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authorArnd Bergmann <arnd@arndb.de>2019-07-10 15:01:53 +0200
committerThomas Gleixner <tglx@linutronix.de>2019-07-10 20:37:49 +0200
commit0df1c9868c3a1916198ee09c323ca5932a0b8a11 (patch)
tree18a8b26434edf1c7766d971bbcdbc3c516c2205d
parent9bdd7bb3a8447fe841cd37ddd9e0a6974b06a0bb (diff)
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timekeeping/vsyscall: Use __iter_div_u64_rem()
On 32-bit x86 when building with clang-9, the 'division' loop gets turned back into an inefficient division that causes a link error: kernel/time/vsyscall.o: In function `update_vsyscall': vsyscall.c:(.text+0xe3): undefined reference to `__udivdi3' Use the existing __iter_div_u64_rem() function which is used to address the same issue in other places. Fixes: 44f57d788e7d ("timekeeping: Provide a generic update_vsyscall() implementation") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Link: https://lkml.kernel.org/r/20190710130206.1670830-1-arnd@arndb.de
-rw-r--r--kernel/time/vsyscall.c6
1 files changed, 1 insertions, 5 deletions
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index a80893180826..8cf3596a4ce6 100644
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -104,11 +104,7 @@ void update_vsyscall(struct timekeeper *tk)
vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
nsec = nsec + tk->wall_to_monotonic.tv_nsec;
- while (nsec >= NSEC_PER_SEC) {
- nsec = nsec - NSEC_PER_SEC;
- vdso_ts->sec++;
- }
- vdso_ts->nsec = nsec;
+ vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec);
if (__arch_use_vsyscall(vdata))
update_vdso_data(vdata, tk);