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Commit 3850db49 authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon
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iommu/io-pgtable: Rationalise quirk handling 



As the number of io-pgtable implementations grows beyond 1, it's time
to rationalise the quirks mechanism before things have a chance to
start getting really ugly and out-of-hand.

To that end:
- Indicate exactly which quirks each format can/does support.
- Fail creating a table if a caller wants unsupported quirks.
- Properly document where each quirk applies and why.

Reviewed-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 88492a47

drivers/iommu/io-pgtable-arm-v7s.c

+5 −0
Original line number Diff line number Diff line
@@ -623,6 +623,11 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg, 
	if (cfg->ias > ARM_V7S_ADDR_BITS || cfg->oas > ARM_V7S_ADDR_BITS)

		return NULL;



	if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS |

			    IO_PGTABLE_QUIRK_NO_PERMS |

			    IO_PGTABLE_QUIRK_TLBI_ON_MAP))

		return NULL;



	data = kmalloc(sizeof(*data), GFP_KERNEL);

	if (!data)

		return NULL;

drivers/iommu/io-pgtable-arm.c

+11 −2
Original line number Diff line number Diff line
@@ -659,8 +659,12 @@ static struct io_pgtable * 
arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)

{

	u64 reg;

	struct arm_lpae_io_pgtable *data = arm_lpae_alloc_pgtable(cfg);

	struct arm_lpae_io_pgtable *data;



	if (cfg->quirks & ~IO_PGTABLE_QUIRK_ARM_NS)

		return NULL;



	data = arm_lpae_alloc_pgtable(cfg);

	if (!data)

		return NULL;
@@ -743,8 +747,13 @@ static struct io_pgtable * 
arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)

{

	u64 reg, sl;

	struct arm_lpae_io_pgtable *data = arm_lpae_alloc_pgtable(cfg);

	struct arm_lpae_io_pgtable *data;



	/* The NS quirk doesn't apply at stage 2 */

	if (cfg->quirks)

		return NULL;



	data = arm_lpae_alloc_pgtable(cfg);

	if (!data)

		return NULL;

drivers/iommu/io-pgtable.h

+18 −4
Original line number Diff line number Diff line
@@ -47,10 +47,24 @@ struct iommu_gather_ops { 
 *                 page table walker.

 */

struct io_pgtable_cfg {

	#define IO_PGTABLE_QUIRK_ARM_NS		BIT(0) /* Set NS bit in PTEs */

	#define IO_PGTABLE_QUIRK_NO_PERMS	BIT(1) /* No AP/XN bits */

	#define IO_PGTABLE_QUIRK_TLBI_ON_MAP	BIT(2) /* TLB Inv. on map */

	int				quirks;

	/*

	 * IO_PGTABLE_QUIRK_ARM_NS: (ARM formats) Set NS and NSTABLE bits in

	 *	stage 1 PTEs, for hardware which insists on validating them

	 *	even in	non-secure state where they should normally be ignored.

	 *

	 * IO_PGTABLE_QUIRK_NO_PERMS: Ignore the IOMMU_READ, IOMMU_WRITE and

	 *	IOMMU_NOEXEC flags and map everything with full access, for

	 *	hardware which does not implement the permissions of a given

	 *	format, and/or requires some format-specific default value.

	 *

	 * IO_PGTABLE_QUIRK_TLBI_ON_MAP: If the format forbids caching invalid

	 *	(unmapped) entries but the hardware might do so anyway, perform

	 *	TLB maintenance when mapping as well as when unmapping.

	 */

	#define IO_PGTABLE_QUIRK_ARM_NS		BIT(0)

	#define IO_PGTABLE_QUIRK_NO_PERMS	BIT(1)

	#define IO_PGTABLE_QUIRK_TLBI_ON_MAP	BIT(2)

	unsigned long			quirks;

	unsigned long			pgsize_bitmap;

	unsigned int			ias;

	unsigned int			oas;