Re: [Valgrind-developers] 1.0.X possibilities

[Julian S. <js...@ac...>]

On Friday 04 October 2002 5:50 pm, Jeremy Fitzhardinge wrote:
> On Fri, 2002-10-04 at 09:22, Julian Seward wrote:
>     The important change is to do with thread-specific data.  New scheme on
>     x86s at least is that the linux kernel creates a GDT entry which points
>     at a thread's local storage; the thread can then access that merely
>     by using a suitable segment override prefix on any old memory
> referencing insn.  Kernel swizzles the GDT entry when scheduling threads,
> and there is a new syscall by which a thread can tell the kernel
>     where it's TLD is [i assume because GDT can't be swizzled from
> user-space] and because the kernel needs to know this anyway.
>
> But if all this is just implementation detail of libpthreads and you're
> replacing all of libpthreads, then surely you wouldn't have to deal with
> it anyway?

Not exacltly true, because gcc >= 3.2 is roped into this game as well,
and generates TLD-accessing code directly for variables declared with
the __thread qualifier.

>     - possibly your patches of 25 Sept if they don't cause build problems
>       on any test platform I have
>
> Oh, you mean the poll/select name issue and the msgsnd/msgrcv
> implementation?

Yes.

J