Re: [PATCH] binfmt_flat: minimum support for theBlackfin relocations

From: Bernd Schmidt
Date: Thu Sep 20 2007 - 08:05:30 EST


Paul Mundt wrote:
I find it a bit disconcerting that blackfin already depends on this
in-tree without there being any earlier discussion on making these
changes.

Parts of the initial submission were picked up (the include/asm directory), other's weren't. Little we can do about that.

*/
if (rev > OLD_FLAT_VERSION) {
+ unsigned long persistent = 0;
for (i=0; i < relocs; i++) {
unsigned long addr, relval;
@@ -749,6 +750,8 @@ static int load_flat_file(struct linux_binprm * bprm,
relocated (of course, the address has to be
relocated first). */
relval = ntohl(reloc[i]);
+ if (flat_set_persistent (relval, &persistent))
+ continue;
addr = flat_get_relocate_addr(relval);
rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
if (rp == (unsigned long *)RELOC_FAILED) {

I don't much care for this API. It's shuffling around a temporary
variable for the architecture code that's set for certain relocations
that are otherwise unhandled.

Since all the architecture is interested in is the relval that has
associated "persistent" data encoded in it, why don't we just have a stub
to give the architecture a chance to validate the relval before the
flat_get_relocate_addr() and move this stuff there instead? ie, blackfin
takes this out-of-line and manages its persistent value there.

What is flat_set_persistent other than a stub to validate the relval? I'm not at all sure what you're proposing or how it would be different.

load_flat_file() is ugly enough without dumping more architecture
callback abuses in it.

The other maintainers who have spoken up didn't seem to think this was ugly, or an abuse. I'm surprised to hear language like that when discussing a patch that adds an if statement, a local variable and one parameter in a function call.


Bernd
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