* [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands
@ 2020-08-27 19:52 Raul E Rangel
2020-08-27 19:52 ` [PATCH 2/2] Input: i8042 - Lock i8042_mutex before flushing Raul E Rangel
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Raul E Rangel @ 2020-08-27 19:52 UTC (permalink / raw)
To: linux-input
Cc: dmitry.torokhov, Shirish.S, Raul E Rangel, Andy Shevchenko,
Dan Murphy, Darren Hart, Jacek Anaszewski, Lee, Chun-Yi,
Pavel Machek, Rajat Jain, Stephen Boyd, linux-kernel, linux-leds,
platform-driver-x86
The i8042_mutex must be held by writers of the AUX and KBD ports, as
well as users of i8042_command. There were a lot of users of
i8042_command that were not calling i8042_lock_chip/i8042_unlock_chip.
This resulted in i8042_commands being issues in between PS/2
transactions.
This change moves the mutex lock into i8042_command and removes the
burden of locking the mutex from the callers.
It is expected that the i8042_mutex is locked before calling
i8042_aux_write or i8042_kbd_write. This is currently done by the PS/2
layer via ps2_begin_command and ps2_end_command. Other modules
(serio_raw) do not currently lock the mutex, so there is still a
possibility for intermixed commands.
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
---
drivers/input/serio/i8042.c | 29 ++++++++++++++---------------
drivers/leds/leds-clevo-mail.c | 9 ---------
drivers/platform/x86/acer-wmi.c | 2 --
drivers/platform/x86/amilo-rfkill.c | 2 --
include/linux/i8042.h | 10 ----------
5 files changed, 14 insertions(+), 38 deletions(-)
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 0dddf273afd94..8590e51bcc087 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -137,8 +137,7 @@ static DEFINE_SPINLOCK(i8042_lock);
/*
* Writers to AUX and KBD ports as well as users issuing i8042_command
- * directly should acquire i8042_mutex (by means of calling
- * i8042_lock_chip() and i8042_unlock_ship() helpers) to ensure that
+ * directly should acquire i8042_mutex to ensure that
* they do not disturb each other (unfortunately in many i8042
* implementations write to one of the ports will immediately abort
* command that is being processed by another port).
@@ -173,18 +172,6 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id);
static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
struct serio *serio);
-void i8042_lock_chip(void)
-{
- mutex_lock(&i8042_mutex);
-}
-EXPORT_SYMBOL(i8042_lock_chip);
-
-void i8042_unlock_chip(void)
-{
- mutex_unlock(&i8042_mutex);
-}
-EXPORT_SYMBOL(i8042_unlock_chip);
-
int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str,
struct serio *serio))
{
@@ -343,10 +330,14 @@ int i8042_command(unsigned char *param, int command)
unsigned long flags;
int retval;
+ mutex_lock(&i8042_mutex);
+
spin_lock_irqsave(&i8042_lock, flags);
retval = __i8042_command(param, command);
spin_unlock_irqrestore(&i8042_lock, flags);
+ mutex_unlock(&i8042_mutex);
+
return retval;
}
EXPORT_SYMBOL(i8042_command);
@@ -379,10 +370,18 @@ static int i8042_kbd_write(struct serio *port, unsigned char c)
static int i8042_aux_write(struct serio *serio, unsigned char c)
{
struct i8042_port *port = serio->port_data;
+ unsigned long flags;
+ int retval = 0;
+
+ spin_lock_irqsave(&i8042_lock, flags);
- return i8042_command(&c, port->mux == -1 ?
+ retval = __i8042_command(&c, port->mux == -1 ?
I8042_CMD_AUX_SEND :
I8042_CMD_MUX_SEND + port->mux);
+
+ spin_unlock_irqrestore(&i8042_lock, flags);
+
+ return retval;
}
diff --git a/drivers/leds/leds-clevo-mail.c b/drivers/leds/leds-clevo-mail.c
index f512e99b976b1..6c3d7e54f95cf 100644
--- a/drivers/leds/leds-clevo-mail.c
+++ b/drivers/leds/leds-clevo-mail.c
@@ -95,17 +95,12 @@ MODULE_DEVICE_TABLE(dmi, clevo_mail_led_dmi_table);
static void clevo_mail_led_set(struct led_classdev *led_cdev,
enum led_brightness value)
{
- i8042_lock_chip();
-
if (value == LED_OFF)
i8042_command(NULL, CLEVO_MAIL_LED_OFF);
else if (value <= LED_HALF)
i8042_command(NULL, CLEVO_MAIL_LED_BLINK_0_5HZ);
else
i8042_command(NULL, CLEVO_MAIL_LED_BLINK_1HZ);
-
- i8042_unlock_chip();
-
}
static int clevo_mail_led_blink(struct led_classdev *led_cdev,
@@ -114,8 +109,6 @@ static int clevo_mail_led_blink(struct led_classdev *led_cdev,
{
int status = -EINVAL;
- i8042_lock_chip();
-
if (*delay_on == 0 /* ms */ && *delay_off == 0 /* ms */) {
/* Special case: the leds subsystem requested us to
* chose one user friendly blinking of the LED, and
@@ -142,8 +135,6 @@ static int clevo_mail_led_blink(struct led_classdev *led_cdev,
*delay_on, *delay_off);
}
- i8042_unlock_chip();
-
return status;
}
diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
index 60c18f21588dd..6cb6f800503b2 100644
--- a/drivers/platform/x86/acer-wmi.c
+++ b/drivers/platform/x86/acer-wmi.c
@@ -1044,9 +1044,7 @@ static acpi_status WMID_set_u32(u32 value, u32 cap)
return AE_BAD_PARAMETER;
if (quirks->mailled == 1) {
param = value ? 0x92 : 0x93;
- i8042_lock_chip();
i8042_command(¶m, 0x1059);
- i8042_unlock_chip();
return 0;
}
break;
diff --git a/drivers/platform/x86/amilo-rfkill.c b/drivers/platform/x86/amilo-rfkill.c
index 493e169c8f615..ce68d0c9ac29f 100644
--- a/drivers/platform/x86/amilo-rfkill.c
+++ b/drivers/platform/x86/amilo-rfkill.c
@@ -30,9 +30,7 @@ static int amilo_a1655_rfkill_set_block(void *data, bool blocked)
u8 param = blocked ? A1655_WIFI_OFF : A1655_WIFI_ON;
int rc;
- i8042_lock_chip();
rc = i8042_command(¶m, A1655_WIFI_COMMAND);
- i8042_unlock_chip();
return rc;
}
diff --git a/include/linux/i8042.h b/include/linux/i8042.h
index 0261e2fb36364..1c081081c161d 100644
--- a/include/linux/i8042.h
+++ b/include/linux/i8042.h
@@ -55,8 +55,6 @@ struct serio;
#if defined(CONFIG_SERIO_I8042) || defined(CONFIG_SERIO_I8042_MODULE)
-void i8042_lock_chip(void);
-void i8042_unlock_chip(void);
int i8042_command(unsigned char *param, int command);
int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str,
struct serio *serio));
@@ -65,14 +63,6 @@ int i8042_remove_filter(bool (*filter)(unsigned char data, unsigned char str,
#else
-static inline void i8042_lock_chip(void)
-{
-}
-
-static inline void i8042_unlock_chip(void)
-{
-}
-
static inline int i8042_command(unsigned char *param, int command)
{
return -ENODEV;
--
2.28.0.297.g1956fa8f8d-goog
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/2] Input: i8042 - Lock i8042_mutex before flushing
2020-08-27 19:52 [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands Raul E Rangel
@ 2020-08-27 19:52 ` Raul E Rangel
2020-08-27 20:12 ` [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands Andy Shevchenko
2020-08-29 7:47 ` Pavel Machek
2 siblings, 0 replies; 7+ messages in thread
From: Raul E Rangel @ 2020-08-27 19:52 UTC (permalink / raw)
To: linux-input
Cc: dmitry.torokhov, Shirish.S, Raul E Rangel, Rajat Jain,
Stephen Boyd, linux-kernel
Make i8042_flush lock the i8042_mutex before flushing the buffer. This
will prevent i8042_flush from clearing the buffer while a PS/2 command is
in progress. I'm not sure if this is really possible. We already
hold the lock when calling i8042_command, so this makes i8042_flush have
the same behavior.
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
---
drivers/input/serio/i8042.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 8590e51bcc087..b693154641500 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -254,6 +254,8 @@ static int i8042_flush(void)
int count = 0;
int retval = 0;
+ mutex_lock(&i8042_mutex);
+
spin_lock_irqsave(&i8042_lock, flags);
while ((str = i8042_read_status()) & I8042_STR_OBF) {
@@ -270,6 +272,8 @@ static int i8042_flush(void)
spin_unlock_irqrestore(&i8042_lock, flags);
+ mutex_unlock(&i8042_mutex);
+
return retval;
}
--
2.28.0.297.g1956fa8f8d-goog
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands
2020-08-27 19:52 [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands Raul E Rangel
2020-08-27 19:52 ` [PATCH 2/2] Input: i8042 - Lock i8042_mutex before flushing Raul E Rangel
@ 2020-08-27 20:12 ` Andy Shevchenko
2020-08-27 20:18 ` Andy Shevchenko
2020-08-27 20:20 ` Raul Rangel
2020-08-29 7:47 ` Pavel Machek
2 siblings, 2 replies; 7+ messages in thread
From: Andy Shevchenko @ 2020-08-27 20:12 UTC (permalink / raw)
To: Raul E Rangel
Cc: linux-input, Dmitry Torokhov, S, Shirish, Andy Shevchenko,
Dan Murphy, Darren Hart, Jacek Anaszewski, Lee, Chun-Yi,
Pavel Machek, Rajat Jain, Stephen Boyd,
Linux Kernel Mailing List, Linux LED Subsystem, Platform Driver
On Thu, Aug 27, 2020 at 10:52 PM Raul E Rangel <rrangel@chromium.org> wrote:
>
> The i8042_mutex must be held by writers of the AUX and KBD ports, as
> well as users of i8042_command. There were a lot of users of
> i8042_command that were not calling i8042_lock_chip/i8042_unlock_chip.
> This resulted in i8042_commands being issues in between PS/2
> transactions.
>
> This change moves the mutex lock into i8042_command and removes the
> burden of locking the mutex from the callers.
Which is wrong according to your very patch. See below.
> It is expected that the i8042_mutex is locked before calling
> i8042_aux_write or i8042_kbd_write. This is currently done by the PS/2
> layer via ps2_begin_command and ps2_end_command. Other modules
> (serio_raw) do not currently lock the mutex, so there is still a
> possibility for intermixed commands.
...
> + mutex_lock(&i8042_mutex);
> +
> spin_lock_irqsave(&i8042_lock, flags);
> retval = __i8042_command(param, command);
> spin_unlock_irqrestore(&i8042_lock, flags);
>
> + mutex_unlock(&i8042_mutex);
Question 1. Why do you need mutex at all in the above situation? Spin
lock isn't enough?
...
> - i8042_lock_chip();
> -
> if (value == LED_OFF)
> i8042_command(NULL, CLEVO_MAIL_LED_OFF);
> else if (value <= LED_HALF)
> i8042_command(NULL, CLEVO_MAIL_LED_BLINK_0_5HZ);
> else
> i8042_command(NULL, CLEVO_MAIL_LED_BLINK_1HZ);
> -
> - i8042_unlock_chip();
> -
Now, these three commands are not considered as a transaction (no
atomicity). That's why your patch is wrong.
> }
...
> int rc;
>
> - i8042_lock_chip();
> rc = i8042_command(¶m, A1655_WIFI_COMMAND);
> - i8042_unlock_chip();
> return rc;
rc become redundant.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands
2020-08-27 20:12 ` [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands Andy Shevchenko
@ 2020-08-27 20:18 ` Andy Shevchenko
2020-08-27 20:20 ` Raul Rangel
1 sibling, 0 replies; 7+ messages in thread
From: Andy Shevchenko @ 2020-08-27 20:18 UTC (permalink / raw)
To: Raul E Rangel
Cc: linux-input, Dmitry Torokhov, S, Shirish, Andy Shevchenko,
Dan Murphy, Darren Hart, Jacek Anaszewski, Lee, Chun-Yi,
Pavel Machek, Rajat Jain, Stephen Boyd,
Linux Kernel Mailing List, Linux LED Subsystem, Platform Driver
On Thu, Aug 27, 2020 at 11:12 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Thu, Aug 27, 2020 at 10:52 PM Raul E Rangel <rrangel@chromium.org> wrote:
...
> > + mutex_lock(&i8042_mutex);
> > +
> > spin_lock_irqsave(&i8042_lock, flags);
> > retval = __i8042_command(param, command);
> > spin_unlock_irqrestore(&i8042_lock, flags);
> >
> > + mutex_unlock(&i8042_mutex);
>
> Question 1. Why do you need mutex at all in the above situation? Spin
> lock isn't enough?
>
> ...
>
> > - i8042_lock_chip();
> > -
> > if (value == LED_OFF)
> > i8042_command(NULL, CLEVO_MAIL_LED_OFF);
> > else if (value <= LED_HALF)
> > i8042_command(NULL, CLEVO_MAIL_LED_BLINK_0_5HZ);
> > else
> > i8042_command(NULL, CLEVO_MAIL_LED_BLINK_1HZ);
> > -
> > - i8042_unlock_chip();
> > -
>
> Now, these three commands are not considered as a transaction (no
> atomicity). That's why your patch is wrong.
Ah, I didn't pay attention that this is one command call. But still Q1 is valid.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands
2020-08-27 20:12 ` [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands Andy Shevchenko
2020-08-27 20:18 ` Andy Shevchenko
@ 2020-08-27 20:20 ` Raul Rangel
1 sibling, 0 replies; 7+ messages in thread
From: Raul Rangel @ 2020-08-27 20:20 UTC (permalink / raw)
To: Andy Shevchenko
Cc: linux-input, Dmitry Torokhov, S, Shirish, Andy Shevchenko,
Dan Murphy, Darren Hart, Jacek Anaszewski, Lee, Chun-Yi,
Pavel Machek, Rajat Jain, Stephen Boyd,
Linux Kernel Mailing List, Linux LED Subsystem, Platform Driver
On Thu, Aug 27, 2020 at 2:12 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, Aug 27, 2020 at 10:52 PM Raul E Rangel <rrangel@chromium.org> wrote:
> >
> > The i8042_mutex must be held by writers of the AUX and KBD ports, as
> > well as users of i8042_command. There were a lot of users of
> > i8042_command that were not calling i8042_lock_chip/i8042_unlock_chip.
> > This resulted in i8042_commands being issues in between PS/2
> > transactions.
> >
> > This change moves the mutex lock into i8042_command and removes the
> > burden of locking the mutex from the callers.
>
> Which is wrong according to your very patch. See below.
>
> > It is expected that the i8042_mutex is locked before calling
> > i8042_aux_write or i8042_kbd_write. This is currently done by the PS/2
> > layer via ps2_begin_command and ps2_end_command. Other modules
> > (serio_raw) do not currently lock the mutex, so there is still a
> > possibility for intermixed commands.
>
> ...
>
> > + mutex_lock(&i8042_mutex);
> > +
> > spin_lock_irqsave(&i8042_lock, flags);
> > retval = __i8042_command(param, command);
> > spin_unlock_irqrestore(&i8042_lock, flags);
> >
> > + mutex_unlock(&i8042_mutex);
>
> Question 1. Why do you need mutex at all in the above situation? Spin
> lock isn't enough?
No. PS/2 transactions/commands consist of multiple calls to ps2_do_sendbyte.
So the spin lock only helps with sending an individual byte. The mutex
is for the
whole transaction. We don't want i8042_commands being sent in between a PS/2
transaction.
>
> ...
>
> > - i8042_lock_chip();
> > -
> > if (value == LED_OFF)
> > i8042_command(NULL, CLEVO_MAIL_LED_OFF);
> > else if (value <= LED_HALF)
> > i8042_command(NULL, CLEVO_MAIL_LED_BLINK_0_5HZ);
> > else
> > i8042_command(NULL, CLEVO_MAIL_LED_BLINK_1HZ);
> > -
> > - i8042_unlock_chip();
> > -
>
> Now, these three commands are not considered as a transaction (no
> atomicity). That's why your patch is wrong.
These are all mutually exclusive. So there is no change in behavior.
>
> > }
>
> ...
>
> > int rc;
> >
> > - i8042_lock_chip();
> > rc = i8042_command(¶m, A1655_WIFI_COMMAND);
> > - i8042_unlock_chip();
> > return rc;
>
> rc become redundant.
Good catch. I'll send a v2 with it removed.
>
> --
> With Best Regards,
> Andy Shevchenko
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands
2020-08-27 19:52 [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands Raul E Rangel
2020-08-27 19:52 ` [PATCH 2/2] Input: i8042 - Lock i8042_mutex before flushing Raul E Rangel
2020-08-27 20:12 ` [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands Andy Shevchenko
@ 2020-08-29 7:47 ` Pavel Machek
2020-08-31 13:39 ` Raul Rangel
2 siblings, 1 reply; 7+ messages in thread
From: Pavel Machek @ 2020-08-29 7:47 UTC (permalink / raw)
To: Raul E Rangel
Cc: linux-input, dmitry.torokhov, Shirish.S, Andy Shevchenko,
Dan Murphy, Darren Hart, Jacek Anaszewski, Lee, Chun-Yi,
Rajat Jain, Stephen Boyd, linux-kernel, linux-leds,
platform-driver-x86
[-- Attachment #1: Type: text/plain, Size: 1378 bytes --]
On Thu 2020-08-27 13:52:22, Raul E Rangel wrote:
> The i8042_mutex must be held by writers of the AUX and KBD ports, as
> well as users of i8042_command. There were a lot of users of
> i8042_command that were not calling i8042_lock_chip/i8042_unlock_chip.
> This resulted in i8042_commands being issues in between PS/2
> transactions.
>
> This change moves the mutex lock into i8042_command and removes the
> burden of locking the mutex from the callers.
>
> It is expected that the i8042_mutex is locked before calling
> i8042_aux_write or i8042_kbd_write. This is currently done by the PS/2
> layer via ps2_begin_command and ps2_end_command. Other modules
> (serio_raw) do not currently lock the mutex, so there is still a
> possibility for intermixed commands.
> @@ -343,10 +330,14 @@ int i8042_command(unsigned char *param, int command)
> unsigned long flags;
> int retval;
>
> + mutex_lock(&i8042_mutex);
> +
> spin_lock_irqsave(&i8042_lock, flags);
> retval = __i8042_command(param, command);
> spin_unlock_irqrestore(&i8042_lock, flags);
>
> + mutex_unlock(&i8042_mutex);
> +
> return retval;
There's something wrong with whitespace here. Checkpatch?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands
2020-08-29 7:47 ` Pavel Machek
@ 2020-08-31 13:39 ` Raul Rangel
0 siblings, 0 replies; 7+ messages in thread
From: Raul Rangel @ 2020-08-31 13:39 UTC (permalink / raw)
To: Pavel Machek
Cc: linux-input, Dmitry Torokhov, S, Shirish, Andy Shevchenko,
Dan Murphy, Darren Hart, Jacek Anaszewski, Lee, Chun-Yi,
Rajat Jain, Stephen Boyd, linux-kernel, Linux LED Subsystem,
Platform Driver
On Sat, Aug 29, 2020 at 1:48 AM Pavel Machek <pavel@ucw.cz> wrote:
>
> On Thu 2020-08-27 13:52:22, Raul E Rangel wrote:
> > The i8042_mutex must be held by writers of the AUX and KBD ports, as
> > well as users of i8042_command. There were a lot of users of
> > i8042_command that were not calling i8042_lock_chip/i8042_unlock_chip.
> > This resulted in i8042_commands being issues in between PS/2
> > transactions.
> >
> > This change moves the mutex lock into i8042_command and removes the
> > burden of locking the mutex from the callers.
> >
> > It is expected that the i8042_mutex is locked before calling
> > i8042_aux_write or i8042_kbd_write. This is currently done by the PS/2
> > layer via ps2_begin_command and ps2_end_command. Other modules
> > (serio_raw) do not currently lock the mutex, so there is still a
> > possibility for intermixed commands.
>
>
> > @@ -343,10 +330,14 @@ int i8042_command(unsigned char *param, int command)
> > unsigned long flags;
> > int retval;
> >
> > + mutex_lock(&i8042_mutex);
> > +
> > spin_lock_irqsave(&i8042_lock, flags);
> > retval = __i8042_command(param, command);
> > spin_unlock_irqrestore(&i8042_lock, flags);
> >
> > + mutex_unlock(&i8042_mutex);
> > +
> > return retval;
>
> There's something wrong with whitespace here. Checkpatch?
> Pavel
It's fixed in the v2 patch: https://patchwork.kernel.org/patch/11741855/
Thanks
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-08-31 13:40 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2020-08-27 19:52 [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands Raul E Rangel
2020-08-27 19:52 ` [PATCH 2/2] Input: i8042 - Lock i8042_mutex before flushing Raul E Rangel
2020-08-27 20:12 ` [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands Andy Shevchenko
2020-08-27 20:18 ` Andy Shevchenko
2020-08-27 20:20 ` Raul Rangel
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