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Date: Mon, 13 Apr 2009 10:45:54 +0800
From: liqin.chen@...plusct.com
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Arnd Bergmann <arnd@...db.de>, Kyle McMartin <kyle@...artin.ca>,
linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
Sam Ravnborg <sam@...nborg.org>,
Thomas Gleixner <tglx@...utronix.de>,
torvalds@...ux-foundation.org
Subject: Re: [PATCH 4/14] score - New architecure port to SunplusCT S+CORE
Hi Andrew Morton,
You only commented 4 patches,
how about others?
We want to update the code after you finished it.
Best Regards
Liqin
Andrew Morton <akpm@...ux-foundation.org> 写于 2009-04-10 14:29:57:
> On Wed, 8 Apr 2009 15:23:28 +0800 liqin.chen@...plusct.com wrote:
>
> > From: Chen Liqin <liqin.chen@...plusct.com>
> >
> > asm/kmap_types.h, asm/linkage.h, asm/local.h, asm/mman.h,
> > asm/mmu_context.h,
> > asm/mmu.h, asm/module.h, asm/msgbuf.h, asm/mutex.h, asm/page.h,
> > asm/param.h,
> > asm/pci.h, asm/percpu.h, asm/pgalloc.h, asm/pgtable-32.h,
> > asm/pgtable-bits.h,
> > asm/pgtable.h, asm/poll.h, asm/posix_types.h and asm/processor.h
> > for the score architecture.
> >
> > ...
> >
> > --- linux-2.6-git.ori/arch/score/include/asm/kmap_types.h 1970-01-01
> > 08:00:00.000000000 +0800
> > +++ linux-2.6-git.new/arch/score/include/asm/kmap_types.h 2009-04-03
> > 17:01:04.000000000 +0800
> > @@ -0,0 +1,21 @@
> > +#ifndef __SCORE_KMAP_TYPES_H
> > +#define __SCORE_KMAP_TYPES_H
> > +
> > +enum km_type {
> > + KM_BOUNCE_READ,
> > + KM_SKB_SUNRPC_DATA,
> > + KM_SKB_DATA_SOFTIRQ,
> > + KM_USER0,
> > + KM_USER1,
> > + KM_BIO_SRC_IRQ,
> > + KM_BIO_DST_IRQ,
> > + KM_PTE0,
> > + KM_PTE1,
> > + KM_IRQ0,
> > + KM_IRQ1,
> > + KM_SOFTIRQ0,
> > + KM_SOFTIRQ1,
> > + KM_TYPE_NR
> > +};
>
> hm. Our nineteenth copy of kmap_types.h, all of them basically the
> same.
>
> That's not a problem for this patchset, but we suck.
>
> >
> > ...
> >
> > +static inline void
> > +get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
> > +{
> > + unsigned long asid = asid_cache(0);
> > +
> > + if (!((asid = asid + ASID_INC) & ASID_MASK)) {
>
> ick. Complex statements likethis are to be avoided, please.
>
> unsigned long asid = asid_cache(0) + ASID_INC;
>
> if (!(asid & ASID_MASK)) {
>
> is nicer, no?
>
> > + local_flush_tlb_all(); /* start new asid
cycle */
> > + if (!asid) /* fix version if
needed
> > */
> > + asid = ASID_FIRST_VERSION;
> > + }
> > + cpu_context(0, mm) = asid_cache(0) = asid;
>
> This style causes less concern, but some would even prefer
>
> cpu_context(0, mm) = asid;
> asid_cache(0) = asid;
>
> C lets you perform lots of weird shortcuts and tricks, but we actively
> avoid many of them in the kernel.
>
> > +}
> > +
> > +/*
> > + * Initialize the context related info for a new mm_struct
> > + * instance.
> > + */
> > +static inline int
> > +init_new_context(struct task_struct *tsk, struct mm_struct *mm)
> > +{
> > + cpu_context(0, mm) = 0;
>
> More stylistic whining - this is one of my pet peeves. It's just a
> meaningless absurdity to call a function and to then modify its return
> value.
>
> So cpu_context() _has_ to be a macro which evaluates to an lvalue.
> Which wrecks any concept of encapsulation.
> Macros-which-look-like-functions should be interchangesable with
> functions, but this one isn't.
>
> I mean, the above statement jusst isn't C. Whereas
>
> set_cpu_context(0, mm0, 0);
>
> _is_ C. See what I mean.
>
> Anwyay. I'm not saying you should go off and change everything. But
> it's daft.
>
> > + return 0;
> > +}
> > +
> > +static inline void switch_mm(struct mm_struct *prev, struct mm_struct
> > *next,
> > + struct task_struct *tsk)
> > +{
> > + unsigned long flags;
> > +
> > + local_irq_save(flags);
> > + if ((cpu_context(0, next) ^ asid_cache(0)) &
ASID_VERSION_MASK)
> > + get_new_mmu_context(next, 0);
> > + set_PEVN(cpu_context(0, next));
> > + TLBMISS_HANDLER_SETUP_PGD(next->pgd);
>
> Some macros are all-lower-case.
>
> Some macros are part-lower-case and part-upper-case.
>
> Some macros are all-upper-case.
>
> Is there any sense behind it all?
>
> > + local_irq_restore(flags);
> > +}
> > +
> > +/*
> > + * Destroy context related info for an mm_struct that is about
> > + * to be put to rest.
> > + */
> > +static inline void destroy_context(struct mm_struct *mm)
> > +{}
> > +
> > +#define deactivate_mm(tsk, mm) do {} while (0)
>
> static inline void deactivate_mm(struct task_struct *task, struct
> mm_struct *mm)
>
> is nicer. It isn't a macro, and it provides typechecking and sometimes
> it can fix an unused-variable warning at callsites.
>
> Probably you copied this from somewhere else. Sigh.
>
> > +/*
> > + * After we have set current->mm to a new value, this activates
> > + * the context for the new mm so we see the new mappings.
> > + */
> > +static inline void
> > +activate_mm(struct mm_struct *prev, struct mm_struct *next)
> > +{
> > + unsigned long flags;
> > +
> > + local_irq_save(flags);
> > + get_new_mmu_context(next, 0);
> > + set_PEVN(cpu_context(0, next));
> > + TLBMISS_HANDLER_SETUP_PGD(next->pgd);
> > + local_irq_restore(flags);
> > +}
> > +
> > +#endif /* __SCORE_MMU_CONTEXT_H */
> > diff -uprN -x linux-2.6-git.ori/Documentation/dontdiff
> > linux-2.6-git.ori/arch/score/include/asm/mmu.h
> > linux-2.6-git.new/arch/score/include/asm/mmu.h
> > --- linux-2.6-git.ori/arch/score/include/asm/mmu.h 1970-01-01
> > 08:00:00.000000000 +0800
> > +++ linux-2.6-git.new/arch/score/include/asm/mmu.h 2009-04-08
> > 10:51:34.000000000 +0800
> > @@ -0,0 +1,6 @@
> > +#ifndef __SCORE_MMU_H
> > +#define __SCORE_MMU_H
> > +
> > +typedef unsigned long mm_context_t[NR_CPUS];
>
> hm. Is this an SMP-capable architecture?
>
> > +#endif /* __SCORE_MMU_H */
> > diff -uprN -x linux-2.6-git.ori/Documentation/dontdiff
> >
> > ...
> >
> > +#ifdef CONFIG_CPU_SCORE7
> > +#define MODULE_PROC_FAMILY "SCORE7"
> > +#else
> > +#error MODULE_PROC_FAMILY undefined for your processor configuration
> > +#endif
>
> Is the #error necessary? If it triggers, that indicates a bug in
> Kconfig, no?
>
> >
> > ...
> >
> > +#define ARCH_PFN_OFFSET PFN_UP(PHYS_OFFSET)
> > +
> > +#define clear_page(page) memset((void *)(page), 0, PAGE_SIZE)
> > +#define copy_page(to, from) memcpy((to), (from), PAGE_SIZE)
> > +
> > +#define clear_user_page(page, vaddr, pg) clear_page(page)
> > +#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
>
> Well that's nice and simple ;)
>
>
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