* [PATCH 1/3] tty: nozomi: avoid a harmless gcc warning
@ 2016-01-25 21:54 ` Arnd Bergmann
0 siblings, 0 replies; 10+ messages in thread
From: Arnd Bergmann @ 2016-01-25 21:54 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-arm-kernel, Arnd Bergmann, Jiri Slaby, linux-kernel
The nozomi wireless data driver has its own helper function to
transfer data from a FIFO, doing an extra byte swap on big-endian
architectures, presumably to bring the data back into byte-serial
order after readw() or readl() perform their implicit byteswap.
This helper function is used in the receive_data() function to
first read the length into a 32-bit variable, which causes
a compile-time warning:
drivers/tty/nozomi.c: In function 'receive_data':
drivers/tty/nozomi.c:857:9: warning: 'size' may be used uninitialized in this function [-Wmaybe-uninitialized]
The problem is that gcc is unsure whether the data was actually
read or not. We know that it is at this point, so we can replace
it with a single readl() to shut up that warning.
I am leaving the byteswap in there, to preserve the existing
behavior, even though this seems fishy: Reading the length of
the data into a cpu-endian variable should normally not use
a second byteswap on big-endian systems, unless the hardware
is aware of the CPU endianess.
There appears to be a lot more confusion about endianess in this
driver, so it probably has not worked on big-endian systems in
a long time, if ever, and I have no way to test it. It's well
possible that this driver has not been used by anyone in a while,
the last patch that looks like it was tested on the hardware is
from 2008.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/tty/nozomi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index 80f9de907563..5cc80b80c82b 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -823,7 +823,7 @@ static int receive_data(enum port_type index, struct nozomi *dc)
struct tty_struct *tty = tty_port_tty_get(&port->port);
int i, ret;
- read_mem32((u32 *) &size, addr, 4);
+ size = __le32_to_cpu(readl(addr));
/* DBG1( "%d bytes port: %d", size, index); */
if (tty && test_bit(TTY_THROTTLED, &tty->flags)) {
--
2.7.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 1/3] tty: nozomi: avoid a harmless gcc warning
@ 2016-01-25 21:54 ` Arnd Bergmann
0 siblings, 0 replies; 10+ messages in thread
From: Arnd Bergmann @ 2016-01-25 21:54 UTC (permalink / raw)
To: linux-arm-kernel
The nozomi wireless data driver has its own helper function to
transfer data from a FIFO, doing an extra byte swap on big-endian
architectures, presumably to bring the data back into byte-serial
order after readw() or readl() perform their implicit byteswap.
This helper function is used in the receive_data() function to
first read the length into a 32-bit variable, which causes
a compile-time warning:
drivers/tty/nozomi.c: In function 'receive_data':
drivers/tty/nozomi.c:857:9: warning: 'size' may be used uninitialized in this function [-Wmaybe-uninitialized]
The problem is that gcc is unsure whether the data was actually
read or not. We know that it is at this point, so we can replace
it with a single readl() to shut up that warning.
I am leaving the byteswap in there, to preserve the existing
behavior, even though this seems fishy: Reading the length of
the data into a cpu-endian variable should normally not use
a second byteswap on big-endian systems, unless the hardware
is aware of the CPU endianess.
There appears to be a lot more confusion about endianess in this
driver, so it probably has not worked on big-endian systems in
a long time, if ever, and I have no way to test it. It's well
possible that this driver has not been used by anyone in a while,
the last patch that looks like it was tested on the hardware is
from 2008.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/tty/nozomi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index 80f9de907563..5cc80b80c82b 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -823,7 +823,7 @@ static int receive_data(enum port_type index, struct nozomi *dc)
struct tty_struct *tty = tty_port_tty_get(&port->port);
int i, ret;
- read_mem32((u32 *) &size, addr, 4);
+ size = __le32_to_cpu(readl(addr));
/* DBG1( "%d bytes port: %d", size, index); */
if (tty && test_bit(TTY_THROTTLED, &tty->flags)) {
--
2.7.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 2/3] tty: cyclades: cyz_interrupt is only used for PCI
2016-01-25 21:54 ` Arnd Bergmann
@ 2016-01-25 21:54 ` Arnd Bergmann
-1 siblings, 0 replies; 10+ messages in thread
From: Arnd Bergmann @ 2016-01-25 21:54 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-arm-kernel, Arnd Bergmann, Jiri Slaby, linux-kernel
When CONFIG_PCI is not set, enabling CONFIG_CYZ_INTR has no
practical effect other than generating a warning about an
unused function:
drivers/tty/cyclades.c:1184:20: warning: 'cyz_interrupt' defined but not used [-Wunused-function]
static irqreturn_t cyz_interrupt(int irq, void *dev_id)
This adds a dependency to avoid that warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/tty/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index c01f45095877..82c4d2e45319 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -226,7 +226,7 @@ config CYCLADES
config CYZ_INTR
bool "Cyclades-Z interrupt mode operation"
- depends on CYCLADES
+ depends on CYCLADES && PCI
help
The Cyclades-Z family of multiport cards allows 2 (two) driver op
modes: polling and interrupt. In polling mode, the driver will check
--
2.7.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 2/3] tty: cyclades: cyz_interrupt is only used for PCI
@ 2016-01-25 21:54 ` Arnd Bergmann
0 siblings, 0 replies; 10+ messages in thread
From: Arnd Bergmann @ 2016-01-25 21:54 UTC (permalink / raw)
To: linux-arm-kernel
When CONFIG_PCI is not set, enabling CONFIG_CYZ_INTR has no
practical effect other than generating a warning about an
unused function:
drivers/tty/cyclades.c:1184:20: warning: 'cyz_interrupt' defined but not used [-Wunused-function]
static irqreturn_t cyz_interrupt(int irq, void *dev_id)
This adds a dependency to avoid that warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/tty/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index c01f45095877..82c4d2e45319 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -226,7 +226,7 @@ config CYCLADES
config CYZ_INTR
bool "Cyclades-Z interrupt mode operation"
- depends on CYCLADES
+ depends on CYCLADES && PCI
help
The Cyclades-Z family of multiport cards allows 2 (two) driver op
modes: polling and interrupt. In polling mode, the driver will check
--
2.7.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 3/3] tty: hvc_xen: hide xen_console_remove when unused
2016-01-25 21:54 ` Arnd Bergmann
@ 2016-01-25 21:54 ` Arnd Bergmann
-1 siblings, 0 replies; 10+ messages in thread
From: Arnd Bergmann @ 2016-01-25 21:54 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: linux-arm-kernel, Arnd Bergmann, Jiri Slaby, David Vrabel,
Julien Grall, Stefano Stabellini, Wei Liu, Jan Beulich,
Boris Ostrovsky, linuxppc-dev, linux-kernel
xencons_disconnect_backend() is only called from xen_console_remove(),
which is conditionally compiled, so we get a harmless warning when
CONFIG_HVC_XEN_FRONTEND is unset:
hvc/hvc_xen.c:350:12: error: 'xen_console_remove' defined but not used [-Werror=unused-function]
This moves the function down into the same #ifdef section to silence
the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/tty/hvc/hvc_xen.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index fa816b7193b6..11725422dacb 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -323,6 +323,7 @@ void xen_console_resume(void)
}
}
+#ifdef CONFIG_HVC_XEN_FRONTEND
static void xencons_disconnect_backend(struct xencons_info *info)
{
if (info->irq > 0)
@@ -363,7 +364,6 @@ static int xen_console_remove(struct xencons_info *info)
return 0;
}
-#ifdef CONFIG_HVC_XEN_FRONTEND
static int xencons_remove(struct xenbus_device *dev)
{
return xen_console_remove(dev_get_drvdata(&dev->dev));
--
2.7.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH 3/3] tty: hvc_xen: hide xen_console_remove when unused
@ 2016-01-25 21:54 ` Arnd Bergmann
0 siblings, 0 replies; 10+ messages in thread
From: Arnd Bergmann @ 2016-01-25 21:54 UTC (permalink / raw)
To: linux-arm-kernel
xencons_disconnect_backend() is only called from xen_console_remove(),
which is conditionally compiled, so we get a harmless warning when
CONFIG_HVC_XEN_FRONTEND is unset:
hvc/hvc_xen.c:350:12: error: 'xen_console_remove' defined but not used [-Werror=unused-function]
This moves the function down into the same #ifdef section to silence
the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/tty/hvc/hvc_xen.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index fa816b7193b6..11725422dacb 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -323,6 +323,7 @@ void xen_console_resume(void)
}
}
+#ifdef CONFIG_HVC_XEN_FRONTEND
static void xencons_disconnect_backend(struct xencons_info *info)
{
if (info->irq > 0)
@@ -363,7 +364,6 @@ static int xen_console_remove(struct xencons_info *info)
return 0;
}
-#ifdef CONFIG_HVC_XEN_FRONTEND
static int xencons_remove(struct xenbus_device *dev)
{
return xen_console_remove(dev_get_drvdata(&dev->dev));
--
2.7.0
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH 3/3] tty: hvc_xen: hide xen_console_remove when unused
2016-01-25 21:54 ` Arnd Bergmann
@ 2016-01-25 23:05 ` Boris Ostrovsky
-1 siblings, 0 replies; 10+ messages in thread
From: Boris Ostrovsky @ 2016-01-25 23:05 UTC (permalink / raw)
To: Arnd Bergmann, Greg Kroah-Hartman
Cc: linux-arm-kernel, Jiri Slaby, David Vrabel, Julien Grall,
Stefano Stabellini, Wei Liu, Jan Beulich, linuxppc-dev,
linux-kernel
On 01/25/2016 04:54 PM, Arnd Bergmann wrote:
> xencons_disconnect_backend() is only called from xen_console_remove(),
and also from xencons_probe()/xencons_resume(). But those two are also
under the
same ifdef.
-boris
> which is conditionally compiled, so we get a harmless warning when
> CONFIG_HVC_XEN_FRONTEND is unset:
>
> hvc/hvc_xen.c:350:12: error: 'xen_console_remove' defined but not used [-Werror=unused-function]
>
> This moves the function down into the same #ifdef section to silence
> the warning.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/tty/hvc/hvc_xen.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
> index fa816b7193b6..11725422dacb 100644
> --- a/drivers/tty/hvc/hvc_xen.c
> +++ b/drivers/tty/hvc/hvc_xen.c
> @@ -323,6 +323,7 @@ void xen_console_resume(void)
> }
> }
>
> +#ifdef CONFIG_HVC_XEN_FRONTEND
> static void xencons_disconnect_backend(struct xencons_info *info)
> {
> if (info->irq > 0)
> @@ -363,7 +364,6 @@ static int xen_console_remove(struct xencons_info *info)
> return 0;
> }
>
> -#ifdef CONFIG_HVC_XEN_FRONTEND
> static int xencons_remove(struct xenbus_device *dev)
> {
> return xen_console_remove(dev_get_drvdata(&dev->dev));
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH 3/3] tty: hvc_xen: hide xen_console_remove when unused
@ 2016-01-25 23:05 ` Boris Ostrovsky
0 siblings, 0 replies; 10+ messages in thread
From: Boris Ostrovsky @ 2016-01-25 23:05 UTC (permalink / raw)
To: linux-arm-kernel
On 01/25/2016 04:54 PM, Arnd Bergmann wrote:
> xencons_disconnect_backend() is only called from xen_console_remove(),
and also from xencons_probe()/xencons_resume(). But those two are also
under the
same ifdef.
-boris
> which is conditionally compiled, so we get a harmless warning when
> CONFIG_HVC_XEN_FRONTEND is unset:
>
> hvc/hvc_xen.c:350:12: error: 'xen_console_remove' defined but not used [-Werror=unused-function]
>
> This moves the function down into the same #ifdef section to silence
> the warning.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/tty/hvc/hvc_xen.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
> index fa816b7193b6..11725422dacb 100644
> --- a/drivers/tty/hvc/hvc_xen.c
> +++ b/drivers/tty/hvc/hvc_xen.c
> @@ -323,6 +323,7 @@ void xen_console_resume(void)
> }
> }
>
> +#ifdef CONFIG_HVC_XEN_FRONTEND
> static void xencons_disconnect_backend(struct xencons_info *info)
> {
> if (info->irq > 0)
> @@ -363,7 +364,6 @@ static int xen_console_remove(struct xencons_info *info)
> return 0;
> }
>
> -#ifdef CONFIG_HVC_XEN_FRONTEND
> static int xencons_remove(struct xenbus_device *dev)
> {
> return xen_console_remove(dev_get_drvdata(&dev->dev));
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 3/3] tty: hvc_xen: hide xen_console_remove when unused
2016-01-25 23:05 ` Boris Ostrovsky
@ 2016-01-26 12:25 ` Stefano Stabellini
-1 siblings, 0 replies; 10+ messages in thread
From: Stefano Stabellini @ 2016-01-26 12:25 UTC (permalink / raw)
To: Boris Ostrovsky
Cc: Arnd Bergmann, Greg Kroah-Hartman, linux-arm-kernel, Jiri Slaby,
David Vrabel, Julien Grall, Stefano Stabellini, Wei Liu,
Jan Beulich, linuxppc-dev, linux-kernel
On Mon, 25 Jan 2016, Boris Ostrovsky wrote:
> On 01/25/2016 04:54 PM, Arnd Bergmann wrote:
> > xencons_disconnect_backend() is only called from xen_console_remove(),
>
> and also from xencons_probe()/xencons_resume(). But those two are also under
> the
> same ifdef.
Good point. Aside from this the patch is good.
> > which is conditionally compiled, so we get a harmless warning when
> > CONFIG_HVC_XEN_FRONTEND is unset:
> >
> > hvc/hvc_xen.c:350:12: error: 'xen_console_remove' defined but not used
> > [-Werror=unused-function]
> >
> > This moves the function down into the same #ifdef section to silence
> > the warning.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > drivers/tty/hvc/hvc_xen.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
> > index fa816b7193b6..11725422dacb 100644
> > --- a/drivers/tty/hvc/hvc_xen.c
> > +++ b/drivers/tty/hvc/hvc_xen.c
> > @@ -323,6 +323,7 @@ void xen_console_resume(void)
> > }
> > }
> > +#ifdef CONFIG_HVC_XEN_FRONTEND
> > static void xencons_disconnect_backend(struct xencons_info *info)
> > {
> > if (info->irq > 0)
> > @@ -363,7 +364,6 @@ static int xen_console_remove(struct xencons_info *info)
> > return 0;
> > }
> > -#ifdef CONFIG_HVC_XEN_FRONTEND
> > static int xencons_remove(struct xenbus_device *dev)
> > {
> > return xen_console_remove(dev_get_drvdata(&dev->dev));
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH 3/3] tty: hvc_xen: hide xen_console_remove when unused
@ 2016-01-26 12:25 ` Stefano Stabellini
0 siblings, 0 replies; 10+ messages in thread
From: Stefano Stabellini @ 2016-01-26 12:25 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, 25 Jan 2016, Boris Ostrovsky wrote:
> On 01/25/2016 04:54 PM, Arnd Bergmann wrote:
> > xencons_disconnect_backend() is only called from xen_console_remove(),
>
> and also from xencons_probe()/xencons_resume(). But those two are also under
> the
> same ifdef.
Good point. Aside from this the patch is good.
> > which is conditionally compiled, so we get a harmless warning when
> > CONFIG_HVC_XEN_FRONTEND is unset:
> >
> > hvc/hvc_xen.c:350:12: error: 'xen_console_remove' defined but not used
> > [-Werror=unused-function]
> >
> > This moves the function down into the same #ifdef section to silence
> > the warning.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > drivers/tty/hvc/hvc_xen.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
> > index fa816b7193b6..11725422dacb 100644
> > --- a/drivers/tty/hvc/hvc_xen.c
> > +++ b/drivers/tty/hvc/hvc_xen.c
> > @@ -323,6 +323,7 @@ void xen_console_resume(void)
> > }
> > }
> > +#ifdef CONFIG_HVC_XEN_FRONTEND
> > static void xencons_disconnect_backend(struct xencons_info *info)
> > {
> > if (info->irq > 0)
> > @@ -363,7 +364,6 @@ static int xen_console_remove(struct xencons_info *info)
> > return 0;
> > }
> > -#ifdef CONFIG_HVC_XEN_FRONTEND
> > static int xencons_remove(struct xenbus_device *dev)
> > {
> > return xen_console_remove(dev_get_drvdata(&dev->dev));
>
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2016-01-26 12:25 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-01-25 21:54 [PATCH 1/3] tty: nozomi: avoid a harmless gcc warning Arnd Bergmann
2016-01-25 21:54 ` Arnd Bergmann
2016-01-25 21:54 ` [PATCH 2/3] tty: cyclades: cyz_interrupt is only used for PCI Arnd Bergmann
2016-01-25 21:54 ` Arnd Bergmann
2016-01-25 21:54 ` [PATCH 3/3] tty: hvc_xen: hide xen_console_remove when unused Arnd Bergmann
2016-01-25 21:54 ` Arnd Bergmann
2016-01-25 23:05 ` Boris Ostrovsky
2016-01-25 23:05 ` Boris Ostrovsky
2016-01-26 12:25 ` Stefano Stabellini
2016-01-26 12:25 ` Stefano Stabellini
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