[PATCH] efi: mark input variables to funcs as const

[PATCH] efi: mark input variables to funcs as const

[Doug Goldstein]

Variables that are input (IN) variables to EFI functions should be
marked as const. Just avoid potential problems of changing data that
shouldn't be changed.

Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
---

So I find myself constantly doing something similar to this when
troubleshooting EFI because I like to put print statements to see data
and figure out where problems are. The EFI print functions all take const
data but much of the data is not marked as const. If you don't like this
that's fine but I was looking at the 3 different EFI branches I have locally
and this change is in all 3 in one shape or another.

---
 xen/include/efi/efidef.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/include/efi/efidef.h b/xen/include/efi/efidef.h
index 86a7e11..1d1c779 100644
--- a/xen/include/efi/efidef.h
+++ b/xen/include/efi/efidef.h
@@ -50,7 +50,7 @@ typedef VOID            *EFI_EVENT;
 //
 
 #ifndef IN
-    #define IN
+    #define IN const
     #define OUT
     #define OPTIONAL
 #endif
-- 
2.4.10

Re: [PATCH] efi: mark input variables to funcs as const

[Jan Beulich]

>>> On 05.12.15 at 21:25, <cardoe@cardoe.com> wrote:
> Variables that are input (IN) variables to EFI functions should be
> marked as const. Just avoid potential problems of changing data that
> shouldn't be changed.

I don't think this is correct (there's no reason for a function to not
use its input arguments as variables), and it certainly should come
from upstream (i.e. UEFI -> gnu-efi -> Xen) if really meant to be
done this way. Also I think if you want this for debugging purposes,
overriding IN, OUT, and OPTIONAL in the source file(s) as intended
by the surrounding #ifdef would be the way to go.

Jan