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authorLinus Torvalds <torvalds@linux-foundation.org>2017-03-12 14:22:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-03-12 14:22:25 -0700
commit56b24d1bbcff213dc9e1625eea5b8e13bb50feb8 (patch)
tree888f40d5c2b77f3d839a14f9781e418b9d48c22a /arch/s390/include/asm/timex.h
parent5a45a5a881aeb82ce31dd1886afe04146965df23 (diff)
parent8bd49ac86677ca43d64f08c45864e438283d6a76 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Martin Schwidefsky: - four patches to get the new cputime code in shape for s390 - add the new statx system call - a few bug fixes * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390: wire up statx system call KVM: s390: Fix guest migration for huge guests resulting in panic s390/ipl: always use load normal for CCW-type re-IPL s390/timex: micro optimization for tod_to_ns s390/cputime: provide archicture specific cputime_to_nsecs s390/cputime: reset all accounting fields on fork s390/cputime: remove last traces of cputime_t s390: fix in-kernel program checks s390/crypt: fix missing unlock in ctr_paes_crypt on error path
Diffstat (limited to 'arch/s390/include/asm/timex.h')
-rw-r--r--arch/s390/include/asm/timex.h12
1 files changed, 4 insertions, 8 deletions
diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h
index 354344dcc198..118535123f34 100644
--- a/arch/s390/include/asm/timex.h
+++ b/arch/s390/include/asm/timex.h
@@ -206,20 +206,16 @@ static inline unsigned long long get_tod_clock_monotonic(void)
* ns = (todval * 125) >> 9;
*
* In order to avoid an overflow with the multiplication we can rewrite this.
- * With a split todval == 2^32 * th + tl (th upper 32 bits, tl lower 32 bits)
+ * With a split todval == 2^9 * th + tl (th upper 55 bits, tl lower 9 bits)
* we end up with
*
- * ns = ((2^32 * th + tl) * 125 ) >> 9;
- * -> ns = (2^23 * th * 125) + ((tl * 125) >> 9);
+ * ns = ((2^9 * th + tl) * 125 ) >> 9;
+ * -> ns = (th * 125) + ((tl * 125) >> 9);
*
*/
static inline unsigned long long tod_to_ns(unsigned long long todval)
{
- unsigned long long ns;
-
- ns = ((todval >> 32) << 23) * 125;
- ns += ((todval & 0xffffffff) * 125) >> 9;
- return ns;
+ return ((todval >> 9) * 125) + (((todval & 0x1ff) * 125) >> 9);
}
#endif