Line data    Source code

       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           0 : void handle_syscall(struct uml_pt_regs *r)
      17             : {
      18           0 :         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           0 :         UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);
      34           0 :         PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS);
      35             : 
      36           0 :         if (syscall_trace_enter(regs))
      37             :                 goto out;
      38             : 
      39             :         /* Do the seccomp check after ptrace; failures should be fast. */
      40           0 :         if (secure_computing() == -1)
      41             :                 goto out;
      42             : 
      43           0 :         syscall = UPT_SYSCALL_NR(r);
      44           0 :         if (syscall >= 0 && syscall < __NR_syscalls)
      45           0 :                 PT_REGS_SET_SYSCALL_RETURN(regs,
      46             :                                 EXECUTE_SYSCALL(syscall, regs));
      47             : 
      48             : out:
      49           0 :         syscall_trace_leave(regs);
      50           0 : }