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iommu/io-pgtable: Rationalise quirk handling

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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: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Robin Murphy 2016-02-12 17:09:46 +00:00 committed by Will Deacon
parent 88492a4700
commit 3850db49da
3 changed files with 34 additions and 6 deletions
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5
drivers/iommu/io-pgtable-arm-v7s.c
View file

@ -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;

13
drivers/iommu/io-pgtable-arm.c
View file

@ -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;

22
drivers/iommu/io-pgtable.h
View file

@ -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;