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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-09-08 01:01:14 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-09-08 01:01:14 -0300
commite5fd91f1ef340da553f7a79da9540c3db711c937 (patch)
treeb11842027dc6641da63f4bcc524f8678263304a3 /kernel/time/time.c
parent2a9b0348e685a63d97486f6749622b61e9e3292f (diff)
Linux-libre 4.2-gnu
Diffstat (limited to 'kernel/time/time.c')
-rw-r--r--kernel/time/time.c78
1 files changed, 27 insertions, 51 deletions
diff --git a/kernel/time/time.c b/kernel/time/time.c
index 2c85b7724..85d5bb1d6 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -41,7 +41,7 @@
#include <asm/uaccess.h>
#include <asm/unistd.h>
-#include "timeconst.h"
+#include <generated/timeconst.h>
#include "timekeeping.h"
/*
@@ -173,6 +173,10 @@ int do_sys_settimeofday(const struct timespec *tv, const struct timezone *tz)
return error;
if (tz) {
+ /* Verify we're witin the +-15 hrs range */
+ if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60)
+ return -EINVAL;
+
sys_tz = *tz;
update_vsyscall_tz();
if (firsttime) {
@@ -483,9 +487,11 @@ struct timespec64 ns_to_timespec64(const s64 nsec)
}
EXPORT_SYMBOL(ns_to_timespec64);
#endif
-/*
- * When we convert to jiffies then we interpret incoming values
- * the following way:
+/**
+ * msecs_to_jiffies: - convert milliseconds to jiffies
+ * @m: time in milliseconds
+ *
+ * conversion is done as follows:
*
* - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
*
@@ -493,66 +499,36 @@ EXPORT_SYMBOL(ns_to_timespec64);
* MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
*
* - all other values are converted to jiffies by either multiplying
- * the input value by a factor or dividing it with a factor
- *
- * We must also be careful about 32-bit overflows.
+ * the input value by a factor or dividing it with a factor and
+ * handling any 32-bit overflows.
+ * for the details see __msecs_to_jiffies()
+ *
+ * msecs_to_jiffies() checks for the passed in value being a constant
+ * via __builtin_constant_p() allowing gcc to eliminate most of the
+ * code, __msecs_to_jiffies() is called if the value passed does not
+ * allow constant folding and the actual conversion must be done at
+ * runtime.
+ * the _msecs_to_jiffies helpers are the HZ dependent conversion
+ * routines found in include/linux/jiffies.h
*/
-unsigned long msecs_to_jiffies(const unsigned int m)
+unsigned long __msecs_to_jiffies(const unsigned int m)
{
/*
* Negative value, means infinite timeout:
*/
if ((int)m < 0)
return MAX_JIFFY_OFFSET;
-
-#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
- /*
- * HZ is equal to or smaller than 1000, and 1000 is a nice
- * round multiple of HZ, divide with the factor between them,
- * but round upwards:
- */
- return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ);
-#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
- /*
- * HZ is larger than 1000, and HZ is a nice round multiple of
- * 1000 - simply multiply with the factor between them.
- *
- * But first make sure the multiplication result cannot
- * overflow:
- */
- if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
- return MAX_JIFFY_OFFSET;
-
- return m * (HZ / MSEC_PER_SEC);
-#else
- /*
- * Generic case - multiply, round and divide. But first
- * check that if we are doing a net multiplication, that
- * we wouldn't overflow:
- */
- if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
- return MAX_JIFFY_OFFSET;
-
- return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32)
- >> MSEC_TO_HZ_SHR32;
-#endif
+ return _msecs_to_jiffies(m);
}
-EXPORT_SYMBOL(msecs_to_jiffies);
+EXPORT_SYMBOL(__msecs_to_jiffies);
-unsigned long usecs_to_jiffies(const unsigned int u)
+unsigned long __usecs_to_jiffies(const unsigned int u)
{
if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
return MAX_JIFFY_OFFSET;
-#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
- return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ);
-#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
- return u * (HZ / USEC_PER_SEC);
-#else
- return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32)
- >> USEC_TO_HZ_SHR32;
-#endif
+ return _usecs_to_jiffies(u);
}
-EXPORT_SYMBOL(usecs_to_jiffies);
+EXPORT_SYMBOL(__usecs_to_jiffies);
/*
* The TICK_NSEC - 1 rounds up the value to the next resolution. Note