Re: [Bug dynamic-link/15128] dynamic loader may clobber floating-point parameters on AArch64

["Ondřej Bílka" <neleai@seznam.cz>]

On Mon, Feb 11, 2013 at 05:00:30AM +0000, bugdal at aerifal dot cx wrote:
> http://sourceware.org/bugzilla/show_bug.cgi?id=15128
> 
> Rich Felker <bugdal at aerifal dot cx> changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |bugdal at aerifal dot cx
> 
> --- Comment #1 from Rich Felker <bugdal at aerifal dot cx> 2013-02-11 05:00:30 UTC ---
> I haven't looked at the code, but the correct fix should just be to make the
> lazy binding resolver function save all registers that might be argument
> registers before calling anything else, and restore them before making the
> final jump to the resolved address. There's no reason to go to great lengths to
> avoid clobbering them in between.
> 

Aarch64 ta calling conventions below you have v16-v31
available.

The first eight registers, v0-v7, are used to pass argument values into
a subroutine and to return result values from a function. They may also
be used to hold intermediate values within a routine (but, in general,
only between subroutine calls).

Registers d8-d15 (s8-s15) must be preserved by a callee across
subroutine calls; the remaining registers (v0-v7, v16-v31) do not need
to be preserved (or should be preserved by the caller). Additionally,
only single-precision, double-precision and 64-bit short vector values
stored in d8-d15 (s8-s15) need to be preserved; it is the responsibility
of the caller to preserve larger values.

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