On Wednesday 25 February 2015 08:33:16 Ezequiel Garcia wrote:
>
> /me is more confused now
>
> In arch/nios2/include/asm/ucontext.h
>
> struct ucontext {
> unsigned long uc_flags;
> struct ucontext *uc_link;
> stack_t uc_stack;
> struct mcontext uc_mcontext;
> sigset_t uc_sigmask;
> };
>
> And in include/uapi/asm-generic/ucontext.h:
>
> struct ucontext {
> unsigned long uc_flags;
> struct ucontext *uc_link;
> stack_t uc_stack;
> struct sigcontext uc_mcontext;
> sigset_t uc_sigmask;
> };
>
> Which one is the one that userspace sees? And why does the kernel has
> two different structures?
Userspace sees the asm-generic header, which I assume is a bug
in this case.
> Given this oddities, I'm wondering how troublesome would be to just
> re-do this and break the ptrace and signal ABI. For instance, just
> pushing pt_regs in PTRACE_GETREGSET would make things much clearer.
Could you change pt_regs to match the layout you have for PTRACE_GETREGSET
instead? It seems much more intuitive.
> I guess Linus would burn me for even suggesting to breaking users... but
> do we have any users at all? This arch has just been mainlined. Altera's
> out-of-tree is already ABI-incompatible with mainline so that's not an
> issue.
>
> The only one using this ABI is gdb, which is easily fixed.
You can change anything you like as long as nobody complains about
regressions.
Arnd
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