Date: Sat, 9 Sep 2006 00:04:03 +0530 From: "Bharath Bhushan" <bharath.bhushan@gmail.com> To: "John Baldwin" <jhb@freebsd.org> Cc: freebsd-ia32@freebsd.org Subject: Re: io apic question Message-ID: <29683db20609081134v3140b663ua376b59041881ed9@mail.gmail.com> In-Reply-To: <200609051446.36261.jhb@freebsd.org> References: <29683db20609012326i351eb455ja3b0aade681c7773@mail.gmail.com> <200609051446.36261.jhb@freebsd.org>
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Thanks John. Can you please point me to the place where cache-disabled mapping is being done in 7.0? I looked at -- ioapic_create -> pmap_mapdev -> pmap_kenter -> pte_store(pte, pa | PG_RW | PG_V | pgeflag); I could not find any references to PG_N in code related to pmap or to IOAPICs. On 9/6/06, John Baldwin <jhb@freebsd.org> wrote: > On Saturday 02 September 2006 02:26, Bharath Bhushan wrote: > > I am looking at 4.9 sources. > > > > When the local apic is mapped into SMPpt in > > sys/i386/i386/pmap.c:pmap_bootstrap(), it is mapped cache-disabled > > (PG_N). > > > > When the IO apics are being mapped into SMPpt in > > sys/i386/i386/mp_machdep.c:mptable_pass2(), it is *not* mapped > > cache-disabled. > > > > Why is this difference? > > Probably a bug. > > > In 5.5, I see that ioapic_create() calls pmap_createdev(), which > > allocates cache-enabled kind of mapping. > > > > Am I missing something here? > > In 7.0 we map them cache-disabled now. > > -- > John Baldwin > -- Thanks Bharath
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