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authorNicolas Pitre <nicolas.pitre@linaro.org>2016-11-11 00:10:10 -0500
committerThomas Gleixner <tglx@linutronix.de>2016-11-16 09:26:35 +0100
commitbaa73d9e478ff32d62f3f9422822b59dd9a95a21 (patch)
treeec1ac1b90e4a6c6337acb564d7fb518418fc510f /kernel/compat.c
parent53d3eaa31508222e445b489f3c3ac4c63542a4ef (diff)
downloadlinux-baa73d9e478ff32d62f3f9422822b59dd9a95a21.tar.bz2
posix-timers: Make them configurable
Some embedded systems have no use for them. This removes about 25KB from the kernel binary size when configured out. Corresponding syscalls are routed to a stub logging the attempt to use those syscalls which should be enough of a clue if they were disabled without proper consideration. They are: timer_create, timer_gettime: timer_getoverrun, timer_settime, timer_delete, clock_adjtime, setitimer, getitimer, alarm. The clock_settime, clock_gettime, clock_getres and clock_nanosleep syscalls are replaced by simple wrappers compatible with CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only which should cover the vast majority of use cases with very little code. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Richard Cochran <richardcochran@gmail.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: Paul Bolle <pebolle@tiscali.nl> Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Michal Marek <mmarek@suse.com> Cc: Edward Cree <ecree@solarflare.com> Link: http://lkml.kernel.org/r/1478841010-28605-7-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/compat.c')
-rw-r--r--kernel/compat.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/compat.c b/kernel/compat.c
index 333d364be29d..b3a047f208a7 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -307,12 +307,17 @@ static inline long put_compat_itimerval(struct compat_itimerval __user *o,
__put_user(i->it_value.tv_usec, &o->it_value.tv_usec)));
}
+asmlinkage long sys_ni_posix_timers(void);
+
COMPAT_SYSCALL_DEFINE2(getitimer, int, which,
struct compat_itimerval __user *, it)
{
struct itimerval kit;
int error;
+ if (!IS_ENABLED(CONFIG_POSIX_TIMERS))
+ return sys_ni_posix_timers();
+
error = do_getitimer(which, &kit);
if (!error && put_compat_itimerval(it, &kit))
error = -EFAULT;
@@ -326,6 +331,9 @@ COMPAT_SYSCALL_DEFINE3(setitimer, int, which,
struct itimerval kin, kout;
int error;
+ if (!IS_ENABLED(CONFIG_POSIX_TIMERS))
+ return sys_ni_posix_timers();
+
if (in) {
if (get_compat_itimerval(&kin, in))
return -EFAULT;