Re: [patch] generic-hardirqs.patch, 2.6.9-rc1-bk14

[Christoph Hellwig <hch@infradead.org>]

On Wed, Sep 08, 2004 at 02:06:13PM +0200, Ingo Molnar wrote:
> 
> the attached patch moves generic hardirq handling bits to
> kernel/hardirq.c. It is not a replacement for any of the existing IRQ
> functions, so architectures can use their existing hardirq code in an
> unmodified form. It is a library of generic functions that an
> architecture can make use of optionally.
> 
> I've fully converted x86's irq.c to use the new functions, and Scott
> Wood has done the same for ppc/ppc64 as well. (the arch-ppc* changes are
> not included in this patch because i couldnt test them myself in the
> current port of this patch - but the generic bits were tested on ppc.)
> 
> i have test-compiled and test-booted the patch on x86 and x64, on SMP &&
> PREEMPT and !SMP && !PREEMPT kernels. x64 needed only a single change (a
> setup_irq() prototype) to work fine, which makes me believe that the
> patch will not break other architectures either.
> 
> (a more complex version of this patch has been tested for weeks as part
> of the voluntary-preempt patches as well.)


> +++ linux/include/asm-x86_64/hardirq.h	
> @@ -25,8 +25,8 @@
>   * - ( bit 26 is the PREEMPT_ACTIVE flag. )
>   *
>   * PREEMPT_MASK: 0x000000ff
> - * HARDIRQ_MASK: 0x0000ff00
> - * SOFTIRQ_MASK: 0x00ff0000
> + * SOFTIRQ_MASK: 0x0000ff00
> + * HARDIRQ_MASK: 0x00ff0000
>   */
>  
>  #define PREEMPT_BITS	8
> @@ -99,4 +99,6 @@ do {									\
>    extern void synchronize_irq(unsigned int irq);
>  #endif /* CONFIG_SMP */
>  
> +extern int setup_irq(unsigned int irq, struct irqaction * new);

This doesn't apply anymore because most of <asm/hardirq.h> moved
to linux/hardirq.h in -mm and a the patch is on it's way to Linus.

> @@ -71,10 +74,21 @@ extern irq_desc_t irq_desc [NR_IRQS];
>  
>  #include <asm/hw_irq.h> /* the arch dependent stuff */
>  
> -extern int setup_irq(unsigned int , struct irqaction * );
> +
> +extern asmlinkage int generic_handle_IRQ_event(unsigned int irq, struct pt_regs *regs, struct irqaction *action);
> +extern void generic_synchronize_irq(unsigned int irq);
> +extern int generic_setup_irq(unsigned int irq, struct irqaction * new);
> +extern void generic_free_irq(unsigned int irq, void *dev_id);
> +extern void generic_disable_irq_nosync(unsigned int irq);
> +extern void generic_disable_irq(unsigned int irq);
> +extern void generic_enable_irq(unsigned int irq);
> +extern void generic_note_interrupt(int irq, irq_desc_t *desc, int action_ret);

Please don't introduce the generic_ names just to have every arch (in your
previous patches, that is) provide a wrapper with normal names again.


> --- linux/kernel/Makefile.orig	
> +++ linux/kernel/Makefile	
> @@ -3,7 +3,7 @@
>  #
>  
>  obj-y     = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
> -	    exit.o itimer.o time.o softirq.o resource.o \
> +	    exit.o itimer.o time.o softirq.o hardirq.o resource.o \

And make hardirq.o dependent on some symbols the architectures set.
Else arches that don't use it carry tons of useless baggage around (and
in fact I'm pretty sure it wouldn't even compie for many)