[PATCH v2 1/6] drm/msm/a6xx: Avoid freeing gmu resources multiple times

[Sean Paul]

From: Sean Paul <seanpaul at chromium.org>

The driver checks for gmu->mmio as a sign that the device has been
initialized, however there are failures in probe below the mmio init.
If one of those is hit, mmio will be non-null but freed.

In that case, a6xx_gmu_probe will return an error to a6xx_gpu_init which
will in turn call a6xx_gmu_remove which checks gmu->mmio and tries to free
resources for a second time. This causes a great boom.

Fix this by adding an initialized member to gmu which is set on
successful probe and cleared on removal.

Changes in v2:
- None

Cc: Jordan Crouse <jcrouse at codeaurora.org>
Signed-off-by: Sean Paul <seanpaul at chromium.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 14 +++++++++-----
 drivers/gpu/drm/msm/adreno/a6xx_gmu.h |  1 +
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index 38e2cfa9cec7..aa84edb25d91 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -74,7 +74,7 @@ bool a6xx_gmu_sptprac_is_on(struct a6xx_gmu *gmu)
 	u32 val;
 
 	/* This can be called from gpu state code so make sure GMU is valid */
-	if (IS_ERR_OR_NULL(gmu->mmio))
+	if (!gmu->initialized)
 		return false;
 
 	val = gmu_read(gmu, REG_A6XX_GMU_SPTPRAC_PWR_CLK_STATUS);
@@ -90,7 +90,7 @@ bool a6xx_gmu_gx_is_on(struct a6xx_gmu *gmu)
 	u32 val;
 
 	/* This can be called from gpu state code so make sure GMU is valid */
-	if (IS_ERR_OR_NULL(gmu->mmio))
+	if (!gmu->initialized)
 		return false;
 
 	val = gmu_read(gmu, REG_A6XX_GMU_SPTPRAC_PWR_CLK_STATUS);
@@ -695,7 +695,7 @@ int a6xx_gmu_resume(struct a6xx_gpu *a6xx_gpu)
 	struct a6xx_gmu *gmu = &a6xx_gpu->gmu;
 	int status, ret;
 
-	if (WARN(!gmu->mmio, "The GMU is not set up yet\n"))
+	if (WARN(!gmu->initialized, "The GMU is not set up yet\n"))
 		return 0;
 
 	gmu->hung = false;
@@ -765,7 +765,7 @@ bool a6xx_gmu_isidle(struct a6xx_gmu *gmu)
 {
 	u32 reg;
 
-	if (!gmu->mmio)
+	if (!gmu->initialized)
 		return true;
 
 	reg = gmu_read(gmu, REG_A6XX_GPU_GMU_AO_GPU_CX_BUSY_STATUS);
@@ -1227,7 +1227,7 @@ void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu)
 {
 	struct a6xx_gmu *gmu = &a6xx_gpu->gmu;
 
-	if (IS_ERR_OR_NULL(gmu->mmio))
+	if (!gmu->initialized)
 		return;
 
 	a6xx_gmu_stop(a6xx_gpu);
@@ -1245,6 +1245,8 @@ void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu)
 	iommu_detach_device(gmu->domain, gmu->dev);
 
 	iommu_domain_free(gmu->domain);
+
+	gmu->initialized = false;
 }
 
 int a6xx_gmu_probe(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
@@ -1309,6 +1311,8 @@ int a6xx_gmu_probe(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
 	/* Set up the HFI queues */
 	a6xx_hfi_init(gmu);
 
+	gmu->initialized = true;
+
 	return 0;
 err:
 	a6xx_gmu_memory_free(gmu, gmu->hfi);
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
index bedd8e6a63aa..39a26dd63674 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
@@ -75,6 +75,7 @@ struct a6xx_gmu {
 
 	struct a6xx_hfi_queue queues[2];
 
+	bool initialized;
 	bool hung;
 };
 
-- 
Sean Paul, Software Engineer, Google / Chromium OS