/usr/share/systemtap/runtime/linux/autoconf-x86-uniregs.c is in systemtap-common 2.6-0.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | #include <asm/ptrace.h>
#if defined (__i386__) || defined (__x86_64__)
struct pt_regs regs = {.ax = 0x0};
#endif
|