Re: [PATCH 2.6.11.2 1/1] PCI Allow OutOfRange PIRQ table address

[jayalk]

> On Thu, 10 Mar 2005, Matthew Wilcox wrote:
> > +extern unsigned int pirq_table_addr;
>
> Completely nitpicking, but I think this should be an unsigned long rather
> than an int -- physical addresses are normally expressed in terms of
> unsigned long.

Yup, good point, I'll fix that.

> Should we fall back to searching if someone's specified an address?  If not,
> it becomes even simpler:

I think it'd be a failsafe in the case where someone mistakenly copied
an incorrect or mistaken boot loader config. I'll add a warning in that case
so that the user can see that there's been a problem.

> >  	for(addr = (u8 *) __va(0xf0000); addr < (u8 *) __va(0x100000); addr += 16) {
>
> This loop would become:
>
> 	for (addr = 0xf0000; addr < 0x100000; addr += 16) {

I prefered the former since the __va conversion only gets done for those
initial addresses rather than throughout the loop. I think the
check_routing... should use va addr not phys, for subjective reasons, feels
cleaner, I guess. I'll deferr to whatever the norm is. Let me know.

Thanks for the feedback.

jayakumar

> On Thu, Mar 10, 2005 at 05:29:35AM -0800, jayalk@xxxxxxxxxxxx wrote:
>
> Nice work, I like it.  You could make it even prettier:
>
> > diff -uprN -X dontdiff linux-2.6.11.2-vanilla/arch/i386/pci/irq.c linux-2.6.11.2/arch/i386/pci/irq.c
> > --- linux-2.6.11.2-vanilla/arch/i386/pci/irq.c	2005-03-10 16:31:25.000000000 +0800
> > +++ linux-2.6.11.2/arch/i386/pci/irq.c	2005-03-10 20:43:02.479487640 +0800
> > @@ -58,6 +58,35 @@ struct irq_router_handler {
> >  int (*pcibios_enable_irq)(struct pci_dev *dev) = NULL;
> >
> >  /*
> > + *  Check passed address for the PCI IRQ Routing Table signature
> > + *  and perform checksum verification.
> > + */
> > +
> > +static inline struct irq_routing_table * __init pirq_check_routing_table(u8 *addr)
> > +{
> > +	struct irq_routing_table *rt;
> > +	int i;
> > +	u8 sum;
> > +
> > +	rt = (struct irq_routing_table *) addr;
>
> static inline struct irq_routing_table * __init pirq_check_routing_table(unsigned long phys)
> {
> 	struct irq_routing_table *rt = __va(phys);
> [...]
>
> > @@ -65,21 +94,16 @@ static struct irq_routing_table * __init
> >  {
> >  	u8 *addr;
>
> 	unsigned long addr;
>
> >  	struct irq_routing_table *rt;
> > -	int i;
> > -	u8 sum;
> >
> > +	if (pirq_table_addr) {
> > +		rt = pirq_check_routing_table((u8 *) __va(pirq_table_addr));
> > +		if (rt) {
> > +			return rt;
> > +		}
> > +	}
>
> 	if (pirq_table_addr) {
> 		rt = pirq_check_routing_table(pirq_table_addr);
> 		if (rt)
> 			return rt;
> 	}
>
> Should we fall back to searching if someone's specified an address?  If not,
> it becomes even simpler:
>
> 	if (pirq_table_addr) {
> 		return pirq_check_routing_table(pirq_table_addr);
> 	}
>
> >  	for(addr = (u8 *) __va(0xf0000); addr < (u8 *) __va(0x100000); addr += 16) {
>
> This loop would become:
>
> 	for (addr = 0xf0000; addr < 0x100000; addr += 16) {
>
> > @@ -27,6 +27,7 @@
> >  #define PCI_ASSIGN_ALL_BUSSES	0x4000
> >
> >  extern unsigned int pci_probe;
> > +extern unsigned int pirq_table_addr;
>
> Completely nitpicking, but I think this should be an unsigned long rather
> than an int -- physical addresses are normally expressed in terms of
> unsigned long.
>
> > +		pirqaddr=0xAAAAA	[IA-32] Specify the physical address
> > +					of the PIRQ table (normally generated
> > +					by the BIOS) if it is outside the .
> > +					F0000h-100000h range.
>
> And you even bothered to update the documentation!  This is definitely
> a cut above most of the patches I review ;-)
-
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