* [PATCH] Fix cpm uart corruption with PREEMPT_RT
@ 2008-05-20 19:39 Rune Torgersen
2008-05-20 19:42 ` Scott Wood
2008-07-01 5:28 ` Kumar Gala
0 siblings, 2 replies; 6+ messages in thread
From: Rune Torgersen @ 2008-05-20 19:39 UTC (permalink / raw)
To: linuxppc-dev
Fix CPM serial port corruption when running with CONFIG_PREEMPT_RT.
Userland usage of console, and kernel printf's were stepping on each others toes.
Also only take lock if not in an oops.
Signed-off-by: Rune Torgersen <runet@innovsys.com>
diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
index fb93403..11bee62 100755
--- a/drivers/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/serial/cpm_uart/cpm_uart_core.c
@@ -1214,6 +1214,14 @@ static void cpm_uart_console_write(struct console *co, const char *s,
unsigned int i;
cbd_t __iomem *bdp, *bdbase;
unsigned char *cp;
+ unsigned long flags;
+ int nolock = oops_in_progress;
+
+ if (unlikely(nolock)) {
+ local_irq_save(flags);
+ } else {
+ spin_lock_irqsave(&pinfo->port.lock, flags);
+ }
/* Get the address of the host memory buffer.
*/
@@ -1282,6 +1290,12 @@ static void cpm_uart_console_write(struct console *co, const char *s,
;
pinfo->tx_cur = bdp;
+
+ if (unlikely(nolock)) {
+ local_irq_restore(flags);
+ } else {
+ spin_unlock_irqrestore(&pinfo->port.lock, flags);
+ }
}
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] Fix cpm uart corruption with PREEMPT_RT
@ 2008-05-20 19:28 Rune Torgersen
2008-05-20 19:33 ` Scott Wood
0 siblings, 1 reply; 6+ messages in thread
From: Rune Torgersen @ 2008-05-20 19:28 UTC (permalink / raw)
To: linuxppc-dev
Fix CPM serial port corruption when running with CONFIG_PREEMPT_RT.
Userland usage of console, and kernel printf's were stepping on each others toes.
Signed-off-by: Rune Torgersen <runet@innovsys.com>
diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
index fb93403..79c109d 100755
--- a/drivers/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/serial/cpm_uart/cpm_uart_core.c
@@ -1214,7 +1214,9 @@ static void cpm_uart_console_write(struct console *co, const char *s,
unsigned int i;
cbd_t __iomem *bdp, *bdbase;
unsigned char *cp;
+ unsigned long flags;
+ spin_lock_irqsave(&pinfo->port.lock, flags);
/* Get the address of the host memory buffer.
*/
bdp = pinfo->tx_cur;
@@ -1282,6 +1284,8 @@ static void cpm_uart_console_write(struct console *co, const char *s,
;
pinfo->tx_cur = bdp;
+
+ spin_unlock_irqrestore(&pinfo->port.lock, flags);
}
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] Fix cpm uart corruption with PREEMPT_RT
2008-05-20 19:28 Rune Torgersen
@ 2008-05-20 19:33 ` Scott Wood
2008-05-20 19:35 ` Rune Torgersen
0 siblings, 1 reply; 6+ messages in thread
From: Scott Wood @ 2008-05-20 19:33 UTC (permalink / raw)
To: Rune Torgersen; +Cc: linuxppc-dev
On Tue, May 20, 2008 at 02:28:16PM -0500, Rune Torgersen wrote:
> Fix CPM serial port corruption when running with CONFIG_PREEMPT_RT.
> Userland usage of console, and kernel printf's were stepping on each others toes.
>
> Signed-off-by: Rune Torgersen <runet@innovsys.com>
>
> diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
> index fb93403..79c109d 100755
> --- a/drivers/serial/cpm_uart/cpm_uart_core.c
> +++ b/drivers/serial/cpm_uart/cpm_uart_core.c
> @@ -1214,7 +1214,9 @@ static void cpm_uart_console_write(struct console *co, const char *s,
> unsigned int i;
> cbd_t __iomem *bdp, *bdbase;
> unsigned char *cp;
> + unsigned long flags;
>
> + spin_lock_irqsave(&pinfo->port.lock, flags);
> /* Get the address of the host memory buffer.
> */
> bdp = pinfo->tx_cur;
> @@ -1282,6 +1284,8 @@ static void cpm_uart_console_write(struct console *co, const char *s,
> ;
>
> pinfo->tx_cur = bdp;
> +
> + spin_unlock_irqrestore(&pinfo->port.lock, flags);
> }
We should bypass the lock when oops_in_progress is set, something like:
diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
index a19dc7e..bc45f8a 100644
--- a/drivers/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/serial/cpm_uart/cpm_uart_core.c
@@ -1178,6 +1178,14 @@ static void cpm_uart_console_write(struct console *co, const char *s,
unsigned int i;
cbd_t __iomem *bdp, *bdbase;
unsigned char *cp;
+ unsigned long flags;
+ int nolock = oops_in_progress;
+
+ if (unlikely(nolock)) {
+ local_irq_save(flags);
+ } else {
+ spin_lock_irqsave(&pinfo->port.lock, flags);
+ }
/* Get the address of the host memory buffer.
*/
@@ -1239,8 +1247,13 @@ static void cpm_uart_console_write(struct console *co, const char *s,
;
pinfo->tx_cur = bdp;
-}
+ if (unlikely(nolock)) {
+ local_irq_restore(flags);
+ } else {
+ spin_unlock_irqrestore(&pinfo->port.lock, flags);
+ }
+}
static int __init cpm_uart_console_setup(struct console *co, char *options)
{
-Scott
^ permalink raw reply related [flat|nested] 6+ messages in thread* RE: [PATCH] Fix cpm uart corruption with PREEMPT_RT
2008-05-20 19:33 ` Scott Wood
@ 2008-05-20 19:35 ` Rune Torgersen
0 siblings, 0 replies; 6+ messages in thread
From: Rune Torgersen @ 2008-05-20 19:35 UTC (permalink / raw)
To: Scott Wood; +Cc: linuxppc-dev
Scott Wood wrote:
> On Tue, May 20, 2008 at 02:28:16PM -0500, Rune Torgersen wrote:
>> Fix CPM serial port corruption when running with CONFIG_PREEMPT_RT.
>> Userland usage of console, and kernel printf's were stepping on each
>> others toes.=20
>>=20
>=20
> We should bypass the lock when oops_in_progress is set, something
> like:=20
>=20
Ok, will respin.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2008-07-01 5:28 UTC | newest]
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2008-05-20 19:39 [PATCH] Fix cpm uart corruption with PREEMPT_RT Rune Torgersen
2008-05-20 19:42 ` Scott Wood
2008-07-01 5:28 ` Kumar Gala
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2008-05-20 19:28 Rune Torgersen
2008-05-20 19:33 ` Scott Wood
2008-05-20 19:35 ` Rune Torgersen
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