| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <88bae26e-d5f4-7a00-a88a-b69194d519a4@arm.com>
Date: Thu, 10 Sep 2020 14:34:18 +0100
From: Robin Murphy <robin.murphy@....com>
To: Christoph Hellwig <hch@....de>, Tony Luck <tony.luck@...el.com>,
Fenghua Yu <fenghua.yu@...el.com>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
iommu@...ts.linux-foundation.org
Cc: Tomasz Figa <tfiga@...omium.org>, Joerg Roedel <joro@...tes.org>,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-ia64@...r.kernel.org, linux-mips@...r.kernel.org
Subject: Re: [PATCH 11/12] dma-mapping: move dma_common_{mmap,get_sgtable} out
of mapping.c
On 2020-09-08 17:47, Christoph Hellwig wrote:
> Add a new file that contains helpera for misc DMA ops, which is only
The Latin plural of the singular "helperum", I guess? :P
> built when CONFIG_DMA_OPS is set.
Reviewed-by: Robin Murphy <robin.murphy@....com>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
> kernel/dma/Makefile | 1 +
> kernel/dma/mapping.c | 47 +-----------------------------------
> kernel/dma/ops_helpers.c | 51 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 53 insertions(+), 46 deletions(-)
> create mode 100644 kernel/dma/ops_helpers.c
>
> diff --git a/kernel/dma/Makefile b/kernel/dma/Makefile
> index 32c7c1942bbd6c..dc755ab68aabf9 100644
> --- a/kernel/dma/Makefile
> +++ b/kernel/dma/Makefile
> @@ -1,6 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0
>
> obj-$(CONFIG_HAS_DMA) += mapping.o direct.o
> +obj-$(CONFIG_DMA_OPS) += ops_helpers.o
> obj-$(CONFIG_DMA_OPS) += dummy.o
> obj-$(CONFIG_DMA_CMA) += contiguous.o
> obj-$(CONFIG_DMA_DECLARE_COHERENT) += coherent.o
> diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
> index 0d129421e75fc8..848c95c27d79ff 100644
> --- a/kernel/dma/mapping.c
> +++ b/kernel/dma/mapping.c
> @@ -8,7 +8,7 @@
> #include <linux/memblock.h> /* for max_pfn */
> #include <linux/acpi.h>
> #include <linux/dma-direct.h>
> -#include <linux/dma-noncoherent.h>
> +#include <linux/dma-mapping.h>
> #include <linux/export.h>
> #include <linux/gfp.h>
> #include <linux/of_device.h>
> @@ -295,22 +295,6 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
> }
> EXPORT_SYMBOL(dma_sync_sg_for_device);
>
> -/*
> - * Create scatter-list for the already allocated DMA buffer.
> - */
> -int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
> - void *cpu_addr, dma_addr_t dma_addr, size_t size,
> - unsigned long attrs)
> -{
> - struct page *page = virt_to_page(cpu_addr);
> - int ret;
> -
> - ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> - if (!ret)
> - sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
> - return ret;
> -}
> -
> /*
> * The whole dma_get_sgtable() idea is fundamentally unsafe - it seems
> * that the intention is to allow exporting memory allocated via the
> @@ -358,35 +342,6 @@ pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs)
> }
> #endif /* CONFIG_MMU */
>
> -/*
> - * Create userspace mapping for the DMA-coherent memory.
> - */
> -int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
> - void *cpu_addr, dma_addr_t dma_addr, size_t size,
> - unsigned long attrs)
> -{
> -#ifdef CONFIG_MMU
> - unsigned long user_count = vma_pages(vma);
> - unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> - unsigned long off = vma->vm_pgoff;
> - int ret = -ENXIO;
> -
> - vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
> -
> - if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
> - return ret;
> -
> - if (off >= count || user_count > count - off)
> - return -ENXIO;
> -
> - return remap_pfn_range(vma, vma->vm_start,
> - page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
> - user_count << PAGE_SHIFT, vma->vm_page_prot);
> -#else
> - return -ENXIO;
> -#endif /* CONFIG_MMU */
> -}
> -
> /**
> * dma_can_mmap - check if a given device supports dma_mmap_*
> * @dev: device to check
> diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
> new file mode 100644
> index 00000000000000..e443c69be4299f
> --- /dev/null
> +++ b/kernel/dma/ops_helpers.c
> @@ -0,0 +1,51 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Helpers for DMA ops implementations. These generally rely on the fact that
> + * the allocated memory contains normal pages in the direct kernel mapping.
> + */
> +#include <linux/dma-noncoherent.h>
> +
> +/*
> + * Create scatter-list for the already allocated DMA buffer.
> + */
> +int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
> + void *cpu_addr, dma_addr_t dma_addr, size_t size,
> + unsigned long attrs)
> +{
> + struct page *page = virt_to_page(cpu_addr);
> + int ret;
> +
> + ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
> + if (!ret)
> + sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
> + return ret;
> +}
> +
> +/*
> + * Create userspace mapping for the DMA-coherent memory.
> + */
> +int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
> + void *cpu_addr, dma_addr_t dma_addr, size_t size,
> + unsigned long attrs)
> +{
> +#ifdef CONFIG_MMU
> + unsigned long user_count = vma_pages(vma);
> + unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> + unsigned long off = vma->vm_pgoff;
> + int ret = -ENXIO;
> +
> + vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
> +
> + if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
> + return ret;
> +
> + if (off >= count || user_count > count - off)
> + return -ENXIO;
> +
> + return remap_pfn_range(vma, vma->vm_start,
> + page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
> + user_count << PAGE_SHIFT, vma->vm_page_prot);
> +#else
> + return -ENXIO;
> +#endif /* CONFIG_MMU */
> +}
>
Powered by blists - more mailing lists