Commit 5fb190b0 authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon
Browse files

iommu/io-pgtable-arm: Simplify level indexing 



The nature of the LPAE format means that data->pg_shift is always
redundant with data->bits_per_level, since they represent the size of a
page and the number of PTEs per page respectively, and the size of a PTE
is constant. Thus it works out more efficient to only store the latter,
and derive the former via a trivial addition where necessary.

Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
[will: Reworked granule check in iopte_to_paddr()]
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent c79278c1

drivers/iommu/io-pgtable-arm.c

+13 −16
Original line number Diff line number Diff line
@@ -36,10 +36,11 @@ 
 * in a virtual address mapped by the pagetable in d.

 */

#define ARM_LPAE_LVL_SHIFT(l,d)						\

	(((ARM_LPAE_MAX_LEVELS - 1 - (l)) * (d)->bits_per_level) +	\

	(d)->pg_shift)

	(((ARM_LPAE_MAX_LEVELS - (l)) * (d)->bits_per_level) +		\

	ilog2(sizeof(arm_lpae_iopte)))



#define ARM_LPAE_GRANULE(d)		(1UL << (d)->pg_shift)

#define ARM_LPAE_GRANULE(d)						\

	(sizeof(arm_lpae_iopte) << (d)->bits_per_level)

#define ARM_LPAE_PGD_SIZE(d)						\

	(sizeof(arm_lpae_iopte) << (d)->pgd_bits)
@@ -55,9 +56,7 @@ 
	 ((1 << ((d)->bits_per_level + ARM_LPAE_PGD_IDX(l,d))) - 1))



/* Calculate the block/page mapping size at level l for pagetable in d. */

#define ARM_LPAE_BLOCK_SIZE(l,d)					\

	(1ULL << (ilog2(sizeof(arm_lpae_iopte)) +			\

		((ARM_LPAE_MAX_LEVELS - (l)) * (d)->bits_per_level)))

#define ARM_LPAE_BLOCK_SIZE(l,d)	(1ULL << ARM_LPAE_LVL_SHIFT(l,d))



/* Page table bits */

#define ARM_LPAE_PTE_TYPE_SHIFT		0
@@ -175,8 +174,7 @@ struct arm_lpae_io_pgtable { 


	int			pgd_bits;

	int			start_level;

	unsigned long		pg_shift;

	unsigned long		bits_per_level;

	int			bits_per_level;



	void			*pgd;

};
@@ -206,7 +204,7 @@ static phys_addr_t iopte_to_paddr(arm_lpae_iopte pte, 
{

	u64 paddr = pte & ARM_LPAE_PTE_ADDR_MASK;



	if (data->pg_shift < 16)

	if (ARM_LPAE_GRANULE(data) < SZ_64K)

		return paddr;



	/* Rotate the packed high-order bits back to the top */
@@ -742,9 +740,8 @@ static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg) 
static struct arm_lpae_io_pgtable *

arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)

{

	unsigned long va_bits;

	struct arm_lpae_io_pgtable *data;

	int levels;

	int levels, va_bits, pg_shift;



	arm_lpae_restrict_pgsizes(cfg);
@@ -766,10 +763,10 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg) 
	if (!data)

		return NULL;



	data->pg_shift = __ffs(cfg->pgsize_bitmap);

	data->bits_per_level = data->pg_shift - ilog2(sizeof(arm_lpae_iopte));

	pg_shift = __ffs(cfg->pgsize_bitmap);

	data->bits_per_level = pg_shift - ilog2(sizeof(arm_lpae_iopte));



	va_bits = cfg->ias - data->pg_shift;

	va_bits = cfg->ias - pg_shift;

	levels = DIV_ROUND_UP(va_bits, data->bits_per_level);

	data->start_level = ARM_LPAE_MAX_LEVELS - levels;
@@ -1135,9 +1132,9 @@ static void __init arm_lpae_dump_ops(struct io_pgtable_ops *ops) 


	pr_err("cfg: pgsize_bitmap 0x%lx, ias %u-bit\n",

		cfg->pgsize_bitmap, cfg->ias);

	pr_err("data: %d levels, 0x%zx pgd_size, %lu pg_shift, %lu bits_per_level, pgd @ %p\n",

	pr_err("data: %d levels, 0x%zx pgd_size, %u pg_shift, %u bits_per_level, pgd @ %p\n",

		ARM_LPAE_MAX_LEVELS - data->start_level, ARM_LPAE_PGD_SIZE(data),

		data->pg_shift, data->bits_per_level, data->pgd);

		ilog2(ARM_LPAE_GRANULE(data)), data->bits_per_level, data->pgd);

}



#define __FAIL(ops, i)	({						\

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