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authorSven Peter <sven@svenpeter.dev>2022-09-16 11:41:50 +0200
committerJoerg Roedel <jroedel@suse.de>2022-09-26 13:49:40 +0200
commitd8fe365a4f1c1aa5e2da3e41f50a08c9bd8d6112 (patch)
tree05b9fbebd40eecd7df3f2716c0fa114a92ee0959 /drivers/iommu
parent745ef1092bcfcf3bca8d82c260947ca498022dde (diff)
downloadlinux-d8fe365a4f1c1aa5e2da3e41f50a08c9bd8d6112.tar.gz
iommu/io-pgtable: Add DART subpage protection support
DART allows to only expose a subpage to the device. While this is an
optional feature on the M1 DARTs the new ones present on the Pro/Max
models require this field in every PTE.

Signed-off-by: Sven Peter <sven@svenpeter.dev>
Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20220916094152.87137-4-j@jannau.net
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/io-pgtable-dart.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/iommu/io-pgtable-dart.c b/drivers/iommu/io-pgtable-dart.c
index 8ca1ea313a80..fc76b6168055 100644
--- a/drivers/iommu/io-pgtable-dart.c
+++ b/drivers/iommu/io-pgtable-dart.c
@@ -14,6 +14,7 @@
 #define pr_fmt(fmt)	"dart io-pgtable: " fmt
 
 #include <linux/atomic.h>
+#include <linux/bitfield.h>
 #include <linux/bitops.h>
 #include <linux/io-pgtable.h>
 #include <linux/kernel.h>
@@ -40,6 +41,9 @@
 #define DART_PTES_PER_TABLE(d)					\
 	(DART_GRANULE(d) >> ilog2(sizeof(dart_iopte)))
 
+#define APPLE_DART_PTE_SUBPAGE_START   GENMASK_ULL(63, 52)
+#define APPLE_DART_PTE_SUBPAGE_END     GENMASK_ULL(51, 40)
+
 #define APPLE_DART1_PADDR_MASK	GENMASK_ULL(35, 12)
 
 /* Apple DART1 protection bits */
@@ -107,6 +111,10 @@ static int dart_init_pte(struct dart_io_pgtable *data,
 			return -EEXIST;
 		}
 
+	/* subpage protection: always allow access to the entire page */
+	pte |= FIELD_PREP(APPLE_DART_PTE_SUBPAGE_START, 0);
+	pte |= FIELD_PREP(APPLE_DART_PTE_SUBPAGE_END, 0xfff);
+
 	pte |= APPLE_DART1_PTE_PROT_SP_DIS;
 	pte |= APPLE_DART_PTE_VALID;