From 83de911cf897a4317147dd9cb379378c2c4abf4c Mon Sep 17 00:00:00 2001
From: =?utf8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
Date: Thu, 5 Jun 2014 10:23:10 +0200
Subject: [PATCH] ARM: make user_addr_max more robust
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With CONFIG_MMU=y get_fs() returns current_thread_info()->addr_limit
which is initialized as USER_DS (which in turn is defined to TASK_SIZE)
for userspace processes. At least theoretically
current_thread_info()->addr_limit is changable by set_fs() to a
different limit, so checking for KERNEL_DS is more robust.

With !CONFIG_MMU get_fs returns KERNEL_DS. To see what the old variant
did you'd have to find out that USER_DS == KERNEL_DS which isn't needed
any more with the variant this patch introduces. So it's a bit easier to
understand, too.

Also if the limit was changed this limit should be returned, not
TASK_SIZE.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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