| Message ID | 20240131074427.70871-3-frankja@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x: Dirty cc before executing tested instructions | expand |
On Wed, 31 Jan 2024 07:44:24 +0000 Janosch Frank <frankja@linux.ibm.com> wrote: > Dirtying the CC allows us to find missing CC changes. > > Signed-off-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > --- > lib/s390x/asm/uv.h | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/lib/s390x/asm/uv.h b/lib/s390x/asm/uv.h > index e9fb19af..611dcd3f 100644 > --- a/lib/s390x/asm/uv.h > +++ b/lib/s390x/asm/uv.h > @@ -216,14 +216,16 @@ struct uv_cb_ssc { > > static inline int uv_call_once(unsigned long r1, unsigned long r2) > { > + uint64_t bogus_cc = 1; > int cc; > > asm volatile( > + " tmll %[bogus_cc],3\n" > "0: .insn rrf,0xB9A40000,%[r1],%[r2],0,0\n" > " ipm %[cc]\n" > " srl %[cc],28\n" > : [cc] "=d" (cc) > - : [r1] "a" (r1), [r2] "a" (r2) > + : [r1] "a" (r1), [r2] "a" (r2), [bogus_cc] "d" (bogus_cc) > : "memory", "cc"); > > if (UVC_ERR_DEBUG && cc == 1)
diff --git a/lib/s390x/asm/uv.h b/lib/s390x/asm/uv.h index e9fb19af..611dcd3f 100644 --- a/lib/s390x/asm/uv.h +++ b/lib/s390x/asm/uv.h @@ -216,14 +216,16 @@ struct uv_cb_ssc { static inline int uv_call_once(unsigned long r1, unsigned long r2) { + uint64_t bogus_cc = 1; int cc; asm volatile( + " tmll %[bogus_cc],3\n" "0: .insn rrf,0xB9A40000,%[r1],%[r2],0,0\n" " ipm %[cc]\n" " srl %[cc],28\n" : [cc] "=d" (cc) - : [r1] "a" (r1), [r2] "a" (r2) + : [r1] "a" (r1), [r2] "a" (r2), [bogus_cc] "d" (bogus_cc) : "memory", "cc"); if (UVC_ERR_DEBUG && cc == 1)
Dirtying the CC allows us to find missing CC changes. Signed-off-by: Janosch Frank <frankja@linux.ibm.com> --- lib/s390x/asm/uv.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)