drm/radeon: fix bad DMA from INTERRUPT_CNTL2

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>

diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index daff9a2af3bed3359665fb6ca5250747b71930a7..acabeaf287326600765af29e91bbcdb6f4d7ac2a 100644 (file)
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -6965,8 +6965,8 @@ 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 e937cc01910d9b00d59c4c4e50f9331361431530..033bc466a862ad0585cffff987e5dcda0a715773 100644 (file)
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -3696,8 +3696,8 @@ 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 05894d198a798fb4ca6c2413cb06a37109b09efb..1d8efb0eefdb4fc41f88858f8b757c3bd203a945 100644 (file)
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -5997,8 +5997,8 @@ 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