int arch_setup_additional_pages()

in kernel/vdso.c [55:97]

• 31 lines of code
• 4 McCabe index (conditional complexity)

int arch_setup_additional_pages(struct linux_binprm *bprm,
	int uses_interp)
{
	struct mm_struct *mm = current->mm;
	unsigned long vdso_base, vdso_len;
	int ret;

	vdso_len = (vdso_pages + 1) << PAGE_SHIFT;

	mmap_write_lock(mm);
	vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
	if (IS_ERR_VALUE(vdso_base)) {
		ret = vdso_base;
		goto end;
	}

	/*
	 * Put vDSO base into mm struct. We need to do this before calling
	 * install_special_mapping or the perf counter mmap tracking code
	 * will fail to recognise it as a vDSO (since arch_vma_name fails).
	 */
	mm->context.vdso = (void *)vdso_base;

	ret =
	   install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
		(VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
		vdso_pagelist);

	if (unlikely(ret)) {
		mm->context.vdso = NULL;
		goto end;
	}

	vdso_base += (vdso_pages << PAGE_SHIFT);
	ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
		(VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]);

	if (unlikely(ret))
		mm->context.vdso = NULL;
end:
	mmap_write_unlock(mm);
	return ret;
}