diff mbox series

[v3,02/24] powerpc/secvar: WARN_ON_ONCE() if multiple secvar ops are set

Message ID 20230118061049.1006141-3-ajd@linux.ibm.com
State New
Headers
Series pSeries dynamic secure boot secvar interface + platform keyring loading |

Commit Message

Andrew Donnellan Jan. 18, 2023, 6:10 a.m. UTC 
  From: Russell Currey <ruscur@russell.cc>

The secvar code only supports one consumer at a time.

Multiple consumers aren't possible at this point in time, but we'd want
it to be obvious if it ever could happen.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
---
 arch/powerpc/kernel/secvar-ops.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Nicholas Piggin Jan. 19, 2023, 12:59 a.m. UTC | #1 
On Wed Jan 18, 2023 at 4:10 PM AEST, Andrew Donnellan wrote:
> From: Russell Currey <ruscur@russell.cc>
>
> The secvar code only supports one consumer at a time.
>
> Multiple consumers aren't possible at this point in time, but we'd want
> it to be obvious if it ever could happen.
>
> Signed-off-by: Russell Currey <ruscur@russell.cc>
> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
>  arch/powerpc/kernel/secvar-ops.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kernel/secvar-ops.c b/arch/powerpc/kernel/secvar-ops.c
> index 6a29777d6a2d..aa1b2adc2710 100644
> --- a/arch/powerpc/kernel/secvar-ops.c
> +++ b/arch/powerpc/kernel/secvar-ops.c
> @@ -8,10 +8,12 @@
>  
>  #include <linux/cache.h>
>  #include <asm/secvar.h>
> +#include <asm/bug.h>
>  
> -const struct secvar_operations *secvar_ops __ro_after_init;
> +const struct secvar_operations *secvar_ops __ro_after_init = NULL;
>  
>  void set_secvar_ops(const struct secvar_operations *ops)
>  {
> +	WARN_ON_ONCE(secvar_ops);
>  	secvar_ops = ops;

You could make it return error here and two line patch in the caller to
handle the error and then things wouldn't get corrupted.

Thanks,
Nick
diff mbox series

Patch

diff --git a/arch/powerpc/kernel/secvar-ops.c b/arch/powerpc/kernel/secvar-ops.c
index 6a29777d6a2d..aa1b2adc2710 100644
--- a/arch/powerpc/kernel/secvar-ops.c
+++ b/arch/powerpc/kernel/secvar-ops.c
@@ -8,10 +8,12 @@ 
 
 #include <linux/cache.h>
 #include <asm/secvar.h>
+#include <asm/bug.h>
 
-const struct secvar_operations *secvar_ops __ro_after_init;
+const struct secvar_operations *secvar_ops __ro_after_init = NULL;
 
 void set_secvar_ops(const struct secvar_operations *ops)
 {
+	WARN_ON_ONCE(secvar_ops);
 	secvar_ops = ops;
 }