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MIPS: Fix CM region target definitions
authorPaul Burton <paul.burton@mips.com>
Tue, 31 Oct 2017 22:09:22 +0000 (15:09 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 15 Nov 2017 16:13:12 +0000 (17:13 +0100)
commit207c2143322ce23b46061ff57dd5356744214293
treea03cb8f74e35b495115f54fcc807fb6c0727ae41
parentff8e97326b6ade630ec70745cc6255ada6dfbe83
MIPS: Fix CM region target definitions

commit 6a6cba1d945a7511cdfaf338526871195e420762 upstream.

The default CM target field in the GCR_BASE register is encoded with 0
meaning memory & 1 being reserved. However the definitions we use for
those bits effectively get these two values backwards - likely because
they were copied from the definitions for the CM regions where the
target is encoded differently. This results in use setting up GCR_BASE
with the reserved target value by default, rather than targeting memory
as intended. Although we currently seem to get away with this it's not a
great idea to rely upon.

Fix this by changing our macros to match the documentated target values.

The incorrect encoding became used as of commit 9f98f3dd0c51 ("MIPS: Add
generic CM probe & access code") in the Linux v3.15 cycle, and was
likely carried forwards from older but unused code introduced by
commit 39b8d5254246 ("[MIPS] Add support for MIPS CMP platform.") in the
v2.6.26 cycle.

Fixes: 9f98f3dd0c51 ("MIPS: Add generic CM probe & access code")
Signed-off-by: Paul Burton <paul.burton@mips.com>
Reported-by: Matt Redfearn <matt.redfearn@mips.com>
Reviewed-by: James Hogan <jhogan@kernel.org>
Cc: Matt Redfearn <matt.redfearn@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # v3.15+
Patchwork: https://patchwork.linux-mips.org/patch/17562/
Signed-off-by: James Hogan <jhogan@kernel.org>
[jhogan@kernel.org: Backported 3.15..4.13]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/mips/include/asm/mips-cm.h