On Fri, Jun 17, 2016 at 10:55:47PM +0000, Scott Wood wrote: > On 06/17/2016 05:13 PM, Aaron Larson wrote: > > When e500 PPC is booted multi-core, the non-boot cores are started via > > the spin table. ppce500_spin.c:spin_kick() calls > > mmubooke_create_initial_mapping() to allocate a 64MB TLB entry, but > > the created TLB entry is only 256KB. > > > > The root cause is that the function computing the size of the TLB > > entry, namely booke206_page_size_to_tlb assumes MAS1.TSIZE as defined > > by latter PPC cores, specifically (n**4)KB. The result is then used by > > mmubooke_create_initial_mapping using MAS1_TSIZE_SHIFT, but > > MAS1_TSIZE_SHIFT is defined assuming TLB entries are (n**2)KB. I.e., a > > difference of shift=7 or shift=8. > > > > Simply changing MAS1_TSIZE_SHIFT from 7 to 8 is not appropriate since > > the macro is used elsewhere. > > > > Signed-off-by: Aaron Larson <[email protected]> > > --- > > hw/ppc/ppce500_spin.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/hw/ppc/ppce500_spin.c b/hw/ppc/ppce500_spin.c > > index 76bd78b..7e38f0c 100644 > > --- a/hw/ppc/ppce500_spin.c > > +++ b/hw/ppc/ppce500_spin.c > > @@ -75,7 +75,11 @@ static void spin_reset(void *opaque) > > /* Create -kernel TLB entries for BookE, linearly spanning 256MB. */ > > static inline hwaddr booke206_page_size_to_tlb(uint64_t size) > > { > > - return ctz32(size >> 10) >> 1; > > + /* The EREF indicates that TLB pages are (4 to the power of 2)KB, which > > + * corresponds to MAS1_TSIZE_SHIFT=8, but to support legacy processors > > that > > + * assume TLB pages are (2 to the power of 2)KB MAS1_TSIZE_SHIFT is > > + * currently 7. */ > > This is backwards. It's the old processors that can only handle > power-of-4 sizes.
To clarify, is this a problem in the code, or just in the comment?
> > + return ctz32(size >> 10) >> (MAS1_TSIZE_SHIFT - 7);
>
> The patch that changed MAS1_TSIZE_SHIFT from 8 to 7 was around the same
> time as the patch that added this code, which is probably why adjusting
> it got missed. Commit 2bd9543cd3 did update the equivalent code in
> ppce500_mpc8544ds.c, which now resides in hw/ppc/e500.c and has been
> changed to not assume a power-of-2 size. The ppce500_spin version
> should be eliminated.
Sounds sensible.
Aaron, for some reason I got multiple copies of your patch mail - a
couple of full ones and then a couple more extras which had 0 size.
Was that just something going wrong with your mailer, or did you
attempt to send a couple of different versions?
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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