Re: [kvm-unit-tests PATCH v2 1/5] lib: s390x: sigp: Dirty CC before sigp execution

Claudio Imbrenda
2024-01-31T11:56:53Z

On Wed, 31 Jan 2024 07:44:23 +0000
Janosch Frank <frankja@linux.ibm.com> wrote:

> Dirtying the CC allows us to find missing CC changes when sigp is
> emulated.
>
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
> lib/s390x/asm/sigp.h | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/lib/s390x/asm/sigp.h b/lib/s390x/asm/sigp.h
> index 61d2c625..4eae95d0 100644
> --- a/lib/s390x/asm/sigp.h
> +++ b/lib/s390x/asm/sigp.h
> @@ -49,13 +49,17 @@ static inline int sigp(uint16_t addr, uint8_t order, unsigned long parm,
> uint32_t *status)
> {
> register unsigned long reg1 asm ("1") = parm;
> + uint64_t bogus_cc = SIGP_CC_NOT_OPERATIONAL;
> int cc;
>
> asm volatile(
> + " tmll %[bogus_cc],3\n"
> " sigp %1,%2,0(%3)\n"
> " ipm %0\n"
> " srl %0,28\n"
> - : "=d" (cc), "+d" (reg1) : "d" (addr), "a" (order) : "cc");
> + : "=d" (cc), "+d" (reg1)
> + : "d" (addr), "a" (order), [bogus_cc] "d" (bogus_cc)
> + : "cc");

since you are doing changes in this inline asm, could you put names for
all the parameters? that way it will be more consistent and readable.

also in all the other patches in the series (except patch 2)

> if (status)
> *status = reg1;
> return cc;