* [PATCH] iio: imu: adis16400: Fix sign extension
@ 2015-01-22 23:34 Rasmus Villemoes
2015-01-23 8:56 ` Lars-Peter Clausen
0 siblings, 1 reply; 13+ messages in thread
From: Rasmus Villemoes @ 2015-01-22 23:34 UTC (permalink / raw)
To: Lars-Peter Clausen, Michael Hennerich, Jonathan Cameron,
Hartmut Knaack, Peter Meerwald
Cc: Rasmus Villemoes, linux-iio, linux-kernel
The intention is obviously to sign-extend a 12 bit quantity. But
because of C's promotion rules, the assignment is equivalent to "val16
&= 0xfff;". Use the proper API for this.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
drivers/iio/imu/adis16400_core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/imu/adis16400_core.c b/drivers/iio/imu/adis16400_core.c
index b70873de04ea..fa795dcd5f75 100644
--- a/drivers/iio/imu/adis16400_core.c
+++ b/drivers/iio/imu/adis16400_core.c
@@ -26,6 +26,7 @@
#include <linux/list.h>
#include <linux/module.h>
#include <linux/debugfs.h>
+#include <linux/bitops.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
@@ -414,7 +415,7 @@ static int adis16400_read_raw(struct iio_dev *indio_dev,
mutex_unlock(&indio_dev->mlock);
if (ret)
return ret;
- val16 = ((val16 & 0xFFF) << 4) >> 4;
+ val16 = sign_extend32(val16, 11);
*val = val16;
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
--
2.1.3
^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH] iio: imu: adis16400: Fix sign extension
2015-01-22 23:34 [PATCH] iio: imu: adis16400: Fix sign extension Rasmus Villemoes
@ 2015-01-23 8:56 ` Lars-Peter Clausen
2015-01-26 21:07 ` Jonathan Cameron
0 siblings, 1 reply; 13+ messages in thread
From: Lars-Peter Clausen @ 2015-01-23 8:56 UTC (permalink / raw)
To: Rasmus Villemoes, Michael Hennerich, Jonathan Cameron,
Hartmut Knaack, Peter Meerwald
Cc: linux-iio, linux-kernel
On 01/23/2015 12:34 AM, Rasmus Villemoes wrote:
> The intention is obviously to sign-extend a 12 bit quantity. But
> because of C's promotion rules, the assignment is equivalent to "val16
> &= 0xfff;". Use the proper API for this.
>
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] iio: imu: adis16400: Fix sign extension
2015-01-23 8:56 ` Lars-Peter Clausen
@ 2015-01-26 21:07 ` Jonathan Cameron
0 siblings, 0 replies; 13+ messages in thread
From: Jonathan Cameron @ 2015-01-26 21:07 UTC (permalink / raw)
To: Lars-Peter Clausen, Rasmus Villemoes, Michael Hennerich,
Hartmut Knaack, Peter Meerwald
Cc: linux-iio, linux-kernel
On 23/01/15 08:56, Lars-Peter Clausen wrote:
> On 01/23/2015 12:34 AM, Rasmus Villemoes wrote:
>> The intention is obviously to sign-extend a 12 bit quantity. But
>> because of C's promotion rules, the assignment is equivalent to "val16
>> &= 0xfff;". Use the proper API for this.
>>
>> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
>
> Acked-by: Lars-Peter Clausen <lars@metafoo.de>
>
Applied to the fixes-togreg branch of iio.git and cc'd to stable.
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [patch] iio: imu: adis16400: Fix sign extension
2015-01-30 9:31 ` Rasmus Villemoes
@ 2015-01-30 10:23 ` Dan Carpenter
-1 siblings, 0 replies; 13+ messages in thread
From: Dan Carpenter @ 2015-01-30 10:23 UTC (permalink / raw)
To: Rasmus Villemoes
Cc: Lars-Peter Clausen, Michael Hennerich, Jonathan Cameron,
Hartmut Knaack, Peter Meerwald, linux-iio, kernel-janitors
On Fri, Jan 30, 2015 at 10:31:55AM +0100, Rasmus Villemoes wrote:
> On Fri, Jan 30 2015, Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> > Rasmus, are you using a static checker? Which one?
>
> Sort of:
>
> https://github.com/Villemoes/linux-cocci/blob/master/misc/sign_extend.cocci
>
Did you find the bug in fm10k_update_xc_addr_pf()? That's the other bug
I found.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [patch] iio: imu: adis16400: Fix sign extension
@ 2015-01-30 10:23 ` Dan Carpenter
0 siblings, 0 replies; 13+ messages in thread
From: Dan Carpenter @ 2015-01-30 10:23 UTC (permalink / raw)
To: Rasmus Villemoes
Cc: Lars-Peter Clausen, Michael Hennerich, Jonathan Cameron,
Hartmut Knaack, Peter Meerwald, linux-iio, kernel-janitors
On Fri, Jan 30, 2015 at 10:31:55AM +0100, Rasmus Villemoes wrote:
> On Fri, Jan 30 2015, Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> > Rasmus, are you using a static checker? Which one?
>
> Sort of:
>
> https://github.com/Villemoes/linux-cocci/blob/master/misc/sign_extend.cocci
>
Did you find the bug in fm10k_update_xc_addr_pf()? That's the other bug
I found.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [patch] iio: imu: adis16400: Fix sign extension
2015-01-30 9:22 ` Dan Carpenter
@ 2015-01-30 9:31 ` Rasmus Villemoes
-1 siblings, 0 replies; 13+ messages in thread
From: Rasmus Villemoes @ 2015-01-30 9:31 UTC (permalink / raw)
To: Dan Carpenter
Cc: Lars-Peter Clausen, Michael Hennerich, Jonathan Cameron,
Hartmut Knaack, Peter Meerwald, linux-iio, kernel-janitors
On Fri, Jan 30 2015, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> Rasmus, are you using a static checker? Which one?
Sort of:
https://github.com/Villemoes/linux-cocci/blob/master/misc/sign_extend.cocci
Rasmus
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [patch] iio: imu: adis16400: Fix sign extension
@ 2015-01-30 9:31 ` Rasmus Villemoes
0 siblings, 0 replies; 13+ messages in thread
From: Rasmus Villemoes @ 2015-01-30 9:31 UTC (permalink / raw)
To: Dan Carpenter
Cc: Lars-Peter Clausen, Michael Hennerich, Jonathan Cameron,
Hartmut Knaack, Peter Meerwald, linux-iio, kernel-janitors
On Fri, Jan 30 2015, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> Rasmus, are you using a static checker? Which one?
Sort of:
https://github.com/Villemoes/linux-cocci/blob/master/misc/sign_extend.cocci
Rasmus
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [patch] iio: imu: adis16400: Fix sign extension
2015-01-30 8:34 ` Lars-Peter Clausen
@ 2015-01-30 9:22 ` Dan Carpenter
-1 siblings, 0 replies; 13+ messages in thread
From: Dan Carpenter @ 2015-01-30 9:22 UTC (permalink / raw)
To: Lars-Peter Clausen
Cc: Michael Hennerich, Jonathan Cameron, Hartmut Knaack,
Peter Meerwald, linux-iio, kernel-janitors, Rasmus Villemoes
On Fri, Jan 30, 2015 at 09:34:01AM +0100, Lars-Peter Clausen wrote:
> On 01/30/2015 09:30 AM, Dan Carpenter wrote:
> >Because of C's type promotion rules, the code shifts in
> >"((val16 & 0xFFF) << 4) >> 4;" cancel each other out and they're a
> >no-op.
> >
> >The intention here was to sign-extend then 11th bit so we can use the
> >sign_extend32() function.
> >
> >Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> >---
> >Please review this carefully. I'm pretty sure it's correct but this is
> >the first time I've ever used the sign_extend32() function.
>
> Hi,
>
> Rasmus already fixed this a couple of days ago.
>
> Thanks,
> - Lars
Oh. Good. I was CC'd on the other one that he fixed so I went looking
for other bugs and I found this one.
Rasmus, are you using a static checker? Which one?
regards,
dan carpenter
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [patch] iio: imu: adis16400: Fix sign extension
@ 2015-01-30 9:22 ` Dan Carpenter
0 siblings, 0 replies; 13+ messages in thread
From: Dan Carpenter @ 2015-01-30 9:22 UTC (permalink / raw)
To: Lars-Peter Clausen
Cc: Michael Hennerich, Jonathan Cameron, Hartmut Knaack,
Peter Meerwald, linux-iio, kernel-janitors, Rasmus Villemoes
On Fri, Jan 30, 2015 at 09:34:01AM +0100, Lars-Peter Clausen wrote:
> On 01/30/2015 09:30 AM, Dan Carpenter wrote:
> >Because of C's type promotion rules, the code shifts in
> >"((val16 & 0xFFF) << 4) >> 4;" cancel each other out and they're a
> >no-op.
> >
> >The intention here was to sign-extend then 11th bit so we can use the
> >sign_extend32() function.
> >
> >Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> >---
> >Please review this carefully. I'm pretty sure it's correct but this is
> >the first time I've ever used the sign_extend32() function.
>
> Hi,
>
> Rasmus already fixed this a couple of days ago.
>
> Thanks,
> - Lars
Oh. Good. I was CC'd on the other one that he fixed so I went looking
for other bugs and I found this one.
Rasmus, are you using a static checker? Which one?
regards,
dan carpenter
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [patch] iio: imu: adis16400: Fix sign extension
2015-01-30 8:30 ` Dan Carpenter
@ 2015-01-30 8:34 ` Lars-Peter Clausen
-1 siblings, 0 replies; 13+ messages in thread
From: Lars-Peter Clausen @ 2015-01-30 8:34 UTC (permalink / raw)
To: Dan Carpenter
Cc: Michael Hennerich, Jonathan Cameron, Hartmut Knaack,
Peter Meerwald, linux-iio, kernel-janitors, Rasmus Villemoes
On 01/30/2015 09:30 AM, Dan Carpenter wrote:
> Because of C's type promotion rules, the code shifts in
> "((val16 & 0xFFF) << 4) >> 4;" cancel each other out and they're a
> no-op.
>
> The intention here was to sign-extend then 11th bit so we can use the
> sign_extend32() function.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> Please review this carefully. I'm pretty sure it's correct but this is
> the first time I've ever used the sign_extend32() function.
Hi,
Rasmus already fixed this a couple of days ago.
Thanks,
- Lars
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [patch] iio: imu: adis16400: Fix sign extension
@ 2015-01-30 8:34 ` Lars-Peter Clausen
0 siblings, 0 replies; 13+ messages in thread
From: Lars-Peter Clausen @ 2015-01-30 8:34 UTC (permalink / raw)
To: Dan Carpenter
Cc: Michael Hennerich, Jonathan Cameron, Hartmut Knaack,
Peter Meerwald, linux-iio, kernel-janitors, Rasmus Villemoes
On 01/30/2015 09:30 AM, Dan Carpenter wrote:
> Because of C's type promotion rules, the code shifts in
> "((val16 & 0xFFF) << 4) >> 4;" cancel each other out and they're a
> no-op.
>
> The intention here was to sign-extend then 11th bit so we can use the
> sign_extend32() function.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> Please review this carefully. I'm pretty sure it's correct but this is
> the first time I've ever used the sign_extend32() function.
Hi,
Rasmus already fixed this a couple of days ago.
Thanks,
- Lars
^ permalink raw reply [flat|nested] 13+ messages in thread
* [patch] iio: imu: adis16400: Fix sign extension
@ 2015-01-30 8:30 ` Dan Carpenter
0 siblings, 0 replies; 13+ messages in thread
From: Dan Carpenter @ 2015-01-30 8:30 UTC (permalink / raw)
To: Lars-Peter Clausen
Cc: Michael Hennerich, Jonathan Cameron, Hartmut Knaack,
Peter Meerwald, linux-iio, kernel-janitors, Rasmus Villemoes
Because of C's type promotion rules, the code shifts in
"((val16 & 0xFFF) << 4) >> 4;" cancel each other out and they're a
no-op.
The intention here was to sign-extend then 11th bit so we can use the
sign_extend32() function.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Please review this carefully. I'm pretty sure it's correct but this is
the first time I've ever used the sign_extend32() function.
diff --git a/drivers/iio/imu/adis16400_core.c b/drivers/iio/imu/adis16400_core.c
index b70873d..ed636c9 100644
--- a/drivers/iio/imu/adis16400_core.c
+++ b/drivers/iio/imu/adis16400_core.c
@@ -414,7 +414,7 @@ static int adis16400_read_raw(struct iio_dev *indio_dev,
mutex_unlock(&indio_dev->mlock);
if (ret)
return ret;
- val16 = ((val16 & 0xFFF) << 4) >> 4;
+ val16 = sign_extend32(val16, 11);
*val = val16;
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [patch] iio: imu: adis16400: Fix sign extension
@ 2015-01-30 8:30 ` Dan Carpenter
0 siblings, 0 replies; 13+ messages in thread
From: Dan Carpenter @ 2015-01-30 8:30 UTC (permalink / raw)
To: Lars-Peter Clausen
Cc: Michael Hennerich, Jonathan Cameron, Hartmut Knaack,
Peter Meerwald, linux-iio, kernel-janitors, Rasmus Villemoes
Because of C's type promotion rules, the code shifts in
"((val16 & 0xFFF) << 4) >> 4;" cancel each other out and they're a
no-op.
The intention here was to sign-extend then 11th bit so we can use the
sign_extend32() function.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Please review this carefully. I'm pretty sure it's correct but this is
the first time I've ever used the sign_extend32() function.
diff --git a/drivers/iio/imu/adis16400_core.c b/drivers/iio/imu/adis16400_core.c
index b70873d..ed636c9 100644
--- a/drivers/iio/imu/adis16400_core.c
+++ b/drivers/iio/imu/adis16400_core.c
@@ -414,7 +414,7 @@ static int adis16400_read_raw(struct iio_dev *indio_dev,
mutex_unlock(&indio_dev->mlock);
if (ret)
return ret;
- val16 = ((val16 & 0xFFF) << 4) >> 4;
+ val16 = sign_extend32(val16, 11);
*val = val16;
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
^ permalink raw reply related [flat|nested] 13+ messages in thread
end of thread, other threads:[~2015-01-30 10:23 UTC | newest]
Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-01-22 23:34 [PATCH] iio: imu: adis16400: Fix sign extension Rasmus Villemoes
2015-01-23 8:56 ` Lars-Peter Clausen
2015-01-26 21:07 ` Jonathan Cameron
2015-01-30 8:30 [patch] " Dan Carpenter
2015-01-30 8:30 ` Dan Carpenter
2015-01-30 8:34 ` Lars-Peter Clausen
2015-01-30 8:34 ` Lars-Peter Clausen
2015-01-30 9:22 ` Dan Carpenter
2015-01-30 9:22 ` Dan Carpenter
2015-01-30 9:31 ` Rasmus Villemoes
2015-01-30 9:31 ` Rasmus Villemoes
2015-01-30 10:23 ` Dan Carpenter
2015-01-30 10:23 ` Dan Carpenter
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