wrappers for uart port lock Maciej W. Rozycki
@ 2023-09-15 9:12 ` Ilpo Järvinen
2023-09-16 19:42 ` John Ogness
2023-09-18 8:23 ` John Ogness
3 siblings, 1 reply; 10+ messages in thread
From: Ilpo Järvinen @ 2023-09-15 9:12 UTC (permalink / raw)
To: John Ogness
Cc: Geert Uytterhoeven, Alim Akhtar, Peter Korsgaard, linux-stm32,
Karol Gugala, Jerome Brunet, linux-samsung-soc, Kevin Hilman,
Hugo Villeneuve, Christophe Leroy, Hammer Hsieh, Jiamei Xie,
NXP Linux Team, Vineet Gupta, Thierry Reding, Petr Mladek,
Arend van Spriel, Sascha Hauer, Nicholas Piggin, linux-unisoc,
Thomas Gleixner, Andrew Jeffery, Greg Kroah-Hartman, LKML,
Richard Genoud, Pengutronix Kernel Team, Andrew Morton,
Maciej W. Rozycki, Alexandre Belloni, linux-aspeed,
Laxman Dewangan, Dmitry Rokosov, Xiongfeng Wang,
Matthias Schiffer, delisun, Fabio Estevam, Ruan Jinjie,
Matthew Howell, Jonathan Hunter, Gabriel Somlo, Hongyu Xie,
Tobias Klauser, Yangtao Li, Martin Blumenstingl, linux-arm-msm,
linux-actions, Biju Das, linux-amlogic, Michal Simek, Sherry Sun,
Neil Armstrong, Chunyan Zhang, David S. Miller,
Kumaravel Thiagarajan, Lukas Wunner, Sergey Organov, Mukesh Ojha,
Maxime Coquelin, Michael Ellerman, Pali Rohár,
Lino Sanfilippo, Tom Rix, Lorenzo Pieralisi, Al Cooper, Yuan Can,
Isaac True, linux-tegra, Jiri Slaby, Rob Herring,
Florian Fainelli, Mateusz Holenko, Kevin Cernekee,
Andy Shevchenko, Shenwei Wang,
Broadcom internal kernel review list, Joel Stanley, Chen-Yu Tsai,
Ilpo Järvinen, linux-snps-arc, Patrice Chotard, Jacky Huang,
Arnd Bergmann, Uwe Kleine-König, Jonathan Neuschäfer,
Vladimir Zapolskiy, Baolin Wang, Orson Zhai, Tharun Kumar P,
Timur Tabi, Claudiu Beznea, Konrad Dybcio, Thierry Reding,
Sudeep Holla, Shawn Guo, Andreas Färber, Baruch Siach,
Valentin Caron, Tony Lindgren, Sebastian Andrzej Siewior,
Liviu Dudau, Alexandre Torgue, sparclinux, Shan-Chun Hung,
linux-riscv, Marek Vasut, Lech Perczak, Russell King, Nick Hu,
Andy Gross, linux-serial, Lukas Bulwahn, Manivannan Sadhasivam,
Johan Hovold, linux-mediatek, Paul Walmsley, Matthias Brugger,
Andy Shevchenko, AngeloGioacchino Del Regno, linux-arm-kernel,
Taichi Sugaya, Bjorn Andersson, Nicolas Ferre, Lucas Tanure,
Andrew Davis, Krzysztof Kozlowski, Palmer Dabbelt, Takao Orito,
linuxppc-dev
On Thu, 14 Sep 2023, John Ogness wrote:
> When a serial port is used for kernel console output, then all
> modifications to the UART registers which are done from other contexts,
> e.g. getty, termios, are interference points for the kernel console.
>
> So far this has been ignored and the printk output is based on the
> principle of hope. The rework of the console infrastructure which aims to
> support threaded and atomic consoles, requires to mark sections which
> modify the UART registers as unsafe. This allows the atomic write function
> to make informed decisions and eventually to restore operational state. It
> also allows to prevent the regular UART code from modifying UART registers
> while printk output is in progress.
Hi John,
Would this also be useful to enable printing to console while under port's
lock (by postponing the output until the lock is released)?
E.g., 8250_dw.c has had this commented out since the dawn on time:
/*
* FIXME: this deadlocks if port->lock is already held
* dev_err(p->dev, "Couldn't set LCR to %d\n", value);
*/
--
i.
> All modifications of UART registers are guarded by the UART port lock,
> which provides an obvious synchronization point with the console
> infrastructure.
>
> Provide and use wrapper functions for spin_[un]lock*(port->lock)
> invocations so that the console mechanics can be applied later on at a
> single place and does not require to copy the same logic all over the
> drivers.
>
> Patch 1 adds the wrapper functions.
>
> Patches 2-74 switch all uart port locking call sites to use the new
> wrappers. These patches were automatically generated using coccinelle.
> The 2 used coccinelle scripts are included below and executed as
> follows:
>
> $ spatch --sp-file uartlock-1.cocci $FILE
> $ spatch --sp-file uartlock-2.cocci --recursive-includes $FILE
>
> This series brings no functional change.
>
> Patches 2-74 contain identical commit message bodies. Feel free to
> fold them into a single commit if that seems more reasonable.
>
> Thomas Gleixner (74):
> serial: core: Provide port lock wrappers
> serial: core: Use lock wrappers
> serial: 21285: Use port lock wrappers
> serial: 8250_aspeed_vuart: Use port lock wrappers
> serial: 8250_bcm7271: Use port lock wrappers
> serial: 8250: Use port lock wrappers
> serial: 8250_dma: Use port lock wrappers
> serial: 8250_dw: Use port lock wrappers
> serial: 8250_exar: Use port lock wrappers
> serial: 8250_fsl: Use port lock wrappers
> serial: 8250_mtk: Use port lock wrappers
> serial: 8250_omap: Use port lock wrappers
> serial: 8250_pci1xxxx: Use port lock wrappers
> serial: altera_jtaguart: Use port lock wrappers
> serial: altera_uart: Use port lock wrappers
> serial: amba-pl010: Use port lock wrappers
> serial: amba-pl011: Use port lock wrappers
> serial: apb: Use port lock wrappers
> serial: ar933x: Use port lock wrappers
> serial: arc_uart: Use port lock wrappers
> serial: atmel: Use port lock wrappers
> serial: bcm63xx-uart: Use port lock wrappers
> serial: cpm_uart: Use port lock wrappers
> serial: digicolor: Use port lock wrappers
> serial: dz: Use port lock wrappers
> serial: linflexuart: Use port lock wrappers
> serial: fsl_lpuart: Use port lock wrappers
> serial: icom: Use port lock wrappers
> serial: imx: Use port lock wrappers
> serial: ip22zilog: Use port lock wrappers
> serial: jsm: Use port lock wrappers
> serial: liteuart: Use port lock wrappers
> serial: lpc32xx_hs: Use port lock wrappers
> serial: ma35d1: Use port lock wrappers
> serial: mcf: Use port lock wrappers
> serial: men_z135_uart: Use port lock wrappers
> serial: meson: Use port lock wrappers
> serial: milbeaut_usio: Use port lock wrappers
> serial: mpc52xx: Use port lock wrappers
> serial: mps2-uart: Use port lock wrappers
> serial: msm: Use port lock wrappers
> serial: mvebu-uart: Use port lock wrappers
> serial: omap: Use port lock wrappers
> serial: owl: Use port lock wrappers
> serial: pch: Use port lock wrappers
> serial: pic32: Use port lock wrappers
> serial: pmac_zilog: Use port lock wrappers
> serial: pxa: Use port lock wrappers
> serial: qcom-geni: Use port lock wrappers
> serial: rda: Use port lock wrappers
> serial: rp2: Use port lock wrappers
> serial: sa1100: Use port lock wrappers
> serial: samsung_tty: Use port lock wrappers
> serial: sb1250-duart: Use port lock wrappers
> serial: sc16is7xx: Use port lock wrappers
> serial: tegra: Use port lock wrappers
> serial: core: Use port lock wrappers
> serial: mctrl_gpio: Use port lock wrappers
> serial: txx9: Use port lock wrappers
> serial: sh-sci: Use port lock wrappers
> serial: sifive: Use port lock wrappers
> serial: sprd: Use port lock wrappers
> serial: st-asc: Use port lock wrappers
> serial: stm32: Use port lock wrappers
> serial: sunhv: Use port lock wrappers
> serial: sunplus-uart: Use port lock wrappers
> serial: sunsab: Use port lock wrappers
> serial: sunsu: Use port lock wrappers
> serial: sunzilog: Use port lock wrappers
> serial: timbuart: Use port lock wrappers
> serial: uartlite: Use port lock wrappers
> serial: ucc_uart: Use port lock wrappers
> serial: vt8500: Use port lock wrappers
> serial: xilinx_uartps: Use port lock wrappers
>
> drivers/tty/serial/21285.c | 8 +-
> drivers/tty/serial/8250/8250_aspeed_vuart.c | 6 +-
> drivers/tty/serial/8250/8250_bcm7271.c | 28 +++---
> drivers/tty/serial/8250/8250_core.c | 12 +--
> drivers/tty/serial/8250/8250_dma.c | 8 +-
> drivers/tty/serial/8250/8250_dw.c | 8 +-
> drivers/tty/serial/8250/8250_exar.c | 4 +-
> drivers/tty/serial/8250/8250_fsl.c | 6 +-
> drivers/tty/serial/8250/8250_mtk.c | 8 +-
> drivers/tty/serial/8250/8250_omap.c | 52 +++++-----
> drivers/tty/serial/8250/8250_pci1xxxx.c | 8 +-
> drivers/tty/serial/8250/8250_port.c | 100 ++++++++++----------
> drivers/tty/serial/altera_jtaguart.c | 28 +++---
> drivers/tty/serial/altera_uart.c | 20 ++--
> drivers/tty/serial/amba-pl010.c | 20 ++--
> drivers/tty/serial/amba-pl011.c | 72 +++++++-------
> drivers/tty/serial/apbuart.c | 8 +-
> drivers/tty/serial/ar933x_uart.c | 26 ++---
> drivers/tty/serial/arc_uart.c | 16 ++--
> drivers/tty/serial/atmel_serial.c | 24 ++---
> drivers/tty/serial/bcm63xx_uart.c | 22 ++---
> drivers/tty/serial/cpm_uart.c | 8 +-
> drivers/tty/serial/digicolor-usart.c | 18 ++--
> drivers/tty/serial/dz.c | 32 +++----
> drivers/tty/serial/fsl_linflexuart.c | 26 ++---
> drivers/tty/serial/fsl_lpuart.c | 88 ++++++++---------
> drivers/tty/serial/icom.c | 26 ++---
> drivers/tty/serial/imx.c | 84 ++++++++--------
> drivers/tty/serial/ip22zilog.c | 36 +++----
> drivers/tty/serial/jsm/jsm_neo.c | 4 +-
> drivers/tty/serial/jsm/jsm_tty.c | 16 ++--
> drivers/tty/serial/liteuart.c | 20 ++--
> drivers/tty/serial/lpc32xx_hs.c | 26 ++---
> drivers/tty/serial/ma35d1_serial.c | 22 ++---
> drivers/tty/serial/mcf.c | 20 ++--
> drivers/tty/serial/men_z135_uart.c | 8 +-
> drivers/tty/serial/meson_uart.c | 30 +++---
> drivers/tty/serial/milbeaut_usio.c | 16 ++--
> drivers/tty/serial/mpc52xx_uart.c | 12 +--
> drivers/tty/serial/mps2-uart.c | 16 ++--
> drivers/tty/serial/msm_serial.c | 38 ++++----
> drivers/tty/serial/mvebu-uart.c | 18 ++--
> drivers/tty/serial/omap-serial.c | 38 ++++----
> drivers/tty/serial/owl-uart.c | 26 ++---
> drivers/tty/serial/pch_uart.c | 10 +-
> drivers/tty/serial/pic32_uart.c | 20 ++--
> drivers/tty/serial/pmac_zilog.c | 52 +++++-----
> drivers/tty/serial/pxa.c | 30 +++---
> drivers/tty/serial/qcom_geni_serial.c | 8 +-
> drivers/tty/serial/rda-uart.c | 34 +++----
> drivers/tty/serial/rp2.c | 20 ++--
> drivers/tty/serial/sa1100.c | 20 ++--
> drivers/tty/serial/samsung_tty.c | 50 +++++-----
> drivers/tty/serial/sb1250-duart.c | 12 +--
> drivers/tty/serial/sc16is7xx.c | 40 ++++----
> drivers/tty/serial/serial-tegra.c | 32 +++----
> drivers/tty/serial/serial_core.c | 88 ++++++++---------
> drivers/tty/serial/serial_mctrl_gpio.c | 4 +-
> drivers/tty/serial/serial_port.c | 4 +-
> drivers/tty/serial/serial_txx9.c | 26 ++---
> drivers/tty/serial/sh-sci.c | 68 ++++++-------
> drivers/tty/serial/sifive.c | 16 ++--
> drivers/tty/serial/sprd_serial.c | 30 +++---
> drivers/tty/serial/st-asc.c | 18 ++--
> drivers/tty/serial/stm32-usart.c | 38 ++++----
> drivers/tty/serial/sunhv.c | 28 +++---
> drivers/tty/serial/sunplus-uart.c | 26 ++---
> drivers/tty/serial/sunsab.c | 34 +++----
> drivers/tty/serial/sunsu.c | 46 ++++-----
> drivers/tty/serial/sunzilog.c | 42 ++++----
> drivers/tty/serial/timbuart.c | 8 +-
> drivers/tty/serial/uartlite.c | 18 ++--
> drivers/tty/serial/ucc_uart.c | 4 +-
> drivers/tty/serial/vt8500_serial.c | 8 +-
> drivers/tty/serial/xilinx_uartps.c | 56 +++++------
> include/linux/serial_core.h | 91 ++++++++++++++++--
> 76 files changed, 1086 insertions(+), 1007 deletions(-)
>
>
> base-commit: 0bb80ecc33a8fb5a682236443c1e740d5c917d1d
>
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^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock
2023-09-15 9:12 ` Ilpo Järvinen
@ 2023-09-16 19:42 ` John Ogness
0 siblings, 0 replies; 10+ messages in thread
From: John Ogness @ 2023-09-16 19:42 UTC (permalink / raw)
To: Ilpo Järvinen
Cc: Geert Uytterhoeven, Alim Akhtar, Peter Korsgaard, linux-stm32,
Karol Gugala, Jerome Brunet, linux-samsung-soc, Kevin Hilman,
Hugo Villeneuve, Christophe Leroy, Hammer Hsieh, Jiamei Xie,
NXP Linux Team, Vineet Gupta, Thierry Reding, Petr Mladek,
Arend van Spriel, Sascha Hauer, Nicholas Piggin, linux-unisoc,
Thomas Gleixner, Andrew Jeffery, Greg Kroah-Hartman, LKML,
Richard Genoud, Pengutronix Kernel Team, Andrew Morton,
Maciej W. Rozycki, Alexandre Belloni, linux-aspeed,
Laxman Dewangan, Dmitry Rokosov, Xiongfeng Wang,
Matthias Schiffer, delisun, Fabio Estevam, Ruan Jinjie,
Matthew Howell, Jonathan Hunter, Gabriel Somlo, Hongyu Xie,
Tobias Klauser, Yangtao Li, Martin Blumenstingl, linux-arm-msm,
linux-actions, Biju Das, linux-amlogic, Michal Simek, Sherry Sun,
Neil Armstrong, Chunyan Zhang, David S. Miller,
Kumaravel Thiagarajan, Lukas Wunner, Sergey Organov, Mukesh Ojha,
Maxime Coquelin, Michael Ellerman, Pali Rohár,
Lino Sanfilippo, Tom Rix, Lorenzo Pieralisi, Al Cooper, Yuan Can,
Isaac True, linux-tegra, Jiri Slaby, Rob Herring,
Florian Fainelli, Mateusz Holenko, Kevin Cernekee,
Andy Shevchenko, Shenwei Wang,
Broadcom internal kernel review list, Joel Stanley, Chen-Yu Tsai,
Ilpo Järvinen, linux-snps-arc, Patrice Chotard, Jacky Huang,
Arnd Bergmann, Uwe Kleine-König, Jonathan Neuschäfer,
Vladimir Zapolskiy, Baolin Wang, Orson Zhai, Tharun Kumar P,
Timur Tabi, Claudiu Beznea, Konrad Dybcio, Thierry Reding,
Sudeep Holla, Shawn Guo, Andreas Färber, Baruch Siach,
Valentin Caron, Tony Lindgren, Sebastian Andrzej Siewior,
Liviu Dudau, Alexandre Torgue, sparclinux, Shan-Chun Hung,
linux-riscv, Marek Vasut, Lech Perczak, Russell King, Nick Hu,
Andy Gross, linux-serial, Lukas Bulwahn, Manivannan Sadhasivam,
Johan Hovold, linux-mediatek, Paul Walmsley, Matthias Brugger,
Andy Shevchenko, AngeloGioacchino Del Regno, linux-arm-kernel,
Taichi Sugaya, Bjorn Andersson, Nicolas Ferre, Lucas Tanure,
Andrew Davis, Krzysztof Kozlowski, Palmer Dabbelt, Takao Orito,
linuxppc-dev
On 2023-09-15, Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> wrote:
> Would this also be useful to enable printing to console while under
> port's lock (by postponing the output until the lock is released)?
>
> E.g., 8250_dw.c has had this commented out since the dawn on time:
> /*
> * FIXME: this deadlocks if port->lock is already held
> * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
> */
Yes, this will fix such issues. However, only for consoles that are
converted to the new NBCON console type.
Good news, the 8250 driver will be the flagship driver that is converted
as part of the rework. So this particular issue will be solved then. I
will try to remember this so that I can remove the FIXME in the series.
Thanks for mentioning it.
John
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock
2023-09-14 18:37 [PATCH tty v1 00/74] serial: wrappers for uart port lock John Ogness
` (2 preceding siblings ...)
2023-09-15 9:12 ` Ilpo Järvinen
@ 2023-09-18 8:23 ` John Ogness
2023-09-18 8:26 ` Greg Kroah-Hartman
3 siblings, 1 reply; 10+ messages in thread
From: John Ogness @ 2023-09-18 8:23 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Geert Uytterhoeven, Alim Akhtar, Peter Korsgaard, linux-stm32,
Karol Gugala, Jerome Brunet, linux-samsung-soc, Kevin Hilman,
Hugo Villeneuve, Christophe Leroy, Hammer Hsieh, Jiamei Xie,
NXP Linux Team, Vineet Gupta, Thierry Reding, Petr Mladek,
Arend van Spriel, Sascha Hauer, Nicholas Piggin, linux-unisoc,
Thomas Gleixner, Andrew Jeffery, linux-kernel, Richard Genoud,
Pengutronix Kernel Team, Andrew Morton, Maciej W. Rozycki,
Alexandre Belloni, linux-aspeed, Laxman Dewangan, Dmitry Rokosov,
Xiongfeng Wang, Matthias Schiffer, delisun, Fabio Estevam,
Ruan Jinjie, Matthew Howell, Jonathan Hunter, Gabriel Somlo,
Hongyu Xie, Tobias Klauser, Yangtao Li, Martin Blumenstingl,
linux-arm-msm, linux-actions, Biju Das, linux-amlogic,
Michal Simek, Sherry Sun, Neil Armstrong, Chunyan Zhang,
David S. Miller, Kumaravel Thiagarajan, Lukas Wunner,
Sergey Organov, Mukesh Ojha, Maxime Coquelin, Michael Ellerman,
Pali Rohár, Lino Sanfilippo, Tom Rix, Lorenzo Pieralisi,
Al Cooper, Yuan Can, Isaac True, linux-tegra, Jiri Slaby,
Rob Herring, Florian Fainelli, Mateusz Holenko, Kevin Cernekee,
Andy Shevchenko, Shenwei Wang,
Broadcom internal kernel review list, Joel Stanley, Chen-Yu Tsai,
Ilpo Järvinen, linux-snps-arc, Patrice Chotard, Jacky Huang,
Arnd Bergmann, Uwe Kleine-König, Jonathan Neuschäfer,
Vladimir Zapolskiy, Baolin Wang, Orson Zhai, Tharun Kumar P,
Timur Tabi, Claudiu Beznea, Konrad Dybcio, Thierry Reding,
Sudeep Holla, Shawn Guo, Andreas Färber, Baruch Siach,
Valentin Caron, Tony Lindgren, Sebastian Andrzej Siewior,
Liviu Dudau, Alexandre Torgue, sparclinux, Shan-Chun Hung,
linux-riscv, Marek Vasut, Lech Perczak, Russell King, Nick Hu,
Andy Gross, linux-serial, Lukas Bulwahn, Manivannan Sadhasivam,
Johan Hovold, linux-mediatek, Paul Walmsley, Matthias Brugger,
Andy Shevchenko, AngeloGioacchino Del Regno, linux-arm-kernel,
Taichi Sugaya, Bjorn Andersson, Nicolas Ferre, Lucas Tanure,
Andrew Davis, Krzysztof Kozlowski, Palmer Dabbelt, Takao Orito,
linuxppc-dev
On 2023-09-14, John Ogness <john.ogness@linutronix.de> wrote:
> Provide and use wrapper functions for spin_[un]lock*(port->lock)
> invocations so that the console mechanics can be applied later on at a
> single place and does not require to copy the same logic all over the
> drivers.
For the full 74-patch series:
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Sorry that my SoB was missing from the initial posting.
John Ogness
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^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH tty v1 00/74] serial: wrappers for uart port lock
2023-09-18 8:23 ` John Ogness
@ 2023-09-18 8:26 ` Greg Kroah-Hartman
0 siblings, 0 replies; 10+ messages in thread
From: Greg Kroah-Hartman @ 2023-09-18 8:26 UTC (permalink / raw)
To: John Ogness
Cc: Geert Uytterhoeven, Alim Akhtar, Peter Korsgaard, linux-stm32,
Karol Gugala, Jerome Brunet, linux-samsung-soc, Kevin Hilman,
Hugo Villeneuve, Christophe Leroy, Hammer Hsieh, Jiamei Xie,
NXP Linux Team, Vineet Gupta, Thierry Reding, Petr Mladek,
Arend van Spriel, Sascha Hauer, Nicholas Piggin, linux-unisoc,
Thomas Gleixner, Andrew Jeffery, linux-kernel, Richard Genoud,
Pengutronix Kernel Team, Andrew Morton, Maciej W. Rozycki,
Alexandre Belloni, linux-aspeed, Laxman Dewangan, Dmitry Rokosov,
Xiongfeng Wang, Matthias Schiffer, delisun, Fabio Estevam,
Ruan Jinjie, Matthew Howell, Jonathan Hunter, Gabriel Somlo,
Hongyu Xie, Tobias Klauser, Yangtao Li, Martin Blumenstingl,
linux-arm-msm, linux-actions, Biju Das, linux-amlogic,
Michal Simek, Sherry Sun, Neil Armstrong, Chunyan Zhang,
David S. Miller, Kumaravel Thiagarajan, Lukas Wunner,
Sergey Organov, Mukesh Ojha, Maxime Coquelin, Michael Ellerman,
Pali Rohár, Lino Sanfilippo, Tom Rix, Lorenzo Pieralisi,
Al Cooper, Yuan Can, Isaac True, linux-tegra, Jiri Slaby,
Rob Herring, Florian Fainelli, Mateusz Holenko, Kevin Cernekee,
Andy Shevchenko, Shenwei Wang,
Broadcom internal kernel review list, Joel Stanley, Chen-Yu Tsai,
Ilpo Järvinen, linux-snps-arc, Patrice Chotard, Jacky Huang,
Arnd Bergmann, Uwe Kleine-König, Jonathan Neuschäfer,
Vladimir Zapolskiy, Baolin Wang, Orson Zhai, Tharun Kumar P,
Timur Tabi, Claudiu Beznea, Konrad Dybcio, Thierry Reding,
Sudeep Holla, Shawn Guo, Andreas Färber, Baruch Siach,
Valentin Caron, Tony Lindgren, Sebastian Andrzej Siewior,
Liviu Dudau, Alexandre Torgue, sparclinux, Shan-Chun Hung,
linux-riscv, Marek Vasut, Lech Perczak, Russell King, Nick Hu,
Andy Gross, linux-serial, Lukas Bulwahn, Manivannan Sadhasivam,
Johan Hovold, linux-mediatek, Paul Walmsley, Matthias Brugger,
Andy Shevchenko, AngeloGioacchino Del Regno, linux-arm-kernel,
Taichi Sugaya, Bjorn Andersson, Nicolas Ferre, Lucas Tanure,
Andrew Davis, Krzysztof Kozlowski, Palmer Dabbelt, Takao Orito,
linuxppc-dev
On Mon, Sep 18, 2023 at 10:29:30AM +0206, John Ogness wrote:
> On 2023-09-14, John Ogness <john.ogness@linutronix.de> wrote:
> > Provide and use wrapper functions for spin_[un]lock*(port->lock)
> > invocations so that the console mechanics can be applied later on at a
> > single place and does not require to copy the same logic all over the
> > drivers.
>
> For the full 74-patch series:
>
> Signed-off-by: John Ogness <john.ogness@linutronix.de>
>
> Sorry that my SoB was missing from the initial posting.
Thanks for this, I'll rebuild my tree with this added.
greg k-h
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^ permalink raw reply [flat|nested] 10+ messages in thread