[PATCH v3 03/13] Rewrite abi-note.S in C.

[Szabolcs Nagy]

The 05/18/2020 17:28, Florian Weimer wrote:
> * Szabolcs Nagy:
> 
> > +/* Note: Custom type is used as ElfW(Nhdr) is wrong on 64 bit targets.  */
> 
> Are you sure about that?
> 
> typedef struct
> {
>   Elf32_Word n_namesz;			/* Length of the note's name.  */
>   Elf32_Word n_descsz;			/* Length of the note's descriptor.  */
>   Elf32_Word n_type;			/* Type of the note.  */
> } Elf32_Nhdr;
> 
> typedef struct
> {
>   Elf64_Word n_namesz;			/* Length of the note's name.  */
>   Elf64_Word n_descsz;			/* Length of the note's descriptor.  */
>   Elf64_Word n_type;			/* Type of the note.  */
> } Elf64_Nhdr;
> 
> The types are the same:
> 
> typedef uint32_t Elf32_Word;
> typedef uint32_t Elf64_Word;
> 
> I admit this is super-confusing.

aah i missed this, then the struct can be

#include <elf.h>

__attribute__ ((used, aligned (4), section (".note.ABI-tag")))
static const struct
{
  ElfW(Nhdr) nhdr;
  char name[4];
  int32_t desc[4];
} __abi_tag = {
  { .n_namesz = 4, .n_descsz = 16, .n_type = 1 },
  "GNU",
  { __ABI_TAG_OS, __ABI_TAG_VERSION }
};

i think the aligned attribute is still needed in case on
some target uint32_t has smaller alignemnt than 4.

i can change this if it is considered to be better
or just remove the incorrect comment.