loadelf_32.c: code review request: was=>Re: ia64 unwind section: Loader implementation

["Cherry G. Mathew" <cherry%sdf.lonestar.org@localhost>]

On 12/31/05, Cherry George Mathew <cherry%sdf.lonestar.org@localhost> wrote:
> On Fri, 2005-12-30 at 09:38 -0500, Allen Briggs wrote:
>
> > Aside from that, this seems like the best option to me, but can it
> > be abstracted a little bit into an md callback?  Either to allow
> > machine-specific selection of extra sections to load (I think this
> > is my preference without digging into the code) or to just call a
> > machine-specific routine to load what it needs?
> >
>
> On IA64, I found it best to implement it via a simple macro which
> returns boolean about whether the
> segment needs to be loaded. The macro would be passed the whole Phdr
> structure which would enable
> the md hook to do post processing ( reloc type thingies ? ) if
> required.
>
> For IA64 unwind sections, a simple one liner did the trick:
>
> #define MD_LOADSEG(phdr) (phdr.p_type == PT_IA_64_UNWIND ? TRUE : FALSE)
>
> I've filed a PR: kern/32423
> http://netbsd.org/cgi-bin/query-pr-single.pl?number=32423
>
> Thanks,
>
> Cherry
>
>

Hi,

Would this affect other ports ?

Thanks,

Cherry


cvs diff -uN loadfile_elf32.c
Index: loadfile_elf32.c
===================================================================
RCS file: /cvsroot/src/sys/lib/libsa/loadfile_elf32.c,v
retrieving revision 1.13
diff -u -r1.13 loadfile_elf32.c
--- loadfile_elf32.c    25 Jan 2006 18:27:23 -0000      1.13
+++ loadfile_elf32.c    1 Apr 2006 19:02:52 -0000
@@ -296,6 +296,13 @@

        for (first = 1, i = 0; i < elf->e_phnum; i++) {
                internalize_phdr(elf->e_ident[EI_DATA], &phdr[i]);
+
+#ifdef MD_LOADSEG /* Allow processor ABI specific segment loads */
+               if ( (phdr[i].p_type & PT_LOPROC) &&
+                    MD_LOADSEG(phdr[i]))
+                       goto loadseg;
+#endif /*MD_LOADSEG*/
+
                if (phdr[i].p_type != PT_LOAD ||
                    (phdr[i].p_flags & (PF_W|PF_X)) == 0)
                        continue;
@@ -309,6 +316,7 @@
                if ((IS_TEXT(phdr[i]) && (flags & LOAD_TEXT)) ||
                    (IS_DATA(phdr[i]) && (flags & LOAD_DATA))) {

+               loadseg:
                        /* Read in segment. */
                        PROGRESS(("%s%lu", first ? "" : "+",
                            (u_long)phdr[i].p_filesz));


--
~Cherry