[PATCH v7 4/4] drm/msm: Extend gpu devcore dumps with pgtbl info

[Akhil P Oommen]

On Tue, Aug 20, 2024 at 10:16:47AM -0700, Rob Clark wrote: > From: Rob Clark <robdclark at chromium.org>
> 
> In the case of iova fault triggered devcore dumps, include additional
> debug information based on what we think is the current page tables,
> including the TTBR0 value (which should match what we have in
> adreno_smmu_fault_info unless things have gone horribly wrong), and
> the pagetable entries traversed in the process of resolving the
> faulting iova.
> 
> Signed-off-by: Rob Clark <robdclark at chromium.org>
> ---
>  drivers/gpu/drm/msm/adreno/adreno_gpu.c | 10 ++++++++++
>  drivers/gpu/drm/msm/msm_gpu.c           |  9 +++++++++
>  drivers/gpu/drm/msm/msm_gpu.h           |  8 ++++++++
>  drivers/gpu/drm/msm/msm_iommu.c         | 22 ++++++++++++++++++++++
>  drivers/gpu/drm/msm/msm_mmu.h           |  3 ++-
>  5 files changed, 51 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index 1c6626747b98..3848b5a64351 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -864,6 +864,16 @@ void adreno_show(struct msm_gpu *gpu, struct msm_gpu_state *state,
>  		drm_printf(p, "  - dir=%s\n", info->flags & IOMMU_FAULT_WRITE ? "WRITE" : "READ");
>  		drm_printf(p, "  - type=%s\n", info->type);
>  		drm_printf(p, "  - source=%s\n", info->block);
> +
> +		/* Information extracted from what we think are the current
> +		 * pgtables.  Hopefully the TTBR0 matches what we've extracted
> +		 * from the SMMU registers in smmu_info!
> +		 */
> +		drm_puts(p, "pgtable-fault-info:\n");
> +		drm_printf(p, "  - ttbr0: %.16llx\n", (u64)info->pgtbl_ttbr0);

"0x" prefix? Otherwise, it is a bit confusing when the below one is
decimal.

> +		drm_printf(p, "  - asid: %d\n", info->asid);
> +		drm_printf(p, "  - ptes: %.16llx %.16llx %.16llx %.16llx\n",
> +			   info->ptes[0], info->ptes[1], info->ptes[2], info->ptes[3]);

Does crashdec decodes this?

-Akhil.

>  	}
>  
>  	drm_printf(p, "rbbm-status: 0x%08x\n", state->rbbm_status);
> diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
> index 3666b42b4ecd..bf2f8b2a7ccc 100644
> --- a/drivers/gpu/drm/msm/msm_gpu.c
> +++ b/drivers/gpu/drm/msm/msm_gpu.c
> @@ -281,6 +281,15 @@ static void msm_gpu_crashstate_capture(struct msm_gpu *gpu,
>  	if (submit) {
>  		int i;
>  
> +		if (state->fault_info.ttbr0) {
> +			struct msm_gpu_fault_info *info = &state->fault_info;
> +			struct msm_mmu *mmu = submit->aspace->mmu;
> +
> +			msm_iommu_pagetable_params(mmu, &info->pgtbl_ttbr0,
> +						   &info->asid);
> +			msm_iommu_pagetable_walk(mmu, info->iova, info->ptes);
> +		}
> +
>  		state->bos = kcalloc(submit->nr_bos,
>  			sizeof(struct msm_gpu_state_bo), GFP_KERNEL);
>  
> diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
> index 1f02bb9956be..82e838ba8c80 100644
> --- a/drivers/gpu/drm/msm/msm_gpu.h
> +++ b/drivers/gpu/drm/msm/msm_gpu.h
> @@ -101,6 +101,14 @@ struct msm_gpu_fault_info {
>  	int flags;
>  	const char *type;
>  	const char *block;
> +
> +	/* Information about what we think/expect is the current SMMU state,
> +	 * for example expected_ttbr0 should match smmu_info.ttbr0 which
> +	 * was read back from SMMU registers.
> +	 */
> +	phys_addr_t pgtbl_ttbr0;
> +	u64 ptes[4];
> +	int asid;
>  };
>  
>  /**
> diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
> index 2a94e82316f9..3e692818ba1f 100644
> --- a/drivers/gpu/drm/msm/msm_iommu.c
> +++ b/drivers/gpu/drm/msm/msm_iommu.c
> @@ -195,6 +195,28 @@ struct iommu_domain_geometry *msm_iommu_get_geometry(struct msm_mmu *mmu)
>  	return &iommu->domain->geometry;
>  }
>  
> +int
> +msm_iommu_pagetable_walk(struct msm_mmu *mmu, unsigned long iova, uint64_t ptes[4])
> +{
> +	struct msm_iommu_pagetable *pagetable;
> +	struct arm_lpae_io_pgtable_walk_data wd = {};
> +
> +	if (mmu->type != MSM_MMU_IOMMU_PAGETABLE)
> +		return -EINVAL;
> +
> +	pagetable = to_pagetable(mmu);
> +
> +	if (!pagetable->pgtbl_ops->pgtable_walk)
> +		return -EINVAL;
> +
> +	pagetable->pgtbl_ops->pgtable_walk(pagetable->pgtbl_ops, iova, &wd);
> +
> +	for (int i = 0; i < ARRAY_SIZE(wd.ptes); i++)
> +		ptes[i] = wd.ptes[i];
> +
> +	return 0;
> +}
> +
>  static const struct msm_mmu_funcs pagetable_funcs = {
>  		.map = msm_iommu_pagetable_map,
>  		.unmap = msm_iommu_pagetable_unmap,
> diff --git a/drivers/gpu/drm/msm/msm_mmu.h b/drivers/gpu/drm/msm/msm_mmu.h
> index 88af4f490881..96e509bd96a6 100644
> --- a/drivers/gpu/drm/msm/msm_mmu.h
> +++ b/drivers/gpu/drm/msm/msm_mmu.h
> @@ -53,7 +53,8 @@ static inline void msm_mmu_set_fault_handler(struct msm_mmu *mmu, void *arg,
>  struct msm_mmu *msm_iommu_pagetable_create(struct msm_mmu *parent);
>  
>  int msm_iommu_pagetable_params(struct msm_mmu *mmu, phys_addr_t *ttbr,
> -		int *asid);
> +			       int *asid);
> +int msm_iommu_pagetable_walk(struct msm_mmu *mmu, unsigned long iova, uint64_t ptes[4]);
>  struct iommu_domain_geometry *msm_iommu_get_geometry(struct msm_mmu *mmu);
>  
>  #endif /* __MSM_MMU_H__ */
> -- 
> 2.46.0
>