On Mon, 2023-04-03 at 17:38 +0200, Thomas Huth wrote:
> On 17/03/2023 14.32, Nina Schoetterl-Glausch wrote:
> > The EXECUTE instruction executes the instruction at the given target
> > address. This address must be halfword aligned, otherwise a
> > specification exception occurs.
> > Add a test for this.
> >
> > Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> > Signed-off-by: Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx>
> > ---
> > s390x/spec_ex.c | 25 +++++++++++++++++++++++++
> > 1 file changed, 25 insertions(+)
> >
> > diff --git a/s390x/spec_ex.c b/s390x/spec_ex.c
> > index ab023347..b4b9095f 100644
> > --- a/s390x/spec_ex.c
> > +++ b/s390x/spec_ex.c
> > @@ -177,6 +177,30 @@ static int short_psw_bit_12_is_0(void)
> > return 0;
> > }
> >
> > +static int odd_ex_target(void)
> > +{
> > + uint64_t pre_target_addr;
> > + int to = 0, from = 0x0dd;
> > +
> > + asm volatile ( ".pushsection .text.ex_odd\n"
> > + " .balign 2\n"
> > + "pre_odd_ex_target:\n"
> > + " . = . + 1\n"
> > + " lr %[to],%[from]\n"
> > + " .popsection\n"
> > +
> > + " larl %[pre_target_addr],pre_odd_ex_target\n"
> > + " ex 0,1(%[pre_target_addr])\n"
> > + : [pre_target_addr] "=&a" (pre_target_addr),
> > + [to] "+d" (to)
> > + : [from] "d" (from)
> > + );
> > +
> > + assert((pre_target_addr + 1) & 1);
> > + report(to != from, "did not perform ex with odd target");
> > + return 0;
> > +}
>
> Hi Nina,
>
> FWIW, this fails to compile with Clang v15 here:
>
> s390x/spec_ex.c:187:4: error: symbol 'pre_odd_ex_target' is already defined
> "pre_odd_ex_target:\n"
> ^
> <inline asm>:3:1: note: instantiated into assembly here
> pre_odd_ex_target:
>
> No clue yet why that happens ... but compiling with Clang seems to be broken
> on some other spots, too, so this is not really critical right now ;-)
Thanks, I guess it inlines the function and emits the asm twice.
Interestingly clang cannot load the address of the misaligned_code symbol in C code due to alignement,
so I had to work around that, too.
>
> Thomas
>
