Query/feature bits are commonly tested via MSB bit numbers on
s390. Let's add test bit functions, so we don't need to copy code to
test query bits.
The test_bit code has been taken from the kernel since most s390x KVM unit
test developers are used to them.
Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx>
---
lib/s390x/asm/bitops.h | 26 ++++++++++++++++++++++++++
lib/s390x/asm/facility.h | 3 ++-
s390x/uv-guest.c | 6 +++---
3 files changed, 31 insertions(+), 4 deletions(-)
diff --git a/lib/s390x/asm/bitops.h b/lib/s390x/asm/bitops.h
index e7cdda9..792881e 100644
--- a/lib/s390x/asm/bitops.h
+++ b/lib/s390x/asm/bitops.h
@@ -1,3 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Bitops taken from the kernel as most developers are already used
+ * to them.
+ *
+ * Copyright IBM Corp. 1999,2013
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@xxxxxxxxxx>,
+ *
+ */
#ifndef _ASMS390X_BITOPS_H_
#define _ASMS390X_BITOPS_H_
@@ -7,4 +17,20 @@
#define BITS_PER_LONG 64
+static inline bool test_bit(unsigned long nr,
+ const volatile unsigned long *ptr)
+{
+ const volatile unsigned char *addr;
+
+ addr = ((const volatile unsigned char *)ptr);
+ addr += (nr ^ (BITS_PER_LONG - 8)) >> 3;
+ return (*addr >> (nr & 7)) & 1;
+}
+
+static inline bool test_bit_inv(unsigned long nr,
+ const volatile unsigned long *ptr)
+{
+ return test_bit(nr ^ (BITS_PER_LONG - 1), ptr);
+}
+
#endif
diff --git a/lib/s390x/asm/facility.h b/lib/s390x/asm/facility.h
index 7828cf8..95d4a15 100644
--- a/lib/s390x/asm/facility.h
+++ b/lib/s390x/asm/facility.h
@@ -11,13 +11,14 @@
#include <libcflat.h>
#include <asm/facility.h>
#include <asm/arch_def.h>
+#include <bitops.h>
#define NB_STFL_DOUBLEWORDS 32
extern uint64_t stfl_doublewords[];
static inline bool test_facility(int nr)
{
- return stfl_doublewords[nr / 64] & (0x8000000000000000UL >> (nr % 64));
+ return test_bit_inv(nr, stfl_doublewords);
}
static inline void stfl(void)
diff --git a/s390x/uv-guest.c b/s390x/uv-guest.c
index bc947ab..e51b85e 100644
--- a/s390x/uv-guest.c
+++ b/s390x/uv-guest.c
@@ -75,11 +75,11 @@ static void test_query(void)
* Ultravisor version and are expected to always be available
* because they are basic building blocks.
*/
- report(uvcb.inst_calls_list[0] & (1UL << (63 - BIT_UVC_CMD_QUI)),
+ report(test_bit_inv(BIT_UVC_CMD_QUI, &uvcb.inst_calls_list[0]),
"query indicated");
- report(uvcb.inst_calls_list[0] & (1UL << (63 - BIT_UVC_CMD_SET_SHARED_ACCESS)),
+ report(test_bit_inv(BIT_UVC_CMD_SET_SHARED_ACCESS, &uvcb.inst_calls_list[0]),
"share indicated");
- report(uvcb.inst_calls_list[0] & (1UL << (63 - BIT_UVC_CMD_REMOVE_SHARED_ACCESS)),
+ report(test_bit_inv(BIT_UVC_CMD_REMOVE_SHARED_ACCESS, &uvcb.inst_calls_list[0]),
"unshare indicated");
report_prefix_pop();
}
--
2.25.1
