Hi Adhemerval, Elliott,
On Wed, Aug 21, 2024 at 03:19:02PM GMT, Adhemerval Zanella Netto wrote:
> I would use either the kernel interface:
>
> arch/x86/kernel/process_64.c
> 961 SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
>
> Where is seems to what most caller do, or maybe something like:
>
> union __arch_prctl_arg
> {
> unsigned long addr;
> unsigned long *vaddr;
> };
>
> int arch_prctl (int option, union __arch_prctl_arg *arg);
Or you could use a transparent union:
$ cat arch_prctl.c
union __attribute__((__transparent_union__)) __arch_prctl_arg {
unsigned long set;
unsigned long *get;
};
int my_arch_prctl(int op, union __arch_prctl_arg arg2);
int
main(void)
{
unsigned long u = 0;
my_arch_prctl(1, u);
my_arch_prctl(1, &u);
}
$ gcc -Wall -Wextra -S arch_prctl.c
$
> And for constants, it would require a x86_64 specific sys/prctl.h header
> with either the has_include tricks to include the kernel one or to just
> copy the kernel one (along with possible a test to check the sync with
> kernel definitions).
I think including would be simpler, if it's possible.
I've seen some problems arise from copying kernel stuff in glibc
headers, such as being unable to include both a some kernel and some
glibc headers in the same program due to redefinitions.
Have a lovely night!
Alex
--
<https://www.alejandro-colomar.es/>
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