On 07/03/2022 14:03, Jan Beulich wrote:
On 07.03.2022 12:53, Bjoern Doebel wrote:
@@ -104,18 +122,36 @@ void noinline arch_livepatch_revive(void)
int arch_livepatch_verify_func(const struct livepatch_func *func)
{
+ BUILD_BUG_ON(sizeof(struct x86_livepatch_meta) != LIVEPATCH_OPAQUE_SIZE);
+
/* If NOPing.. */
if ( !func->new_addr )
{
+ struct x86_livepatch_meta *lp;
+
+ lp = (struct x86_livepatch_meta *)func->opaque;
/* Only do up to maximum amount we can put in the ->opaque. */
- if ( func->new_size > sizeof(func->opaque) )
+ if ( func->new_size > sizeof(lp->instruction) )
return -EOPNOTSUPP;
if ( func->old_size < func->new_size )
return -EINVAL;
}
I continue to be concerned of the new local variable causing compiler
warnings. With the adjustment made compared to v1, the specific
warning would have changed, and we're now liable to see set-but-never-
used ones.
Linux has a sizeof_field() macro for this sort of use.
/**
* sizeof_field() - Report the size of a struct field in bytes
*
* @TYPE: The structure containing the field of interest
* @MEMBER: The field to return the size of
*/
#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
David
