Re: [PATCH v3 21/31] arm64: 32-bit (compat) applications support
From: Arnd Bergmann <arnd@arndb.de>
Date: 2012-09-13 11:03:38
Also in:
linux-arm-kernel, lkml
On Thursday 13 September 2012, Catalin Marinas wrote:
Here they are. For converting the other architectures, I'll post separate patches as I don't want to add an extra dependency to the arm64 series.
Ok, thanks!
quoted hunk ↗ jump to hunk
diff --git a/kernel/compat.c b/kernel/compat.c index c28a306..5f07388 100644 --- a/kernel/compat.c +++ b/kernel/compat.c@@ -1215,6 +1215,50 @@ compat_sys_sysinfo(struct compat_sysinfo __user *info) return 0; } +#ifdef __ARCH_WANT_COMPAT_SYS_SENDFILE +asmlinkage int compat_sys_sendfile(int out_fd, int in_fd, + compat_off_t __user *offset, s32 count) +{ + mm_segment_t old_fs = get_fs(); + int ret; + off_t of; + + if (offset && get_user(of, offset)) + return -EFAULT; + + set_fs(KERNEL_DS); + ret = sys_sendfile(out_fd, in_fd, + offset ? (off_t __user *)&of : NULL, count); + set_fs(old_fs); + + if (offset && put_user(of, offset)) + return -EFAULT; + return ret; +} +#endif /* __ARCH_WANT_COMPAT_SYS_SENDFILE */
Looking at this code in detail now, I think it's better to move the functions to
fs/read_write.c and get rid of the get_fs/set_fs hack, like
asmlinkage int compat_sys_sendfile(int out_fd, int in_fd,
compat_off_t __user *offset, s32 count)
{
loff_t pos;
compat_off_t off;
ssize_t ret;
if (offset) {
if (unlikely(get_user(off, offset)))
return -EFAULT;
pos = off;
ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
This implementation is smaller and more efficient than the common one.
Same for compat_sys_sendfile64, although I don't think there is ever
a case where loff_t is defined differently from compat_loff_t, so
you can probably just use the native sys_sendfile64 for the compat
case.
+#ifdef __ARCH_WANT_COMPAT_SYS_SCHED_RR_GET_INTERVAL
+asmlinkage int 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 */
+This one looks reasonable. It would be nice to kill the get_fs/set_fs but here it would just make the native code slower or duplicate a lot of it. Acked-by: Arnd Bergmann <arnd@arndb.de>