arch/um/kernel/tt/syscall_user.c

   1 /*
   2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <unistd.h>
   7 #include <signal.h>
   8 #include <errno.h>
   9 #include <asm/unistd.h>
  10 #include "sysdep/ptrace.h"
  11 #include "sigcontext.h"
  12 #include "ptrace_user.h"
  13 #include "task.h"
  14 #include "user_util.h"
  15 #include "kern_util.h"
  16 #include "syscall_user.h"
  17 #include "tt.h"
  18
  19
  20 void syscall_handler_tt(int sig, union uml_pt_regs *regs)
  21 {
  22         void *sc;
  23         long result;
  24         int syscall;
  25 #ifdef UML_CONFIG_DEBUG_SYSCALL
  26         int index;
  27 #endif
  28
  29         syscall = UPT_SYSCALL_NR(regs);
  30         sc = UPT_SC(regs);
  31         SC_START_SYSCALL(sc);
  32
  33 #ifdef UML_CONFIG_DEBUG_SYSCALL
  34         index = record_syscall_start(syscall);
  35 #endif
  36         syscall_trace(regs, 0);
  37         result = execute_syscall_tt(regs);
  38
  39         /* regs->sc may have changed while the system call ran (there may
  40          * have been an interrupt or segfault), so it needs to be refreshed.
  41          */
  42         UPT_SC(regs) = sc;
  43
  44         SC_SET_SYSCALL_RETURN(sc, result);
  45
  46         syscall_trace(regs, 1);
  47 #ifdef UML_CONFIG_DEBUG_SYSCALL
  48         record_syscall_end(index, result);
  49 #endif
  50 }
  51
  52 void do_sigtrap(void *task)
  53 {
  54         UPT_SYSCALL_NR(TASK_REGS(task)) = -1;
  55 }
  56
  57 void do_syscall(void *task, int pid, int local_using_sysemu)
  58 {
  59         unsigned long proc_regs[FRAME_SIZE];
  60
  61         if(ptrace_getregs(pid, proc_regs) < 0)
  62                 tracer_panic("Couldn't read registers");
  63
  64         UPT_SYSCALL_NR(TASK_REGS(task)) = PT_SYSCALL_NR(proc_regs);
  65
  66         if(((unsigned long *) PT_IP(proc_regs) >= &_stext) &&
  67            ((unsigned long *) PT_IP(proc_regs) <= &_etext))
  68                 tracer_panic("I'm tracing myself and I can't get out");
  69
  70         /* advanced sysemu mode set syscall number to -1 automatically */
  71         if (local_using_sysemu==2)
  72                 return;
  73
  74         /* syscall number -1 in sysemu skips syscall restarting in host */
  75         if(ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
  76                   local_using_sysemu ? -1 : __NR_getpid) < 0)
  77                 tracer_panic("do_syscall : Nullifying syscall failed, "
  78                              "errno = %d", errno);
  79 }
  80
  81 /*
  82  * Overrides for Emacs so that we follow Linus's tabbing style.
  83  * Emacs will notice this stuff at the end of the file and automatically
  84  * adjust the settings for this buffer only.  This must remain at the end
  85  * of the file.
  86  * ---------------------------------------------------------------------------
  87  * Local variables:
  88  * c-file-style: "linux"
  89  * End:
  90  */