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s390x: STFLE operates on doublewords

PATCH In review David Hildenbrand 3 participants 4 messages Apr 1, 2020 – Apr 2, 2020 KVM

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#0 lore raw

PATCH 1/1 s390x: STFLE operates on doublewords

STFLE operates on doublewords, not bytes. Passing in "256" resulted in some ignored bits getting set. Not bad, but also not clean.

Let's just convert our stfle handling code to operate on doublewords.

---
 lib/s390x/asm/facility.h | 14 +++++++-------
 lib/s390x/io.c           |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)
lib/s390x/asm/facility.h +7 -7
index e34dc2c..def2705 100644
@@ -14,12 +14,12 @@
 #include <asm/facility.h>
 #include <asm/arch_def.h>
 
-#define NR_STFL_BYTES 256
-extern uint8_t stfl_bytes[];
+#define NB_STFL_DOUBLEWORDS 32
+extern uint64_t stfl_doublewords[];
 
 static inline bool test_facility(int nr)
 {
-	return stfl_bytes[nr / 8] & (0x80U >> (nr % 8));
+	return stfl_doublewords[nr / 64] & (0x8000000000000000UL >> (nr % 64));
 }
 
 static inline void stfl(void)
@@ -27,9 +27,9 @@ static inline void stfl(void)
 	asm volatile("	stfl	0(0)\n" : : : "memory");
 }
 
-static inline void stfle(uint8_t *fac, unsigned int len)
+static inline void stfle(uint64_t *fac, unsigned int nb_doublewords)
 {
-	register unsigned long r0 asm("0") = len - 1;
+	register unsigned long r0 asm("0") = nb_doublewords - 1;
 
 	asm volatile("	.insn	s,0xb2b00000,0(%1)\n"
 		     : "+d" (r0) : "a" (fac) : "memory", "cc");
@@ -40,9 +40,9 @@ static inline void setup_facilities(void)
 	struct lowcore *lc = NULL;
 
 	stfl();
-	memcpy(stfl_bytes, &lc->stfl, sizeof(lc->stfl));
+	memcpy(stfl_doublewords, &lc->stfl, sizeof(lc->stfl));
 	if (test_facility(7))
-		stfle(stfl_bytes, NR_STFL_BYTES);
+		stfle(stfl_doublewords, NB_STFL_DOUBLEWORDS);
 }
 
 #endif
lib/s390x/io.c +1 -1
index e091c37..c0f0bf7 100644
@@ -19,7 +19,7 @@
 #include "smp.h"
 
 extern char ipl_args[];
-uint8_t stfl_bytes[NR_STFL_BYTES] __attribute__((aligned(8)));
+uint64_t stfl_doublewords[NB_STFL_DOUBLEWORDS];
 
 static struct spinlock lock;
 
Signature · 1 line
2.25.1
Reviewed-by on v1 1/1
#1 lore raw
Quoted 6 lines · David Hildenbrand

STFLE operates on doublewords, not bytes. Passing in "256" resulted in some ignored bits getting set. Not bad, but also not clean.

Let's just convert our stfle handling code to operate on doublewords.

Quoted 63 lines
---
 lib/s390x/asm/facility.h | 14 +++++++-------
 lib/s390x/io.c           |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)
lib/s390x/asm/facility.h +7 -7
index e34dc2c..def2705 100644
@@ -14,12 +14,12 @@
 #include <asm/facility.h>
 #include <asm/arch_def.h>
 
-#define NR_STFL_BYTES 256
-extern uint8_t stfl_bytes[];
+#define NB_STFL_DOUBLEWORDS 32
+extern uint64_t stfl_doublewords[];
 
 static inline bool test_facility(int nr)
 {
-	return stfl_bytes[nr / 8] & (0x80U >> (nr % 8));
+	return stfl_doublewords[nr / 64] & (0x8000000000000000UL >> (nr % 64));
 }
 
 static inline void stfl(void)
@@ -27,9 +27,9 @@ static inline void stfl(void)
 	asm volatile("	stfl	0(0)\n" : : : "memory");
 }
 
-static inline void stfle(uint8_t *fac, unsigned int len)
+static inline void stfle(uint64_t *fac, unsigned int nb_doublewords)
 {
-	register unsigned long r0 asm("0") = len - 1;
+	register unsigned long r0 asm("0") = nb_doublewords - 1;
 
 	asm volatile("	.insn	s,0xb2b00000,0(%1)\n"
 		     : "+d" (r0) : "a" (fac) : "memory", "cc");
@@ -40,9 +40,9 @@ static inline void setup_facilities(void)
 	struct lowcore *lc = NULL;
 
 	stfl();
-	memcpy(stfl_bytes, &lc->stfl, sizeof(lc->stfl));
+	memcpy(stfl_doublewords, &lc->stfl, sizeof(lc->stfl));
 	if (test_facility(7))
-		stfle(stfl_bytes, NR_STFL_BYTES);
+		stfle(stfl_doublewords, NB_STFL_DOUBLEWORDS);
 }
 
 #endif
lib/s390x/io.c +1 -1
index e091c37..c0f0bf7 100644
@@ -19,7 +19,7 @@
 #include "smp.h"
 
 extern char ipl_args[];
-uint8_t stfl_bytes[NR_STFL_BYTES] __attribute__((aligned(8)));
+uint64_t stfl_doublewords[NB_STFL_DOUBLEWORDS];
 
 static struct spinlock lock;
 
Reviewed-by on v1 1/1
#2 lore raw
In reply to David Hildenbrand
Quoted 6 lines · David Hildenbrand

STFLE operates on doublewords, not bytes. Passing in "256" resulted in some ignored bits getting set. Not bad, but also not clean.

Let's just convert our stfle handling code to operate on doublewords.

Quoted 63 lines
---
 lib/s390x/asm/facility.h | 14 +++++++-------
 lib/s390x/io.c           |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)
lib/s390x/asm/facility.h +7 -7
index e34dc2c..def2705 100644
@@ -14,12 +14,12 @@
 #include <asm/facility.h>
 #include <asm/arch_def.h>
 
-#define NR_STFL_BYTES 256
-extern uint8_t stfl_bytes[];
+#define NB_STFL_DOUBLEWORDS 32
+extern uint64_t stfl_doublewords[];
 
 static inline bool test_facility(int nr)
 {
-	return stfl_bytes[nr / 8] & (0x80U >> (nr % 8));
+	return stfl_doublewords[nr / 64] & (0x8000000000000000UL >> (nr % 64));
 }
 
 static inline void stfl(void)
@@ -27,9 +27,9 @@ static inline void stfl(void)
 	asm volatile("	stfl	0(0)\n" : : : "memory");
 }
 
-static inline void stfle(uint8_t *fac, unsigned int len)
+static inline void stfle(uint64_t *fac, unsigned int nb_doublewords)
 {
-	register unsigned long r0 asm("0") = len - 1;
+	register unsigned long r0 asm("0") = nb_doublewords - 1;
 
 	asm volatile("	.insn	s,0xb2b00000,0(%1)\n"
 		     : "+d" (r0) : "a" (fac) : "memory", "cc");
@@ -40,9 +40,9 @@ static inline void setup_facilities(void)
 	struct lowcore *lc = NULL;
 
 	stfl();
-	memcpy(stfl_bytes, &lc->stfl, sizeof(lc->stfl));
+	memcpy(stfl_doublewords, &lc->stfl, sizeof(lc->stfl));
 	if (test_facility(7))
-		stfle(stfl_bytes, NR_STFL_BYTES);
+		stfle(stfl_doublewords, NB_STFL_DOUBLEWORDS);
 }
 
 #endif
lib/s390x/io.c +1 -1
index e091c37..c0f0bf7 100644
@@ -19,7 +19,7 @@
 #include "smp.h"
 
 extern char ipl_args[];
-uint8_t stfl_bytes[NR_STFL_BYTES] __attribute__((aligned(8)));
+uint64_t stfl_doublewords[NB_STFL_DOUBLEWORDS];
 
 static struct spinlock lock;
 
#3 lore raw
In reply to David Hildenbrand
Quoted 61 lines · David Hildenbrand

STFLE operates on doublewords, not bytes. Passing in "256" resulted in some ignored bits getting set. Not bad, but also not clean.

Let's just convert our stfle handling code to operate on doublewords.

---
 lib/s390x/asm/facility.h | 14 +++++++-------
 lib/s390x/io.c           |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)
lib/s390x/asm/facility.h +7 -7
index e34dc2c..def2705 100644
@@ -14,12 +14,12 @@
 #include <asm/facility.h>
 #include <asm/arch_def.h>
 
-#define NR_STFL_BYTES 256
-extern uint8_t stfl_bytes[];
+#define NB_STFL_DOUBLEWORDS 32
+extern uint64_t stfl_doublewords[];
 
 static inline bool test_facility(int nr)
 {
-	return stfl_bytes[nr / 8] & (0x80U >> (nr % 8));
+	return stfl_doublewords[nr / 64] & (0x8000000000000000UL >> (nr % 64));
 }
 
 static inline void stfl(void)
@@ -27,9 +27,9 @@ static inline void stfl(void)
 	asm volatile("	stfl	0(0)\n" : : : "memory");
 }
 
-static inline void stfle(uint8_t *fac, unsigned int len)
+static inline void stfle(uint64_t *fac, unsigned int nb_doublewords)
 {
-	register unsigned long r0 asm("0") = len - 1;
+	register unsigned long r0 asm("0") = nb_doublewords - 1;
 
 	asm volatile("	.insn	s,0xb2b00000,0(%1)\n"
 		     : "+d" (r0) : "a" (fac) : "memory", "cc");
@@ -40,9 +40,9 @@ static inline void setup_facilities(void)
 	struct lowcore *lc = NULL;
 
 	stfl();
-	memcpy(stfl_bytes, &lc->stfl, sizeof(lc->stfl));
+	memcpy(stfl_doublewords, &lc->stfl, sizeof(lc->stfl));
 	if (test_facility(7))
-		stfle(stfl_bytes, NR_STFL_BYTES);
+		stfle(stfl_doublewords, NB_STFL_DOUBLEWORDS);
 }
 
 #endif
lib/s390x/io.c +0 -0
index e091c37..c0f0bf7 100644

lib/s390x/io.c line 25

Quoted 8 lines
lib/s390x/io.c +1 -1
@@ -19,7 +19,7 @@
 #include "smp.h"
 
 extern char ipl_args[];
-uint8_t stfl_bytes[NR_STFL_BYTES] __attribute__((aligned(8)));
+uint64_t stfl_doublewords[NB_STFL_DOUBLEWORDS];
 
 static struct spinlock lock;
 

Queued to

https://github.com/davidhildenbrand/kvm-unit-tests.git s390x-next

thanks for the review

Signature · 3 lines
Thanks,

David / dhildenb