/* utrace-only subset of register accessors */ %{ #include "syscall.h" %} function _utrace_syscall_nr:long () %{ /* pure */ THIS->__retvalue = syscall_get_nr(current, CONTEXT->regs); %} function _utrace_syscall_arg:long (n:long) %{ /* pure */ unsigned long arg = 0; syscall_get_arguments(current, CONTEXT->regs, (int)THIS->n, 1, &arg); THIS->__retvalue = arg; %} function _utrace_syscall_return:long () %{ /* pure */ /* * Here's the reason for the "unsigned long" cast. Since all * values inside systemtap are 64-bit numbers, return values were * getting sign extended. This caused return values to not match * up with the same values passes as arguments. */ THIS->__retvalue = (unsigned long)syscall_get_return_value(current, CONTEXT->regs); %}