Re: [Xen-devel] [PATCH 4/4] xen: use generated hypercall symbols in arch/x86/xen/xen-head.S

[Juergen Gross]

On 12/16/2014 11:24 AM, David Vrabel wrote:
> On 16/12/14 05:55, Juergen Gross wrote:
> > On 12/15/2014 01:05 PM, David Vrabel wrote:
> > > On 11/12/14 18:04, Juergen Gross wrote:
> > > > Instead of manually list each hypercall in arch/x86/xen/xen-head.S
> > > > use the auto generated symbol list.
> > > >
> > > > This also corrects the wrong address of xen_hypercall_mca which was
> > > > located 32 bytes higher than it should.
> > > >
> > > > Symbol addresses have been verified to match the correct ones via
> > > > objdump output.
> > > [...]
> > > > +
> > > > +#define HYPERCALL(n) \
> > > > +    .equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \
> > > > +    .type xen_hypercall_##n, function; .size xen_hypercall_##n, 32
> > > > +#include <asm/xen-hypercalls.h>
> > > > +#undef HYPERCALL
> > >
> > > The gas manual[1] suggests the syntax you've used for .type is invalid
> > > and suggest using .type <name>, STT_FUNC
> >
> > Really? In the link below I see:
> >
> > The types supported are:
> >
> > STT_FUNC
> > function
> >      Mark the symbol as being a function name.
> > ...
> >
> > So "function" seems to be okay.
>
> > From the manual
>
>      The syntaxes supported are:
>
>         .type <name> STT_<TYPE_IN_UPPER_CASE>
>         .type <name>,#<type>
>         .type <name>,@<type>
>         .type <name>,%<type>
>         .type <name>,"<type>"
>
> And
>
>      The first variant will be accepted by the GNU assembler on all
>      architectures...

grepping through the x86 assembler sources

.type <name>,@function

seems to be the preferred syntax (100%). I think I'll switch to that.


Juergen

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