1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * KUnit userspace memory allocation resource management.
  4 */
  5#include <kunit/resource.h>
  6#include <kunit/test.h>
  7#include <linux/kthread.h>
  8#include <linux/mm.h>
  9
 10struct kunit_vm_mmap_resource {
 11	unsigned long addr;
 12	size_t size;
 13};
 14
 15/* vm_mmap() arguments */
 16struct kunit_vm_mmap_params {
 17	struct file *file;
 18	unsigned long addr;
 19	unsigned long len;
 20	unsigned long prot;
 21	unsigned long flag;
 22	unsigned long offset;
 23};
 24
 25/* Create and attach a new mm if it doesn't already exist. */
 26static int kunit_attach_mm(void)
 27{
 28	struct mm_struct *mm;
 29
 30	if (current->mm)
 31		return 0;
 32
 33	/* arch_pick_mmap_layout() is only sane with MMU systems. */
 34	if (!IS_ENABLED(CONFIG_MMU))
 35		return -EINVAL;
 36
 37	mm = mm_alloc();
 38	if (!mm)
 39		return -ENOMEM;
 40
 41	/* Define the task size. */
 42	mm->task_size = TASK_SIZE;
 43
 44	/* Make sure we can allocate new VMAs. */
 45	arch_pick_mmap_layout(mm, &current->signal->rlim[RLIMIT_STACK]);
 46
 47	/* Attach the mm. It will be cleaned up when the process dies. */
 48	kthread_use_mm(mm);
 49
 50	return 0;
 51}
 52
 53static int kunit_vm_mmap_init(struct kunit_resource *res, void *context)
 54{
 55	struct kunit_vm_mmap_params *p = context;
 56	struct kunit_vm_mmap_resource vres;
 57	int ret;
 58
 59	ret = kunit_attach_mm();
 60	if (ret)
 61		return ret;
 62
 63	vres.size = p->len;
 64	vres.addr = vm_mmap(p->file, p->addr, p->len, p->prot, p->flag, p->offset);
 65	if (!vres.addr)
 66		return -ENOMEM;
 67	res->data = kmemdup(&vres, sizeof(vres), GFP_KERNEL);
 68	if (!res->data) {
 69		vm_munmap(vres.addr, vres.size);
 70		return -ENOMEM;
 71	}
 72
 73	return 0;
 74}
 75
 76static void kunit_vm_mmap_free(struct kunit_resource *res)
 77{
 78	struct kunit_vm_mmap_resource *vres = res->data;
 79
 80	/*
 81	 * Since this is executed from the test monitoring process,
 82	 * the test's mm has already been torn down. We don't need
 83	 * to run vm_munmap(vres->addr, vres->size), only clean up
 84	 * the vres.
 85	 */
 86
 87	kfree(vres);
 88	res->data = NULL;
 89}
 90
 91unsigned long kunit_vm_mmap(struct kunit *test, struct file *file,
 92			    unsigned long addr, unsigned long len,
 93			    unsigned long prot, unsigned long flag,
 94			    unsigned long offset)
 95{
 96	struct kunit_vm_mmap_params params = {
 97		.file = file,
 98		.addr = addr,
 99		.len = len,
100		.prot = prot,
101		.flag = flag,
102		.offset = offset,
103	};
104	struct kunit_vm_mmap_resource *vres;
105
106	vres = kunit_alloc_resource(test,
107				    kunit_vm_mmap_init,
108				    kunit_vm_mmap_free,
109				    GFP_KERNEL,
110				    &params);
111	if (vres)
112		return vres->addr;
113	return 0;
114}
115EXPORT_SYMBOL_GPL(kunit_vm_mmap);
116
117MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");