[PATCH v7 20/23] aarch64: Process gnu properties in static exe

[Yury Khrustalev]

On Thu, Jan 09, 2025 at 03:01:37PM -0300, Adhemerval Zanella Netto wrote:
> 
> 
> On 03/01/25 12:41, Yury Khrustalev wrote:
> > From: Szabolcs Nagy <szabolcs.nagy@arm.com>
> > 
> > Unlike for BTI, the kernel does not process GCS properties so update
> > GL(dl_aarch64_gcs) before the GCS status is set.
> > 
> > Co-authored-by: Yury Khrustalev <yury.khrustalev@arm.com>
> > ---
> >  csu/libc-start.c                             | 12 ++++++++++++
> >  sysdeps/generic/libc-start.h                 |  1 +
> >  sysdeps/unix/sysv/linux/aarch64/libc-start.h | 19 +++++++++++++++++++
> >  3 files changed, 32 insertions(+)
> > 
> > diff --git a/csu/libc-start.c b/csu/libc-start.c
> > index 6f3d52e223..325ef010d4 100644
> > --- a/csu/libc-start.c
> > +++ b/csu/libc-start.c
> > @@ -206,6 +206,10 @@ call_fini (void *unused)
> >  
> >  #include <libc-start.h>
> >  
> > +#ifndef ARCH_PROCESS_NOTES
> > +# define ARCH_PROCESS_NOTES()
> > +#endif
> > +
> 
> I think it would be better to avoid the old way of defining arch-hooks,
> since they are error-prone.  For instance, although is not the case
> (since the function is currently empty) if/when we need to add generic
> __libc_process_notes code, just adding on the function below will not 
> be suffice for x86_64/powerpc because they have its own libc-start.h 
> (and this patch did not add an ARCH_PROCESS_NOTES for such ABIs).
> 
> Instead, the usual way is to either use the generic definitions
> on sysdeps/generic or add a new one.  For this case, I think it would
> be better to add new a file with the notes processing function instead
> of reuse the dl-prop.h.  
> 
> I plan to use it to add the generic memory seal support, which requires 
> PT_GNU_PROPERTY for all ABIs, without the need to replicate the same 
> code on x86_64 (in fact, I can move the aarch64 definitions on generic 
> code and remove aarch64 libc-prop.h).

In the interest of time, would it be OK if I revert this patch to its
original version [1] so that we could make property processing generic
later (as this is not require for GCS and would delay merging of this
patch series)?

[1] https://inbox.sourceware.org/libc-alpha/20241129163721.2385847-20-yury.khrustalev@arm.com/

Thanks,
Yury