[RFC PATCH v4 0/3] ARM: VFP: Save / restore VFP state on the signal handler path

[Imre Deak]

On Wed, Apr 07, 2010 at 06:24:39PM +0200, ext Dirk Behme wrote:
> On 31.03.2010 23:23, imre.deak at nokia.com wrote:
> > Changes since v3:
> > - Rebased against mainline v2.6.34-rc3, since some parts have already
> >    been applied there.
> >
> > Note that this problem might affect more people than previously thought.
> > The CodeSourcery 2009q1-203 glibc_ports has some NEON optimized functions;
> > for example using memset or memcpy in a signal handler and floating point
> > in the main thread can corrupt the main thread's context. You can test this
> > by replacing the floating point ops in the signal handler below with some
> > dummy memset/memcpy.
> >
> > I could only test these patches on a Cortex A8 UP system; it would be great
> > if someone with an SMP board could give it a go. The test app to reproduce
> > the problem (I've built it with -mfloat-abi=softfp -mfpu=neon):
> 
> Do you think this is relevant for ARM11 SMP (ARM11 MPCore), too? Or do 
> you think this is necessary only for NEON systems, i.e. Cortex Ax?

I think ARM11 has VFP, so it is relevant for it. This actually means that it's
enough to provide -mfpu=vfp above..

--Imre