'struct timeval' uses a 32-bit representation for the
seconds field which will overflow in the year 2038 and beyond.
This patch replaces the usage of 'struct timeval' with
ktime_t which uses a 64-bit time representation and does not
suffer from the y2038 problem. This patch is part of a larger
effort to remove all instances of 'struct timeval', 'struct
timespec', time_t and other 32-bit timekeeping variables
from the kernel.
The patch also replaces the use of real time (do_gettimeofday)
with monotonic time (ktime_get).
Signed-off-by: Tina Ruchandani <[email protected]>
---
drivers/video/fbdev/aty/radeon_base.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
diff --git a/drivers/video/fbdev/aty/radeon_base.c b/drivers/video/fbdev/aty/radeon_base.c
index 01237c8..9747e9e 100644
--- a/drivers/video/fbdev/aty/radeon_base.c
+++ b/drivers/video/fbdev/aty/radeon_base.c
@@ -64,6 +64,7 @@
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/time.h>
+#include <linux/ktime.h>
#include <linux/fb.h>
#include <linux/ioport.h>
#include <linux/init.h>
@@ -461,8 +462,8 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
int hTotal, vTotal, num, denom, m, n;
unsigned long long hz, vclk;
long xtal;
- struct timeval start_tv, stop_tv;
- long total_secs, total_usecs;
+ ktime_t start, stop;
+ s64 delta;
int i;
/* Ugh, we cut interrupts, bad bad bad, but we want some precision
@@ -478,7 +479,7 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
if (((INREG(CRTC_VLINE_CRNT_VLINE) >> 16) & 0x3ff) == 0)
break;
- do_gettimeofday(&start_tv);
+ start = ktime_get();
for(i=0; i<1000000; i++)
if (((INREG(CRTC_VLINE_CRNT_VLINE) >> 16) & 0x3ff) != 0)
@@ -487,20 +488,18 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
for(i=0; i<1000000; i++)
if (((INREG(CRTC_VLINE_CRNT_VLINE) >> 16) & 0x3ff) == 0)
break;
-
- do_gettimeofday(&stop_tv);
-
+
+ stop = ktime_get();
+
local_irq_enable();
- total_secs = stop_tv.tv_sec - start_tv.tv_sec;
- if (total_secs > 10)
+ delta = ktime_us_delta(stop, start);
+
+ /* Return -1 if more than 10 seconds have elapsed */
+ if (delta > (10*1000000))
return -1;
- total_usecs = stop_tv.tv_usec - start_tv.tv_usec;
- total_usecs += total_secs * 1000000;
- if (total_usecs < 0)
- total_usecs = -total_usecs;
- hz = 1000000/total_usecs;
-
+ hz = 1000000/delta;
+
hTotal = ((INREG(CRTC_H_TOTAL_DISP) & 0x1ff) + 1) * 8;
vTotal = ((INREG(CRTC_V_TOTAL_DISP) & 0x3ff) + 1);
vclk = (long long)hTotal * (long long)vTotal * hz;
@@ -548,7 +547,7 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
denom *= 3;
break;
case 6:
- denom *= 6;
+ denom *= 6;
break;
case 7:
denom *= 12;
--
2.2.0.rc0.207.ga3a616c
On 25/05/15 07:07, Tina Ruchandani wrote:
> 'struct timeval' uses a 32-bit representation for the
> seconds field which will overflow in the year 2038 and beyond.
> This patch replaces the usage of 'struct timeval' with
> ktime_t which uses a 64-bit time representation and does not
> suffer from the y2038 problem. This patch is part of a larger
> effort to remove all instances of 'struct timeval', 'struct
> timespec', time_t and other 32-bit timekeeping variables
> from the kernel.
> The patch also replaces the use of real time (do_gettimeofday)
> with monotonic time (ktime_get).
>
> Signed-off-by: Tina Ruchandani <[email protected]>
> ---
> drivers/video/fbdev/aty/radeon_base.c | 29 ++++++++++++++---------------
> 1 file changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/video/fbdev/aty/radeon_base.c b/drivers/video/fbdev/aty/radeon_base.c
> index 01237c8..9747e9e 100644
> --- a/drivers/video/fbdev/aty/radeon_base.c
> +++ b/drivers/video/fbdev/aty/radeon_base.c
> @@ -64,6 +64,7 @@
> #include <linux/slab.h>
> #include <linux/delay.h>
> #include <linux/time.h>
> +#include <linux/ktime.h>
> #include <linux/fb.h>
> #include <linux/ioport.h>
> #include <linux/init.h>
> @@ -461,8 +462,8 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
> int hTotal, vTotal, num, denom, m, n;
> unsigned long long hz, vclk;
> long xtal;
> - struct timeval start_tv, stop_tv;
> - long total_secs, total_usecs;
> + ktime_t start, stop;
> + s64 delta;
> int i;
>
> /* Ugh, we cut interrupts, bad bad bad, but we want some precision
> @@ -478,7 +479,7 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
> if (((INREG(CRTC_VLINE_CRNT_VLINE) >> 16) & 0x3ff) == 0)
> break;
>
> - do_gettimeofday(&start_tv);
> + start = ktime_get();
>
> for(i=0; i<1000000; i++)
> if (((INREG(CRTC_VLINE_CRNT_VLINE) >> 16) & 0x3ff) != 0)
> @@ -487,20 +488,18 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
> for(i=0; i<1000000; i++)
> if (((INREG(CRTC_VLINE_CRNT_VLINE) >> 16) & 0x3ff) == 0)
> break;
> -
> - do_gettimeofday(&stop_tv);
> -
> +
> + stop = ktime_get();
> +
> local_irq_enable();
>
> - total_secs = stop_tv.tv_sec - start_tv.tv_sec;
> - if (total_secs > 10)
> + delta = ktime_us_delta(stop, start);
> +
> + /* Return -1 if more than 10 seconds have elapsed */
> + if (delta > (10*1000000))
> return -1;
> - total_usecs = stop_tv.tv_usec - start_tv.tv_usec;
> - total_usecs += total_secs * 1000000;
> - if (total_usecs < 0)
> - total_usecs = -total_usecs;
> - hz = 1000000/total_usecs;
> -
> + hz = 1000000/delta;
> +
> hTotal = ((INREG(CRTC_H_TOTAL_DISP) & 0x1ff) + 1) * 8;
> vTotal = ((INREG(CRTC_V_TOTAL_DISP) & 0x3ff) + 1);
> vclk = (long long)hTotal * (long long)vTotal * hz;
> @@ -548,7 +547,7 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
> denom *= 3;
> break;
> case 6:
> - denom *= 6;
> + denom *= 6;
> break;
> case 7:
> denom *= 12;
The above change was extra. I removed it, and queued this for 4.2.
Tomi
On 3 June 2015 at 21:59, Tomi Valkeinen <[email protected]> wrote:
>
>
> On 25/05/15 07:07, Tina Ruchandani wrote:
>> 'struct timeval' uses a 32-bit representation for the
>> seconds field which will overflow in the year 2038 and beyond.
>> This patch replaces the usage of 'struct timeval' with
>> ktime_t which uses a 64-bit time representation and does not
>> suffer from the y2038 problem. This patch is part of a larger
>> effort to remove all instances of 'struct timeval', 'struct
>> timespec', time_t and other 32-bit timekeeping variables
>> from the kernel.
>> The patch also replaces the use of real time (do_gettimeofday)
>> with monotonic time (ktime_get).
>>
>> Signed-off-by: Tina Ruchandani <[email protected]>
>> ---
>> drivers/video/fbdev/aty/radeon_base.c | 29 ++++++++++++++---------------
>> 1 file changed, 14 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/video/fbdev/aty/radeon_base.c b/drivers/video/fbdev/aty/radeon_base.c
>> index 01237c8..9747e9e 100644
>> --- a/drivers/video/fbdev/aty/radeon_base.c
>> +++ b/drivers/video/fbdev/aty/radeon_base.c
>> @@ -64,6 +64,7 @@
>> #include <linux/slab.h>
>> #include <linux/delay.h>
>> #include <linux/time.h>
>> +#include <linux/ktime.h>
>> #include <linux/fb.h>
>> #include <linux/ioport.h>
>> #include <linux/init.h>
>> @@ -461,8 +462,8 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
>> int hTotal, vTotal, num, denom, m, n;
>> unsigned long long hz, vclk;
>> long xtal;
>> - struct timeval start_tv, stop_tv;
>> - long total_secs, total_usecs;
>> + ktime_t start, stop;
>> + s64 delta;
>> int i;
>>
>> /* Ugh, we cut interrupts, bad bad bad, but we want some precision
>> @@ -478,7 +479,7 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
>> if (((INREG(CRTC_VLINE_CRNT_VLINE) >> 16) & 0x3ff) == 0)
>> break;
>>
>> - do_gettimeofday(&start_tv);
>> + start = ktime_get();
>>
>> for(i=0; i<1000000; i++)
>> if (((INREG(CRTC_VLINE_CRNT_VLINE) >> 16) & 0x3ff) != 0)
>> @@ -487,20 +488,18 @@ static int radeon_probe_pll_params(struct radeonfb_info *rinfo)
>> for(i=0; i<1000000; i++)
>> if (((INREG(CRTC_VLINE_CRNT_VLINE) >> 16) & 0x3ff) == 0)
>> break;
>> -
>> - do_gettimeofday(&stop_tv);
>> -
>> +
>> + stop = ktime_get();
>> +
>> local_irq_enable();
>>
>> - total_secs = stop_tv.tv_sec - start_tv.tv_sec;
>> - if (total_secs > 10)
>> + delta = ktime_us_delta(stop, start);
>> +
>> + /* Return -1 if more than 10 seconds have elapsed */
>> + if (delta > (10*1000000))
>> return -1;
>> - total_usecs = stop_tv.tv_usec - start_tv.tv_usec;
>> - total_usecs += total_secs * 1000000;
>> - if (total_usecs < 0)
>> - total_usecs = -total_usecs;
>> - hz = 1000000/total_usecs;
>> -
>> + hz = 1000000/delta;
This needs to be on of the do_div family.
Dave.
>>> + hz = 1000000/delta;
>
> This needs to be on of the do_div family.
>
> Dave.
Hi Dave,
I build-tested the patch for both 32-bit and 64-bit x86. If my
understanding is correct, since the divisor is 64-bit here, the
compiler will do "if (delta > 1000000) hz = 0; else hz =
1000000/(s32)delta" automatically?
In general, is this a good thumb-rule to follow - use do_div if the
dividend is 64-bit, and normal divide operator if only the divisor is
64-bit?
Tina
On Friday 05 June 2015 00:55:05 Tina Ruchandani wrote:
> >>> + hz = 1000000/delta;
> >
> > This needs to be on of the do_div family.
> >
> > Dave.
>
> Hi Dave,
> I build-tested the patch for both 32-bit and 64-bit x86. If my
> understanding is correct, since the divisor is 64-bit here, the
> compiler will do "if (delta > 1000000) hz = 0; else hz =
> 1000000/(s32)delta" automatically?
> In general, is this a good thumb-rule to follow - use do_div if the
> dividend is 64-bit, and normal divide operator if only the divisor is
> 64-bit?
>
I got a build error on 32-bit arm now. There is already a check
for an overflow of 10 seconds in there (10 million microseconds),
so it is safe to do the easiest fix is to cast that microsecond
value to a u32.
Arnd
Hi Tina,
On 25/05/15 07:07, Tina Ruchandani wrote:
> 'struct timeval' uses a 32-bit representation for the
> seconds field which will overflow in the year 2038 and beyond.
> This patch replaces the usage of 'struct timeval' with
> ktime_t which uses a 64-bit time representation and does not
> suffer from the y2038 problem. This patch is part of a larger
> effort to remove all instances of 'struct timeval', 'struct
> timespec', time_t and other 32-bit timekeeping variables
> from the kernel.
> The patch also replaces the use of real time (do_gettimeofday)
> with monotonic time (ktime_get).
>
> Signed-off-by: Tina Ruchandani <[email protected]>
I had dropped this from 4.2 as there were issues reported, but forgot to
write a mail about it...
Can you send a updated patch with the issues fixed?
Tomi