Re: [kvm-unit-tests PATCH 1/2] arm/arm64: spinlock-test fixup

[Paolo Bonzini <pbonzini@redhat.com>]

On 06/07/2015 15:31, Andrew Jones wrote:
> +	if (argc && strcmp(argv[0], "non-atomic") != 0) {

You want == here, don't you?

The reason I switched was that the non-atomic test didn't work for me.
I have now debugged it, and it needs this:

@@ -29,12 +29,12 @@ static void gcc_builtin_unlock(int *lock_var)
 }
 static void none_lock(int *lock_var)
 {
-       while (*lock_var != 0);
-       *lock_var = 1;
+       while (*(volatile int *)lock_var != 0);
+       *(volatile int *)lock_var = 1;
 }
 static void none_unlock(int *lock_var)
 {
-       *lock_var = 0;
+       *(volatile int *)lock_var = 0;
 }

 static int global_a, global_b;

Otherwise the none_lock function does not reload lock_var.

Paolo

>  		lock_ops.lock = none_lock;
>  		lock_ops.unlock = none_unlock;
> +	} else {
> +		lock_ops.lock = gcc_builtin_lock;
> +		lock_ops.unlock = gcc_builtin_unlock;
>  	}