linux-kernel - Re: [RFC PATCH 3/4] drm/panfrost: Support ARM_64_LPAE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250227155539.59944e18@collabora.com>
Date: Thu, 27 Feb 2025 15:55:39 +0100
From: Boris Brezillon <boris.brezillon@...labora.com>
To: Ariel D'Alessandro <ariel.dalessandro@...labora.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 robh@...nel.org, steven.price@....com, maarten.lankhorst@...ux.intel.com,
 mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com, simona@...ll.ch
Subject: Re: [RFC PATCH 3/4] drm/panfrost: Support ARM_64_LPAE_S1 page table

On Wed, 26 Feb 2025 15:30:42 -0300
Ariel D'Alessandro <ariel.dalessandro@...labora.com> wrote:

> @@ -642,8 +713,15 @@ struct panfrost_mmu *panfrost_mmu_ctx_create(struct panfrost_device *pfdev)
>  		.iommu_dev	= pfdev->dev,
>  	};
>  
> -	mmu->pgtbl_ops = alloc_io_pgtable_ops(ARM_MALI_LPAE, &mmu->pgtbl_cfg,
> -					      mmu);
> +	if (panfrost_has_hw_feature(pfdev, HW_FEATURE_AARCH64_MMU)) {
> +		fmt = ARM_64_LPAE_S1;
> +		mmu->enable = mmu_lpae_s1_enable;
> +	} else {
> +		fmt = ARM_MALI_LPAE;
> +		mmu->enable = mmu_mali_lpae_enable;
> +	}

How about we stick to the legacy pgtable format for all currently
supported GPUs, and make this an opt-in property attached to the
compatible. This way, we can progressively move away from the legacy
format once enough testing has been done, while allowing support for
GPUs that can't use the old format because the cachability/shareability
configuration is too limited.