1 // SPDX-License-Identifier: GPL-2.0-only
3  * sigreturn.c - tests that x86 avoids Intel SYSRET pitfalls
4  * Copyright (c) 2014-2016 Andrew Lutomirski
30 	".fill 4094,1,0xcc\n\t"
33 	".ifne . - test_page - 4096\n\t"
51 		err(1, "sigaction");  in sethandler()
61 		err(1, "sigaction");  in clearhandler()
73 	if (rip != ctx->uc_mcontext.gregs[REG_RIP]) {  in sigsegv_for_sigreturn_test()
75 		       rip, (unsigned long)ctx->uc_mcontext.gregs[REG_RIP]);  in sigsegv_for_sigreturn_test()
77 		_exit(1);  in sigsegv_for_sigreturn_test()
80 	memcpy(&ctx->uc_mcontext.gregs, &initial_regs, sizeof(gregset_t));  in sigsegv_for_sigreturn_test()
89 	memcpy(&initial_regs, &ctx->uc_mcontext.gregs, sizeof(gregset_t));  in sigusr1()
92 	ctx->uc_mcontext.gregs[REG_RIP] = rip;  in sigusr1()
93 	ctx->uc_mcontext.gregs[REG_RCX] = rip;  in sigusr1()
96 	assert(ctx->uc_mcontext.gregs[REG_EFL] ==  in sigusr1()
97 	       ctx->uc_mcontext.gregs[REG_R11]);  in sigusr1()
117 	if (rip != ctx->uc_mcontext.gregs[REG_RIP]) {  in sigsegv_for_fallthrough()
119 		       rip, (unsigned long)ctx->uc_mcontext.gregs[REG_RIP]);  in sigsegv_for_fallthrough()
121 		_exit(1);  in sigsegv_for_fallthrough()
124 	siglongjmp(jmpbuf, 1);  in sigsegv_for_fallthrough()
129 	void *new_address = (void *)(ip - 4096);  in test_syscall_fallthrough_to()
137 		if (ip <= (1UL << 47) - PAGE_SIZE) {  in test_syscall_fallthrough_to()
138 			err(1, "mremap to %p", new_address);  in test_syscall_fallthrough_to()
146 		errx(1, "mremap malfunctioned: asked for %p but got %p\n",  in test_syscall_fallthrough_to()
152 	if (sigsetjmp(jmpbuf, 1) == 0) {  in test_syscall_fallthrough_to()
154 			      [syscall_insn] "rm" (ip - 2));  in test_syscall_fallthrough_to()
155 		errx(1, "[FAIL]\tSyscall trampoline returned");  in test_syscall_fallthrough_to()
164 	 * When the kernel returns from a slow-path syscall, it will  in main()
170 	for (int i = 47; i < 64; i++)  in main()
171 		test_sigreturn_to(1UL<<i);  in main()
178 	test_syscall_fallthrough_to((1UL << 47) - 2*PAGE_SIZE);  in main()
181 	for (int i = 47; i < 64; i++) {  in main()
182 		test_syscall_fallthrough_to((1UL<<i) - PAGE_SIZE);  in main()
183 		test_syscall_fallthrough_to(1UL<<i);  in main()