On 12/02/16 12:32, Laurent Pinchart wrote:
On Friday 12 February 2016 12:08:58 Will Deacon wrote:
On Thu, Feb 11, 2016 at 04:13:45PM +0000, Robin Murphy wrote:
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.
Signed-off-by: Robin Murphy <robin.mur...@arm.com>
---
drivers/iommu/io-pgtable-arm-v7s.c | 3 +++
drivers/iommu/io-pgtable-arm.c | 2 ++
drivers/iommu/io-pgtable.c | 3 +++
drivers/iommu/io-pgtable.h | 24 ++++++++++++++++++++----
4 files changed, 28 insertions(+), 4 deletions(-)
Note that I can't merge this until we've figured out the plan for Yong's
driver.
Indeed (hence 4/3) - it just ended up seeming like a significant enough
change to warrant its own patch, but not critical enough to warrant
splitting it for the sake of applying the parts touching the existing
code right now.
diff --git a/drivers/iommu/io-pgtable-arm-v7s.c
b/drivers/iommu/io-pgtable-arm-v7s.c index d39a021..9bc607a 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -690,6 +690,9 @@ out_free_data:
struct io_pgtable_init_fns io_pgtable_arm_v7s_init_fns = {
.alloc = arm_v7s_alloc_pgtable,
.free = arm_v7s_free_pgtable,
+ .supported_quirks = IO_PGTABLE_QUIRK_ARM_NS |
+ IO_PGTABLE_QUIRK_NO_PERMS |
+ IO_PGTABLE_QUIRK_TLBI_ON_MAP,
};
#ifdef CONFIG_IOMMU_IO_PGTABLE_ARMV7S_SELFTEST
diff --git a/drivers/iommu/io-pgtable-arm.c
b/drivers/iommu/io-pgtable-arm.c index 4095af2..32f94f1 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -863,6 +863,7 @@ arm_32_lpae_alloc_pgtable_s2(struct io_pgtable_cfg
*cfg, void *cookie)>
struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s1_init_fns = {
.alloc = arm_64_lpae_alloc_pgtable_s1,
.free = arm_lpae_free_pgtable,
+ .supported_quirks = IO_PGTABLE_QUIRK_ARM_NS,
};
struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s2_init_fns = {
@@ -873,6 +874,7 @@ struct io_pgtable_init_fns
io_pgtable_arm_64_lpae_s2_init_fns = {>
struct io_pgtable_init_fns io_pgtable_arm_32_lpae_s1_init_fns = {
.alloc = arm_32_lpae_alloc_pgtable_s1,
.free = arm_lpae_free_pgtable,
+ .supported_quirks = IO_PGTABLE_QUIRK_ARM_NS,
};
struct io_pgtable_init_fns io_pgtable_arm_32_lpae_s2_init_fns = {
diff --git a/drivers/iommu/io-pgtable.c b/drivers/iommu/io-pgtable.c
index 876f6a7..0f57a45 100644
--- a/drivers/iommu/io-pgtable.c
+++ b/drivers/iommu/io-pgtable.c
@@ -52,6 +52,9 @@ struct io_pgtable_ops *alloc_io_pgtable_ops(enum
io_pgtable_fmt fmt,>
if (!fns)
return NULL;
+ if (cfg->quirks & ~fns->supported_quirks)
+ return NULL;
+
iop = fns->alloc(cfg, cookie);
if (!iop)
return NULL;
diff --git a/drivers/iommu/io-pgtable.h b/drivers/iommu/io-pgtable.h
index 4faee7d..6e7f11e 100644
--- a/drivers/iommu/io-pgtable.h
+++ b/drivers/iommu/io-pgtable.h
@@ -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.
+ */
Much better, cheers.
+ #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 int quirks;
Let's just make this unsigned long.
unsigned long pgsize_bitmap;
unsigned int ias;
unsigned int oas;
@@ -173,10 +187,12 @@ static inline void io_pgtable_tlb_sync(struct
io_pgtable *iop)
*
* @alloc: Allocate a set of page tables described by cfg.
* @free: Free the page tables associated with iop.
+ * @supported_quirks: Bitmap of quirks supported by the format.
*/
struct io_pgtable_init_fns {
struct io_pgtable *(*alloc)(struct io_pgtable_cfg *cfg, void
*cookie);
void (*free)(struct io_pgtable *iop);
+ unsigned int supported_quirks;
};
My only gripe here is that this is supposed to be a struct of function
pointers... get_supported_quirks() ?
Can't we instead say it's a struct of function pointers and static data ? :-)
A function to retrieve the supported quirks will just contribute to kernel
bloat without adding any extra benefit.
Bleh - personally I think it's marginally more obvious and readable to
have the information looking like data, but I'd much sooner just have a
hard-coded "if (cfq->quirks & ..." check in every format's alloc
function than introduce a whole new callback. Does that sound like a
reasonable compromise?
Robin.
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