Messages in this thread Patch in this message | | | Date | Fri, 7 Feb 2003 10:03:19 +0000 | From | Russell King <> | Subject | Re: [PATCH] Restore module support. |
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On Fri, Feb 07, 2003 at 03:53:44PM +1100, Rusty Russell wrote: > Yes. PPC and PPC64 have the same issues: currently this is done by > (1) putting nothing in the .init sections (on PPC64), and (2) with > stubs when jumping outside the module code. > > This gives the same effect as the previous userspace loader: for PPC64 > noone cares about discarding init stuff, so it's firmly on the TODO > list. ARM's priorities are obviously different.
As I say, I have this solution working, but its suboptimal, and I'll probably push this Linus-wards if I can't resolve (2) soon.
> > 2. fix vmalloc and /proc/kcore to be able to cope with a separate module > > region located below PAGE_OFFSET. Currently, neither play well with > > this option. > > x86_64 has this, as does sparc64: they do their own allocation. Does > ARM require something special in this regard? I'd love to see what > you've got...
There are two problems - one I mentioned during on LKML recently:
Message-ID: <20030131102013.A19646@flint.arm.linux.org.uk>
This seems simple to resolve. We just need to make get_vm_area() ignore mappings for invalid areas:
--- orig/mm/vmalloc.c Tue Nov 5 12:51:41 2002 +++ linux/mm/vmalloc.c Fri Feb 7 09:48:42 2003 @@ -210,6 +210,8 @@ write_lock(&vmlist_lock); for (p = &vmlist; (tmp = *p) ;p = &tmp->next) { + if (tmp->addr < addr) + continue; if ((size + addr) < addr) goto out; if (size + addr <= (unsigned long)tmp->addr) Since the vmlist is an ordered list, and we place the modules below VMALLOC_START, this change ensures that we will completely ignore any vmlist entries below the current minimum address (addr) we're looking for.
/proc/kcore currently assumes that:
1. all vmlist mappings are above PAGE_OFFSET. 2. all vmlist mappings are within VMALLOC_START to VMALLOC_END
Looking at fs/proc/kcore.c this morning, I have a couple of ideas to solve this problem. Patch will follow later today, hopefully without any ifdefs.
-- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html
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