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 | |
16 | void handle_syscall(struct uml_pt_regs *r) |
17 | { |
18 | struct pt_regs *regs = container_of(r, struct pt_regs, regs); |
19 | int syscall; |
20 | |
21 | /* |
22 | * If we have infinite CPU resources, then make every syscall also a |
23 | * preemption point, since we don't have any other preemption in this |
24 | * case, and kernel threads would basically never run until userspace |
25 | * went to sleep, even if said userspace interacts with the kernel in |
26 | * various ways. |
27 | */ |
28 | if (time_travel_mode == TT_MODE_INFCPU || |
29 | time_travel_mode == TT_MODE_EXTERNAL) |
30 | schedule(); |
31 | |
32 | /* Initialize the syscall number and default return value. */ |
33 | UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp); |
34 | PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS); |
35 | |
36 | if (syscall_trace_enter(regs)) |
37 | goto out; |
38 | |
39 | /* Do the seccomp check after ptrace; failures should be fast. */ |
40 | if (secure_computing() == -1) |
41 | goto out; |
42 | |
43 | syscall = UPT_SYSCALL_NR(r); |
44 | if (syscall >= 0 && syscall < __NR_syscalls) |
45 | PT_REGS_SET_SYSCALL_RETURN(regs, |
46 | EXECUTE_SYSCALL(syscall, regs)); |
47 | |
48 | out: |
49 | syscall_trace_leave(regs); |
50 | } |
51 | |