[PATCH 4/6] ARM: reset: add reset functionality for jumping to a physical address
frank.hofmann at tomtom.com
Wed Jun 8 12:10:05 EDT 2011
On Wed, 8 Jun 2011, Will Deacon wrote:
> On Wed, Jun 08, 2011 at 04:55:11PM +0100, Frank Hofmann wrote:
>> On Tue, 7 Jun 2011, Frank Hofmann wrote:
>>> On Tue, 7 Jun 2011, Dave Martin wrote:
>> [ ... ]
>>>> How about:
>>>> typeof(cpu_reset) *phys_reset =
>>>> (typeof(cpu_reset) *)virt_to_phys(cpu_reset);
>>> Function pointers ;-)
>> Hmmm ...
>> Just found a problem with this.
>> If you have a MULTI_CPU config, this doesn't compile. For two reasons:
>> 1. you cannot use cpu_reset as argument to virt_to_phys because you can't
>> take the address
>> That bit can be fixed by changing the MULTI_CPU #define in
>> <asm/proc-fns.h> not to include the macro argument.
>> (There is no code in the arm tree using cpu_reset_whatever names which
>> would break from that change ... still, not that nice)
>> 2. even when you do that, you loose the "typeof()" information and the
>> above still doesn't compile.
>> Only a manual type override,
>> void (*phys_reset)(unsigned long) = (void (*)(unsigned long))cpu_reset;
>> is accepted then.
> Damn, yes, I assumed the MULTI_CPU case would just pointer at the structure field,
> but it takes the argument as parameter for the invocation. Oh well, I'll hardcode
> the type after all then!
It's not just that - the worse bit is that as long as the #define looks
#define cpu_reset(addr) processor.reset(addr)
compile is being refused; one has to ditch the argument part of the macro
to be able to take the address.
I'm unsure how desirable that change is; it's got the unwanted consequence
that people who decide to use function names like "graphics_cpu_reset" or
"cpu_reset_specialregisters" would fall flat on their face.
As said, not that anyone does so right now; just not nice to introduce
> I'll send a v2 once I've finished cleaning up the code as I've tried to make it
> more useful following on from your earlier feedback.
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