1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/ptrace.h> 8 #include <linux/seccomp.h> 9 #include <kern_util.h> 10 #include <sysdep/ptrace.h> 11 #include <sysdep/ptrace_user.h> 12 #include <sysdep/syscalls.h> 13 #include <linux/time-internal.h> 14 #include <asm/unistd.h> 15 #include <asm/delay.h> 16 17 void handle_syscall(struct uml_pt_regs *r) 18 { 19 struct pt_regs *regs = container_of(r, struct pt_regs, regs); 20 int syscall; 21 22 /* Initialize the syscall number and default return value. */ 23 UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp); 24 PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS); 25 26 if (syscall_trace_enter(regs)) 27 goto out; 28 29 /* Do the seccomp check after ptrace; failures should be fast. */ 30 if (secure_computing() == -1) 31 goto out; 32 33 syscall = UPT_SYSCALL_NR(r); 34 if (syscall >= 0 && syscall < __NR_syscalls) { 35 unsigned long ret = EXECUTE_SYSCALL(syscall, regs); 36 37 PT_REGS_SET_SYSCALL_RETURN(regs, ret); 38 39 /* 40 * An error value here can be some form of -ERESTARTSYS 41 * and then we'd just loop. Make any error syscalls take 42 * some time, so that it won't just loop if something is 43 * not ready, and hopefully other things will make some 44 * progress. 45 */ 46 if (IS_ERR_VALUE(ret) && 47 (time_travel_mode == TT_MODE_INFCPU || 48 time_travel_mode == TT_MODE_EXTERNAL)) { 49 um_udelay(1); 50 schedule(); 51 } 52 } 53 54 out: 55 syscall_trace_leave(regs); 56 } 57