[PATCH] fix CONFIG_IO_STRICT_DEVMEM, do not enable by default

From: Dan Williams
Date: Wed Jan 20 2016 - 17:37:54 EST

Larry reports: "My PowerBook G4 Aluminum with a 32-bit PPC processor
fails to boot for the 4.4-git series". This is likely due to X still
needing /dev/mem access on this platform.

CONFIG_IO_STRICT_DEVMEM is not yet safe to turn on when
CONFIG_STRICT_DEVMEM=y. Remove the default so that old configurations
do not change behavior.

Fixes: 90a545e98126 ("restrict /dev/mem to idle io memory ranges")
Reported-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
Tested-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
Link: http://marc.info/?l=linux-kernel&m=145332012023825&w=2
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
lib/Kconfig.debug | 1 -
1 file changed, 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index f75a33f29f6e..7d0b49c536c5 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1919,7 +1919,6 @@ config STRICT_DEVMEM
bool "Filter I/O access to /dev/mem"
depends on STRICT_DEVMEM
If this option is disabled, you allow userspace (root) access to all
io-memory regardless of whether a driver is actively using that