On Fri, Sep 13, 2019 at 5:28 PM Andy Lutomirski <l...@amacapital.net> wrote:
> Ah, I get it. Doesn’t this cause a little bit of code bloat, though?
A little bit yes, a few extra functions for syscalls that are not
otherwise implemented.
> What if you made __x86_ni_syscall, etc (possibly using the *DEFINE_SYSCALL0
> macros) and then generate weak aliases to those?
That would be convenient, but COND_SYSCALL is used in kernel/sys_ni.c,
and we can't create an alias to a function defined elsewhere:
$ cat test.c
long b(void);
long a(void) __attribute__((alias("b")));
$ gcc -c test.c
test.c:2:6: error: ‘a’ aliased to undefined symbol ‘b’
long a(void) __attribute__((alias("b")));
^
Curiously, when we use inline assembly to create the alias (similarly
to the current cond_syscall), gcc just quietly drops the alias if the
function is not defined.
Sami
