Linux-IIO Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH v1] iio: hid-sensor-attributes: Fix divisions for 32-bit platforms
@ 2019-09-05 11:27 Andy Shevchenko
  2019-09-06  1:35 ` Pandruvada, Srinivas
  0 siblings, 1 reply; 2+ messages in thread
From: Andy Shevchenko @ 2019-09-05 11:27 UTC (permalink / raw)
  To: Nathan Chancellor, linux-iio, Jonathan Cameron, Hartmut Knaack,
	Lars-Peter Clausen, Peter Meerwald-Stadler, Srinivas Pandruvada,
	Greg KH
  Cc: Andy Shevchenko, kbuild test robot

The commit 473d12f7638c

  ("iio: hid-sensor-attributes: Convert to use int_pow()")

converted to use generic int_pow() helper. Though, the generic one returns
64-bit value and, in cases when it is used as divisor, it compels 64-bit
division from compiler.

In order to fix this, introduce a temporary 32-bit variable to hold the result
of int_pow() and use it as divisor afterwards.

In couple of cases, replace int_pow() with a predefined unit factors for time
and frequency.

Fixes: 473d12f7638c ("iio: hid-sensor-attributes: Convert to use int_pow()")
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 .../hid-sensors/hid-sensor-attributes.c       | 42 ++++++++++++-------
 1 file changed, 28 insertions(+), 14 deletions(-)

diff --git a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
index b9dd19b34267..442ff787f7af 100644
--- a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
+++ b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
@@ -10,10 +10,14 @@
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
+#include <linux/time.h>
+
 #include <linux/hid-sensor-hub.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 
+#define HZ_PER_MHZ	1000000L
+
 static struct {
 	u32 usage_id;
 	int unit; /* 0 for default others from HID sensor spec */
@@ -93,8 +97,10 @@ static void simple_div(int dividend, int divisor, int *whole,
 
 static void split_micro_fraction(unsigned int no, int exp, int *val1, int *val2)
 {
-	*val1 = no / int_pow(10, exp);
-	*val2 = no % int_pow(10, exp) * int_pow(10, 6 - exp);
+	int divisor = int_pow(10, exp);
+
+	*val1 = no / divisor;
+	*val2 = no % divisor * int_pow(10, 6 - exp);
 }
 
 /*
@@ -129,6 +135,7 @@ static void convert_from_vtf_format(u32 value, int size, int exp,
 
 static u32 convert_to_vtf_format(int size, int exp, int val1, int val2)
 {
+	int divisor;
 	u32 value;
 	int sign = 1;
 
@@ -136,10 +143,13 @@ static u32 convert_to_vtf_format(int size, int exp, int val1, int val2)
 		sign = -1;
 	exp = hid_sensor_convert_exponent(exp);
 	if (exp < 0) {
+		divisor = int_pow(10, 6 + exp);
 		value = abs(val1) * int_pow(10, -exp);
-		value += abs(val2) / int_pow(10, 6 + exp);
-	} else
-		value = abs(val1) / int_pow(10, exp);
+		value += abs(val2) / divisor;
+	} else {
+		divisor = int_pow(10, exp);
+		value = abs(val1) / divisor;
+	}
 	if (sign < 0)
 		value =  ((1LL << (size * 8)) - value);
 
@@ -202,12 +212,12 @@ int hid_sensor_write_samp_freq_value(struct hid_sensor_common *st,
 	if (val1 < 0 || val2 < 0)
 		return -EINVAL;
 
-	value = val1 * int_pow(10, 6) + val2;
+	value = val1 * HZ_PER_MHZ + val2;
 	if (value) {
 		if (st->poll.units == HID_USAGE_SENSOR_UNITS_MILLISECOND)
-			value = int_pow(10, 9) / value;
+			value = NSEC_PER_SEC / value;
 		else if (st->poll.units == HID_USAGE_SENSOR_UNITS_SECOND)
-			value = int_pow(10, 6) / value;
+			value = USEC_PER_SEC / value;
 		else
 			value = 0;
 	}
@@ -296,6 +306,7 @@ EXPORT_SYMBOL(hid_sensor_write_raw_hyst_value);
 static void adjust_exponent_nano(int *val0, int *val1, int scale0,
 				  int scale1, int exp)
 {
+	int divisor;
 	int i;
 	int x;
 	int res;
@@ -309,9 +320,10 @@ static void adjust_exponent_nano(int *val0, int *val1, int scale0,
 			return;
 		}
 		for (i = 0; i < exp; ++i) {
-			x = scale1 / int_pow(10, 8 - i);
+			divisor = int_pow(10, 8 - i);
+			x = scale1 / divisor;
 			res += int_pow(10, exp - 1 - i) * x;
-			scale1 = scale1 % int_pow(10, 8 - i);
+			scale1 = scale1 % divisor;
 		}
 		*val0 += res;
 		*val1 = scale1 * int_pow(10, exp);
@@ -321,13 +333,15 @@ static void adjust_exponent_nano(int *val0, int *val1, int scale0,
 			*val0 = *val1 = 0;
 			return;
 		}
-		*val0 = scale0 / int_pow(10, exp);
-		rem = scale0 % int_pow(10, exp);
+		divisor = int_pow(10, exp);
+		*val0 = scale0 / divisor;
+		rem = scale0 % divisor;
 		res = 0;
 		for (i = 0; i < (9 - exp); ++i) {
-			x = scale1 / int_pow(10, 8 - i);
+			divisor = int_pow(10, 8 - i);
+			x = scale1 / divisor;
 			res += int_pow(10, 8 - exp - i) * x;
-			scale1 = scale1 % int_pow(10, 8 - i);
+			scale1 = scale1 % divisor;
 		}
 		*val1 = rem * int_pow(10, 9 - exp) + res;
 	} else {
-- 
2.23.0.rc1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH v1] iio: hid-sensor-attributes: Fix divisions for 32-bit platforms
  2019-09-05 11:27 [PATCH v1] iio: hid-sensor-attributes: Fix divisions for 32-bit platforms Andy Shevchenko
@ 2019-09-06  1:35 ` Pandruvada, Srinivas
  0 siblings, 0 replies; 2+ messages in thread
From: Pandruvada, Srinivas @ 2019-09-06  1:35 UTC (permalink / raw)
  To: lars, knaack.h, jic23, linux-iio, pmeerw, gregkh, natechancellor,
	andriy.shevchenko
  Cc: lkp

[-- Attachment #1: Type: text/plain, Size: 4918 bytes --]

On Thu, 2019-09-05 at 14:27 +0300, Andy Shevchenko wrote:
> The commit 473d12f7638c
> 
>   ("iio: hid-sensor-attributes: Convert to use int_pow()")
> 
> converted to use generic int_pow() helper. Though, the generic one
> returns
> 64-bit value and, in cases when it is used as divisor, it compels 64-
> bit
> division from compiler.
> 
> In order to fix this, introduce a temporary 32-bit variable to hold
> the result
> of int_pow() and use it as divisor afterwards.
> 
> In couple of cases, replace int_pow() with a predefined unit factors
> for time
> and frequency.
> 
> Fixes: 473d12f7638c ("iio: hid-sensor-attributes: Convert to use
> int_pow()")
> Reported-by: kbuild test robot <lkp@intel.com>
> Reported-by: Nathan Chancellor <natechancellor@gmail.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

> ---
>  .../hid-sensors/hid-sensor-attributes.c       | 42 ++++++++++++-----
> --
>  1 file changed, 28 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
> b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
> index b9dd19b34267..442ff787f7af 100644
> --- a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
> +++ b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
> @@ -10,10 +10,14 @@
>  #include <linux/irq.h>
>  #include <linux/kernel.h>
>  #include <linux/slab.h>
> +#include <linux/time.h>
> +
>  #include <linux/hid-sensor-hub.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
>  
> +#define HZ_PER_MHZ	1000000L
> +
>  static struct {
>  	u32 usage_id;
>  	int unit; /* 0 for default others from HID sensor spec */
> @@ -93,8 +97,10 @@ static void simple_div(int dividend, int divisor,
> int *whole,
>  
>  static void split_micro_fraction(unsigned int no, int exp, int
> *val1, int *val2)
>  {
> -	*val1 = no / int_pow(10, exp);
> -	*val2 = no % int_pow(10, exp) * int_pow(10, 6 - exp);
> +	int divisor = int_pow(10, exp);
> +
> +	*val1 = no / divisor;
> +	*val2 = no % divisor * int_pow(10, 6 - exp);
>  }
>  
>  /*
> @@ -129,6 +135,7 @@ static void convert_from_vtf_format(u32 value,
> int size, int exp,
>  
>  static u32 convert_to_vtf_format(int size, int exp, int val1, int
> val2)
>  {
> +	int divisor;
>  	u32 value;
>  	int sign = 1;
>  
> @@ -136,10 +143,13 @@ static u32 convert_to_vtf_format(int size, int
> exp, int val1, int val2)
>  		sign = -1;
>  	exp = hid_sensor_convert_exponent(exp);
>  	if (exp < 0) {
> +		divisor = int_pow(10, 6 + exp);
>  		value = abs(val1) * int_pow(10, -exp);
> -		value += abs(val2) / int_pow(10, 6 + exp);
> -	} else
> -		value = abs(val1) / int_pow(10, exp);
> +		value += abs(val2) / divisor;
> +	} else {
> +		divisor = int_pow(10, exp);
> +		value = abs(val1) / divisor;
> +	}
>  	if (sign < 0)
>  		value =  ((1LL << (size * 8)) - value);
>  
> @@ -202,12 +212,12 @@ int hid_sensor_write_samp_freq_value(struct
> hid_sensor_common *st,
>  	if (val1 < 0 || val2 < 0)
>  		return -EINVAL;
>  
> -	value = val1 * int_pow(10, 6) + val2;
> +	value = val1 * HZ_PER_MHZ + val2;
>  	if (value) {
>  		if (st->poll.units ==
> HID_USAGE_SENSOR_UNITS_MILLISECOND)
> -			value = int_pow(10, 9) / value;
> +			value = NSEC_PER_SEC / value;
>  		else if (st->poll.units ==
> HID_USAGE_SENSOR_UNITS_SECOND)
> -			value = int_pow(10, 6) / value;
> +			value = USEC_PER_SEC / value;
>  		else
>  			value = 0;
>  	}
> @@ -296,6 +306,7 @@ EXPORT_SYMBOL(hid_sensor_write_raw_hyst_value);
>  static void adjust_exponent_nano(int *val0, int *val1, int scale0,
>  				  int scale1, int exp)
>  {
> +	int divisor;
>  	int i;
>  	int x;
>  	int res;
> @@ -309,9 +320,10 @@ static void adjust_exponent_nano(int *val0, int
> *val1, int scale0,
>  			return;
>  		}
>  		for (i = 0; i < exp; ++i) {
> -			x = scale1 / int_pow(10, 8 - i);
> +			divisor = int_pow(10, 8 - i);
> +			x = scale1 / divisor;
>  			res += int_pow(10, exp - 1 - i) * x;
> -			scale1 = scale1 % int_pow(10, 8 - i);
> +			scale1 = scale1 % divisor;
>  		}
>  		*val0 += res;
>  		*val1 = scale1 * int_pow(10, exp);
> @@ -321,13 +333,15 @@ static void adjust_exponent_nano(int *val0, int
> *val1, int scale0,
>  			*val0 = *val1 = 0;
>  			return;
>  		}
> -		*val0 = scale0 / int_pow(10, exp);
> -		rem = scale0 % int_pow(10, exp);
> +		divisor = int_pow(10, exp);
> +		*val0 = scale0 / divisor;
> +		rem = scale0 % divisor;
>  		res = 0;
>  		for (i = 0; i < (9 - exp); ++i) {
> -			x = scale1 / int_pow(10, 8 - i);
> +			divisor = int_pow(10, 8 - i);
> +			x = scale1 / divisor;
>  			res += int_pow(10, 8 - exp - i) * x;
> -			scale1 = scale1 % int_pow(10, 8 - i);
> +			scale1 = scale1 % divisor;
>  		}
>  		*val1 = rem * int_pow(10, 9 - exp) + res;
>  	} else {

[-- Attachment #2: smime.p7s --]
[-- Type: application/x-pkcs7-signature, Size: 3290 bytes --]

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, back to index

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-05 11:27 [PATCH v1] iio: hid-sensor-attributes: Fix divisions for 32-bit platforms Andy Shevchenko
2019-09-06  1:35 ` Pandruvada, Srinivas

Linux-IIO Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-iio/0 linux-iio/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-iio linux-iio/ https://lore.kernel.org/linux-iio \
		linux-iio@vger.kernel.org linux-iio@archiver.kernel.org
	public-inbox-index linux-iio


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-iio


AGPL code for this site: git clone https://public-inbox.org/ public-inbox