linux-kernel - Re: [PATCH v2] drm/msm: a6xx: Make sure the SQE microcode is safe

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Message-ID: <af099fda-a7be-8fe5-ed9e-cfcd6f13c09c@linaro.org>
Date:   Wed, 31 Mar 2021 16:40:07 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Jordan Crouse <jcrouse@...eaurora.org>,
        linux-arm-msm@...r.kernel.org
Cc:     Akhil P Oommen <akhilpo@...eaurora.org>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>, Eric Anholt <eric@...olt.net>,
        Jonathan Marek <jonathan@...ek.ca>,
        Rob Clark <robdclark@...il.com>,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        Sean Paul <sean@...rly.run>,
        Sharat Masetty <smasetty@...eaurora.org>,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm/msm: a6xx: Make sure the SQE microcode is safe

Hello,

On 10/02/2021 03:52, Jordan Crouse wrote:
> Most a6xx targets have security issues that were fixed with new versions
> of the microcode(s). Make sure that we are booting with a safe version of
> the microcode for the target and print a message and error if not.
> 
> v2: Add more informative error messages and fix typos
> 
> Signed-off-by: Jordan Crouse <jcrouse@...eaurora.org>

[skipped]

> +	}  else {
> +		/*
> +		 * a650 tier targets don't need whereami but still need to be
> +		 * equal to or newer than 1.95 for other security fixes
> +		 */
> +		if (adreno_is_a650(adreno_gpu)) {
> +			if ((buf[0] & 0xfff) >= 0x195) {
> +				ret = true;
> +				goto out;
> +			}

I think this is incorrect. The latest firmware i have here also fails 
this check, with the buf[0] = 0x016dd099, so buf[0] & 0xfff = 0x099.

Could you please confirm the versioning?

> +
> +			DRM_DEV_ERROR(&gpu->pdev->dev,
> +				"a650 SQE ucode is too old. Have version %x need at least %x\n",
> +				buf[0] & 0xfff, 0x195);
> +		}
> +
> +		/*
> +		 * When a660 is added those targets should return true here
> +		 * since those have all the critical security fixes built in
> +		 * from the start
> +		 */
> +	}
> +out:
>   	msm_gem_put_vaddr(obj);
> +	return ret;
>   }
>   
>   static int a6xx_ucode_init(struct msm_gpu *gpu)
> @@ -566,7 +611,13 @@ static int a6xx_ucode_init(struct msm_gpu *gpu)
>   		}
>   
>   		msm_gem_object_set_name(a6xx_gpu->sqe_bo, "sqefw");
> -		a6xx_ucode_check_version(a6xx_gpu, a6xx_gpu->sqe_bo);
> +		if (!a6xx_ucode_check_version(a6xx_gpu, a6xx_gpu->sqe_bo)) {
> +			msm_gem_unpin_iova(a6xx_gpu->sqe_bo, gpu->aspace);
> +			drm_gem_object_put(a6xx_gpu->sqe_bo);
> +
> +			a6xx_gpu->sqe_bo = NULL;
> +			return -EPERM;
> +		}
>   	}
>   
>   	gpu_write64(gpu, REG_A6XX_CP_SQE_INSTR_BASE_LO,


-- 
With best wishes
Dmitry