On Tue, Oct 25, 2022 at 4:00 AM Alan Liu <HaoPing.Liu@xxxxxxx> wrote:
>
> [Why]
> Before we call psp_securedisplay_invoke(), we call
> psp_prep_securedisplay_cmd_buf() to prepare and initialize the command
> buffer.
>
> However, we didn't use the mutex_lock to protect the status of command
> buffer. So when multiple threads are using the command buffer, after
> thread A return from psp_securedisplay_invoke() and the command buffer
> status is set to SUCCESS, another thread B may call
> psp_prep_securedisplay_cmd_buf() and initialize the status to FAILURE
> again, and cause Thread A to get a failure return status.
>
> [How]
> Move the mutex_lock out of psp_securedisplay_invoke() to its caller to
> cover psp_prep_securedisplay_cmd_buf() and the code checking the return
> status of command buffer.
>
> Signed-off-by: Alan Liu <HaoPing.Liu@xxxxxxx>
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c | 9 +++++----
> drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c | 4 ++++
> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c | 4 ++++
> 3 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c
> index effa7df3ddbf..7bbf869f4f0d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c
> @@ -1938,10 +1938,15 @@ static int psp_securedisplay_initialize(struct psp_context *psp)
> } else
> return ret;
>
> + mutex_lock(&psp->securedisplay_context.mutex);
> +
> psp_prep_securedisplay_cmd_buf(psp, &securedisplay_cmd,
> TA_SECUREDISPLAY_COMMAND__QUERY_TA);
>
> ret = psp_securedisplay_invoke(psp, TA_SECUREDISPLAY_COMMAND__QUERY_TA);
> +
> + mutex_unlock(&psp->securedisplay_context.mutex);
> +
> if (ret) {
> psp_securedisplay_terminate(psp);
> /* free securedisplay shared memory */
> @@ -1990,12 +1995,8 @@ int psp_securedisplay_invoke(struct psp_context *psp, uint32_t ta_cmd_id)
> ta_cmd_id != TA_SECUREDISPLAY_COMMAND__SEND_ROI_CRC)
> return -EINVAL;
>
> - mutex_lock(&psp->securedisplay_context.mutex);
> -
> ret = psp_ta_invoke(psp, ta_cmd_id, &psp->securedisplay_context.context);
>
> - mutex_unlock(&psp->securedisplay_context.mutex);
> -
> return ret;
> }
> /* SECUREDISPLAY end */
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c
> index cc7597a15fe9..2c1d82fc4c34 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c
> @@ -121,6 +121,7 @@ static ssize_t amdgpu_securedisplay_debugfs_write(struct file *f, const char __u
>
> switch (op) {
> case 1:
> + mutex_lock(&psp->securedisplay_context.mutex);
> psp_prep_securedisplay_cmd_buf(psp, &securedisplay_cmd,
> TA_SECUREDISPLAY_COMMAND__QUERY_TA);
> ret = psp_securedisplay_invoke(psp, TA_SECUREDISPLAY_COMMAND__QUERY_TA);
> @@ -131,8 +132,10 @@ static ssize_t amdgpu_securedisplay_debugfs_write(struct file *f, const char __u
> else
> psp_securedisplay_parse_resp_status(psp, securedisplay_cmd->status);
> }
> + mutex_unlock(&psp->securedisplay_context.mutex);
> break;
> case 2:
> + mutex_lock(&psp->securedisplay_context.mutex);
> psp_prep_securedisplay_cmd_buf(psp, &securedisplay_cmd,
> TA_SECUREDISPLAY_COMMAND__SEND_ROI_CRC);
> securedisplay_cmd->securedisplay_in_message.send_roi_crc.phy_id = phy_id;
> @@ -146,6 +149,7 @@ static ssize_t amdgpu_securedisplay_debugfs_write(struct file *f, const char __u
> psp_securedisplay_parse_resp_status(psp, securedisplay_cmd->status);
> }
> }
> + mutex_unlock(&psp->securedisplay_context.mutex);
> break;
> default:
> dev_err(adev->dev, "Invalid input: %s\n", str);
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
> index 8a441a22c46e..515352ba788e 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
> @@ -123,6 +123,8 @@ static void amdgpu_dm_crtc_notify_ta_to_read(struct work_struct *work)
> phy_id = crc_rd_wrk->phy_inst;
> spin_unlock_irq(&crc_rd_wrk->crc_rd_work_lock);
>
> + mutex_lock(&psp->securedisplay_context.mutex);
> +
> psp_prep_securedisplay_cmd_buf(psp, &securedisplay_cmd,
> TA_SECUREDISPLAY_COMMAND__SEND_ROI_CRC);
> securedisplay_cmd->securedisplay_in_message.send_roi_crc.phy_id =
> @@ -133,6 +135,8 @@ static void amdgpu_dm_crtc_notify_ta_to_read(struct work_struct *work)
> psp_securedisplay_parse_resp_status(psp, securedisplay_cmd->status);
> }
> }
> +
> + mutex_unlock(&psp->securedisplay_context.mutex);
> }
>
> bool amdgpu_dm_crc_window_is_activated(struct drm_crtc *crtc)
> --
> 2.25.1
>
