From: Christian König christian.koenig@amd.com

When we set the valid bit on invalid GART entries they are loaded into the TLB when an adjacent entry is loaded. This poisons the TLB with invalid entries which are sometimes not correctly removed on TLB flush.

v2: rebased on 3.15 for stable inclusion

Signed-off-by: Christian König christian.koenig@amd.com Cc: stable@vger.kernel.org Signed-off-by: Alex Deucher alexander.deucher@amd.com --- drivers/gpu/drm/radeon/rs600.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/radeon/rs600.c b/drivers/gpu/drm/radeon/rs600.c index 72d3616..95b693c 100644 --- a/drivers/gpu/drm/radeon/rs600.c +++ b/drivers/gpu/drm/radeon/rs600.c @@ -646,8 +646,10 @@ int rs600_gart_set_page(struct radeon_device *rdev, int i, uint64_t addr) return -EINVAL; } addr = addr & 0xFFFFFFFFFFFFF000ULL; - addr |= R600_PTE_VALID | R600_PTE_SYSTEM | R600_PTE_SNOOPED; - addr |= R600_PTE_READABLE | R600_PTE_WRITEABLE; + if (addr != rdev->dummy_page.addr) + addr |= R600_PTE_VALID | R600_PTE_READABLE | + R600_PTE_WRITEABLE; + addr |= R600_PTE_SYSTEM | R600_PTE_SNOOPED; writeq(addr, ptr + (i * 8)); return 0; }