[kvm-unit-tests PATCH] s390x: Use the right constraints in intercept.c

[kvm-unit-tests PATCH] s390x: Use the right constraints in intercept.c

[Thomas Huth]

stpx, spx, stap and stidp use addressing via "base register", i.e.
if register 0 is used, the base address will be 0, independent from
the value of the register. Thus we must not use the "r" constraint
here to avoid register 0. This fixes test failures when compiling
with Clang instead of GCC, since Clang apparently prefers to use
register 0 in some cases where GCC never uses register 0.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 s390x/intercept.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/s390x/intercept.c b/s390x/intercept.c
index 9e826b6c..faa74bbb 100644
--- a/s390x/intercept.c
+++ b/s390x/intercept.c
@@ -36,16 +36,16 @@ static void test_stpx(void)
 
 	expect_pgm_int();
 	low_prot_enable();
-	asm volatile(" stpx 0(%0) " : : "r"(8));
+	asm volatile(" stpx 0(%0) " : : "a"(8));
 	low_prot_disable();
 	check_pgm_int_code(PGM_INT_CODE_PROTECTION);
 
 	expect_pgm_int();
-	asm volatile(" stpx 0(%0) " : : "r"(1));
+	asm volatile(" stpx 0(%0) " : : "a"(1));
 	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
 
 	expect_pgm_int();
-	asm volatile(" stpx 0(%0) " : : "r"(-8L));
+	asm volatile(" stpx 0(%0) " : : "a"(-8L));
 	check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
 }
 
@@ -70,13 +70,13 @@ static void test_spx(void)
 
 	report_prefix_push("operand not word aligned");
 	expect_pgm_int();
-	asm volatile(" spx 0(%0) " : : "r"(1));
+	asm volatile(" spx 0(%0) " : : "a"(1));
 	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
 	report_prefix_pop();
 
 	report_prefix_push("operand outside memory");
 	expect_pgm_int();
-	asm volatile(" spx 0(%0) " : : "r"(-8L));
+	asm volatile(" spx 0(%0) " : : "a"(-8L));
 	check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
 	report_prefix_pop();
 
@@ -113,16 +113,16 @@ static void test_stap(void)
 
 	expect_pgm_int();
 	low_prot_enable();
-	asm volatile ("stap 0(%0)\n" : : "r"(8));
+	asm volatile ("stap 0(%0)\n" : : "a"(8));
 	low_prot_disable();
 	check_pgm_int_code(PGM_INT_CODE_PROTECTION);
 
 	expect_pgm_int();
-	asm volatile ("stap 0(%0)\n" : : "r"(1));
+	asm volatile ("stap 0(%0)\n" : : "a"(1));
 	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
 
 	expect_pgm_int();
-	asm volatile ("stap 0(%0)\n" : : "r"(-8L));
+	asm volatile ("stap 0(%0)\n" : : "a"(-8L));
 	check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
 }
 
@@ -138,16 +138,16 @@ static void test_stidp(void)
 
 	expect_pgm_int();
 	low_prot_enable();
-	asm volatile ("stidp 0(%0)\n" : : "r"(8));
+	asm volatile ("stidp 0(%0)\n" : : "a"(8));
 	low_prot_disable();
 	check_pgm_int_code(PGM_INT_CODE_PROTECTION);
 
 	expect_pgm_int();
-	asm volatile ("stidp 0(%0)\n" : : "r"(1));
+	asm volatile ("stidp 0(%0)\n" : : "a"(1));
 	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
 
 	expect_pgm_int();
-	asm volatile ("stidp 0(%0)\n" : : "r"(-8L));
+	asm volatile ("stidp 0(%0)\n" : : "a"(-8L));
 	check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
 }
 
-- 
2.31.1

Re: [kvm-unit-tests PATCH] s390x: Use the right constraints in intercept.c

[Claudio Imbrenda]

On Tue,  4 Apr 2023 12:24:37 +0200
Thomas Huth <thuth@redhat.com> wrote:

> stpx, spx, stap and stidp use addressing via "base register", i.e.
> if register 0 is used, the base address will be 0, independent from
> the value of the register. Thus we must not use the "r" constraint
> here to avoid register 0. This fixes test failures when compiling
> with Clang instead of GCC, since Clang apparently prefers to use
> register 0 in some cases where GCC never uses register 0.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

maybe you can also add a couple of Fixes tags:

Fixes: 2667b05e ("s390x: Interception tests")
Fixes: 484a3a57 ("s390x: add stidp interception test")

in any case:

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

> ---
>  s390x/intercept.c | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/s390x/intercept.c b/s390x/intercept.c
> index 9e826b6c..faa74bbb 100644
> --- a/s390x/intercept.c
> +++ b/s390x/intercept.c
> @@ -36,16 +36,16 @@ static void test_stpx(void)
>  
>  	expect_pgm_int();
>  	low_prot_enable();
> -	asm volatile(" stpx 0(%0) " : : "r"(8));
> +	asm volatile(" stpx 0(%0) " : : "a"(8));
>  	low_prot_disable();
>  	check_pgm_int_code(PGM_INT_CODE_PROTECTION);
>  
>  	expect_pgm_int();
> -	asm volatile(" stpx 0(%0) " : : "r"(1));
> +	asm volatile(" stpx 0(%0) " : : "a"(1));
>  	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
>  
>  	expect_pgm_int();
> -	asm volatile(" stpx 0(%0) " : : "r"(-8L));
> +	asm volatile(" stpx 0(%0) " : : "a"(-8L));
>  	check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
>  }
>  
> @@ -70,13 +70,13 @@ static void test_spx(void)
>  
>  	report_prefix_push("operand not word aligned");
>  	expect_pgm_int();
> -	asm volatile(" spx 0(%0) " : : "r"(1));
> +	asm volatile(" spx 0(%0) " : : "a"(1));
>  	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
>  	report_prefix_pop();
>  
>  	report_prefix_push("operand outside memory");
>  	expect_pgm_int();
> -	asm volatile(" spx 0(%0) " : : "r"(-8L));
> +	asm volatile(" spx 0(%0) " : : "a"(-8L));
>  	check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
>  	report_prefix_pop();
>  
> @@ -113,16 +113,16 @@ static void test_stap(void)
>  
>  	expect_pgm_int();
>  	low_prot_enable();
> -	asm volatile ("stap 0(%0)\n" : : "r"(8));
> +	asm volatile ("stap 0(%0)\n" : : "a"(8));
>  	low_prot_disable();
>  	check_pgm_int_code(PGM_INT_CODE_PROTECTION);
>  
>  	expect_pgm_int();
> -	asm volatile ("stap 0(%0)\n" : : "r"(1));
> +	asm volatile ("stap 0(%0)\n" : : "a"(1));
>  	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
>  
>  	expect_pgm_int();
> -	asm volatile ("stap 0(%0)\n" : : "r"(-8L));
> +	asm volatile ("stap 0(%0)\n" : : "a"(-8L));
>  	check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
>  }
>  
> @@ -138,16 +138,16 @@ static void test_stidp(void)
>  
>  	expect_pgm_int();
>  	low_prot_enable();
> -	asm volatile ("stidp 0(%0)\n" : : "r"(8));
> +	asm volatile ("stidp 0(%0)\n" : : "a"(8));
>  	low_prot_disable();
>  	check_pgm_int_code(PGM_INT_CODE_PROTECTION);
>  
>  	expect_pgm_int();
> -	asm volatile ("stidp 0(%0)\n" : : "r"(1));
> +	asm volatile ("stidp 0(%0)\n" : : "a"(1));
>  	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
>  
>  	expect_pgm_int();
> -	asm volatile ("stidp 0(%0)\n" : : "r"(-8L));
> +	asm volatile ("stidp 0(%0)\n" : : "a"(-8L));
>  	check_pgm_int_code(PGM_INT_CODE_ADDRESSING);
>  }
>  

Re: [kvm-unit-tests PATCH] s390x: Use the right constraints in intercept.c

[Nico Boehr]

Quoting Thomas Huth (2023-04-04 12:24:37)
> stpx, spx, stap and stidp use addressing via "base register", i.e.
> if register 0 is used, the base address will be 0, independent from
> the value of the register. Thus we must not use the "r" constraint
> here to avoid register 0. This fixes test failures when compiling
> with Clang instead of GCC, since Clang apparently prefers to use
> register 0 in some cases where GCC never uses register 0.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

Reviewed-by: Nico Boehr <nrb@linux.ibm.com>