Commit fdb1d7be authored by Will Deacon's avatar Will Deacon
Browse files

iommu: introduce generic page table allocation framework 



This patch introduces a generic framework for allocating page tables for
an IOMMU. There are a number of reasons we want to do this:

  - It avoids duplication of complex table management code in IOMMU
    drivers that use the same page table format

  - It removes any coupling with the CPU table format (and even the
    architecture!)

  - It defines an API for IOMMU TLB maintenance

Tested-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent eaa27f34

drivers/iommu/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -13,6 +13,14 @@ menuconfig IOMMU_SUPPORT 


if IOMMU_SUPPORT



menu "Generic IOMMU Pagetable Support"



# Selected by the actual pagetable implementations

config IOMMU_IO_PGTABLE

	bool



endmenu



config OF_IOMMU

       def_bool y

       depends on OF && IOMMU_API

drivers/iommu/Makefile

+1 −0
Original line number Diff line number Diff line 
obj-$(CONFIG_IOMMU_API) += iommu.o

obj-$(CONFIG_IOMMU_API) += iommu-traces.o

obj-$(CONFIG_IOMMU_API) += iommu-sysfs.o

obj-$(CONFIG_IOMMU_IO_PGTABLE) += io-pgtable.o

obj-$(CONFIG_OF_IOMMU)	+= of_iommu.o

obj-$(CONFIG_MSM_IOMMU) += msm_iommu.o msm_iommu_dev.o

obj-$(CONFIG_AMD_IOMMU) += amd_iommu.o amd_iommu_init.o

drivers/iommu/io-pgtable.c

0 → 100644
+71 −0
Original line number Diff line number Diff line 
/*

 * Generic page table allocator for IOMMUs.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 * Copyright (C) 2014 ARM Limited

 *

 * Author: Will Deacon <will.deacon@arm.com>

 */



#include <linux/bug.h>

#include <linux/kernel.h>

#include <linux/types.h>



#include "io-pgtable.h"



static const struct io_pgtable_init_fns *

io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] =

{

};



struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,

					    struct io_pgtable_cfg *cfg,

					    void *cookie)

{

	struct io_pgtable *iop;

	const struct io_pgtable_init_fns *fns;



	if (fmt >= IO_PGTABLE_NUM_FMTS)

		return NULL;



	fns = io_pgtable_init_table[fmt];

	if (!fns)

		return NULL;



	iop = fns->alloc(cfg, cookie);

	if (!iop)

		return NULL;



	iop->fmt	= fmt;

	iop->cookie	= cookie;

	iop->cfg	= *cfg;



	return &iop->ops;

}



/*

 * It is the IOMMU driver's responsibility to ensure that the page table

 * is no longer accessible to the walker by this point.

 */

void free_io_pgtable_ops(struct io_pgtable_ops *ops)

{

	struct io_pgtable *iop;



	if (!ops)

		return;



	iop = container_of(ops, struct io_pgtable, ops);

	iop->cfg.tlb->tlb_flush_all(iop->cookie);

	io_pgtable_init_table[iop->fmt]->free(iop);

}

drivers/iommu/io-pgtable.h

0 → 100644
+128 −0
Original line number Diff line number Diff line 
#ifndef __IO_PGTABLE_H

#define __IO_PGTABLE_H



/*

 * Public API for use by IOMMU drivers

 */

enum io_pgtable_fmt {

	IO_PGTABLE_NUM_FMTS,

};



/**

 * struct iommu_gather_ops - IOMMU callbacks for TLB and page table management.

 *

 * @tlb_flush_all: Synchronously invalidate the entire TLB context.

 * @tlb_add_flush: Queue up a TLB invalidation for a virtual address range.

 * @tlb_sync:      Ensure any queue TLB invalidation has taken effect.

 * @flush_pgtable: Ensure page table updates are visible to the IOMMU.

 *

 * Note that these can all be called in atomic context and must therefore

 * not block.

 */

struct iommu_gather_ops {

	void (*tlb_flush_all)(void *cookie);

	void (*tlb_add_flush)(unsigned long iova, size_t size, bool leaf,

			      void *cookie);

	void (*tlb_sync)(void *cookie);

	void (*flush_pgtable)(void *ptr, size_t size, void *cookie);

};



/**

 * struct io_pgtable_cfg - Configuration data for a set of page tables.

 *

 * @quirks:        A bitmap of hardware quirks that require some special

 *                 action by the low-level page table allocator.

 * @pgsize_bitmap: A bitmap of page sizes supported by this set of page

 *                 tables.

 * @ias:           Input address (iova) size, in bits.

 * @oas:           Output address (paddr) size, in bits.

 * @tlb:           TLB management callbacks for this set of tables.

 */

struct io_pgtable_cfg {

	int				quirks; /* IO_PGTABLE_QUIRK_* */

	unsigned long			pgsize_bitmap;

	unsigned int			ias;

	unsigned int			oas;

	const struct iommu_gather_ops	*tlb;



	/* Low-level data specific to the table format */

	union {

	};

};



/**

 * struct io_pgtable_ops - Page table manipulation API for IOMMU drivers.

 *

 * @map:          Map a physically contiguous memory region.

 * @unmap:        Unmap a physically contiguous memory region.

 * @iova_to_phys: Translate iova to physical address.

 *

 * These functions map directly onto the iommu_ops member functions with

 * the same names.

 */

struct io_pgtable_ops {

	int (*map)(struct io_pgtable_ops *ops, unsigned long iova,

		   phys_addr_t paddr, size_t size, int prot);

	int (*unmap)(struct io_pgtable_ops *ops, unsigned long iova,

		     size_t size);

	phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,

				    unsigned long iova);

};



/**

 * alloc_io_pgtable_ops() - Allocate a page table allocator for use by an IOMMU.

 *

 * @fmt:    The page table format.

 * @cfg:    The page table configuration. This will be modified to represent

 *          the configuration actually provided by the allocator (e.g. the

 *          pgsize_bitmap may be restricted).

 * @cookie: An opaque token provided by the IOMMU driver and passed back to

 *          the callback routines in cfg->tlb.

 */

struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,

					    struct io_pgtable_cfg *cfg,

					    void *cookie);



/**

 * free_io_pgtable_ops() - Free an io_pgtable_ops structure. The caller

 *                         *must* ensure that the page table is no longer

 *                         live, but the TLB can be dirty.

 *

 * @ops: The ops returned from alloc_io_pgtable_ops.

 */

void free_io_pgtable_ops(struct io_pgtable_ops *ops);





/*

 * Internal structures for page table allocator implementations.

 */



/**

 * struct io_pgtable - Internal structure describing a set of page tables.

 *

 * @fmt:    The page table format.

 * @cookie: An opaque token provided by the IOMMU driver and passed back to

 *          any callback routines.

 * @cfg:    A copy of the page table configuration.

 * @ops:    The page table operations in use for this set of page tables.

 */

struct io_pgtable {

	enum io_pgtable_fmt	fmt;

	void			*cookie;

	struct io_pgtable_cfg	cfg;

	struct io_pgtable_ops	ops;

};



/**

 * struct io_pgtable_init_fns - Alloc/free a set of page tables for a

 *                              particular format.

 *

 * @alloc: Allocate a set of page tables described by cfg.

 * @free:  Free the page tables associated with iop.

 */

struct io_pgtable_init_fns {

	struct io_pgtable *(*alloc)(struct io_pgtable_cfg *cfg, void *cookie);

	void (*free)(struct io_pgtable *iop);

};



#endif /* __IO_PGTABLE_H */

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