Re: [PATCH 1/2] kallsyms: Allow kernel symbols in L1 to be found inBlackfin architecture

From: Andrew Morton
Date: Wed Apr 30 2008 - 11:44:24 EST


On Wed, 30 Apr 2008 09:51:43 -0400 Robin Getz <rgetz@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Tue 29 Apr 2008 18:00, Andrew Morton pondered:
> > That's a bit grubby. I suppose we could pretend not to have noticed,
> > but this really isn't the preferred way of putting arch-specific hooks into
> > arch-neutral code.
> >
> > Nicer might be to add
> >
> > void __weak arch_is_kernel_text(unsigned long addr)
> > {
> > return 0;
> > }
> >
> > with a declaration in linux/kallsyms.h and then override
> > arch_is_kernel_text() in arch/blackfin/ code.
>
> I will refactor, and send again.
>

Thanks.

There are of course lots of other ways of doing it, apart from __weak.
Many involve unpleasing ARCH_HAVE_FOO things.

Possibly cleaner would be, in kallsyms.c:

#ifndef arch_is_kernel_text
static inline int arch_is_kernel_text(unsigned long addr)
{
return 0;
}
#define arch_is_kernel_text(addr) arch_is_kernel_text(addr) // not really needed
#endif



and then, in a blackfin header file do

extern int arch_is_kernel_text(unsigned long addr);
#define arch_is_kernel_text(addr) arch_is_kernel_text(addr)


But personally I find all these party tricks a bit unpleasant. The
definitive approach to implementing a per-arch kernel->arch interface is to
just implement it, dammit. That means adding

static inline int arch_is_kernel_text(unsigned long addr)
{
return 0;
}

to every architecture's include/asm/kallsyms.h, then doing blackfin's one
differently.

Verbose, but complete.
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