cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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videobuf2-memops.c (3716B)

      1/*
      2 * videobuf2-memops.c - generic memory handling routines for videobuf2
      3 *
      4 * Copyright (C) 2010 Samsung Electronics
      5 *
      6 * Author: Pawel Osciak <pawel@osciak.com>
      7 *	   Marek Szyprowski <m.szyprowski@samsung.com>
      8 *
      9 * This program is free software; you can redistribute it and/or modify
     10 * it under the terms of the GNU General Public License as published by
     11 * the Free Software Foundation.
     12 */
     13
     14#include <linux/slab.h>
     15#include <linux/module.h>
     16#include <linux/dma-mapping.h>
     17#include <linux/vmalloc.h>
     18#include <linux/mm.h>
     19#include <linux/sched.h>
     20#include <linux/file.h>
     21
     22#include <media/videobuf2-v4l2.h>
     23#include <media/videobuf2-memops.h>
     24
     25/**
     26 * vb2_create_framevec() - map virtual addresses to pfns
     27 * @start:	Virtual user address where we start mapping
     28 * @length:	Length of a range to map
     29 *
     30 * This function allocates and fills in a vector with pfns corresponding to
     31 * virtual address range passed in arguments. If pfns have corresponding pages,
     32 * page references are also grabbed to pin pages in memory. The function
     33 * returns pointer to the vector on success and error pointer in case of
     34 * failure. Returned vector needs to be freed via vb2_destroy_pfnvec().
     35 */
     36struct frame_vector *vb2_create_framevec(unsigned long start,
     37					 unsigned long length)
     38{
     39	int ret;
     40	unsigned long first, last;
     41	unsigned long nr;
     42	struct frame_vector *vec;
     43
     44	first = start >> PAGE_SHIFT;
     45	last = (start + length - 1) >> PAGE_SHIFT;
     46	nr = last - first + 1;
     47	vec = frame_vector_create(nr);
     48	if (!vec)
     49		return ERR_PTR(-ENOMEM);
     50	ret = get_vaddr_frames(start & PAGE_MASK, nr, vec);
     51	if (ret < 0)
     52		goto out_destroy;
     53	/* We accept only complete set of PFNs */
     54	if (ret != nr) {
     55		ret = -EFAULT;
     56		goto out_release;
     57	}
     58	return vec;
     59out_release:
     60	put_vaddr_frames(vec);
     61out_destroy:
     62	frame_vector_destroy(vec);
     63	return ERR_PTR(ret);
     64}
     65EXPORT_SYMBOL(vb2_create_framevec);
     66
     67/**
     68 * vb2_destroy_framevec() - release vector of mapped pfns
     69 * @vec:	vector of pfns / pages to release
     70 *
     71 * This releases references to all pages in the vector @vec (if corresponding
     72 * pfns are backed by pages) and frees the passed vector.
     73 */
     74void vb2_destroy_framevec(struct frame_vector *vec)
     75{
     76	put_vaddr_frames(vec);
     77	frame_vector_destroy(vec);
     78}
     79EXPORT_SYMBOL(vb2_destroy_framevec);
     80
     81/**
     82 * vb2_common_vm_open() - increase refcount of the vma
     83 * @vma:	virtual memory region for the mapping
     84 *
     85 * This function adds another user to the provided vma. It expects
     86 * struct vb2_vmarea_handler pointer in vma->vm_private_data.
     87 */
     88static void vb2_common_vm_open(struct vm_area_struct *vma)
     89{
     90	struct vb2_vmarea_handler *h = vma->vm_private_data;
     91
     92	pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n",
     93	       __func__, h, refcount_read(h->refcount), vma->vm_start,
     94	       vma->vm_end);
     95
     96	refcount_inc(h->refcount);
     97}
     98
     99/**
    100 * vb2_common_vm_close() - decrease refcount of the vma
    101 * @vma:	virtual memory region for the mapping
    102 *
    103 * This function releases the user from the provided vma. It expects
    104 * struct vb2_vmarea_handler pointer in vma->vm_private_data.
    105 */
    106static void vb2_common_vm_close(struct vm_area_struct *vma)
    107{
    108	struct vb2_vmarea_handler *h = vma->vm_private_data;
    109
    110	pr_debug("%s: %p, refcount: %d, vma: %08lx-%08lx\n",
    111	       __func__, h, refcount_read(h->refcount), vma->vm_start,
    112	       vma->vm_end);
    113
    114	h->put(h->arg);
    115}
    116
    117/*
    118 * vb2_common_vm_ops - common vm_ops used for tracking refcount of mmapped
    119 * video buffers
    120 */
    121const struct vm_operations_struct vb2_common_vm_ops = {
    122	.open = vb2_common_vm_open,
    123	.close = vb2_common_vm_close,
    124};
    125EXPORT_SYMBOL_GPL(vb2_common_vm_ops);
    126
    127MODULE_DESCRIPTION("common memory handling routines for videobuf2");
    128MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
    129MODULE_LICENSE("GPL");