RE: [PATCH] Restore module support.

From: Luck, Tony (tony.luck@intel.com)
Date: Fri Feb 07 2003 - 16:15:54 EST


Russell King wrote:
> On Fri, Feb 07, 2003 at 10:43:19AM -0800, Luck, Tony wrote:
> > > (2) has the disadvantage that its touching
> non-architecture specific
> > > code, but this is the option I'd prefer due to the
> obvious performance
> > > advantage. However, I'm afraid that it isn't worth the
> effort to fix
> > > up vmalloc and /proc/kcore. vmalloc fix appears simple,
> but /proc/kcore
> > > has issues (anyone know what KCORE_BASE is all about?)
> >
> > KCORE_BASE is my fault ... it was an attempt to fix the "modules
> > below PAGE_OFFSET" problem for the ia64 port. For a few nanoseconds
> > the code just here looked like this:
> >
> > #if VMALLOC_START < PAGE_OFFSET
> > #define KCORE_BASE VMALLOC_START
> > #else
> > #define KCORE_BASE PAGE_OFFSET
> > #endif
>
> Ah, ok. What I'm thinking of is something like the following
> (untested
> and probably improperly thought out patch...):
>
> --- orig/fs/proc/kcore.c Sat Nov 2 18:58:18 2002
> +++ linux/fs/proc/kcore.c Fri Feb 7 19:48:35 2003
> @@ -99,7 +99,10 @@
> }
> #else /* CONFIG_KCORE_AOUT */
>
> +#ifndef KCORE_BASE
> #define KCORE_BASE PAGE_OFFSET
> +) < #define in_vmlist_region(x) ((x) >= VMALLOC_START && (x
> VMALLOC_END)
> +#endif
>
> #define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
>
> @@ -394,7 +397,7 @@
> tsz = buflen;
>
> while (buflen) {
> - if ((start >= VMALLOC_START) && (start < VMALLOC_END)) {
> + if (in_vmlist_region(start)) {
> char * elf_buf;
> struct vm_struct *m;
> unsigned long curstart = start;
>
> An architecture could then define KCORE_BASE and in_vmlist_region()
> alongside their VMALLOC_START definition if they needed to change
> them.

Looks pretty good. What's the motivation for the in_vmlist_region()?
I don't think that I need that for ia64 ... so it might be better to
have separate #ifdefs:

#ifndef KCORE_BASE
#define KCORE_BASE PAGE_OFFSET
endif
#ifndef in_vmlist_region
#define in_vmlist_region(x) ((x) >= VMALLOC_START && (x < VMALLOC_END))
#endif

-Tony
-
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