[kvm-unit-tests PATCH v8 4/6] s390x: lib: add SPX and STPX instruction wrapper

Claudio Imbrenda
2020-01-20T18:43:06Z

Add a wrapper for the SET PREFIX and STORE PREFIX instructions, and
use it instead of using inline assembly.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
---
lib/s390x/asm/arch_def.h | 13 +++++++++++++
s390x/intercept.c | 24 +++++++++---------------
2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 1a5e3c6..15a4d49 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -284,4 +284,17 @@ static inline int servc(uint32_t command, unsigned long sccb)
return cc;
}

+static inline void set_prefix(uint32_t new_prefix)
+{
+ asm volatile(" spx %0" : : "Q" (new_prefix) : "memory");
+}
+
+static inline uint32_t get_prefix(void)
+{
+ uint32_t current_prefix;
+
+ asm volatile(" stpx %0" : "=Q" (current_prefix));
+ return current_prefix;
+}
+
#endif
diff --git a/s390x/intercept.c b/s390x/intercept.c
index 3696e33..5f46b82 100644
--- a/s390x/intercept.c
+++ b/s390x/intercept.c
@@ -13,6 +13,7 @@
#include <asm/asm-offsets.h>
#include <asm/interrupt.h>
#include <asm/page.h>
+#include <asm/facility.h>

static uint8_t pagebuf[PAGE_SIZE * 2] __attribute__((aligned(PAGE_SIZE * 2)));

@@ -26,13 +27,10 @@ static void test_stpx(void)
uint32_t new_prefix = (uint32_t)(intptr_t)pagebuf;

/* Can we successfully change the prefix? */
- asm volatile (
- " stpx %0\n"
- " spx %2\n"
- " stpx %1\n"
- " spx %0\n"
- : "+Q"(old_prefix), "+Q"(tst_prefix)
- : "Q"(new_prefix));
+ old_prefix = get_prefix();
+ set_prefix(new_prefix);
+ tst_prefix = get_prefix();
+ set_prefix(old_prefix);
report(old_prefix == 0 && tst_prefix == new_prefix, "store prefix");

expect_pgm_int();
@@ -63,14 +61,10 @@ static void test_spx(void)
* some facility bits there ... at least some of them should be
* set in our buffer afterwards.
*/
- asm volatile (
- " stpx %0\n"
- " spx %1\n"
- " stfl 0\n"
- " spx %0\n"
- : "+Q"(old_prefix)
- : "Q"(new_prefix)
- : "memory");
+ old_prefix = get_prefix();
+ set_prefix(new_prefix);
+ stfl();
+ set_prefix(old_prefix);
report(pagebuf[GEN_LC_STFL] != 0, "stfl to new prefix");

expect_pgm_int();
--
2.24.1