Revision e3818697e1d9140d0b990fecf4429d40c41ca0b5 authored by Chris Wilson on 09 January 2017, 11:19:32 UTC, committed by Jani Nikula on 08 February 2017, 11:10:24 UTC
On a non-llc system, the objects are created with .cache_level = CACHE_NONE and so the transition to uncached for scanout is a no-op. However, if the object was never written to, it will still be in the CPU domain (having been zeroed out by shmemfs). Those cachelines need to be flushed prior to display. Reported-and-tested-by: Vito Caputo Fixes: a6a7cc4b7db6 ("drm/i915: Always flush the dirty CPU cache when pinning the scanout") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.10-rc1+ Link: http://patchwork.freedesktop.org/patch/msgid/20170109111932.6342-1-chris@chris-wilson.co.uk Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> (cherry picked from commit 69aeafeae9b30d797c439a30d1a4ccc8dc5b0eb0) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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Kconfig.kasan
config HAVE_ARCH_KASAN
bool
if HAVE_ARCH_KASAN
config KASAN
bool "KASan: runtime memory debugger"
depends on SLUB || (SLAB && !DEBUG_SLAB)
select CONSTRUCTORS
select STACKDEPOT
help
Enables kernel address sanitizer - runtime memory debugger,
designed to find out-of-bounds accesses and use-after-free bugs.
This is strictly a debugging feature and it requires a gcc version
of 4.9.2 or later. Detection of out of bounds accesses to stack or
global variables requires gcc 5.0 or later.
This feature consumes about 1/8 of available memory and brings about
~x3 performance slowdown.
For better error detection enable CONFIG_STACKTRACE.
Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
(the resulting kernel does not boot).
choice
prompt "Instrumentation type"
depends on KASAN
default KASAN_OUTLINE
config KASAN_OUTLINE
bool "Outline instrumentation"
help
Before every memory access compiler insert function call
__asan_load*/__asan_store*. These functions performs check
of shadow memory. This is slower than inline instrumentation,
however it doesn't bloat size of kernel's .text section so
much as inline does.
config KASAN_INLINE
bool "Inline instrumentation"
help
Compiler directly inserts code checking shadow memory before
memory accesses. This is faster than outline (in some workloads
it gives about x2 boost over outline instrumentation), but
make kernel's .text size much bigger.
This requires a gcc version of 5.0 or later.
endchoice
config TEST_KASAN
tristate "Module for testing kasan for bug detection"
depends on m && KASAN
help
This is a test module doing various nasty things like
out of bounds accesses, use after free. It is useful for testing
kernel debugging features like kernel address sanitizer.
endif
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