sched/cputime: Convert task/group cputime to nsecs

Now that most cputime readers use the transition API which return the
task cputime in old style cputime_t, we can safely store the cputime in
nsecs. This will eventually make cputime statistics less opaque and more
granular. Back and forth convertions between cputime_t and nsecs in order
to deal with cputime_t random granularity won't be needed anymore.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1485832191-26889-8-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 68b9156..6d45193 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1411,6 +1411,8 @@
 static void fill_prstatus(struct elf_prstatus *prstatus,
 		struct task_struct *p, long signr)
 {
+	struct timeval tv;
+
 	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
 	prstatus->pr_sigpend = p->pending.signal.sig[0];
 	prstatus->pr_sighold = p->blocked.sig[0];
@@ -1437,8 +1439,13 @@
 		cputime_to_timeval(utime, &prstatus->pr_utime);
 		cputime_to_timeval(stime, &prstatus->pr_stime);
 	}
-	cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
-	cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
+	tv = ns_to_timeval(p->signal->cutime);
+	prstatus->pr_cutime.tv_sec = tv.tv_sec;
+	prstatus->pr_cutime.tv_usec = tv.tv_usec;
+
+	tv = ns_to_timeval(p->signal->cstime);
+	prstatus->pr_cstime.tv_sec = tv.tv_sec;
+	prstatus->pr_cstime.tv_usec = tv.tv_usec;
 }
 
 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,