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linux-next/drivers/gpu
Karol Herbst fe9748b7b4 drm/nouveau/pmu/fuc: don't use movw directly anymore
Fixes failure to compile with recent envyas as a result of the 'movw'
alias being removed for v5.

A bit of history:

v3 only has a 16-bit sign-extended immediate mov op. In order to set
the high bits, there's a separate 'sethi' op. envyas validates that
the value passed to mov(imm) is between -0x8000 and 0x7fff. In order
to simplify macros that load both the low and high word, a 'movw'
alias was added which takes an unsigned 16-bit immediate. However the
actual hardware op still sign extends.

v5 has a full 32-bit immediate mov op. The v3 16-bit immediate mov op
is gone (loads 0 into the dst reg). However due to a bug in envyas,
the movw alias still existed, and selected the no-longer-present v3
16-bit immediate mov op. As a result usage of movw on v5 is the same
as mov with a 0x0 argument.

The proper fix throughout is to only ever use the 'movw' alias in
combination with 'sethi'. Anything else should get the sign-extended
validation to ensure that the intended value ends up in the
destination register.

Changes in fuc3 binaries is the result of a different encoding being
selected for a mov with an 8-bit value.

v2: added commit message written by Ilia, thanks for that!
v3: messed up rebasing, now it should apply

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2018-02-02 15:24:03 +10:00
..
drm drm/nouveau/pmu/fuc: don't use movw directly anymore 2018-02-02 15:24:03 +10:00
host1x gpu: host1x: Use IOMMU groups 2017-12-21 14:52:36 +01:00
ipu-v3 gpu: ipu-v3: allow to build with COMPILE_TEST 2017-12-19 12:49:11 +01:00
vga vgaarb: Factor out EFI and fallback default device selection 2017-10-18 10:04:56 +02:00
Makefile