compat: generic compat_sys_sched_rr_get_interval() implementation

This function is used by sparc, powerpc tile and arm64 for compat support.
 The patch adds a generic implementation with a wrapper for PowerPC to do
the u32->int sign extension.

The reason for a single patch covering powerpc, tile, sparc and arm64 is
to keep it bisectable, otherwise kernel building may fail with mismatched
function declarations.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>  [for tile]
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/kernel/compat.c b/kernel/compat.c
index c28a306ae05c..f6150e92dfc9 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -1215,6 +1215,23 @@ compat_sys_sysinfo(struct compat_sysinfo __user *info)
         return 0;
 }
 
+#ifdef __ARCH_WANT_COMPAT_SYS_SCHED_RR_GET_INTERVAL
+asmlinkage long compat_sys_sched_rr_get_interval(compat_pid_t pid,
+                                                 struct compat_timespec __user *interval)
+{
+        struct timespec t;
+        int ret;
+        mm_segment_t old_fs = get_fs();
+
+        set_fs(KERNEL_DS);
+        ret = sys_sched_rr_get_interval(pid, (struct timespec __user *)&t);
+        set_fs(old_fs);
+        if (put_compat_timespec(&t, interval))
+                return -EFAULT;
+        return ret;
+}
+#endif /* __ARCH_WANT_COMPAT_SYS_SCHED_RR_GET_INTERVAL */
+
 /*
  * Allocate user-space memory for the duration of a single system call,
  * in order to marshall parameters inside a compat thunk.