1 // SPDX-License-Identifier: GPL-2.0
8  * In order to avoid pre-faulting the signal stack memory and to force the
14  * the same mechanism used to avoid pre-faulting the signal stack memory.
44  * Data that will be copied into the faulting pages (instead of zero-filled
48  * paged-in it will contain the expected content.
78 	uf_mem_offset = (uf_mem_offset + pagesize - 1) & ~(pagesize - 1);  in get_uf_mem()
96 		if (poll(&pollfd, 1, -1) == -1) {  in fault_handler_thread()
107 		if (nread == -1) {  in fault_handler_thread()
122 		uffdio_copy.dst = msg.arg.pagefault.address & ~(pagesize-1);  in fault_handler_thread()
124 		offset = (char *) uffdio_copy.dst - uf_mem;  in fault_handler_thread()
130 		if (ioctl(uffd, UFFDIO_COPY, &uffdio_copy) == -1) {  in fault_handler_thread()
131 			perror("ioctl-UFFDIO_COPY failed");  in fault_handler_thread()
149 	if (uffd == -1) {  in setup_uf_mem()
155 	if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) {  in setup_uf_mem()
156 		perror("ioctl-UFFDIO_API failed");  in setup_uf_mem()
161 	 * Create a private anonymous mapping. The memory will be demand-zero  in setup_uf_mem()
166 		      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);  in setup_uf_mem()
175 	 * missing pages (i.e. pages that have not yet been faulted-in).  in setup_uf_mem()
180 	if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {  in setup_uf_mem()
181 		perror("ioctl-UFFDIO_REGISTER");  in setup_uf_mem()
195  * suspended state, i.e. uc->uc_link != NULL.
202 	ucp->uc_link->uc_mcontext.regs->nip += 4;  in signal_handler()
204 	ucp->uc_mcontext.v_regs =  in signal_handler()
205 		get_uf_mem(sizeof(elf_vrreg_t), ucp->uc_mcontext.v_regs);  in signal_handler()
207 	ucp->uc_link->uc_mcontext.v_regs =  in signal_handler()
208 		get_uf_mem(sizeof(elf_vrreg_t), ucp->uc_link->uc_mcontext.v_regs);  in signal_handler()
210 	ucp->uc_link = get_uf_mem(sizeof(ucontext_t), ucp->uc_link);  in signal_handler()
218 	rc = syscall(__NR_userfaultfd, -1);  in have_userfaultfd()
242 	if (sigaltstack(&ss, NULL) == -1) {  in tm_signal_pagefault()
249 	if (sigaction(SIGTRAP, &sa, NULL) == -1) {  in tm_signal_pagefault()