From nobody Fri Dec 19 20:53:16 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D948288517 for ; Fri, 6 Jun 2025 12:06:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749211581; cv=none; b=IQWbrs6t84Epa0OE4qvd2583jU0aWrw14cIsGr48RF7YN9KqeYuOuax6z1h6mxhAUOdGPA2SRbsEh6z1iloHy7rMsrGlZ7WNZhrxoPiIu8w47kTWfh22SQ/lz7QWHihu+QpaWnSgviH90qXodznk6780153XhC/7cdz8cYo+XEM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749211581; c=relaxed/simple; bh=YChnwPKjQ5Co6nll2v+KEbNjJtvS29A9fQfFAOtkapE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dBzj4pCu7/zRuLNtrKC6I8GirlU911OcXcawEmUEmJSefpBZ5hvataHlIHsN4/m7vusA0cH7Lsj72Nb0JA2Uul3SAN1IqcBB5uJgovJzRrQQHn33OjTvnqyGM3zQv48wcg8gQyhdZooJuZR35+5Dp56OZEdrmi8F1JtZSA8j9fM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=dyJJ/CT1; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dyJJ/CT1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749211577; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=P3qImNDgs5IKpXU7/qApHixAm6FFP9iiOGE/4sAcQeA=; b=dyJJ/CT1LWOcr3OvGA6oddBFyWh6fBfSNYw44DqUW/3N0YHyPhfFCKKL/Hppda99IcdhBg 9RP27HPs3VGrEjhjCG/TIvqhI6taNxBrcAI0q1uFXvl9MEsfs6cWvQz8eTQOqGr7Fzmbb6 kYT+S1ON+HWaDYvZAShtXQVpUq4QkOQ= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-590-toXoOkylOterjQg5xUPlQg-1; Fri, 06 Jun 2025 08:06:14 -0400 X-MC-Unique: toXoOkylOterjQg5xUPlQg-1 X-Mimecast-MFC-AGG-ID: toXoOkylOterjQg5xUPlQg_1749211572 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 09DBC1800EC5; Fri, 6 Jun 2025 12:06:12 +0000 (UTC) Received: from hydra.redhat.com (unknown [10.44.33.65]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B9DA718003FD; Fri, 6 Jun 2025 12:06:02 +0000 (UTC) From: Jocelyn Falempe To: Jani Nikula , Rodrigo Vivi , Joonas Lahtinen , Tvrtko Ursulin , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , David Airlie , Simona Vetter , Christian Koenig , 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 Cc: Jocelyn Falempe Subject: [PATCH v8 4/9] drm/ttm: Add ttm_bo_kmap_try_from_panic() Date: Fri, 6 Jun 2025 13:48:08 +0200 Message-ID: <20250606120519.753928-5-jfalempe@redhat.com> In-Reply-To: <20250606120519.753928-1-jfalempe@redhat.com> References: <20250606120519.753928-1-jfalempe@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" 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 --- v8: * Added in v8 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..9c3f3b379c2a 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 *b= o, return (!map->virtual) ? -ENOMEM : 0; } =20 +/** + * + * 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 can safely be called from the panic handler, if you make sure the = bo + * is the one being displayed, so is properly allocated, and won't be modi= fied. + * + * Returns the vaddr, that you can use to write to the bo, and that you sh= ould + * 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 lo= ng 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, struc= t 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 lo= ng 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); --=20 2.49.0