[PATCH AUTOSEL 4.9 248/251] drm/radeon: fix bad DMA from INTERRUPT_CNTL2

Sasha Levin
2020-01-16T18:01:27Z

From: Sam Bobroff <sbobroff@linux.ibm.com>

[ Upstream commit 62d91dd2851e8ae2ca552f1b090a3575a4edf759 ]

The INTERRUPT_CNTL2 register expects a valid DMA address, but is
currently set with a GPU MC address. This can cause problems on
systems that detect the resulting DMA read from an invalid address
(found on a Power8 guest).

Instead, use the DMA address of the dummy page because it will always
be safe.

Fixes: d8f60cfc9345 ("drm/radeon/kms: Add support for interrupts on r6xx/r7xx chips (v3)")
Fixes: 25a857fbe973 ("drm/radeon/kms: add support for interrupts on SI")
Fixes: a59781bbe528 ("drm/radeon: add support for interrupts on CIK (v5)")
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/radeon/cik.c | 4 ++--
drivers/gpu/drm/radeon/r600.c | 4 ++--
drivers/gpu/drm/radeon/si.c | 4 ++--
3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index b99f3e59011c..5fcb5869a489 100644
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -7026,8 +7026,8 @@ static int cik_irq_init(struct radeon_device *rdev)
}

/* setup interrupt control */
- /* XXX this should actually be a bus address, not an MC address. same on older asics */
- WREG32(INTERRUPT_CNTL2, rdev->ih.gpu_addr >> 8);
+ /* set dummy read address to dummy page address */
+ WREG32(INTERRUPT_CNTL2, rdev->dummy_page.addr >> 8);
interrupt_cntl = RREG32(INTERRUPT_CNTL);
/* IH_DUMMY_RD_OVERRIDE=0 - dummy read disabled with msi, enabled without msi
* IH_DUMMY_RD_OVERRIDE=1 - dummy read controlled by IH_DUMMY_RD_EN
diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index f2eac6b6c46a..9569c35f8766 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -3697,8 +3697,8 @@ int r600_irq_init(struct radeon_device *rdev)
}

/* setup interrupt control */
- /* set dummy read address to ring address */
- WREG32(INTERRUPT_CNTL2, rdev->ih.gpu_addr >> 8);
+ /* set dummy read address to dummy page address */
+ WREG32(INTERRUPT_CNTL2, rdev->dummy_page.addr >> 8);
interrupt_cntl = RREG32(INTERRUPT_CNTL);
/* IH_DUMMY_RD_OVERRIDE=0 - dummy read disabled with msi, enabled without msi
* IH_DUMMY_RD_OVERRIDE=1 - dummy read controlled by IH_DUMMY_RD_EN
diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index b75d809c292e..919d389869ce 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -6018,8 +6018,8 @@ static int si_irq_init(struct radeon_device *rdev)
}

/* setup interrupt control */
- /* set dummy read address to ring address */
- WREG32(INTERRUPT_CNTL2, rdev->ih.gpu_addr >> 8);
+ /* set dummy read address to dummy page address */
+ WREG32(INTERRUPT_CNTL2, rdev->dummy_page.addr >> 8);
interrupt_cntl = RREG32(INTERRUPT_CNTL);
/* IH_DUMMY_RD_OVERRIDE=0 - dummy read disabled with msi, enabled without msi
* IH_DUMMY_RD_OVERRIDE=1 - dummy read controlled by IH_DUMMY_RD_EN
--
2.20.1