[PATCH v5 2/9] scatterlist: Add a flag for the restricted memory

From: Yong Wu <yong.wu@mediatek.com>
To: Rob Herring <robh+dt@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	<christian.koenig@amd.com>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Benjamin Gaignard <benjamin.gaignard@collabora.com>,
	Brian Starkey <Brian.Starkey@arm.com>,
	John Stultz <jstultz@google.com>, <tjmercier@google.com>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	Yong Wu <yong.wu@mediatek.com>, <devicetree@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <linux-media@vger.kernel.org>,
	<dri-devel@lists.freedesktop.org>,
	<linaro-mm-sig@lists.linaro.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Vijayanand Jitta <quic_vjitta@quicinc.com>,
	Joakim Bech <joakim.bech@linaro.org>,
	Jeffrey Kardatzke <jkardatzke@google.com>,
	Pavel Machek <pavel@ucw.cz>, Simon Ser <contact@emersion.fr>,
	Pekka Paalanen <ppaalanen@gmail.com>, <willy@infradead.org>,
	Logan Gunthorpe <logang@deltatee.com>,
	Daniel Vetter <daniel@ffwll.ch>, <jianjiao.zeng@mediatek.com>,
	<kuohong.wang@mediatek.com>, <youlin.pei@mediatek.com>
Subject: [PATCH v5 2/9] scatterlist: Add a flag for the restricted memory
Date: Wed, 15 May 2024 19:23:01 +0800	[thread overview]
Message-ID: <20240515112308.10171-3-yong.wu@mediatek.com> (raw)
In-Reply-To: <20240515112308.10171-1-yong.wu@mediatek.com>

Introduce a FLAG for the restricted memory which means the memory is
protected by TEE or hypervisor, then it's inaccessiable for kernel.

Currently we don't use sg_dma_unmark_restricted, thus this interface
has not been added.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 include/linux/scatterlist.h | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 77df3d7b18a6..a6ad9018eca0 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -282,6 +282,7 @@ static inline void sg_unmark_end(struct scatterlist *sg)
 
 #define SG_DMA_BUS_ADDRESS	(1 << 0)
 #define SG_DMA_SWIOTLB		(1 << 1)
+#define SG_DMA_RESTRICTED	(2 << 1)
 
 /**
  * sg_dma_is_bus_address - Return whether a given segment was marked
@@ -352,6 +353,31 @@ static inline void sg_dma_mark_swiotlb(struct scatterlist *sg)
 	sg->dma_flags |= SG_DMA_SWIOTLB;
 }
 
+/**
+ * sg_dma_mark_restricted - Mark the scatterlist for restricted buffer.
+ * @sg:		SG entry
+ *
+ * Description:
+ *   Marks a a scatterlist for the restricted buffer that may be inaccessiable
+ *   in kernel if it is protected.
+ */
+static inline void sg_dma_mark_restricted(struct scatterlist *sg)
+{
+	sg->dma_flags |= SG_DMA_RESTRICTED;
+}
+
+/**
+ * sg_dma_is_restricted - Return whether the scatterlist was marked as restricted
+ *                        buffer.
+ * @sg:		SG entry
+ *
+ * Description:
+ *   Returns true if the scatterlist was marked as restricted buffer.
+ */
+static inline bool sg_dma_is_restricted(struct scatterlist *sg)
+{
+	return sg->dma_flags & SG_DMA_RESTRICTED;
+}
 #else
 
 static inline bool sg_dma_is_bus_address(struct scatterlist *sg)
@@ -372,6 +398,14 @@ static inline void sg_dma_mark_swiotlb(struct scatterlist *sg)
 {
 }
 
+static inline bool sg_dma_is_restricted(struct scatterlist *sg)
+{
+	return false;
+}
+
+static inline void sg_dma_mark_restrited(struct scatterlist *sg)
+{
+}
 #endif	/* CONFIG_NEED_SG_DMA_FLAGS */
 
 /**
-- 
2.25.1


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