tools/testing/vma/tests/vma.c

Source file repositories/reference/linux-study-clean/tools/testing/vma/tests/vma.c

File Facts

System
Linux kernel
Corpus path
tools/testing/vma/tests/vma.c
Extension
.c
Size
18775 bytes
Lines
657
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later

static bool compare_legacy_flags(vm_flags_t legacy_flags, vma_flags_t flags)
{
	const unsigned long legacy_val = legacy_flags;
	/* The lower word should contain the precise same value. */
	const unsigned long flags_lower = flags.__vma_flags[0];
	vma_flags_t converted_flags;
#if NUM_VMA_FLAG_BITS > BITS_PER_LONG
	int i;

	/* All bits in higher flag values should be zero. */
	for (i = 1; i < NUM_VMA_FLAG_BITS / BITS_PER_LONG; i++) {
		if (flags.__vma_flags[i] != 0)
			return false;
	}
#endif

	static_assert(sizeof(legacy_flags) == sizeof(unsigned long));

	/* Assert that legacy flag helpers work correctly. */
	converted_flags = legacy_to_vma_flags(legacy_flags);
	ASSERT_FLAGS_SAME_MASK(&converted_flags, flags);
	ASSERT_EQ(vma_flags_to_legacy(flags), legacy_flags);

	return legacy_val == flags_lower;
}

static bool test_copy_vma(void)
{
	vma_flags_t vma_flags = mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT,
					     VMA_MAYREAD_BIT, VMA_MAYWRITE_BIT);
	struct mm_struct mm = {};
	bool need_locks = false;
	VMA_ITERATOR(vmi, &mm, 0);
	struct vm_area_struct *vma, *vma_new, *vma_next;

	/* Move backwards and do not merge. */

	vma = alloc_and_link_vma(&mm, 0x3000, 0x5000, 3, vma_flags);
	vma_new = copy_vma(&vma, 0, 0x2000, 0, &need_locks);
	ASSERT_NE(vma_new, vma);
	ASSERT_EQ(vma_new->vm_start, 0);
	ASSERT_EQ(vma_new->vm_end, 0x2000);
	ASSERT_EQ(vma_new->vm_pgoff, 0);
	vma_assert_attached(vma_new);

	cleanup_mm(&mm, &vmi);

	/* Move a VMA into position next to another and merge the two. */

	vma = alloc_and_link_vma(&mm, 0, 0x2000, 0, vma_flags);
	vma_next = alloc_and_link_vma(&mm, 0x6000, 0x8000, 6, vma_flags);
	vma_new = copy_vma(&vma, 0x4000, 0x2000, 4, &need_locks);
	vma_assert_attached(vma_new);

	ASSERT_EQ(vma_new, vma_next);

	cleanup_mm(&mm, &vmi);
	return true;
}

static bool test_vma_flags_unchanged(void)
{
	vma_flags_t flags = EMPTY_VMA_FLAGS;
	vm_flags_t legacy_flags = 0;
	int bit;
	struct vm_area_struct vma;
	struct vm_area_desc desc;

	vma.flags = EMPTY_VMA_FLAGS;
	desc.vma_flags = EMPTY_VMA_FLAGS;

	for (bit = 0; bit < BITS_PER_LONG; bit++) {
		vma_flags_t mask = mk_vma_flags(bit);

		legacy_flags |= (1UL << bit);

		/* Individual flags. */
		vma_flags_set(&flags, bit);
		ASSERT_TRUE(compare_legacy_flags(legacy_flags, flags));

		/* Via mask. */
		vma_flags_set_mask(&flags, mask);
		ASSERT_TRUE(compare_legacy_flags(legacy_flags, flags));

		/* Same for VMA. */
		vma_set_flags(&vma, bit);
		ASSERT_TRUE(compare_legacy_flags(legacy_flags, vma.flags));
		vma_set_flags_mask(&vma, mask);

Annotation

Implementation Notes