// SPDX-License-Identifier: GPL-2.0-only #include <linux/gfp.h>#include <linux/init.h>#include <linux/mm.h>#include <linux/time_namespace.h>#include <linux/types.h>#include <linux/vdso_datastore.h>#include <vdso/datapage.h> static u8 vdso_initdata[VDSO_NR_PAGES * PAGE_SIZE] __aligned(PAGE_SIZE) __initdata = {}; #ifdef CONFIG_GENERIC_GETTIMEOFDAYstruct vdso_time_data *vdso_k_time_data __ro_after_init =	(void *)&vdso_initdata[VDSO_TIME_PAGE_OFFSET * PAGE_SIZE]; static_assert(sizeof(struct vdso_time_data) <= PAGE_SIZE);#endif /* CONFIG_GENERIC_GETTIMEOFDAY */ #ifdef CONFIG_VDSO_GETRANDOMstruct vdso_rng_data *vdso_k_rng_data __ro_after_init =	(void *)&vdso_initdata[VDSO_RNG_PAGE_OFFSET * PAGE_SIZE]; static_assert(sizeof(struct vdso_rng_data) <= PAGE_SIZE);#endif /* CONFIG_VDSO_GETRANDOM */ #ifdef CONFIG_ARCH_HAS_VDSO_ARCH_DATAstruct vdso_arch_data *vdso_k_arch_data __ro_after_init =	(void *)&vdso_initdata[VDSO_ARCH_PAGES_START * PAGE_SIZE];#endif /* CONFIG_ARCH_HAS_VDSO_ARCH_DATA */ static struct page *vdso_data_pages __ro_after_init; void __init vdso_setup_data_pages(void){	unsigned int order = get_order(VDSO_NR_PAGES * PAGE_SIZE); 	/*	 * Allocate the data pages dynamically. SPARC does not support mapping	 * static pages to be mapped into userspace.	 * It is also a requirement for mlockall() support.	 *	 * Do not use folios. In time namespaces the pages are mapped in a different order	 * to userspace, which is not handled by the folio optimizations in finish_fault().	 */	vdso_data_pages = alloc_pages(GFP_KERNEL, order);	if (!vdso_data_pages)		panic("Unable to allocate VDSO storage pages"); 	/* The pages are mapped one-by-one into userspace and each one needs to be refcounted. */	split_page(vdso_data_pages, order); 	/* Move the data already written by other subsystems to the new pages */	memcpy(page_address(vdso_data_pages), vdso_initdata, VDSO_NR_PAGES * PAGE_SIZE); 	if (IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY))		vdso_k_time_data = page_address(vdso_data_pages + VDSO_TIME_PAGE_OFFSET); 	if (IS_ENABLED(CONFIG_VDSO_GETRANDOM))		vdso_k_rng_data = page_address(vdso_data_pages + VDSO_RNG_PAGE_OFFSET); 	if (IS_ENABLED(CONFIG_ARCH_HAS_VDSO_ARCH_DATA))		vdso_k_arch_data = page_address(vdso_data_pages + VDSO_ARCH_PAGES_START);} static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,			     struct vm_area_struct *vma, struct vm_fault *vmf){	struct page *page, *timens_page; 	if (unlikely(vmf->flags & FAULT_FLAG_REMOTE))		return VM_FAULT_SIGBUS; 	page = vdso_data_pages + vmf->pgoff;	timens_page = find_timens_vvar_page(vma); 	switch (vmf->pgoff) {	case VDSO_TIME_PAGE_OFFSET:		if (!IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY) || !timens_page)			break;		/*		 * Fault in VVAR page too, since it will be accessed		 * to get clock data anyway.		 */		unsigned long addr;		vm_fault_t err; 		addr = vmf->address + VDSO_TIMENS_PAGE_OFFSET * PAGE_SIZE;		err = vmf_insert_page(vma, addr, page);		if (unlikely(err & VM_FAULT_ERROR))			return err;		page = timens_page;		break;	case VDSO_TIMENS_PAGE_OFFSET:		/*		 * If a task belongs to a time namespace then a namespace		 * specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and		 * the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET		 * offset.		 * See also the comment near timens_setup_vdso_data().		 */		if (!IS_ENABLED(CONFIG_TIME_NS) || !timens_page)			break;		page = vdso_data_pages + VDSO_TIME_PAGE_OFFSET;		break;	case VDSO_RNG_PAGE_OFFSET:	case VDSO_ARCH_PAGES_START ... VDSO_ARCH_PAGES_END:		break;	default:		return VM_FAULT_SIGBUS;	} 	get_page(page);	vmf->page = page;	return 0;} const struct vm_special_mapping vdso_vvar_mapping = {	.name	= "[vvar]",	.fault	= vvar_fault,}; struct vm_area_struct *vdso_install_vvar_mapping(struct mm_struct *mm, unsigned long addr){	return _install_special_mapping(mm, addr, VDSO_NR_PAGES * PAGE_SIZE,					VM_READ | VM_MAYREAD | VM_DONTDUMP |					VM_MIXEDMAP | VM_SEALED_SYSMAP,					&vdso_vvar_mapping);}