From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 37AC4C7EE3A for ; Fri, 27 Jun 2025 10:05:43 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 90C7010E9BC; Fri, 27 Jun 2025 10:05:42 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="WwmNx5g7"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1408D10E9B7; Fri, 27 Jun 2025 10:05:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1751018741; x=1782554741; h=message-id:date:mime-version:subject:to:references:from: in-reply-to:content-transfer-encoding; bh=U/iUPHZms8/d1NTXseNwYjOJRWmmDMGgAZNq0coOhs0=; b=WwmNx5g7e3j8LfKzYgj5TyPJCsE34I4FDkxXvC1x1oYtH3W/zmf/iICi u8AUb6Uf3x20FpwZiR9ktW2TaNn+EfgRfrEHXFAWrNvjNFnjPVN72ranZ zIicyMdx54z90T8gufPRLwC8IYxfvj94BDRUcMxY2I4GRDjYead111PmX bt2tEiuUOC4n4hT8V+d059u93gMQMWXe1FdlqxJfvN3NXMqxoL65u/rWy iOYQAstUShY0l/OCIxSfNrpk6QTonMwg4AuJJRBuqhs5pVkbmAoLdeNlb WvVSksbpeKnZaVEXYkMN6dfWK5yAfX+z0C9NAaE2UC29F0pBwyzDlw1rO g==; X-CSE-ConnectionGUID: 6ZxL7cU9RlO4e4nPjpznkQ== X-CSE-MsgGUID: UiVYMvhCR+qyGY+W1NBYCg== X-IronPort-AV: E=McAfee;i="6800,10657,11476"; a="64019349" X-IronPort-AV: E=Sophos;i="6.16,270,1744095600"; d="scan'208";a="64019349" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2025 03:05:41 -0700 X-CSE-ConnectionGUID: Sg5LPVnvQsax1LVExsuxxg== X-CSE-MsgGUID: 55Ja624hRB+Qm9dlYTWKyg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,270,1744095600"; d="scan'208";a="157315117" Received: from dalessan-mobl3.ger.corp.intel.com (HELO [10.245.245.17]) ([10.245.245.17]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2025 03:05:36 -0700 Message-ID: <3c948554-cc0a-4ccd-a010-41260dc7a3b2@linux.intel.com> Date: Fri, 27 Jun 2025 12:05:33 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 05/10] drm/ttm: Add ttm_bo_kmap_try_from_panic() To: =?UTF-8?Q?Christian_K=C3=B6nig?= , Jocelyn Falempe , Jani Nikula , Rodrigo Vivi , Joonas Lahtinen , Tvrtko Ursulin , =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= , David Airlie , Simona Vetter , Huang Rui , Matthew Auld , Matthew Brost , Maxime Ripard , Thomas Zimmermann , intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20250618094011.238154-1-jfalempe@redhat.com> <20250618094011.238154-6-jfalempe@redhat.com> Content-Language: en-US From: Maarten Lankhorst In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hey, On 2025-06-18 15:55, Christian König wrote: > > > On 6/18/25 11:31, Jocelyn Falempe wrote: >> If the ttm bo is backed by pages, then it's possible to safely kmap >> one page at a time, using kmap_try_from_panic(). >> Unfortunately there is no way to do the same with ioremap, so it >> only supports the kmap case. >> This is needed for proper drm_panic support with xe driver. >> >> Signed-off-by: Jocelyn Falempe > > Reviewed-by: Christian König > > Preferred through drm-misc-next, but feel free to merge it through every branch you want if it makes thinks easier for you. > Thanks for the ack there. I had to merge this patch through drm-intel-next-queued because of a rework affecting the series. Kind regards, ~Maarten > Regards, > Christian. > >> --- >> >> v8: >> * Added in v8 >> >> v9: >> * Fix comment in ttm_bo_kmap_try_from_panic(), this can *only* be called >> from the panic handler (Christian König) >> >> drivers/gpu/drm/ttm/ttm_bo_util.c | 27 +++++++++++++++++++++++++++ >> include/drm/ttm/ttm_bo.h | 1 + >> 2 files changed, 28 insertions(+) >> >> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c >> index 15cab9bda17f..6912e6dfda25 100644 >> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c >> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c >> @@ -377,6 +377,33 @@ static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo, >> return (!map->virtual) ? -ENOMEM : 0; >> } >> >> +/** >> + * >> + * ttm_bo_kmap_try_from_panic >> + * >> + * @bo: The buffer object >> + * @page: The page to map >> + * >> + * Sets up a kernel virtual mapping using kmap_local_page_try_from_panic(). >> + * This should only be called from the panic handler, if you make sure the bo >> + * is the one being displayed, so is properly allocated, and protected. >> + * >> + * Returns the vaddr, that you can use to write to the bo, and that you should >> + * pass to kunmap_local() when you're done with this page, or NULL if the bo >> + * is in iomem. >> + */ >> +void *ttm_bo_kmap_try_from_panic(struct ttm_buffer_object *bo, unsigned long page) >> +{ >> + if (page + 1 > PFN_UP(bo->resource->size)) >> + return NULL; >> + >> + if (!bo->resource->bus.is_iomem && bo->ttm->pages && bo->ttm->pages[page]) >> + return kmap_local_page_try_from_panic(bo->ttm->pages[page]); >> + >> + return NULL; >> +} >> +EXPORT_SYMBOL(ttm_bo_kmap_try_from_panic); >> + >> /** >> * ttm_bo_kmap >> * >> diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h >> index cf027558b6db..8c0ce3fa077f 100644 >> --- a/include/drm/ttm/ttm_bo.h >> +++ b/include/drm/ttm/ttm_bo.h >> @@ -429,6 +429,7 @@ int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo, >> int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page, >> unsigned long num_pages, struct ttm_bo_kmap_obj *map); >> void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map); >> +void *ttm_bo_kmap_try_from_panic(struct ttm_buffer_object *bo, unsigned long page); >> int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map); >> void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct iosys_map *map); >> int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo); >