Re: [PATCH v1 05/10] asm-generic: Define 'funct_descr_t' to commonly describe function descriptors

[Christophe Leroy]

Le 13/10/2021 à 09:01, Kees Cook a écrit :
> On Mon, Oct 11, 2021 at 05:25:32PM +0200, Christophe Leroy wrote:
> > We have three architectures using function descriptors, each with its
> > own name.
> >
> > Add a common typedef that can be used in generic code.
> >
> > Also add a stub typedef for architecture without function descriptors,
>
> nit: funct_descr_t reads weird to me. why not func_desc_t ? Either way:

func_desc_t already exists in powerpc. I have a patch to remove it as it 
is redundant with struct ppc64_opd_entry, but I didnt' want to include 
it in this series.

But after all I can add it in this series, I'll add it in v2.

Christophe

> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
>
>
> > to avoid a forest of #ifdefs.
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> > ---
> >   arch/ia64/include/asm/sections.h    | 1 +
> >   arch/parisc/include/asm/sections.h  | 1 +
> >   arch/powerpc/include/asm/sections.h | 1 +
> >   include/asm-generic/sections.h      | 3 +++
> >   4 files changed, 6 insertions(+)
> >
> > diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
> > index 80f5868afb06..929b5c535620 100644
> > --- a/arch/ia64/include/asm/sections.h
> > +++ b/arch/ia64/include/asm/sections.h
> > @@ -8,6 +8,7 @@
> >    */
> >   
> >   #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
> > +typedef struct fdesc funct_descr_t;
> >   
> >   #include <linux/elf.h>
> >   #include <linux/uaccess.h>
> > diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h
> > index 2e781ee19b66..329e80f7af0a 100644
> > --- a/arch/parisc/include/asm/sections.h
> > +++ b/arch/parisc/include/asm/sections.h
> > @@ -4,6 +4,7 @@
> >   
> >   #ifdef CONFIG_64BIT
> >   #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
> > +typedef Elf64_Fdesc funct_descr_t;
> >   #endif
> >   
> >   /* nothing to see, move along */
> > diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
> > index b7f1ba04e756..d0d5287fa568 100644
> > --- a/arch/powerpc/include/asm/sections.h
> > +++ b/arch/powerpc/include/asm/sections.h
> > @@ -10,6 +10,7 @@
> >   
> >   #ifdef PPC64_ELF_ABI_v1
> >   #define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
> > +typedef struct ppc64_opd_entry funct_descr_t;
> >   #endif
> >   
> >   #include <asm-generic/sections.h>
> > diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
> > index 1db5cfd69817..436412d94054 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;
> > +} funct_descr_t;
> >   #endif
> >   
> >   /* random extra sections (if any).  Override
> > --
> > 2.31.1