From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 19 Sep 2001 12:14:03 +1000 From: David Gibson To: linuxppc-embedded@lists.linuxppc.org Subject: Re: 4xx icache and tlb flushing Message-ID: <20010919121403.C13693@zax> References: <20010918143359.B817@zax> <3BA79D3E.E5BA495A@mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <3BA79D3E.E5BA495A@mvista.com> Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: On Tue, Sep 18, 2001 at 03:15:10PM -0400, Dan Malek wrote: > > David Gibson wrote: > > > First on icache flushing. I noticed that flush_icache_page() has been > > changed to a no-op, wheras it used to flush the whole icache on 4xx. > > It is now done when we detect a PTE change that affects an executable > region. > > > Now two questions on tlb flushing. First, 4xx uses a __tlbia() macro > > in local_flush_tlb_*(). Is there a reason we don't use the _tlbia() > > function already included in misc.S? > > I dunno, avoids the function call? We keep swapping between macros > and functions. Whatever. Well, given that the tlbia is about to cause a bunch of TLB miss traps to occur, the function call overhead is surely trivial. In the interests of not duplicating code, here is a patch which eliminates __tlbia() in favour of _tlbia(): diff -urN /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/mm/mmu_decl.h linux-bungo/arch/ppc/mm/mmu_decl.h --- /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/mm/mmu_decl.h Tue Aug 28 07:59:35 2001 +++ linux-bungo/arch/ppc/mm/mmu_decl.h Tue Sep 18 16:10:42 2001 @@ -52,7 +52,8 @@ #define MMU_init_hw() do { } while(0) #elif defined(CONFIG_4xx) -#define flush_HPTE(X, va, pg) __tlbia() +#define flush_HPTE(X, va, pg) _tlbia() +extern void MMU_init_hw(void); #else /* anything except 4xx or 8xx */ diff -urN /home/dgibson/kernel/linuxppc_2_4_devel/include/asm-ppc/pgtable.h linux-bungo/include/asm-ppc/pgtable.h --- /home/dgibson/kernel/linuxppc_2_4_devel/include/asm-ppc/pgtable.h Tue Sep 18 11:25:44 2001 +++ linux-bungo/include/asm-ppc/pgtable.h Tue Sep 18 16:02:25 2001 @@ -15,18 +15,16 @@ #include #if defined(CONFIG_4xx) -#define __tlbia() asm volatile ("tlbia; sync" : : : "memory") - static inline void local_flush_tlb_all(void) - { __tlbia(); } + { _tlbia(); } static inline void local_flush_tlb_mm(struct mm_struct *mm) - { __tlbia(); } + { _tlbia(); } static inline void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr) - { __tlbia(); } + { _tlbia(); } static inline void local_flush_tlb_range(struct mm_struct *mm, unsigned long start, unsigned long end) - { __tlbia(); } + { _tlbia(); } #define update_mmu_cache(vma, addr, pte) do { } while (0) #elif defined(CONFIG_8xx) > > ... Is this a bug, or am I missing something? > > I thought I checked that in....maybe it's still hanging out in my > with a bunch of other random 4xx patches. I'll look again. Ok.. -- David Gibson | For every complex problem there is a david@gibson.dropbear.id.au | solution which is simple, neat and | wrong. -- H.L. Mencken http://www.ozlabs.org/people/dgibson ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/