ece6e6f021
On RT, iommu_dma_map_msi_msg() may be called from non-preemptible
context. This will lead to a splat with CONFIG_DEBUG_ATOMIC_SLEEP as
the function is using spin_lock (they can sleep on RT).
iommu_dma_map_msi_msg() is used to map the MSI page in the IOMMU PT
and update the MSI message with the IOVA.
Only the part to lookup for the MSI page requires to be called in
preemptible context. As the MSI page cannot change over the lifecycle
of the MSI interrupt, the lookup can be cached and re-used later on.
iomma_dma_map_msi_msg() is now split in two functions:
- iommu_dma_prepare_msi(): This function will prepare the mapping
in the IOMMU and store the cookie in the structure msi_desc. This
function should be called in preemptible context.
- iommu_dma_compose_msi_msg(): This function will update the MSI
message with the IOVA when the device is behind an IOMMU.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
138 lines
4.2 KiB
C
138 lines
4.2 KiB
C
/*
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* Copyright (C) 2014-2015 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __DMA_IOMMU_H
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#define __DMA_IOMMU_H
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#ifdef __KERNEL__
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#include <linux/types.h>
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#include <asm/errno.h>
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#ifdef CONFIG_IOMMU_DMA
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#include <linux/dma-mapping.h>
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#include <linux/iommu.h>
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#include <linux/msi.h>
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int iommu_dma_init(void);
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/* Domain management interface for IOMMU drivers */
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int iommu_get_dma_cookie(struct iommu_domain *domain);
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int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base);
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void iommu_put_dma_cookie(struct iommu_domain *domain);
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/* Setup call for arch DMA mapping code */
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int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
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u64 size, struct device *dev);
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/* General helpers for DMA-API <-> IOMMU-API interaction */
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int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
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unsigned long attrs);
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/*
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* These implement the bulk of the relevant DMA mapping callbacks, but require
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* the arch code to take care of attributes and cache maintenance
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*/
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struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
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unsigned long attrs, int prot, dma_addr_t *handle,
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void (*flush_page)(struct device *, const void *, phys_addr_t));
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void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
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dma_addr_t *handle);
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int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma);
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dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size, int prot);
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int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
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int nents, int prot);
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/*
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* Arch code with no special attribute handling may use these
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* directly as DMA mapping callbacks for simplicity
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*/
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void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
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enum dma_data_direction dir, unsigned long attrs);
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void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
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enum dma_data_direction dir, unsigned long attrs);
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dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
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size_t size, enum dma_data_direction dir, unsigned long attrs);
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void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
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size_t size, enum dma_data_direction dir, unsigned long attrs);
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/* The DMA API isn't _quite_ the whole story, though... */
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/*
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* iommu_dma_prepare_msi() - Map the MSI page in the IOMMU device
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*
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* The MSI page will be stored in @desc.
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*
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* Return: 0 on success otherwise an error describing the failure.
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*/
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int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr);
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/* Update the MSI message if required. */
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void iommu_dma_compose_msi_msg(struct msi_desc *desc,
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struct msi_msg *msg);
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void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg);
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void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list);
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#else
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struct iommu_domain;
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struct msi_desc;
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struct msi_msg;
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struct device;
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static inline int iommu_dma_init(void)
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{
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return 0;
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}
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static inline int iommu_get_dma_cookie(struct iommu_domain *domain)
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{
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return -ENODEV;
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}
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static inline int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
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{
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return -ENODEV;
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}
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static inline void iommu_put_dma_cookie(struct iommu_domain *domain)
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{
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}
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static inline int iommu_dma_prepare_msi(struct msi_desc *desc,
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phys_addr_t msi_addr)
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{
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return 0;
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}
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static inline void iommu_dma_compose_msi_msg(struct msi_desc *desc,
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struct msi_msg *msg)
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{
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}
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static inline void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg)
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{
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}
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static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list)
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{
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}
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#endif /* CONFIG_IOMMU_DMA */
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#endif /* __KERNEL__ */
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#endif /* __DMA_IOMMU_H */
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