Le 18/10/2021 à 08:29, Nicholas Piggin a écrit :
Excerpts from Christophe Leroy's message of October 17, 2021 10:38 pm:
We have three architectures using function descriptors, each with its
own type and name.
Add a common typedef that can be used in generic code.
Also add a stub typedef for architecture without function descriptors,
to avoid a forest of #ifdefs.
It replaces the similar 'func_desc_t' previously defined in
arch/powerpc/kernel/module_64.c
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
[...]
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index a918388d9bf6..33b51efe3a24 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -63,6 +63,9 @@ extern __visible const void __nosave_begin, __nosave_end;
#else
#define dereference_function_descriptor(p) ((void *)(p))
#define dereference_kernel_function_descriptor(p) ((void *)(p))
+typedef struct {
+ unsigned long addr;
+} func_desc_t;
#endif
I think that deserves a comment. If it's just to allow ifdef to be
avoided, I guess that's okay with a comment. Would be nice if you could
cause it to generate a link time error if it was ever used like
undefined functions, but I guess you can't. It's not a necessity though.
I tried to explain it in the commit message, but I can add a comment
here in addition for sure.
By the way, it IS used in powerpc's module_64.c:
static func_desc_t func_desc(unsigned long addr)
{
return (func_desc_t){addr};
}
static unsigned long func_addr(unsigned long addr)
{
return func_desc(addr).addr;
}
