diff options
| -rw-r--r-- | tapset/utrace.stp | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/tapset/utrace.stp b/tapset/utrace.stp index 00f427e6..0d26ed5f 100644 --- a/tapset/utrace.stp +++ b/tapset/utrace.stp @@ -1,20 +1,26 @@ /* utrace-only subset of register accessors */ - %{ #include "syscall.h" %} -function _utrace_syscall_nr:long () %{ - THIS->__retvalue = syscall_get_nr(current, CONTEXT->regs); /* pure */ +function _utrace_syscall_nr:long () %{ /* pure */ + THIS->__retvalue = syscall_get_nr(current, CONTEXT->regs); %} -function _utrace_syscall_arg:long (n:long) %{ - unsigned long arg = 0; /* pure */ - syscall_get_arguments(current, CONTEXT->regs, (int)THIS->n, 1, &arg); - THIS->__retvalue = arg; +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 () %{ - THIS->__retvalue = syscall_get_return_value(current, CONTEXT->regs); /* pure */ +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); %} |