Re: [PATCH 16/22] gpu: host1x: Forbid unrelated SETCLASS opcode in the firewall

[Mikko Perttunen <cyndis-/1wQRMveznE@public.gmane.org>]

With the simplification below and the is_addr_reg change mentioned,

Reviewed-by: Mikko Perttunen <mperttunen-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

On 05/23/2017 03:14 AM, Dmitry Osipenko wrote:
> Several channels could be made to write the same unit concurrently via the
> SETCLASS opcode, trusting userspace is a bad idea. It should be possible to
> drop the per-client channel reservation and add a per-unit locking by
> inserting MLOCK's to the command stream to re-allow the SETCLASS opcode, but
> it will be much more work. Let's forbid the unit-unrelated class changes for
> now.
> 
> Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>   drivers/gpu/drm/tegra/drm.c  |  1 +
>   drivers/gpu/drm/tegra/drm.h  |  1 +
>   drivers/gpu/drm/tegra/gr2d.c | 12 ++++++++++++
>   drivers/gpu/host1x/job.c     | 24 ++++++++++++++++++++----
>   include/linux/host1x.h       |  5 ++++-
>   5 files changed, 38 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> index cdb05d6efde4..17416e1c219a 100644
> --- a/drivers/gpu/drm/tegra/drm.c
> +++ b/drivers/gpu/drm/tegra/drm.c
> @@ -531,6 +531,7 @@ int tegra_drm_submit(struct tegra_drm_context *context,
>   	}
>   
>   	job->is_addr_reg = context->client->ops->is_addr_reg;
> +	job->is_valid_class = context->client->ops->is_valid_class;
>   	job->syncpt_incrs = syncpt.incrs;
>   	job->syncpt_id = syncpt.id;
>   	job->timeout = 10000;
> diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
> index 85aa2e3d9d4e..6d6da01282f3 100644
> --- a/drivers/gpu/drm/tegra/drm.h
> +++ b/drivers/gpu/drm/tegra/drm.h
> @@ -83,6 +83,7 @@ struct tegra_drm_client_ops {
>   			    struct tegra_drm_context *context);
>   	void (*close_channel)(struct tegra_drm_context *context);
>   	int (*is_addr_reg)(struct device *dev, u32 class, u32 offset);
> +	int (*is_valid_class)(u32 class);
>   	int (*submit)(struct tegra_drm_context *context,
>   		      struct drm_tegra_submit *args, struct drm_device *drm,
>   		      struct drm_file *file);
> diff --git a/drivers/gpu/drm/tegra/gr2d.c b/drivers/gpu/drm/tegra/gr2d.c
> index 02cd3e37a6ec..782231c41a1a 100644
> --- a/drivers/gpu/drm/tegra/gr2d.c
> +++ b/drivers/gpu/drm/tegra/gr2d.c
> @@ -109,10 +109,22 @@ static int gr2d_is_addr_reg(struct device *dev, u32 class, u32 offset)
>   	return 0;
>   }
>   
> +static int gr2d_is_valid_class(u32 class)
> +{
> +	switch (class) {
> +	case HOST1X_CLASS_GR2D:
> +	case HOST1X_CLASS_GR2D_SB:
> +		return 1;
> +	}
> +
> +	return 0;
> +}

This could be just

return (class == HOST1X_CLASS_GR2D || class == HOST1X_CLASS_GR2D_SB);

> +
>   static const struct tegra_drm_client_ops gr2d_ops = {
>   	.open_channel = gr2d_open_channel,
>   	.close_channel = gr2d_close_channel,
>   	.is_addr_reg = gr2d_is_addr_reg,
> +	.is_valid_class = gr2d_is_valid_class,
>   	.submit = tegra_drm_submit,
>   };
>   
> diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
> index cf335c5979e2..65e12219405a 100644
> --- a/drivers/gpu/host1x/job.c
> +++ b/drivers/gpu/host1x/job.c
> @@ -358,6 +358,9 @@ struct host1x_firewall {
>   
>   static int check_register(struct host1x_firewall *fw, unsigned long offset)
>   {
> +	if (!fw->job->is_addr_reg)
> +		return 0;
> +
>   	if (fw->job->is_addr_reg(fw->dev, fw->class, offset)) {
>   		if (!fw->num_relocs)
>   			return -EINVAL;
> @@ -372,6 +375,19 @@ static int check_register(struct host1x_firewall *fw, unsigned long offset)
>   	return 0;
>   }
>   
> +static int check_class(struct host1x_firewall *fw, u32 class)
> +{
> +	if (!fw->job->is_valid_class) {
> +		if (fw->class != class)
> +			return -EINVAL;
> +	} else {
> +		if (!fw->job->is_valid_class(fw->class))
> +			return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>   static int check_mask(struct host1x_firewall *fw)
>   {
>   	u32 mask = fw->mask;
> @@ -445,11 +461,9 @@ static int validate(struct host1x_firewall *fw, struct host1x_job_gather *g)
>   {
>   	u32 *cmdbuf_base = (u32 *)fw->job->gather_copy_mapped +
>   		(g->offset / sizeof(u32));
> +	u32 job_class = fw->class;
>   	int err = 0;
>   
> -	if (!fw->job->is_addr_reg)
> -		return 0;
> -
>   	fw->words = g->words;
>   	fw->cmdbuf = g->bo;
>   	fw->offset = 0;
> @@ -469,7 +483,9 @@ static int validate(struct host1x_firewall *fw, struct host1x_job_gather *g)
>   			fw->class = word >> 6 & 0x3ff;
>   			fw->mask = word & 0x3f;
>   			fw->reg = word >> 16 & 0xfff;
> -			err = check_mask(fw);
> +			err = check_class(fw, job_class);
> +			if (!err)
> +				err = check_mask(fw);
>   			if (err)
>   				goto out;
>   			break;
> diff --git a/include/linux/host1x.h b/include/linux/host1x.h
> index aa323e43ae4e..561d6bb6580d 100644
> --- a/include/linux/host1x.h
> +++ b/include/linux/host1x.h
> @@ -233,7 +233,10 @@ struct host1x_job {
>   	u8 *gather_copy_mapped;
>   
>   	/* Check if register is marked as an address reg */
> -	int (*is_addr_reg)(struct device *dev, u32 reg, u32 class);
> +	int (*is_addr_reg)(struct device *dev, u32 class, u32 reg);
> +
> +	/* Check if class belongs to the unit */
> +	int (*is_valid_class)(u32 class);
>   
>   	/* Request a SETCLASS to this class */
>   	u32 class;
>