Revert "x86/uaccess, ftrace: Fix ftrace_likely_update() vs. SMAP"

This reverts commit 1a3188d737ceb922166d8fe78a5fc4f89907e31b, which was
upstream commit 4a6c91fbdef846ec7250b82f2eeeb87ac5f18cf9.

On Tue, Jun 25, 2019 at 09:39:45AM +0200, Sebastian Andrzej Siewior wrote:
>Please backport commit e74deb11931ff682b59d5b9d387f7115f689698e to
>stable _or_ revert the backport of commit 4a6c91fbdef84 ("x86/uaccess,
>ftrace: Fix ftrace_likely_update() vs. SMAP"). It uses
>user_access_{save|restore}() which has been introduced in the following
>commit.
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

kernel/trace/trace_branch.c

@@ -205,8 +205,6 @@ void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
 void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 			  int expect, int is_constant)
 {
-	unsigned long flags = user_access_save();
-
 	/* A constant is always correct */
 	if (is_constant) {
 		f->constant++;
@@ -225,8 +223,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 		f->data.correct++;
 	else
 		f->data.incorrect++;
-
-	user_access_restore(flags);
 }
 EXPORT_SYMBOL(ftrace_likely_update);