Re: [Qemu-devel] [patch] NPTL/TLS support

[Fabrice Bellard <fabrice@bellard.org>]

Paul Brook wrote:
> The attached patch adds partial support for ARM NPTL binaries.
> 
> It implements the following things:
> 
> - The Arm magic kernel code page. This is used on recent Arm kernels to 
> provide efficient access to kernel/CPU features. For example atomic 
> operations, and reading the TLS register (which may or may not be a real 
> hardware register). This is simplified version of the VDSO used on recent x86 
> and ppc kernels.
> - A new Arm specific syscall to set the TLS register.
> - Support for the 5-argument form of sys_clone.
> 
> This is sufficient to run single-threaded NPTL enabled binaries. I've not yet 
> implemented the futex syscalls, so multithreaded applications probaby won't 
> work.
> 
> NPTL support is only enabled for ARM.  Other architectures may need 
> architecture specific bits implementing before they can be enabled.

On i386 there are AUXENTs to define the address of the VDSO page 
(AT_SYSINFO and AT_SYSINFO_EHDR). If it was supported by the ARM glibc, 
it would avoid some hacks you need to do to intercept calls to it. Can 
you check that ?

Fabrice.