Re: [PATCH v4 5/6] drm/msm: Add crashdump support for stalled SMMU

From: Rob Clark
Date: Wed Jun 09 2021 - 17:43:27 EST

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In reply to: Jordan Crouse: "Re: [PATCH v4 5/6] drm/msm: Add crashdump support for stalled SMMU"
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On Tue, Jun 8, 2021 at 8:12 AM Jordan Crouse <jordan@xxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, Jun 01, 2021 at 03:47:24PM -0700, Rob Clark wrote:
> > From: Rob Clark <robdclark@xxxxxxxxxxxx>
> >
> > For collecting devcoredumps with the SMMU stalled after an iova fault,
> > we need to skip the parts of the GPU state which are normally collected
> > with the hw crashdumper, since with the SMMU stalled the hw would be
> > unable to write out the requested state to memory.
>
> On a5xx and a6xx you can query RBBM_STATUS3 bit 24 to see if the IOMMU is
> stalled. That could be an alternative option to adding the "stalled"
> infrastructure across all targets.

Hmm, I suppose it is really only a5xx/a6xx that needs to do something
differently in this case, because of crashdumper, so maybe this would
be a reasonable approach

BR,
-R

> Jordan
> >
> > Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/msm/adreno/a2xx_gpu.c | 2 +-
> > drivers/gpu/drm/msm/adreno/a3xx_gpu.c | 2 +-
> > drivers/gpu/drm/msm/adreno/a4xx_gpu.c | 2 +-
> > drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 5 ++-
> > drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 2 +-
> > drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c | 43 ++++++++++++++++-----
> > drivers/gpu/drm/msm/msm_debugfs.c | 2 +-
> > drivers/gpu/drm/msm/msm_gpu.c | 7 ++--
> > drivers/gpu/drm/msm/msm_gpu.h | 2 +-
> > 9 files changed, 47 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/a2xx_gpu.c b/drivers/gpu/drm/msm/adreno/a2xx_gpu.c
> > index bdc989183c64..d2c31fae64fd 100644
> > --- a/drivers/gpu/drm/msm/adreno/a2xx_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/a2xx_gpu.c
> > @@ -434,7 +434,7 @@ static void a2xx_dump(struct msm_gpu *gpu)
> > adreno_dump(gpu);
> > }
> >
> > -static struct msm_gpu_state *a2xx_gpu_state_get(struct msm_gpu *gpu)
> > +static struct msm_gpu_state *a2xx_gpu_state_get(struct msm_gpu *gpu, bool stalled)
> > {
> > struct msm_gpu_state *state = kzalloc(sizeof(*state), GFP_KERNEL);
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/a3xx_gpu.c b/drivers/gpu/drm/msm/adreno/a3xx_gpu.c
> > index 4534633fe7cd..b1a6f87d74ef 100644
> > --- a/drivers/gpu/drm/msm/adreno/a3xx_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/a3xx_gpu.c
> > @@ -464,7 +464,7 @@ static void a3xx_dump(struct msm_gpu *gpu)
> > adreno_dump(gpu);
> > }
> >
> > -static struct msm_gpu_state *a3xx_gpu_state_get(struct msm_gpu *gpu)
> > +static struct msm_gpu_state *a3xx_gpu_state_get(struct msm_gpu *gpu, bool stalled)
> > {
> > struct msm_gpu_state *state = kzalloc(sizeof(*state), GFP_KERNEL);
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/a4xx_gpu.c b/drivers/gpu/drm/msm/adreno/a4xx_gpu.c
> > index 82bebb40234d..22780a594d6f 100644
> > --- a/drivers/gpu/drm/msm/adreno/a4xx_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/a4xx_gpu.c
> > @@ -549,7 +549,7 @@ static const unsigned int a405_registers[] = {
> > ~0 /* sentinel */
> > };
> >
> > -static struct msm_gpu_state *a4xx_gpu_state_get(struct msm_gpu *gpu)
> > +static struct msm_gpu_state *a4xx_gpu_state_get(struct msm_gpu *gpu, bool stalled)
> > {
> > struct msm_gpu_state *state = kzalloc(sizeof(*state), GFP_KERNEL);
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> > index a0eef5d9b89b..2e7714b1a17f 100644
> > --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> > @@ -1519,7 +1519,7 @@ static void a5xx_gpu_state_get_hlsq_regs(struct msm_gpu *gpu,
> > msm_gem_kernel_put(dumper.bo, gpu->aspace, true);
> > }
> >
> > -static struct msm_gpu_state *a5xx_gpu_state_get(struct msm_gpu *gpu)
> > +static struct msm_gpu_state *a5xx_gpu_state_get(struct msm_gpu *gpu, bool stalled)
> > {
> > struct a5xx_gpu_state *a5xx_state = kzalloc(sizeof(*a5xx_state),
> > GFP_KERNEL);
> > @@ -1536,7 +1536,8 @@ static struct msm_gpu_state *a5xx_gpu_state_get(struct msm_gpu *gpu)
> > a5xx_state->base.rbbm_status = gpu_read(gpu, REG_A5XX_RBBM_STATUS);
> >
> > /* Get the HLSQ regs with the help of the crashdumper */
> > - a5xx_gpu_state_get_hlsq_regs(gpu, a5xx_state);
> > + if (!stalled)
> > + a5xx_gpu_state_get_hlsq_regs(gpu, a5xx_state);
> >
> > a5xx_set_hwcg(gpu, true);
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > index ce0610c5256f..e0f06ce4e1a9 100644
> > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > @@ -86,7 +86,7 @@ unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu);
> > void a6xx_show(struct msm_gpu *gpu, struct msm_gpu_state *state,
> > struct drm_printer *p);
> >
> > -struct msm_gpu_state *a6xx_gpu_state_get(struct msm_gpu *gpu);
> > +struct msm_gpu_state *a6xx_gpu_state_get(struct msm_gpu *gpu, bool stalled);
> > int a6xx_gpu_state_put(struct msm_gpu_state *state);
> >
> > #endif /* __A6XX_GPU_H__ */
> > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
> > index c1699b4f9a89..d0af68a76c4f 100644
> > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
> > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
> > @@ -833,6 +833,21 @@ static void a6xx_get_registers(struct msm_gpu *gpu,
> > a6xx_state, &a6xx_vbif_reglist,
> > &a6xx_state->registers[index++]);
> >
> > + if (!dumper) {
> > + /*
> > + * We can't use the crashdumper when the SMMU is stalled,
> > + * because the GPU has no memory access until we resume
> > + * translation (but we don't want to do that until after
> > + * we have captured as much useful GPU state as possible).
> > + * So instead collect registers via the CPU:
> > + */
> > + for (i = 0; i < ARRAY_SIZE(a6xx_reglist); i++)
> > + a6xx_get_ahb_gpu_registers(gpu,
> > + a6xx_state, &a6xx_reglist[i],
> > + &a6xx_state->registers[index++]);
> > + return;
> > + }
> > +
> > for (i = 0; i < ARRAY_SIZE(a6xx_reglist); i++)
> > a6xx_get_crashdumper_registers(gpu,
> > a6xx_state, &a6xx_reglist[i],
> > @@ -903,9 +918,9 @@ static void a6xx_get_indexed_registers(struct msm_gpu *gpu,
> > a6xx_state->nr_indexed_regs = count;
> > }
> >
> > -struct msm_gpu_state *a6xx_gpu_state_get(struct msm_gpu *gpu)
> > +struct msm_gpu_state *a6xx_gpu_state_get(struct msm_gpu *gpu, bool stalled)
> > {
> > - struct a6xx_crashdumper dumper = { 0 };
> > + struct a6xx_crashdumper _dumper = { 0 }, *dumper = NULL;
> > struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > struct a6xx_gpu_state *a6xx_state = kzalloc(sizeof(*a6xx_state),
> > @@ -928,14 +943,24 @@ struct msm_gpu_state *a6xx_gpu_state_get(struct msm_gpu *gpu)
> > /* Get the banks of indexed registers */
> > a6xx_get_indexed_registers(gpu, a6xx_state);
> >
> > - /* Try to initialize the crashdumper */
> > - if (!a6xx_crashdumper_init(gpu, &dumper)) {
> > - a6xx_get_registers(gpu, a6xx_state, &dumper);
> > - a6xx_get_shaders(gpu, a6xx_state, &dumper);
> > - a6xx_get_clusters(gpu, a6xx_state, &dumper);
> > - a6xx_get_dbgahb_clusters(gpu, a6xx_state, &dumper);
> > + /*
> > + * Try to initialize the crashdumper, if we are not dumping state
> > + * with the SMMU stalled. The crashdumper needs memory access to
> > + * write out GPU state, so we need to skip this when the SMMU is
> > + * stalled in response to an iova fault
> > + */
> > + if (!stalled && !a6xx_crashdumper_init(gpu, &_dumper)) {
> > + dumper = &_dumper;
> > + }
> > +
> > + a6xx_get_registers(gpu, a6xx_state, dumper);
> > +
> > + if (dumper) {
> > + a6xx_get_shaders(gpu, a6xx_state, dumper);
> > + a6xx_get_clusters(gpu, a6xx_state, dumper);
> > + a6xx_get_dbgahb_clusters(gpu, a6xx_state, dumper);
> >
> > - msm_gem_kernel_put(dumper.bo, gpu->aspace, true);
> > + msm_gem_kernel_put(dumper->bo, gpu->aspace, true);
> > }
> >
> > if (snapshot_debugbus)
> > diff --git a/drivers/gpu/drm/msm/msm_debugfs.c b/drivers/gpu/drm/msm/msm_debugfs.c
> > index 7a2b53d35e6b..90558e826934 100644
> > --- a/drivers/gpu/drm/msm/msm_debugfs.c
> > +++ b/drivers/gpu/drm/msm/msm_debugfs.c
> > @@ -77,7 +77,7 @@ static int msm_gpu_open(struct inode *inode, struct file *file)
> > goto free_priv;
> >
> > pm_runtime_get_sync(&gpu->pdev->dev);
> > - show_priv->state = gpu->funcs->gpu_state_get(gpu);
> > + show_priv->state = gpu->funcs->gpu_state_get(gpu, false);
> > pm_runtime_put_sync(&gpu->pdev->dev);
> >
> > mutex_unlock(&dev->struct_mutex);
> > diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
> > index fa7691cb4614..4d280bf446e6 100644
> > --- a/drivers/gpu/drm/msm/msm_gpu.c
> > +++ b/drivers/gpu/drm/msm/msm_gpu.c
> > @@ -381,7 +381,8 @@ static void msm_gpu_crashstate_get_bo(struct msm_gpu_state *state,
> > }
> >
> > static void msm_gpu_crashstate_capture(struct msm_gpu *gpu,
> > - struct msm_gem_submit *submit, char *comm, char *cmd)
> > + struct msm_gem_submit *submit, char *comm, char *cmd,
> > + bool stalled)
> > {
> > struct msm_gpu_state *state;
> >
> > @@ -393,7 +394,7 @@ static void msm_gpu_crashstate_capture(struct msm_gpu *gpu,
> > if (gpu->crashstate)
> > return;
> >
> > - state = gpu->funcs->gpu_state_get(gpu);
> > + state = gpu->funcs->gpu_state_get(gpu, stalled);
> > if (IS_ERR_OR_NULL(state))
> > return;
> >
> > @@ -519,7 +520,7 @@ static void recover_worker(struct kthread_work *work)
> >
> > /* Record the crash state */
> > pm_runtime_get_sync(&gpu->pdev->dev);
> > - msm_gpu_crashstate_capture(gpu, submit, comm, cmd);
> > + msm_gpu_crashstate_capture(gpu, submit, comm, cmd, false);
> > pm_runtime_put_sync(&gpu->pdev->dev);
> >
> > kfree(cmd);
> > diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
> > index 7a082a12d98f..c15e5fd675d2 100644
> > --- a/drivers/gpu/drm/msm/msm_gpu.h
> > +++ b/drivers/gpu/drm/msm/msm_gpu.h
> > @@ -60,7 +60,7 @@ struct msm_gpu_funcs {
> > void (*debugfs_init)(struct msm_gpu *gpu, struct drm_minor *minor);
> > #endif
> > unsigned long (*gpu_busy)(struct msm_gpu *gpu);
> > - struct msm_gpu_state *(*gpu_state_get)(struct msm_gpu *gpu);
> > + struct msm_gpu_state *(*gpu_state_get)(struct msm_gpu *gpu, bool stalled);
> > int (*gpu_state_put)(struct msm_gpu_state *state);
> > unsigned long (*gpu_get_freq)(struct msm_gpu *gpu);
> > void (*gpu_set_freq)(struct msm_gpu *gpu, struct dev_pm_opp *opp);
> > --
> > 2.31.1
> >

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In reply to: Jordan Crouse: "Re: [PATCH v4 5/6] drm/msm: Add crashdump support for stalled SMMU"
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