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Filename : sysc_membarrier.stp
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# membarrier _______________________________________________________
# SYSCALL_DEFINE2(membarrier, int, cmd, int, flags)

@define _SYSCALL_MEMBARRIER_NAME
%(
	name = "membarrier"
%)

@define _SYSCALL_MEMBARRIER_ARGSTR
%(
	argstr = sprintf("%s, %d", cmd_str, flags)
%)

@define _SYSCALL_MEMBARRIER_REGARGS
%(
	cmd = int_arg(1)
	cmd_str = _membarrier_cmd_str(cmd)
	flags = int_arg(2)
%)

probe syscall.membarrier = dw_syscall.membarrier !, nd_syscall.membarrier ? {}
probe syscall.membarrier.return = dw_syscall.membarrier.return !,
                                  nd_syscall.membarrier.return ? {}

# dw_membarrier _____________________________________________________

probe dw_syscall.membarrier = kernel.function("sys_membarrier").call ?
{
	@_SYSCALL_MEMBARRIER_NAME
	cmd = __int32($cmd)
	cmd_str = _membarrier_cmd_str(cmd)
	flags = __int32($flags)
	@_SYSCALL_MEMBARRIER_ARGSTR
}
probe dw_syscall.membarrier.return = kernel.function("sys_membarrier").return ?
{
	@_SYSCALL_MEMBARRIER_NAME
	@SYSC_RETVALSTR($return)
}

# nd_membarrier _____________________________________________________

probe nd_syscall.membarrier = nd1_syscall.membarrier!, nd2_syscall.membarrier!, tp_syscall.membarrier
  { }

probe nd1_syscall.membarrier = kprobe.function("sys_membarrier").call ?
{
	@_SYSCALL_MEMBARRIER_NAME
	asmlinkage()
	@_SYSCALL_MEMBARRIER_REGARGS
	@_SYSCALL_MEMBARRIER_ARGSTR
}

/* kernel 4.17+ */
probe nd2_syscall.membarrier = kprobe.function(@arch_syscall_prefix "sys_membarrier") ?
{
	__set_syscall_pt_regs(pointer_arg(1))
	@_SYSCALL_MEMBARRIER_NAME
	@_SYSCALL_MEMBARRIER_REGARGS
	@_SYSCALL_MEMBARRIER_ARGSTR
}

/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.membarrier = kernel.trace("sys_enter")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_membarrier"), @const("__NR_compat_membarrier"))
	@_SYSCALL_MEMBARRIER_NAME
	@_SYSCALL_MEMBARRIER_REGARGS
	@_SYSCALL_MEMBARRIER_ARGSTR
}

probe nd_syscall.membarrier.return = nd1_syscall.membarrier.return!, nd2_syscall.membarrier.return!, tp_syscall.membarrier.return
  { }
  
probe nd1_syscall.membarrier.return = kprobe.function("sys_membarrier").return ?
{
	@_SYSCALL_MEMBARRIER_NAME
	@SYSC_RETVALSTR(returnval())
}

/* kernel 4.17+ */
probe nd2_syscall.membarrier.return = kprobe.function(@arch_syscall_prefix "sys_membarrier").return ?
{
	@_SYSCALL_MEMBARRIER_NAME
	@SYSC_RETVALSTR(returnval())
}
 
/* kernel 3.5+, but undesirable because it affects all syscalls */
probe tp_syscall.membarrier.return = kernel.trace("sys_exit")
{
	__set_syscall_pt_regs($regs)
	@__syscall_compat_gate(@const("__NR_membarrier"), @const("__NR_compat_membarrier"))
	@_SYSCALL_MEMBARRIER_NAME
	@SYSC_RETVALSTR($ret)
}