linux-kernel - [PATCH 3/5] iommu/sun50i: Fix R/W permission check

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Date:   Thu, 13 Oct 2022 20:12:18 +0200
From:   Jernej Skrabec <jernej.skrabec@...il.com>
To:     maxime@...no.tech, joro@...tes.org, will@...nel.org,
        robin.murphy@....com, wens@...e.org, samuel@...lland.org
Cc:     iommu@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
        linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Jernej Skrabec <jernej.skrabec@...il.com>
Subject: [PATCH 3/5] iommu/sun50i: Fix R/W permission check

Because driver has enum type permissions and iommu subsystem has bitmap
type, we have to be careful how check for combined read and write
permissions is done. In such case, we have to mask both permissions and
check that both are set at the same time.

Current code just masks both flags but doesn't check that both are set.
In short, it always sets R/W permission, regardles if requested
permissions were RO, WO or RW. Fix that.

Fixes: 4100b8c229b3 ("iommu: Add Allwinner H6 IOMMU driver")
Signed-off-by: Jernej Skrabec <jernej.skrabec@...il.com>
---
 drivers/iommu/sun50i-iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
index 38d1069cf383..135df6934a9e 100644
--- a/drivers/iommu/sun50i-iommu.c
+++ b/drivers/iommu/sun50i-iommu.c
@@ -271,7 +271,7 @@ static u32 sun50i_mk_pte(phys_addr_t page, int prot)
 	enum sun50i_iommu_aci aci;
 	u32 flags = 0;
 
-	if (prot & (IOMMU_READ | IOMMU_WRITE))
+	if ((prot & (IOMMU_READ | IOMMU_WRITE)) == (IOMMU_READ | IOMMU_WRITE))
 		aci = SUN50I_IOMMU_ACI_RD_WR;
 	else if (prot & IOMMU_READ)
 		aci = SUN50I_IOMMU_ACI_RD;
-- 
2.38.0