Re: [kvm-unit-tests PATCH v4 3/3] s390x/spec_ex: Add test of EXECUTE with odd target address

[Thomas Huth <thuth@redhat.com>]

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@linux.ibm.com>
> Signed-off-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
> ---
>   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 ;-)

  Thomas