12025cf9eSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2a9c909ceSAndy Lutomirski /* 3a9c909ceSAndy Lutomirski * syscall_nt.c - checks syscalls with NT set 4a9c909ceSAndy Lutomirski * Copyright (c) 2014-2015 Andrew Lutomirski 5a9c909ceSAndy Lutomirski * 6a9c909ceSAndy Lutomirski * Some obscure user-space code requires the ability to make system calls 7a9c909ceSAndy Lutomirski * with FLAGS.NT set. Make sure it works. 8a9c909ceSAndy Lutomirski */ 9a9c909ceSAndy Lutomirski 10a9c909ceSAndy Lutomirski #include <stdio.h> 11a9c909ceSAndy Lutomirski #include <unistd.h> 12a318beeaSAndy Lutomirski #include <string.h> 13a318beeaSAndy Lutomirski #include <signal.h> 14a318beeaSAndy Lutomirski #include <err.h> 15a9c909ceSAndy Lutomirski #include <sys/syscall.h> 16a9c909ceSAndy Lutomirski 17cced0b24SAndy Lutomirski #include "helpers.h" 18a9c909ceSAndy Lutomirski 19a318beeaSAndy Lutomirski static unsigned int nerrs; 20a318beeaSAndy Lutomirski 21a318beeaSAndy Lutomirski static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), 22a318beeaSAndy Lutomirski int flags) 23a318beeaSAndy Lutomirski { 24a318beeaSAndy Lutomirski struct sigaction sa; 25a318beeaSAndy Lutomirski memset(&sa, 0, sizeof(sa)); 26a318beeaSAndy Lutomirski sa.sa_sigaction = handler; 27a318beeaSAndy Lutomirski sa.sa_flags = SA_SIGINFO | flags; 28a318beeaSAndy Lutomirski sigemptyset(&sa.sa_mask); 29a318beeaSAndy Lutomirski if (sigaction(sig, &sa, 0)) 30a318beeaSAndy Lutomirski err(1, "sigaction"); 31a318beeaSAndy Lutomirski } 32a318beeaSAndy Lutomirski 33a318beeaSAndy Lutomirski static void sigtrap(int sig, siginfo_t *si, void *ctx_void) 34a318beeaSAndy Lutomirski { 35a318beeaSAndy Lutomirski } 36a318beeaSAndy Lutomirski 37a318beeaSAndy Lutomirski static void do_it(unsigned long extraflags) 38a318beeaSAndy Lutomirski { 39a318beeaSAndy Lutomirski unsigned long flags; 40a318beeaSAndy Lutomirski 41a318beeaSAndy Lutomirski set_eflags(get_eflags() | extraflags); 42a318beeaSAndy Lutomirski syscall(SYS_getpid); 43a318beeaSAndy Lutomirski flags = get_eflags(); 44a61fa279SAndy Lutomirski set_eflags(X86_EFLAGS_IF | X86_EFLAGS_FIXED); 45a318beeaSAndy Lutomirski if ((flags & extraflags) == extraflags) { 46a318beeaSAndy Lutomirski printf("[OK]\tThe syscall worked and flags are still set\n"); 47a318beeaSAndy Lutomirski } else { 48a318beeaSAndy Lutomirski printf("[FAIL]\tThe syscall worked but flags were cleared (flags = 0x%lx but expected 0x%lx set)\n", 49a318beeaSAndy Lutomirski flags, extraflags); 50a318beeaSAndy Lutomirski nerrs++; 51a318beeaSAndy Lutomirski } 52a318beeaSAndy Lutomirski } 53a318beeaSAndy Lutomirski 54a318beeaSAndy Lutomirski int main(void) 55a9c909ceSAndy Lutomirski { 56a9c909ceSAndy Lutomirski printf("[RUN]\tSet NT and issue a syscall\n"); 57a318beeaSAndy Lutomirski do_it(X86_EFLAGS_NT); 58a318beeaSAndy Lutomirski 59e4ef7de1SAndy Lutomirski printf("[RUN]\tSet AC and issue a syscall\n"); 60e4ef7de1SAndy Lutomirski do_it(X86_EFLAGS_AC); 61e4ef7de1SAndy Lutomirski 62e4ef7de1SAndy Lutomirski printf("[RUN]\tSet NT|AC and issue a syscall\n"); 63e4ef7de1SAndy Lutomirski do_it(X86_EFLAGS_NT | X86_EFLAGS_AC); 64e4ef7de1SAndy Lutomirski 65a318beeaSAndy Lutomirski /* 66a318beeaSAndy Lutomirski * Now try it again with TF set -- TF forces returns via IRET in all 67a318beeaSAndy Lutomirski * cases except non-ptregs-using 64-bit full fast path syscalls. 68a318beeaSAndy Lutomirski */ 69a318beeaSAndy Lutomirski 70a318beeaSAndy Lutomirski sethandler(SIGTRAP, sigtrap, 0); 71a318beeaSAndy Lutomirski 72e4ef7de1SAndy Lutomirski printf("[RUN]\tSet TF and issue a syscall\n"); 73e4ef7de1SAndy Lutomirski do_it(X86_EFLAGS_TF); 74e4ef7de1SAndy Lutomirski 75a318beeaSAndy Lutomirski printf("[RUN]\tSet NT|TF and issue a syscall\n"); 76a318beeaSAndy Lutomirski do_it(X86_EFLAGS_NT | X86_EFLAGS_TF); 77a318beeaSAndy Lutomirski 78e4ef7de1SAndy Lutomirski printf("[RUN]\tSet AC|TF and issue a syscall\n"); 79e4ef7de1SAndy Lutomirski do_it(X86_EFLAGS_AC | X86_EFLAGS_TF); 80e4ef7de1SAndy Lutomirski 81e4ef7de1SAndy Lutomirski printf("[RUN]\tSet NT|AC|TF and issue a syscall\n"); 82e4ef7de1SAndy Lutomirski do_it(X86_EFLAGS_NT | X86_EFLAGS_AC | X86_EFLAGS_TF); 83e4ef7de1SAndy Lutomirski 84a318beeaSAndy Lutomirski return nerrs == 0 ? 0 : 1; 85a9c909ceSAndy Lutomirski } 86