arch/um/kernel/skas/syscall.c

   1 /*
   2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   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
  14 void handle_syscall(struct uml_pt_regs *r)
  15 {
  16         struct pt_regs *regs = container_of(r, struct pt_regs, regs);
  17         int syscall;
  18
  19         /* Initialize the syscall number and default return value. */
  20         UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);
  21         PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS);
  22
  23         if (syscall_trace_enter(regs))
  24                 return;
  25
  26         /* Do the seccomp check after ptrace; failures should be fast. */
  27         if (secure_computing(NULL) == -1)
  28                 return;
  29
  30         /* Update the syscall number after orig_ax has potentially been updated
  31          * with ptrace.
  32          */
  33         UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);
  34         syscall = UPT_SYSCALL_NR(r);
  35
  36         if (syscall >= 0 && syscall <= __NR_syscall_max)
  37                 PT_REGS_SET_SYSCALL_RETURN(regs,
  38                                 EXECUTE_SYSCALL(syscall, regs));
  39
  40         syscall_trace_leave(regs);
  41 }