xref: /external/valgrind/main/coregrind/m_syswrap/syswrap-amd64-linux.c

/*--------------------------------------------------------------------*/
/*--- Platform-specific syscalls stuff.      syswrap-amd64-linux.c ---*/
/*--------------------------------------------------------------------*/

/*
   This file is part of Valgrind, a dynamic binary instrumentation
   framework.

   Copyright (C) 2000-2013 Nicholas Nethercote
      njn@valgrind.org

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file COPYING.
*/

#if defined(VGP_amd64_linux)

#include "pub_core_basics.h"
#include "pub_core_vki.h"
#include "pub_core_vkiscnums.h"
#include "pub_core_libcsetjmp.h"    // to keep _threadstate.h happy
#include "pub_core_threadstate.h"
#include "pub_core_aspacemgr.h"
#include "pub_core_debuglog.h"
#include "pub_core_options.h"
#include "pub_core_libcbase.h"
#include "pub_core_libcassert.h"
#include "pub_core_libcprint.h"
#include "pub_core_libcproc.h"
#include "pub_core_libcsignal.h"
#include "pub_core_scheduler.h"
#include "pub_core_sigframe.h"
#include "pub_core_signals.h"
#include "pub_core_syscall.h"
#include "pub_core_syswrap.h"
#include "pub_core_tooliface.h"
#include "pub_core_stacks.h"        // VG_(register_stack)

#include "priv_types_n_macros.h"
#include "priv_syswrap-generic.h"   /* for decls of generic wrappers */
#include "priv_syswrap-linux.h"     /* for decls of linux-ish wrappers */
#include "priv_syswrap-linux-variants.h" /* decls of linux variant wrappers */
#include "priv_syswrap-main.h"


/* ---------------------------------------------------------------------
   clone() handling
   ------------------------------------------------------------------ */

/* Call f(arg1), but first switch stacks, using 'stack' as the new
   stack, and use 'retaddr' as f's return-to address.  Also, clear all
   the integer registers before entering f.  */
__attribute__((noreturn))
void ML_(call_on_new_stack_0_1) ( Addr stack,
			          Addr retaddr,
			          void (*f)(Word),
                                  Word arg1 );
// %rdi == stack
// %rsi == retaddr
// %rdx == f
// %rcx == arg1
asm(
".text\n"
".globl vgModuleLocal_call_on_new_stack_0_1\n"
"vgModuleLocal_call_on_new_stack_0_1:\n"
"   movq   %rdi, %rsp\n"   // set stack
"   pushq  %rsi\n"         // retaddr to stack
"   pushq  %rdx\n"         // f to stack
"   pushq  %rcx\n"         // arg1 to stack
"   movq $0, %rax\n"       // zero all GP regs
"   movq $0, %rbx\n"
"   movq $0, %rcx\n"
"   movq $0, %rdx\n"
"   movq $0, %rsi\n"
"   movq $0, %rdi\n"
"   movq $0, %rbp\n"
"   movq $0, %r8\n"
"   movq $0, %r9\n"
"   movq $0, %r10\n"
"   movq $0, %r11\n"
"   movq $0, %r12\n"
"   movq $0, %r13\n"
"   movq $0, %r14\n"
"   movq $0, %r15\n"
"   popq   %rdi\n"         // arg1 to correct arg reg
"   ret\n"                 // jump to f
"   ud2\n"                 // should never get here
".previous\n"
);

/*
        Perform a clone system call.  clone is strange because it has
        fork()-like return-twice semantics, so it needs special
        handling here.

	Upon entry, we have:

	    int (*fn)(void*)	in %rdi
	    void*  child_stack	in %rsi
	    int    flags	in %rdx
	    void*  arg		in %rcx
	    pid_t* child_tid	in %r8
	    pid_t* parent_tid	in %r9
	    void*  tls_ptr      at 8(%rsp)

	System call requires:

	    int    $__NR_clone  in %rax
	    int    flags	in %rdi
	    void*  child_stack	in %rsi
	    pid_t* parent_tid	in %rdx
	    pid_t* child_tid	in %r10
	    void*  tls_ptr      in %r8

	Returns a Long encoded in the linux-amd64 way, not a SysRes.
 */
#define __NR_CLONE        VG_STRINGIFY(__NR_clone)
#define __NR_EXIT         VG_STRINGIFY(__NR_exit)

extern
Long do_syscall_clone_amd64_linux ( Word (*fn)(void *),
                                    void* stack,
                                    Long  flags,
                                    void* arg,
                                    Long* child_tid,
                                    Long* parent_tid,
                                    vki_modify_ldt_t * );
asm(
".text\n"
".globl do_syscall_clone_amd64_linux\n"
"do_syscall_clone_amd64_linux:\n"
        // set up child stack, temporarily preserving fn and arg
"       subq    $16, %rsi\n"            // make space on stack
"       movq    %rcx, 8(%rsi)\n"        // save arg
"       movq    %rdi, 0(%rsi)\n"        // save fn

        // setup syscall
"       movq    $"__NR_CLONE", %rax\n"  // syscall number
"       movq    %rdx,     %rdi\n"       // syscall arg1: flags
        // %rsi already setup           // syscall arg2: child_stack
"       movq    %r9,      %rdx\n"       // syscall arg3: parent_tid
"       movq    %r8,      %r10\n"       // syscall arg4: child_tid
"       movq    8(%rsp),  %r8\n"        // syscall arg5: tls_ptr

"       syscall\n"                      // clone()

"       testq   %rax, %rax\n"           // child if retval == 0
"       jnz     1f\n"

        // CHILD - call thread function
"       pop     %rax\n"                 // pop fn
"       pop     %rdi\n"                 // pop fn arg1: arg
"       call    *%rax\n"                // call fn

        // exit with result
"       movq    %rax, %rdi\n"           // arg1: return value from fn
"       movq    $"__NR_EXIT", %rax\n"

"       syscall\n"

        // Exit returned?!
"       ud2\n"

"1:\n"  // PARENT or ERROR
"       ret\n"
".previous\n"
);

#undef __NR_CLONE
#undef __NR_EXIT


// forward declaration
static void setup_child ( ThreadArchState*, ThreadArchState* );

/*
   When a client clones, we need to keep track of the new thread.  This means:
   1. allocate a ThreadId+ThreadState+stack for the the thread

   2. initialize the thread's new VCPU state

   3. create the thread using the same args as the client requested,
   but using the scheduler entrypoint for EIP, and a separate stack
   for ESP.
 */
static SysRes do_clone ( ThreadId ptid,
                         ULong flags, Addr rsp,
                         Long* parent_tidptr,
                         Long* child_tidptr,
                         Addr tlsaddr )
{
   static const Bool debug = False;

   ThreadId     ctid = VG_(alloc_ThreadState)();
   ThreadState* ptst = VG_(get_ThreadState)(ptid);
   ThreadState* ctst = VG_(get_ThreadState)(ctid);
   UWord*       stack;
   NSegment const* seg;
   SysRes       res;
   Long         rax;
   vki_sigset_t blockall, savedmask;

   VG_(sigfillset)(&blockall);

   vg_assert(VG_(is_running_thread)(ptid));
   vg_assert(VG_(is_valid_tid)(ctid));

   stack = (UWord*)ML_(allocstack)(ctid);
   if (stack == NULL) {
      res = VG_(mk_SysRes_Error)( VKI_ENOMEM );
      goto out;
   }

   /* Copy register state

      Both parent and child return to the same place, and the code
      following the clone syscall works out which is which, so we
      don't need to worry about it.

      The parent gets the child's new tid returned from clone, but the
      child gets 0.

      If the clone call specifies a NULL rsp for the new thread, then
      it actually gets a copy of the parent's rsp.
   */
   setup_child( &ctst->arch, &ptst->arch );

   /* Make sys_clone appear to have returned Success(0) in the
      child. */
   ctst->arch.vex.guest_RAX = 0;

   if (rsp != 0)
      ctst->arch.vex.guest_RSP = rsp;

   ctst->os_state.parent = ptid;

   /* inherit signal mask */
   ctst->sig_mask = ptst->sig_mask;
   ctst->tmp_sig_mask = ptst->sig_mask;

   /* Start the child with its threadgroup being the same as the
      parent's.  This is so that any exit_group calls that happen
      after the child is created but before it sets its
      os_state.threadgroup field for real (in thread_wrapper in
      syswrap-linux.c), really kill the new thread.  a.k.a this avoids
      a race condition in which the thread is unkillable (via
      exit_group) because its threadgroup is not set.  The race window
      is probably only a few hundred or a few thousand cycles long.
      See #226116. */
   ctst->os_state.threadgroup = ptst->os_state.threadgroup;

   /* We don't really know where the client stack is, because its
      allocated by the client.  The best we can do is look at the
      memory mappings and try to derive some useful information.  We
      assume that esp starts near its highest possible value, and can
      only go down to the start of the mmaped segment. */
   seg = VG_(am_find_nsegment)((Addr)rsp);
   if (seg && seg->kind != SkResvn) {
      ctst->client_stack_highest_word = (Addr)VG_PGROUNDUP(rsp);
      ctst->client_stack_szB = ctst->client_stack_highest_word - seg->start;

      VG_(register_stack)(seg->start, ctst->client_stack_highest_word);

      if (debug)
	 VG_(printf)("tid %d: guessed client stack range %#lx-%#lx\n",
		     ctid, seg->start, VG_PGROUNDUP(rsp));
   } else {
      VG_(message)(Vg_UserMsg,
                   "!? New thread %d starts with RSP(%#lx) unmapped\n",
		   ctid, rsp);
      ctst->client_stack_szB  = 0;
   }

   /* Assume the clone will succeed, and tell any tool that wants to
      know that this thread has come into existence.  If the clone
      fails, we'll send out a ll_exit notification for it at the out:
      label below, to clean up. */
   vg_assert(VG_(owns_BigLock_LL)(ptid));
   VG_TRACK ( pre_thread_ll_create, ptid, ctid );

   if (flags & VKI_CLONE_SETTLS) {
      if (debug)
	 VG_(printf)("clone child has SETTLS: tls at %#lx\n", tlsaddr);
      ctst->arch.vex.guest_FS_ZERO = tlsaddr;
   }

   flags &= ~VKI_CLONE_SETTLS;

   /* start the thread with everything blocked */
   VG_(sigprocmask)(VKI_SIG_SETMASK, &blockall, &savedmask);

   /* Create the new thread */
   rax = do_syscall_clone_amd64_linux(
            ML_(start_thread_NORETURN), stack, flags, &VG_(threads)[ctid],
            child_tidptr, parent_tidptr, NULL
         );
   res = VG_(mk_SysRes_amd64_linux)( rax );

   VG_(sigprocmask)(VKI_SIG_SETMASK, &savedmask, NULL);

  out:
   if (sr_isError(res)) {
      /* clone failed */
      VG_(cleanup_thread)(&ctst->arch);
      ctst->status = VgTs_Empty;
      /* oops.  Better tell the tool the thread exited in a hurry :-) */
      VG_TRACK( pre_thread_ll_exit, ctid );
   }

   return res;
}


/* ---------------------------------------------------------------------
   More thread stuff
   ------------------------------------------------------------------ */

void VG_(cleanup_thread) ( ThreadArchState *arch )
{
}

void setup_child ( /*OUT*/ ThreadArchState *child,
                   /*IN*/  ThreadArchState *parent )
{
   /* We inherit our parent's guest state. */
   child->vex = parent->vex;
   child->vex_shadow1 = parent->vex_shadow1;
   child->vex_shadow2 = parent->vex_shadow2;
}


/* ---------------------------------------------------------------------
   PRE/POST wrappers for AMD64/Linux-specific syscalls
   ------------------------------------------------------------------ */

#define PRE(name)       DEFN_PRE_TEMPLATE(amd64_linux, name)
#define POST(name)      DEFN_POST_TEMPLATE(amd64_linux, name)

/* Add prototypes for the wrappers declared here, so that gcc doesn't
   harass us for not having prototypes.  Really this is a kludge --
   the right thing to do is to make these wrappers 'static' since they
   aren't visible outside this file, but that requires even more macro
   magic. */
DECL_TEMPLATE(amd64_linux, sys_clone);
DECL_TEMPLATE(amd64_linux, sys_rt_sigreturn);
DECL_TEMPLATE(amd64_linux, sys_arch_prctl);
DECL_TEMPLATE(amd64_linux, sys_ptrace);
DECL_TEMPLATE(amd64_linux, sys_fadvise64);
DECL_TEMPLATE(amd64_linux, sys_mmap);
DECL_TEMPLATE(amd64_linux, sys_syscall184);


PRE(sys_clone)
{
   ULong cloneflags;

   PRINT("sys_clone ( %lx, %#lx, %#lx, %#lx, %#lx )",ARG1,ARG2,ARG3,ARG4,ARG5);
   PRE_REG_READ2(int, "clone",
                 unsigned long, flags,
                 void *, child_stack);

   if (ARG1 & VKI_CLONE_PARENT_SETTID) {
      if (VG_(tdict).track_pre_reg_read) {
         PRA3("clone", int *, parent_tidptr);
      }
      PRE_MEM_WRITE("clone(parent_tidptr)", ARG3, sizeof(Int));
      if (!VG_(am_is_valid_for_client)(ARG3, sizeof(Int), VKI_PROT_WRITE)) {
         SET_STATUS_Failure( VKI_EFAULT );
         return;
      }
   }
   if (ARG1 & VKI_CLONE_SETTLS) {
      if (VG_(tdict).track_pre_reg_read) {
         PRA4("clone", vki_modify_ldt_t *, tlsinfo);
      }
      PRE_MEM_READ("clone(tlsinfo)", ARG4, sizeof(vki_modify_ldt_t));
      if (!VG_(am_is_valid_for_client)(ARG4, sizeof(vki_modify_ldt_t),
                                             VKI_PROT_READ)) {
         SET_STATUS_Failure( VKI_EFAULT );
         return;
      }
   }
   if (ARG1 & (VKI_CLONE_CHILD_SETTID | VKI_CLONE_CHILD_CLEARTID)) {
      if (VG_(tdict).track_pre_reg_read) {
         PRA5("clone", int *, child_tidptr);
      }
      PRE_MEM_WRITE("clone(child_tidptr)", ARG4, sizeof(Int));
      if (!VG_(am_is_valid_for_client)(ARG4, sizeof(Int), VKI_PROT_WRITE)) {
         SET_STATUS_Failure( VKI_EFAULT );
         return;
      }
   }

   cloneflags = ARG1;

   if (!ML_(client_signal_OK)(ARG1 & VKI_CSIGNAL)) {
      SET_STATUS_Failure( VKI_EINVAL );
      return;
   }

   /* Only look at the flags we really care about */
   switch (cloneflags & (VKI_CLONE_VM | VKI_CLONE_FS
                         | VKI_CLONE_FILES | VKI_CLONE_VFORK)) {
   case VKI_CLONE_VM | VKI_CLONE_FS | VKI_CLONE_FILES:
      /* thread creation */
      SET_STATUS_from_SysRes(
         do_clone(tid,
                  ARG1,          /* flags */
                  (Addr)ARG2,    /* child ESP */
                  (Long *)ARG3,  /* parent_tidptr */
                  (Long *)ARG4,  /* child_tidptr */
                  (Addr)ARG5));  /* set_tls */
      break;

   case VKI_CLONE_VFORK | VKI_CLONE_VM: /* vfork */
      /* FALLTHROUGH - assume vfork == fork */
      cloneflags &= ~(VKI_CLONE_VFORK | VKI_CLONE_VM);

   case 0: /* plain fork */
      SET_STATUS_from_SysRes(
         ML_(do_fork_clone)(tid,
                       cloneflags,      /* flags */
                       (Int *)ARG3,     /* parent_tidptr */
                       (Int *)ARG4));   /* child_tidptr */
      break;

   default:
      /* should we just ENOSYS? */
      VG_(message)(Vg_UserMsg,
                   "Unsupported clone() flags: 0x%lx\n", ARG1);
      VG_(message)(Vg_UserMsg,
                   "\n");
      VG_(message)(Vg_UserMsg,
                   "The only supported clone() uses are:\n");
      VG_(message)(Vg_UserMsg,
                   " - via a threads library (LinuxThreads or NPTL)\n");
      VG_(message)(Vg_UserMsg,
                   " - via the implementation of fork or vfork\n");
      VG_(unimplemented)
         ("Valgrind does not support general clone().");
   }

   if (SUCCESS) {
      if (ARG1 & VKI_CLONE_PARENT_SETTID)
         POST_MEM_WRITE(ARG3, sizeof(Int));
      if (ARG1 & (VKI_CLONE_CHILD_SETTID | VKI_CLONE_CHILD_CLEARTID))
         POST_MEM_WRITE(ARG4, sizeof(Int));

      /* Thread creation was successful; let the child have the chance
         to run */
      *flags |= SfYieldAfter;
   }
}

PRE(sys_rt_sigreturn)
{
   /* This isn't really a syscall at all - it's a misuse of the
      syscall mechanism by m_sigframe.  VG_(sigframe_create) sets the
      return address of the signal frames it creates to be a short
      piece of code which does this "syscall".  The only purpose of
      the syscall is to call VG_(sigframe_destroy), which restores the
      thread's registers from the frame and then removes it.
      Consequently we must ask the syswrap driver logic not to write
      back the syscall "result" as that would overwrite the
      just-restored register state. */

   ThreadState* tst;
   PRINT("sys_rt_sigreturn ( )");

   vg_assert(VG_(is_valid_tid)(tid));
   vg_assert(tid >= 1 && tid < VG_N_THREADS);
   vg_assert(VG_(is_running_thread)(tid));

   /* Adjust RSP to point to start of frame; skip back up over handler
      ret addr */
   tst = VG_(get_ThreadState)(tid);
   tst->arch.vex.guest_RSP -= sizeof(Addr);

   /* This is only so that the RIP is (might be) useful to report if
      something goes wrong in the sigreturn.  JRS 20070318: no idea
      what this is for */
   ML_(fixup_guest_state_to_restart_syscall)(&tst->arch);

   /* Restore register state from frame and remove it, as
      described above */
   VG_(sigframe_destroy)(tid, True);

   /* Tell the driver not to update the guest state with the "result",
      and set a bogus result to keep it happy. */
   *flags |= SfNoWriteResult;
   SET_STATUS_Success(0);

   /* Check to see if any signals arose as a result of this. */
   *flags |= SfPollAfter;
}

PRE(sys_arch_prctl)
{
   ThreadState* tst;
   PRINT( "arch_prctl ( %ld, %lx )", ARG1, ARG2 );

   vg_assert(VG_(is_valid_tid)(tid));
   vg_assert(tid >= 1 && tid < VG_N_THREADS);
   vg_assert(VG_(is_running_thread)(tid));

   // Nb: can't use "ARG2".."ARG5" here because that's our own macro...
   PRE_REG_READ2(long, "arch_prctl",
                 int, option, unsigned long, arg2);
   // XXX: totally wrong... we need to look at the 'option' arg, and do
   // PRE_MEM_READs/PRE_MEM_WRITEs as necessary...

   /* "do" the syscall ourselves; the kernel never sees it */
   if (ARG1 == VKI_ARCH_SET_FS) {
      tst = VG_(get_ThreadState)(tid);
      tst->arch.vex.guest_FS_ZERO = ARG2;
   }
   else if (ARG1 == VKI_ARCH_GET_FS) {
      PRE_MEM_WRITE("arch_prctl(addr)", ARG2, sizeof(unsigned long));
      tst = VG_(get_ThreadState)(tid);
      *(unsigned long *)ARG2 = tst->arch.vex.guest_FS_ZERO;
      POST_MEM_WRITE(ARG2, sizeof(unsigned long));
   }
   else {
      VG_(core_panic)("Unsupported arch_prtctl option");
   }

   /* Note; the Status writeback to guest state that happens after
      this wrapper returns does not change guest_FS_ZERO; hence that
      direct assignment to the guest state is safe here. */
   SET_STATUS_Success( 0 );
}

// Parts of this are amd64-specific, but the *PEEK* cases are generic.
//
// ARG3 is only used for pointers into the traced process's address
// space and for offsets into the traced process's struct
// user_regs_struct. It is never a pointer into this process's memory
// space, and we should therefore not check anything it points to.
PRE(sys_ptrace)
{
   PRINT("sys_ptrace ( %ld, %ld, %#lx, %#lx )", ARG1,ARG2,ARG3,ARG4);
   PRE_REG_READ4(int, "ptrace",
                 long, request, long, pid, long, addr, long, data);
   switch (ARG1) {
   case VKI_PTRACE_PEEKTEXT:
   case VKI_PTRACE_PEEKDATA:
   case VKI_PTRACE_PEEKUSR:
      PRE_MEM_WRITE( "ptrace(peek)", ARG4,
		     sizeof (long));
      break;
   case VKI_PTRACE_GETREGS:
      PRE_MEM_WRITE( "ptrace(getregs)", ARG4,
		     sizeof (struct vki_user_regs_struct));
      break;
   case VKI_PTRACE_GETFPREGS:
      PRE_MEM_WRITE( "ptrace(getfpregs)", ARG4,
		     sizeof (struct vki_user_i387_struct));
      break;
   case VKI_PTRACE_SETREGS:
      PRE_MEM_READ( "ptrace(setregs)", ARG4,
		     sizeof (struct vki_user_regs_struct));
      break;
   case VKI_PTRACE_SETFPREGS:
      PRE_MEM_READ( "ptrace(setfpregs)", ARG4,
		     sizeof (struct vki_user_i387_struct));
      break;
   case VKI_PTRACE_GETEVENTMSG:
      PRE_MEM_WRITE( "ptrace(geteventmsg)", ARG4, sizeof(unsigned long));
      break;
   case VKI_PTRACE_GETSIGINFO:
      PRE_MEM_WRITE( "ptrace(getsiginfo)", ARG4, sizeof(vki_siginfo_t));
      break;
   case VKI_PTRACE_SETSIGINFO:
      PRE_MEM_READ( "ptrace(setsiginfo)", ARG4, sizeof(vki_siginfo_t));
      break;
   case VKI_PTRACE_GETREGSET:
      ML_(linux_PRE_getregset)(tid, ARG3, ARG4);
      break;
   case VKI_PTRACE_SETREGSET:
      ML_(linux_PRE_setregset)(tid, ARG3, ARG4);
      break;
   default:
      break;
   }
}

POST(sys_ptrace)
{
   switch (ARG1) {
   case VKI_PTRACE_PEEKTEXT:
   case VKI_PTRACE_PEEKDATA:
   case VKI_PTRACE_PEEKUSR:
      POST_MEM_WRITE( ARG4, sizeof (long));
      break;
   case VKI_PTRACE_GETREGS:
      POST_MEM_WRITE( ARG4, sizeof (struct vki_user_regs_struct));
      break;
   case VKI_PTRACE_GETFPREGS:
      POST_MEM_WRITE( ARG4, sizeof (struct vki_user_i387_struct));
      break;
   case VKI_PTRACE_GETEVENTMSG:
      POST_MEM_WRITE( ARG4, sizeof(unsigned long));
      break;
   case VKI_PTRACE_GETSIGINFO:
      /* XXX: This is a simplification. Different parts of the
       * siginfo_t are valid depending on the type of signal.
       */
      POST_MEM_WRITE( ARG4, sizeof(vki_siginfo_t));
      break;
   case VKI_PTRACE_GETREGSET:
      ML_(linux_POST_getregset)(tid, ARG3, ARG4);
      break;
   default:
      break;
   }
}

PRE(sys_fadvise64)
{
   PRINT("sys_fadvise64 ( %ld, %ld, %lu, %ld )", ARG1,ARG2,ARG3,ARG4);
   PRE_REG_READ4(long, "fadvise64",
                 int, fd, vki_loff_t, offset, vki_size_t, len, int, advice);
}

PRE(sys_mmap)
{
   SysRes r;

   PRINT("sys_mmap ( %#lx, %llu, %ld, %ld, %d, %ld )",
         ARG1, (ULong)ARG2, ARG3, ARG4, (Int)ARG5, ARG6 );
   PRE_REG_READ6(long, "mmap",
                 unsigned long, start, unsigned long, length,
                 unsigned long, prot,  unsigned long, flags,
                 unsigned long, fd,    unsigned long, offset);

   r = ML_(generic_PRE_sys_mmap)( tid, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6 );
   SET_STATUS_from_SysRes(r);
}


/* ---------------------------------------------------------------
   PRE/POST wrappers for AMD64/Linux-variant specific syscalls
   ------------------------------------------------------------ */

PRE(sys_syscall184)
{
   Int err;

   /* 184 is used by sys_bproc.  If we're not on a declared bproc
      variant, fail in the usual way, since it is otherwise unused. */

   if (!VG_(strstr)(VG_(clo_kernel_variant), "bproc")) {
      PRINT("non-existent syscall! (syscall 184)");
      PRE_REG_READ0(long, "ni_syscall(184)");
      SET_STATUS_Failure( VKI_ENOSYS );
      return;
   }

   err = ML_(linux_variant_PRE_sys_bproc)( ARG1, ARG2, ARG3,
                                           ARG4, ARG5, ARG6 );
   if (err) {
      SET_STATUS_Failure( err );
      return;
   }
   /* Let it go through. */
   *flags |= SfMayBlock; /* who knows?  play safe. */
}

POST(sys_syscall184)
{
   ML_(linux_variant_POST_sys_bproc)( ARG1, ARG2, ARG3,
                                      ARG4, ARG5, ARG6 );
}

#undef PRE
#undef POST


/* ---------------------------------------------------------------------
   The AMD64/Linux syscall table
   ------------------------------------------------------------------ */

/* Add an amd64-linux specific wrapper to a syscall table. */
#define PLAX_(const, name)    WRAPPER_ENTRY_X_(amd64_linux, const, name)
#define PLAXY(const, name)    WRAPPER_ENTRY_XY(amd64_linux, const, name)

// This table maps from __NR_xxx syscall numbers (from
// linux/include/asm-x86_64/unistd.h) to the appropriate PRE/POST sys_foo()
// wrappers on AMD64 (as per sys_call_table in
// linux/arch/x86_64/kernel/entry.S).
//
// When implementing these wrappers, you need to work out if the wrapper is
// generic, Linux-only (but arch-independent), or AMD64/Linux only.

static SyscallTableEntry syscall_table[] = {
   GENXY(__NR_read,              sys_read),           // 0
   GENX_(__NR_write,             sys_write),          // 1
   GENXY(__NR_open,              sys_open),           // 2
   GENXY(__NR_close,             sys_close),          // 3
   GENXY(__NR_stat,              sys_newstat),        // 4

   GENXY(__NR_fstat,             sys_newfstat),       // 5
   GENXY(__NR_lstat,             sys_newlstat),       // 6
   GENXY(__NR_poll,              sys_poll),           // 7
   LINX_(__NR_lseek,             sys_lseek),          // 8
   PLAX_(__NR_mmap,              sys_mmap),           // 9

   GENXY(__NR_mprotect,          sys_mprotect),       // 10
   GENXY(__NR_munmap,            sys_munmap),         // 11
   GENX_(__NR_brk,               sys_brk),            // 12
   LINXY(__NR_rt_sigaction,      sys_rt_sigaction),   // 13
   LINXY(__NR_rt_sigprocmask,    sys_rt_sigprocmask), // 14

   PLAX_(__NR_rt_sigreturn,      sys_rt_sigreturn),   // 15
   LINXY(__NR_ioctl,             sys_ioctl),          // 16
   GENXY(__NR_pread64,           sys_pread64),        // 17
   GENX_(__NR_pwrite64,          sys_pwrite64),       // 18
   GENXY(__NR_readv,             sys_readv),          // 19

   GENX_(__NR_writev,            sys_writev),         // 20
   GENX_(__NR_access,            sys_access),         // 21
   LINXY(__NR_pipe,              sys_pipe),           // 22
   GENX_(__NR_select,            sys_select),         // 23
   LINX_(__NR_sched_yield,       sys_sched_yield),    // 24

   GENX_(__NR_mremap,            sys_mremap),         // 25
   GENX_(__NR_msync,             sys_msync),          // 26
   GENXY(__NR_mincore,           sys_mincore),        // 27
   GENX_(__NR_madvise,           sys_madvise),        // 28
   LINX_(__NR_shmget,            sys_shmget),         // 29

   LINXY(__NR_shmat,             wrap_sys_shmat),     // 30
   LINXY(__NR_shmctl,            sys_shmctl),         // 31
   GENXY(__NR_dup,               sys_dup),            // 32
   GENXY(__NR_dup2,              sys_dup2),           // 33
   GENX_(__NR_pause,             sys_pause),          // 34

   GENXY(__NR_nanosleep,         sys_nanosleep),      // 35
   GENXY(__NR_getitimer,         sys_getitimer),      // 36
   GENX_(__NR_alarm,             sys_alarm),          // 37
   GENXY(__NR_setitimer,         sys_setitimer),      // 38
   GENX_(__NR_getpid,            sys_getpid),         // 39

   LINXY(__NR_sendfile,          sys_sendfile),       // 40
   LINXY(__NR_socket,            sys_socket),         // 41
   LINX_(__NR_connect,           sys_connect),        // 42
   LINXY(__NR_accept,            sys_accept),         // 43
   LINX_(__NR_sendto,            sys_sendto),         // 44

   LINXY(__NR_recvfrom,          sys_recvfrom),       // 45
   LINX_(__NR_sendmsg,           sys_sendmsg),        // 46
   LINXY(__NR_recvmsg,           sys_recvmsg),        // 47
   LINX_(__NR_shutdown,          sys_shutdown),       // 48
   LINX_(__NR_bind,              sys_bind),           // 49

   LINX_(__NR_listen,            sys_listen),         // 50
   LINXY(__NR_getsockname,       sys_getsockname),    // 51
   LINXY(__NR_getpeername,       sys_getpeername),    // 52
   LINXY(__NR_socketpair,        sys_socketpair),     // 53
   LINX_(__NR_setsockopt,        sys_setsockopt),     // 54

   LINXY(__NR_getsockopt,        sys_getsockopt),     // 55
   PLAX_(__NR_clone,             sys_clone),          // 56
   GENX_(__NR_fork,              sys_fork),           // 57
   GENX_(__NR_vfork,             sys_fork),           // 58 treat as fork
   GENX_(__NR_execve,            sys_execve),         // 59

   GENX_(__NR_exit,              sys_exit),           // 60
   GENXY(__NR_wait4,             sys_wait4),          // 61
   GENX_(__NR_kill,              sys_kill),           // 62
   GENXY(__NR_uname,             sys_newuname),       // 63
   LINX_(__NR_semget,            sys_semget),         // 64

   LINX_(__NR_semop,             sys_semop),          // 65
   LINXY(__NR_semctl,            sys_semctl),         // 66
   LINXY(__NR_shmdt,             sys_shmdt),          // 67
   LINX_(__NR_msgget,            sys_msgget),         // 68
   LINX_(__NR_msgsnd,            sys_msgsnd),         // 69

   LINXY(__NR_msgrcv,            sys_msgrcv),         // 70
   LINXY(__NR_msgctl,            sys_msgctl),         // 71
   LINXY(__NR_fcntl,             sys_fcntl),          // 72
   GENX_(__NR_flock,             sys_flock),          // 73
   GENX_(__NR_fsync,             sys_fsync),          // 74

   GENX_(__NR_fdatasync,         sys_fdatasync),      // 75
   GENX_(__NR_truncate,          sys_truncate),       // 76
   GENX_(__NR_ftruncate,         sys_ftruncate),      // 77
   GENXY(__NR_getdents,          sys_getdents),       // 78
   GENXY(__NR_getcwd,            sys_getcwd),         // 79

   GENX_(__NR_chdir,             sys_chdir),          // 80
   GENX_(__NR_fchdir,            sys_fchdir),         // 81
   GENX_(__NR_rename,            sys_rename),         // 82
   GENX_(__NR_mkdir,             sys_mkdir),          // 83
   GENX_(__NR_rmdir,             sys_rmdir),          // 84

   GENXY(__NR_creat,             sys_creat),          // 85
   GENX_(__NR_link,              sys_link),           // 86
   GENX_(__NR_unlink,            sys_unlink),         // 87
   GENX_(__NR_symlink,           sys_symlink),        // 88
   GENX_(__NR_readlink,          sys_readlink),       // 89

   GENX_(__NR_chmod,             sys_chmod),          // 90
   GENX_(__NR_fchmod,            sys_fchmod),         // 91
   GENX_(__NR_chown,             sys_chown),          // 92
   GENX_(__NR_fchown,            sys_fchown),         // 93
   GENX_(__NR_lchown,            sys_lchown),         // 94

   GENX_(__NR_umask,             sys_umask),          // 95
   GENXY(__NR_gettimeofday,      sys_gettimeofday),   // 96
   GENXY(__NR_getrlimit,         sys_getrlimit),      // 97
   GENXY(__NR_getrusage,         sys_getrusage),      // 98
   LINXY(__NR_sysinfo,           sys_sysinfo),        // 99

   GENXY(__NR_times,             sys_times),          // 100
   PLAXY(__NR_ptrace,            sys_ptrace),         // 101
   GENX_(__NR_getuid,            sys_getuid),         // 102
   LINXY(__NR_syslog,            sys_syslog),         // 103
   GENX_(__NR_getgid,            sys_getgid),         // 104

   GENX_(__NR_setuid,            sys_setuid),         // 105
   GENX_(__NR_setgid,            sys_setgid),         // 106
   GENX_(__NR_geteuid,           sys_geteuid),        // 107
   GENX_(__NR_getegid,           sys_getegid),        // 108
   GENX_(__NR_setpgid,           sys_setpgid),        // 109

   GENX_(__NR_getppid,           sys_getppid),        // 110
   GENX_(__NR_getpgrp,           sys_getpgrp),        // 111
   GENX_(__NR_setsid,            sys_setsid),         // 112
   GENX_(__NR_setreuid,          sys_setreuid),       // 113
   GENX_(__NR_setregid,          sys_setregid),       // 114

   GENXY(__NR_getgroups,         sys_getgroups),      // 115
   GENX_(__NR_setgroups,         sys_setgroups),      // 116
   LINX_(__NR_setresuid,         sys_setresuid),      // 117
   LINXY(__NR_getresuid,         sys_getresuid),      // 118
   LINX_(__NR_setresgid,         sys_setresgid),      // 119

   LINXY(__NR_getresgid,         sys_getresgid),      // 120
   GENX_(__NR_getpgid,           sys_getpgid),        // 121
   LINX_(__NR_setfsuid,          sys_setfsuid),       // 122
   LINX_(__NR_setfsgid,          sys_setfsgid),       // 123
   GENX_(__NR_getsid,            sys_getsid),         // 124

   LINXY(__NR_capget,            sys_capget),         // 125
   LINX_(__NR_capset,            sys_capset),         // 126
   LINXY(__NR_rt_sigpending,     sys_rt_sigpending),  // 127
   LINXY(__NR_rt_sigtimedwait,   sys_rt_sigtimedwait),// 128
   LINXY(__NR_rt_sigqueueinfo,   sys_rt_sigqueueinfo),// 129

   LINX_(__NR_rt_sigsuspend,     sys_rt_sigsuspend),  // 130
   GENXY(__NR_sigaltstack,       sys_sigaltstack),    // 131
   LINX_(__NR_utime,             sys_utime),          // 132
   GENX_(__NR_mknod,             sys_mknod),          // 133
   //   (__NR_uselib,            sys_uselib),         // 134

   LINX_(__NR_personality,       sys_personality),    // 135
   //   (__NR_ustat,             sys_ustat),          // 136
   GENXY(__NR_statfs,            sys_statfs),         // 137
   GENXY(__NR_fstatfs,           sys_fstatfs),        // 138
   //   (__NR_sysfs,             sys_sysfs),          // 139

   GENX_(__NR_getpriority,             sys_getpriority),             // 140
   GENX_(__NR_setpriority,             sys_setpriority),             // 141
   LINXY(__NR_sched_setparam,          sys_sched_setparam),          // 142
   LINXY(__NR_sched_getparam,          sys_sched_getparam),          // 143
   LINX_(__NR_sched_setscheduler,      sys_sched_setscheduler),      // 144

   LINX_(__NR_sched_getscheduler,      sys_sched_getscheduler),      // 145
   LINX_(__NR_sched_get_priority_max,  sys_sched_get_priority_max),  // 146
   LINX_(__NR_sched_get_priority_min,  sys_sched_get_priority_min),  // 147
   LINXY(__NR_sched_rr_get_interval,   sys_sched_rr_get_interval),   // 148
   GENX_(__NR_mlock,                   sys_mlock),                   // 149

   GENX_(__NR_munlock,           sys_munlock),        // 150
   GENX_(__NR_mlockall,          sys_mlockall),       // 151
   LINX_(__NR_munlockall,        sys_munlockall),     // 152
   LINX_(__NR_vhangup,           sys_vhangup),        // 153
   //   (__NR_modify_ldt,        sys_modify_ldt),     // 154

   //   (__NR_pivot_root,        sys_pivot_root),     // 155
   LINXY(__NR__sysctl,           sys_sysctl),         // 156
   LINXY(__NR_prctl,             sys_prctl),          // 157
   PLAX_(__NR_arch_prctl,	 sys_arch_prctl),     // 158
   LINXY(__NR_adjtimex,          sys_adjtimex),       // 159

   GENX_(__NR_setrlimit,         sys_setrlimit),      // 160
   GENX_(__NR_chroot,            sys_chroot),         // 161
   GENX_(__NR_sync,              sys_sync),           // 162
   //   (__NR_acct,              sys_acct),           // 163
   GENX_(__NR_settimeofday,      sys_settimeofday),   // 164

   LINX_(__NR_mount,             sys_mount),          // 165
   LINX_(__NR_umount2,           sys_umount),         // 166
   //   (__NR_swapon,            sys_swapon),         // 167
   //   (__NR_swapoff,           sys_swapoff),        // 168
   //   (__NR_reboot,            sys_reboot),         // 169

   GENX_(__NR_sethostname,       sys_sethostname),    // 170
   //   (__NR_setdomainname,     sys_setdomainname),  // 171
   GENX_(__NR_iopl,              sys_iopl),           // 172
   LINX_(__NR_ioperm,            sys_ioperm),         // 173
   GENX_(__NR_create_module,     sys_ni_syscall),     // 174

   LINX_(__NR_init_module,       sys_init_module),    // 175
   LINX_(__NR_delete_module,     sys_delete_module),  // 176
   //   (__NR_get_kernel_syms,   sys_ni_syscall),     // 177
   //   (__NR_query_module,      sys_ni_syscall),     // 178
   LINX_(__NR_quotactl,          sys_quotactl),       // 179

   //   (__NR_nfsservctl,        sys_nfsservctl),     // 180
   //   (__NR_getpmsg,           sys_ni_syscall),     // 181
   //   (__NR_putpmsg,           sys_ni_syscall),     // 182
   //   (__NR_afs_syscall,       sys_ni_syscall),     // 183
   PLAXY(184,                    sys_syscall184),     // 184 // sys_bproc?

   //   (__NR_security,          sys_ni_syscall),     // 185
   LINX_(__NR_gettid,            sys_gettid),         // 186
   LINX_(__NR_readahead,         sys_readahead),      // 187
   LINX_(__NR_setxattr,          sys_setxattr),       // 188
   LINX_(__NR_lsetxattr,         sys_lsetxattr),      // 189

   LINX_(__NR_fsetxattr,         sys_fsetxattr),      // 190
   LINXY(__NR_getxattr,          sys_getxattr),       // 191
   LINXY(__NR_lgetxattr,         sys_lgetxattr),      // 192
   LINXY(__NR_fgetxattr,         sys_fgetxattr),      // 193
   LINXY(__NR_listxattr,         sys_listxattr),      // 194

   LINXY(__NR_llistxattr,        sys_llistxattr),     // 195
   LINXY(__NR_flistxattr,        sys_flistxattr),     // 196
   LINX_(__NR_removexattr,       sys_removexattr),    // 197
   LINX_(__NR_lremovexattr,      sys_lremovexattr),   // 198
   LINX_(__NR_fremovexattr,      sys_fremovexattr),   // 199

   LINXY(__NR_tkill,             sys_tkill),             // 200
   GENXY(__NR_time,              sys_time), /*was sys_time64*/ // 201
   LINXY(__NR_futex,             sys_futex),             // 202
   LINX_(__NR_sched_setaffinity, sys_sched_setaffinity), // 203
   LINXY(__NR_sched_getaffinity, sys_sched_getaffinity), // 204

   //   (__NR_set_thread_area,   sys_ni_syscall),     // 205
   LINXY(__NR_io_setup,          sys_io_setup),       // 206
   LINX_(__NR_io_destroy,        sys_io_destroy),     // 207
   LINXY(__NR_io_getevents,      sys_io_getevents),   // 208
   LINX_(__NR_io_submit,         sys_io_submit),      // 209

   LINXY(__NR_io_cancel,         sys_io_cancel),      // 210
   //   (__NR_get_thread_area,   sys_ni_syscall),     // 211
   LINXY(__NR_lookup_dcookie,    sys_lookup_dcookie), // 212
   LINXY(__NR_epoll_create,      sys_epoll_create),   // 213
   //   (__NR_epoll_ctl_old,     sys_ni_syscall),     // 214

   //   (__NR_epoll_wait_old,    sys_ni_syscall),     // 215
   //   (__NR_remap_file_pages,  sys_remap_file_pages)// 216
   GENXY(__NR_getdents64,        sys_getdents64),     // 217
   LINX_(__NR_set_tid_address,   sys_set_tid_address),// 218
   //   (__NR_restart_syscall,   sys_restart_syscall),// 219

   LINX_(__NR_semtimedop,        sys_semtimedop),     // 220
   PLAX_(__NR_fadvise64,         sys_fadvise64),      // 221
   LINXY(__NR_timer_create,      sys_timer_create),   // 222
   LINXY(__NR_timer_settime,     sys_timer_settime),  // 223
   LINXY(__NR_timer_gettime,     sys_timer_gettime),  // 224

   LINX_(__NR_timer_getoverrun,  sys_timer_getoverrun), // 225
   LINX_(__NR_timer_delete,      sys_timer_delete),   // 226
   LINX_(__NR_clock_settime,     sys_clock_settime),  // 227
   LINXY(__NR_clock_gettime,     sys_clock_gettime),  // 228
   LINXY(__NR_clock_getres,      sys_clock_getres),   // 229

   LINXY(__NR_clock_nanosleep,   sys_clock_nanosleep),// 230
   LINX_(__NR_exit_group,        sys_exit_group),     // 231
   LINXY(__NR_epoll_wait,        sys_epoll_wait),     // 232
   LINX_(__NR_epoll_ctl,         sys_epoll_ctl),      // 233
   LINXY(__NR_tgkill,            sys_tgkill),         // 234

   GENX_(__NR_utimes,            sys_utimes),         // 235
   //   (__NR_vserver,           sys_ni_syscall),     // 236
   LINX_(__NR_mbind,             sys_mbind),          // 237
   LINX_(__NR_set_mempolicy,     sys_set_mempolicy),  // 238
   LINXY(__NR_get_mempolicy,     sys_get_mempolicy),  // 239

   LINXY(__NR_mq_open,           sys_mq_open),        // 240
   LINX_(__NR_mq_unlink,         sys_mq_unlink),      // 241
   LINX_(__NR_mq_timedsend,      sys_mq_timedsend),   // 242
   LINXY(__NR_mq_timedreceive,   sys_mq_timedreceive),// 243
   LINX_(__NR_mq_notify,         sys_mq_notify),      // 244

   LINXY(__NR_mq_getsetattr,     sys_mq_getsetattr),  // 245
   //   (__NR_kexec_load,        sys_ni_syscall),     // 246
   LINXY(__NR_waitid,            sys_waitid),         // 247
   LINX_(__NR_add_key,           sys_add_key),        // 248
   LINX_(__NR_request_key,       sys_request_key),    // 249

   LINXY(__NR_keyctl,            sys_keyctl),         // 250
   LINX_(__NR_ioprio_set,        sys_ioprio_set),     // 251
   LINX_(__NR_ioprio_get,        sys_ioprio_get),     // 252
   LINX_(__NR_inotify_init,	 sys_inotify_init),   // 253
   LINX_(__NR_inotify_add_watch, sys_inotify_add_watch), // 254

   LINX_(__NR_inotify_rm_watch,	 sys_inotify_rm_watch), // 255
//   LINX_(__NR_migrate_pages,	 sys_migrate_pages),    // 256
   LINXY(__NR_openat,		 sys_openat),           // 257
   LINX_(__NR_mkdirat,		 sys_mkdirat),          // 258
   LINX_(__NR_mknodat,		 sys_mknodat),          // 259

   LINX_(__NR_fchownat,		 sys_fchownat),         // 260
   LINX_(__NR_futimesat,	 sys_futimesat),        // 261
   LINXY(__NR_newfstatat,	 sys_newfstatat),       // 262
   LINX_(__NR_unlinkat,		 sys_unlinkat),         // 263
   LINX_(__NR_renameat,		 sys_renameat),         // 264

   LINX_(__NR_linkat,		 sys_linkat),           // 265
   LINX_(__NR_symlinkat,	 sys_symlinkat),        // 266
   LINX_(__NR_readlinkat,	 sys_readlinkat),       // 267
   LINX_(__NR_fchmodat,		 sys_fchmodat),         // 268
   LINX_(__NR_faccessat,	 sys_faccessat),        // 269

   LINX_(__NR_pselect6,		 sys_pselect6),         // 270
   LINXY(__NR_ppoll,		 sys_ppoll),            // 271
//   LINX_(__NR_unshare,		 sys_unshare),          // 272
   LINX_(__NR_set_robust_list,	 sys_set_robust_list),  // 273
   LINXY(__NR_get_robust_list,	 sys_get_robust_list),  // 274

   LINX_(__NR_splice,            sys_splice),           // 275
   LINX_(__NR_tee,               sys_tee),              // 276
   LINX_(__NR_sync_file_range,   sys_sync_file_range),  // 277
   LINXY(__NR_vmsplice,          sys_vmsplice),         // 278
   LINXY(__NR_move_pages,        sys_move_pages),       // 279

   LINX_(__NR_utimensat,         sys_utimensat),        // 280
   LINXY(__NR_epoll_pwait,       sys_epoll_pwait),      // 281
   LINXY(__NR_signalfd,          sys_signalfd),         // 282
   LINXY(__NR_timerfd_create,    sys_timerfd_create),   // 283
   LINXY(__NR_eventfd,           sys_eventfd),          // 284

   LINX_(__NR_fallocate,         sys_fallocate),        // 285
   LINXY(__NR_timerfd_settime,   sys_timerfd_settime),  // 286
   LINXY(__NR_timerfd_gettime,   sys_timerfd_gettime),  // 287
   LINXY(__NR_accept4,           sys_accept4),          // 288
   LINXY(__NR_signalfd4,         sys_signalfd4),        // 289

   LINXY(__NR_eventfd2,          sys_eventfd2),         // 290
   LINXY(__NR_epoll_create1,     sys_epoll_create1),    // 291
   LINXY(__NR_dup3,              sys_dup3),             // 292
   LINXY(__NR_pipe2,             sys_pipe2),            // 293
   LINXY(__NR_inotify_init1,     sys_inotify_init1),    // 294

   LINXY(__NR_preadv,            sys_preadv),           // 295
   LINX_(__NR_pwritev,           sys_pwritev),          // 296
   LINXY(__NR_rt_tgsigqueueinfo, sys_rt_tgsigqueueinfo),// 297
   LINXY(__NR_perf_event_open,   sys_perf_event_open),  // 298
   LINXY(__NR_recvmmsg,          sys_recvmmsg),         // 299

   LINXY(__NR_fanotify_init,     sys_fanotify_init),    // 300
   LINX_(__NR_fanotify_mark,     sys_fanotify_mark),    // 301
   LINXY(__NR_prlimit64,         sys_prlimit64),        // 302
   LINXY(__NR_name_to_handle_at, sys_name_to_handle_at),// 303
   LINXY(__NR_open_by_handle_at, sys_open_by_handle_at),// 304

   LINXY(__NR_clock_adjtime,     sys_clock_adjtime),    // 305
//   LINX_(__NR_syncfs,            sys_ni_syscall),       // 306
   LINXY(__NR_sendmmsg,          sys_sendmmsg),         // 307
//   LINX_(__NR_setns,             sys_ni_syscall),       // 308
   LINXY(__NR_getcpu,            sys_getcpu),           // 309

   LINXY(__NR_process_vm_readv,  sys_process_vm_readv), // 310
   LINX_(__NR_process_vm_writev, sys_process_vm_writev) // 311
};

SyscallTableEntry* ML_(get_linux_syscall_entry) ( UInt sysno )
{
   const UInt syscall_table_size
      = sizeof(syscall_table) / sizeof(syscall_table[0]);

   /* Is it in the contiguous initial section of the table? */
   if (sysno < syscall_table_size) {
      SyscallTableEntry* sys = &syscall_table[sysno];
      if (sys->before == NULL)
         return NULL; /* no entry */
      else
         return sys;
   }

   /* Can't find a wrapper */
   return NULL;
}

#endif // defined(VGP_amd64_linux)

/*--------------------------------------------------------------------*/
/*--- end                                                          ---*/
/*--------------------------------------------------------------------*/