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[kvm-unit-tests,v2,4/5] s390x: sclp: add service call instruction wrapper

Message ID 1572023194-14370-5-git-send-email-imbrenda@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series s390x: SCLP Unit test | expand

Commit Message

Claudio Imbrenda Oct. 25, 2019, 5:06 p.m. UTC
Add a wrapper for the service call instruction, and use it for SCLP
interactions instead of using inline assembly everywhere.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
---
 lib/s390x/asm/arch_def.h | 13 +++++++++++++
 lib/s390x/sclp.c         |  7 +------
 2 files changed, 14 insertions(+), 6 deletions(-)

Comments

Janosch Frank Nov. 4, 2019, 9:22 a.m. UTC | #1
On 10/25/19 7:06 PM, Claudio Imbrenda wrote:
> Add a wrapper for the service call instruction, and use it for SCLP
> interactions instead of using inline assembly everywhere.

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> ---
>  lib/s390x/asm/arch_def.h | 13 +++++++++++++
>  lib/s390x/sclp.c         |  7 +------
>  2 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index 96cca2e..b3caff6 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -269,4 +269,17 @@ static inline int stsi(void *addr, int fc, int sel1, int sel2)
>  	return cc;
>  }
>  
> +static inline int servc(uint32_t command, unsigned long sccb)
> +{
> +	int cc;
> +
> +	asm volatile(
> +		"       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
> +		"       ipm     %0\n"
> +		"       srl     %0,28"
> +		: "=&d" (cc) : "d" (command), "a" (sccb)
> +		: "cc", "memory");
> +	return cc;
> +}
> +
>  #endif
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 7798f04..e35c282 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -116,12 +116,7 @@ int sclp_service_call(unsigned int command, void *sccb)
>  	int cc;
>  
>  	sclp_setup_int();
> -	asm volatile(
> -		"       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
> -		"       ipm     %0\n"
> -		"       srl     %0,28"
> -		: "=&d" (cc) : "d" (command), "a" (__pa(sccb))
> -		: "cc", "memory");
> +	cc = servc(command, __pa(sccb));
>  	sclp_wait_busy();
>  	if (cc == 3)
>  		return -1;
>
David Hildenbrand Nov. 4, 2019, 10:06 a.m. UTC | #2
On 25.10.19 19:06, Claudio Imbrenda wrote:
> Add a wrapper for the service call instruction, and use it for SCLP
> interactions instead of using inline assembly everywhere.
> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> ---
>   lib/s390x/asm/arch_def.h | 13 +++++++++++++
>   lib/s390x/sclp.c         |  7 +------
>   2 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index 96cca2e..b3caff6 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -269,4 +269,17 @@ static inline int stsi(void *addr, int fc, int sel1, int sel2)
>   	return cc;
>   }
>   
> +static inline int servc(uint32_t command, unsigned long sccb)
> +{
> +	int cc;
> +
> +	asm volatile(
> +		"       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
> +		"       ipm     %0\n"
> +		"       srl     %0,28"
> +		: "=&d" (cc) : "d" (command), "a" (sccb)
> +		: "cc", "memory");
> +	return cc;
> +}
> +
>   #endif
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 7798f04..e35c282 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -116,12 +116,7 @@ int sclp_service_call(unsigned int command, void *sccb)
>   	int cc;
>   
>   	sclp_setup_int();
> -	asm volatile(
> -		"       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
> -		"       ipm     %0\n"
> -		"       srl     %0,28"
> -		: "=&d" (cc) : "d" (command), "a" (__pa(sccb))
> -		: "cc", "memory");
> +	cc = servc(command, __pa(sccb));
>   	sclp_wait_busy();
>   	if (cc == 3)
>   		return -1;
> 

I do wonder if we should really do that. Shouldn't we always set/wait if 
busy (especially, if testing for an error condition that won't trigger)? 
IOW, shouldn't we have a modified sclp_service_call() that returns the 
CC (and also calls sclp_setup_int()/sclp_wait_busy())?

We could also simply make sclp_service_call() return the cc and handle 
the cc in the existing callers.
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Patch

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 96cca2e..b3caff6 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -269,4 +269,17 @@  static inline int stsi(void *addr, int fc, int sel1, int sel2)
 	return cc;
 }
 
+static inline int servc(uint32_t command, unsigned long sccb)
+{
+	int cc;
+
+	asm volatile(
+		"       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
+		"       ipm     %0\n"
+		"       srl     %0,28"
+		: "=&d" (cc) : "d" (command), "a" (sccb)
+		: "cc", "memory");
+	return cc;
+}
+
 #endif
diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
index 7798f04..e35c282 100644
--- a/lib/s390x/sclp.c
+++ b/lib/s390x/sclp.c
@@ -116,12 +116,7 @@  int sclp_service_call(unsigned int command, void *sccb)
 	int cc;
 
 	sclp_setup_int();
-	asm volatile(
-		"       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
-		"       ipm     %0\n"
-		"       srl     %0,28"
-		: "=&d" (cc) : "d" (command), "a" (__pa(sccb))
-		: "cc", "memory");
+	cc = servc(command, __pa(sccb));
 	sclp_wait_busy();
 	if (cc == 3)
 		return -1;