Re: [kvm-unit-tests PATCH v2 3/3] s390x/spec_ex: Add test of EXECUTE with odd target address

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Tue, 21 Feb 2023 18:48:22 +0100
Nina Schoetterl-Glausch <nsg@linux.ibm.com> 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.
> 
> 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 a26c56aa..dd097f9b 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 .rodata\n"

and this should go in a .text.something subsection, as we discussed
offline

> +		"pre_odd_ex_target:\n"

shouldn't the label be after the align?

> +		"	.balign	2\n"

(i.e. here)

> +		"	. = . + 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;
> +}
> +
>  static int bad_alignment(void)
>  {
>  	uint32_t words[5] __attribute__((aligned(16)));
> @@ -218,6 +242,7 @@ static const struct spec_ex_trigger spec_ex_triggers[] = {
>  	{ "psw_bit_12_is_1", &psw_bit_12_is_1, false, &fixup_invalid_psw },
>  	{ "short_psw_bit_12_is_0", &short_psw_bit_12_is_0, false, &fixup_invalid_psw },
>  	{ "psw_odd_address", &psw_odd_address, false, &fixup_invalid_psw },
> +	{ "odd_ex_target", &odd_ex_target, true, NULL },
>  	{ "bad_alignment", &bad_alignment, true, NULL },
>  	{ "not_even", &not_even, true, NULL },
>  	{ NULL, NULL, false, NULL },