[POWERPC] spufs: Cleanup ELF coredump extra notes logic

To start with, arch_notes_size() etc. is a little too ambiguous a name for
my liking, so change the function names to be more explicit.

Calling through macros is ugly, especially with hidden parameters, so don't
do that, call the routines directly.

Use ARCH_HAVE_EXTRA_ELF_NOTES as the only flag, and based on it decide
whether we want the extern declarations or the empty versions.

Since we have empty routines, actually use them in the coredump code to
save a few #ifdefs.

We want to change the handling of foffset so that the write routine updates
foffset as it goes, instead of using file->f_pos (so that writing to a pipe
works).  So pass foffset to the write routine, and for now just set it to
file->f_pos at the end of writing.

It should also be possible for the write routine to fail, so change it to
return int and treat a non-zero return as failure.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 8b17ffe..d2da84a 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -389,12 +389,14 @@
 
 #endif
 
+/* Optional callbacks to write extra ELF notes. */
 #ifndef ARCH_HAVE_EXTRA_ELF_NOTES
-static inline int arch_notes_size(void) { return 0; }
-static inline void arch_write_notes(struct file *file) { }
-
-#define ELF_CORE_EXTRA_NOTES_SIZE arch_notes_size()
-#define ELF_CORE_WRITE_EXTRA_NOTES arch_write_notes(file)
-#endif /* ARCH_HAVE_EXTRA_ELF_NOTES */
+static inline int elf_coredump_extra_notes_size(void) { return 0; }
+static inline int elf_coredump_extra_notes_write(struct file *file,
+			loff_t *foffset) { return 0; }
+#else
+extern int elf_coredump_extra_notes_size(void);
+extern int elf_coredump_extra_notes_write(struct file *file, loff_t *foffset);
+#endif
 
 #endif /* _LINUX_ELF_H */